merged from upstream.

internal/platform/implementation/BUILD

@@ -17,69 +17,6 @@ load("@rules_cc//cc:cc_test.bzl", "cc_test")
 
 licenses(["notice"])
 
-cc_library(
-    name = "auth_status",
-    hdrs = ["auth_status.h"],
-    visibility = [
-        "//internal/auth:__pkg__",
-        "//internal/platform/implementation:__subpackages__",
-        "//location/nearby/cpp/sharing/clients/cpp:__subpackages__",
-    ],
-)
-
-cc_library(
-    name = "account_info",
-    hdrs = ["account_info.h"],
-    visibility = [
-        "//internal/auth:__pkg__",
-        "//internal/platform/implementation:__subpackages__",
-        "//location/nearby/cpp/sharing/clients/cpp:__subpackages__",
-    ],
-)
-
-cc_library(
-    name = "account_manager",
-    hdrs = ["account_manager.h"],
-    visibility = [
-        "//internal/account:__pkg__",
-        "//internal/platform:__pkg__",
-        "//internal/platform/implementation:__subpackages__",
-        "//internal/test:__subpackages__",
-        "//location/nearby/cpp/sharing/clients/cpp:__subpackages__",
-        "//location/nearby/sharing/lib:__subpackages__",
-        "//location/nearby/sharing/sdk/quick_share_server:__pkg__",
-        "//sharing:__subpackages__",
-    ],
-    deps = [
-        ":account_info",
-        ":signin_attempt",
-        "@com_google_absl//absl/functional:any_invocable",
-        "@com_google_absl//absl/status",
-        "@com_google_absl//absl/status:statusor",
-        "@com_google_absl//absl/strings:string_view",
-    ],
-)
-
-cc_library(
-    name = "signin_attempt",
-    hdrs = ["signin_attempt.h"],
-    visibility = [
-        "//internal/account:__pkg__",
-        "//internal/auth:__pkg__",
-        "//internal/platform/implementation:__subpackages__",
-        "//internal/test:__subpackages__",
-        "//location/nearby/cpp/sharing/clients/cpp:__subpackages__",
-        "//location/nearby/sharing/sdk/quick_share_server:__pkg__",
-        "//sharing:__subpackages__",
-    ],
-    deps = [
-        ":account_info",
-        ":auth_status",
-        "@com_google_absl//absl/functional:any_invocable",
-        "@com_google_absl//absl/strings:string_view",
-    ],
-)
-
 cc_library(
     name = "types",
     hdrs = [
@@ -112,11 +49,12 @@ cc_library(
         "//internal/test:__subpackages__",
         "//location/nearby/analytics/cpp:__subpackages__",
         "//location/nearby/cpp/sharing:__subpackages__",
-        "//presence:__subpackages__",
         "//sharing:__subpackages__",
+        "//third_party/nearby/presence:__subpackages__",
     ],
     deps = [
         "//internal/base:file_path",
+        "//internal/base:files",
         "//internal/crypto_cros",
         "//internal/platform:base",
         "//internal/platform:mac_address",
@@ -149,6 +87,26 @@ cc_library(
     ],
 )
 
+cc_library(
+    name = "webrtc_platform",
+    hdrs = [
+        "webrtc.h",
+        "webrtc_platform.h",
+    ],
+    compatible_with = ["//buildenv/target:non_prod"],
+    visibility = [
+        "//:__subpackages__",
+    ],
+    deps = [
+        "//connections/implementation/proto:offline_wire_formats_cc_proto",
+        "//internal/platform:base",
+        "//third_party/webrtc/files/stable/webrtc/api:libjingle_peerconnection_api",
+        "//third_party/webrtc/files/stable/webrtc/api:scoped_refptr",
+        "@com_google_absl//absl/functional:any_invocable",
+        "@com_google_absl//absl/strings:string_view",
+    ],
+)
+
 cc_library(
     name = "comm",
     hdrs = [
@@ -162,30 +120,26 @@ cc_library(
         "http_loader.h",
         "psk_info.h",
         "upgrade_address_info.h",
-        "webrtc.h",
         "wifi.h",
         "wifi_direct.h",
         "wifi_hotspot.h",
         "wifi_lan.h",
     ],
-    copts = ["-DNO_WEBRTC"],
     visibility = [
         "//connections/implementation:__subpackages__",
         "//internal/network:__subpackages__",
         "//internal/platform:__pkg__",
         "//internal/platform/implementation:__subpackages__",
-        "//presence:__subpackages__",
-        "//presence/implementation:__subpackages__",
+        "//third_party/nearby/presence:__subpackages__",
+        "//third_party/nearby/presence/implementation:__subpackages__",
     ],
     deps = [
-        "//connections/implementation/proto:offline_wire_formats_cc_proto",
         "//internal/platform:base",
         "//internal/platform:cancellation_flag",
         "//internal/platform:mac_address",
         "//internal/platform:uuid",
         "//internal/proto:credential_cc_proto",
         "//internal/proto:local_credential_cc_proto",
-        # TODO: Support WebRTC
         "@com_google_absl//absl/base:core_headers",
         "@com_google_absl//absl/container:flat_hash_map",
         "@com_google_absl//absl/functional:any_invocable",
@@ -194,7 +148,6 @@ cc_library(
         "@com_google_absl//absl/strings",
         "@com_google_absl//absl/strings:str_format",
         "@com_google_absl//absl/time",
-        "@com_google_absl//absl/types:optional",
     ],
 )
 
@@ -203,7 +156,6 @@ cc_library(
     hdrs = [
         "platform.h",
     ],
-    defines = ["NO_WEBRTC"],
     visibility = [
         "//connections/implementation:__subpackages__",
         "//internal:__subpackages__",
@@ -213,6 +165,7 @@ cc_library(
         "//location/nearby/analytics/cpp:__subpackages__",
         "//location/nearby/apps/better_together/plugins/preferences_native:__subpackages__",
         "//location/nearby/cpp/sharing:__subpackages__",
+        "//sharing/internal/impl/common:__subpackages__",
     ],
     deps = [
         ":comm",
@@ -229,6 +182,8 @@ cc_library(
     tags = ["keep_dep"],  # Prevent build_cleaner from removing the dependency.
     visibility = [
         "//:__subpackages__",
+        "//location/nearby/analytics/cpp:__subpackages__",
+        "//location/nearby/cpp:__subpackages__",
         "//location/nearby/sharing/lib:__subpackages__",
     ],
     deps = [
@@ -259,3 +214,16 @@ cc_test(
         "@com_google_googletest//:gtest_main",
     ],
 )
+
+cc_test(
+    name = "device_info_test",
+    size = "small",
+    timeout = "moderate",
+    srcs = ["device_info_test.cc"],
+    deps = [
+        ":types",
+        "@com_github_protobuf_matchers//protobuf-matchers",
+        "@com_google_absl//absl/strings",
+        "@com_google_googletest//:gtest_main",
+    ],
+)

internal/platform/implementation/account_info.h

@@ -1,35 +0,0 @@
-// Copyright 2024 Google LLC
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     https://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-#ifndef THIRD_PARTY_NEARBY_INTERNAL_PLATFORM_IMPLEMENTATION_ACCOUNT_INFO_H_
-#define THIRD_PARTY_NEARBY_INTERNAL_PLATFORM_IMPLEMENTATION_ACCOUNT_INFO_H_
-
-#include <string>
-
-namespace nearby {
-
-// Describes a Nearby account. The account class will have more properties
-// and methods in the future based on the new feature added.
-struct AccountInfo {
-  std::string id;  // The unique identify of the account.
-  std::string display_name;
-  std::string family_name;
-  std::string given_name;
-  std::string picture_url;
-  std::string email;
-};
-
-}  // namespace nearby
-
-#endif  // THIRD_PARTY_NEARBY_INTERNAL_PLATFORM_IMPLEMENTATION_ACCOUNT_INFO_H_

internal/platform/implementation/account_manager.h

@@ -1,89 +0,0 @@
-// Copyright 2022 Google LLC
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     https://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-#ifndef PLATFORM_API_ACCOUNT_MANAGER_H_
-#define PLATFORM_API_ACCOUNT_MANAGER_H_
-
-#include <memory>
-#include <optional>
-#include <string>
-#include <utility>
-
-#include "absl/functional/any_invocable.h"
-#include "absl/status/status.h"
-#include "absl/status/statusor.h"
-#include "absl/strings/string_view.h"
-#include "internal/platform/implementation/account_info.h"
-#include "internal/platform/implementation/signin_attempt.h"
-
-namespace nearby {
-
-// AccountManager manages the accounts are used to access Nearby backend.
-// In current design, AccountManager only support one active account.
-class AccountManager {
- public:
-  using Account = AccountInfo;
-
-  // Observes the activity of the account manager.
-  class Observer {
-   public:
-    virtual ~Observer() = default;
-
-    virtual void OnLoginSucceeded(absl::string_view account_id) = 0;
-    // |credential_error| is true if the logout is due to critical auth error.
-    virtual void OnLogoutSucceeded(absl::string_view account_id,
-                                   bool credential_error) = 0;
-  };
-
-  virtual ~AccountManager() = default;
-
-  // Gets current active account. If no login user, return std::nullopt.
-  virtual std::optional<Account> GetCurrentAccount() = 0;
-
-  // Initializes the login process for a Google account from an oauth client.
-  // |client_id| GCP client_id of the client
-  // |client_secret| GCP client_secret of the client
-  // Returns a SigninAttempt object that can be used to complete the login
-  // process.
-  virtual std::unique_ptr<SigninAttempt> Login(
-      absl::string_view client_id, absl::string_view client_secret) = 0;
-
-  // Logs out current active account. |logout_callback| is called when logout is
-  // completed.
-  virtual void Logout(
-      absl::AnyInvocable<void(absl::Status)> logout_callback) = 0;
-
-  // Gets access token for the active account.
-  // |callback| is called with the access token or error status.
-  //
-  // Returns false if callback is null.
-  virtual bool GetAccessToken(
-      absl::AnyInvocable<void(absl::StatusOr<std::string>)> callback) = 0;
-
-  // Returns a pair containing the client id and client secret used in the most
-  // recent Login request.
-  // If no current user is logged in, returns empty string for both.
-  virtual std::pair<std::string, std::string> GetOAuthClientCredential() = 0;
-
-  virtual void AddObserver(Observer* observer) = 0;
-  virtual void RemoveObserver(Observer* observer) = 0;
-
-  virtual void SaveAccountPrefs(absl::string_view user_id,
-                                absl::string_view client_id,
-                                absl::string_view client_secret) = 0;
-};
-
-}  // namespace nearby
-
-#endif  // PLATFORM_API_ACCOUNT_MANAGER_H_

internal/platform/implementation/apple/BUILD

@@ -51,6 +51,18 @@ objc_library(
     ],
 )
 
+objc_library(
+    name = "apple_webrtc",
+    srcs = [
+        "webrtc_platform.mm",
+    ],
+    deps = [
+        "//connections/implementation/mediums/webrtc:webrtc_medium_impl",
+        "//internal/platform/implementation:webrtc_platform",
+        "//third_party/apple_frameworks:Foundation",
+    ],
+)
+
 objc_library(
     name = "apple",
     srcs = [
@@ -61,7 +73,6 @@ objc_library(
         "preferences_manager.mm",
         "scheduled_executor.mm",
         "timer.mm",
-        "webrtc.mm",
         "wifi_hotspot.mm",
         "wifi_lan.mm",
     ],
@@ -70,7 +81,6 @@ objc_library(
         "device_info.h",
         "preferences_manager.h",
         "timer.h",
-        "webrtc.h",
         "wifi.h",
         "wifi_hotspot.h",
         "wifi_lan.h",
@@ -102,6 +112,7 @@ objc_library(
         "//internal/base:file_path",
         "//internal/base:files",
         "//internal/base:masker",
+        "//internal/platform/implementation/apple/Flags",
         "//internal/platform/implementation/apple/Mediums/Hotspot",
         "//internal/account",
         "//internal/crypto_cros",
@@ -109,10 +120,6 @@ objc_library(
         "//internal/platform:logging",
         "//internal/platform:types",
         "//internal/proto:tachyon_cc_proto",
-        "//third_party/webrtc/files/stable/webrtc/api/task_queue:default_task_queue_factory",
-        "//third_party/webrtc/files/stable/webrtc/api:create_modular_peer_connection_factory",
-        "//third_party/webrtc/files/stable/webrtc/api:libjingle_peerconnection_api",
-        "//third_party/webrtc/files/stable/webrtc/rtc_base:checks",
         "//internal/platform:base",
         "//internal/platform/implementation:comm",
         "//internal/platform/implementation:platform",
@@ -345,11 +352,11 @@ cc_test(
     deps = [
         ":Platform_cc",
         "//internal/platform/implementation/g3:crypto",
+        "//third_party/gloop/thread/fiber",
         "@com_github_protobuf_matchers//protobuf-matchers",
         "@com_google_absl//absl/base:core_headers",
         "@com_google_absl//absl/synchronization",
         "@com_google_absl//absl/time",
         "@com_google_googletest//:gtest_main",
-        "@com_google_nisaba//nisaba/port:thread_pool/fiber",
     ],
 )

internal/platform/implementation/apple/Flags/GNCFeatureFlags.h

@@ -29,4 +29,13 @@
 /** Checks whether BLE L2CAP refactor is enabled in the Nearby Connections SDK. */
 @property(nonatomic, class, readonly) BOOL refactorBleL2capEnabled;
 
+/** Checks whether shared peripheral manager is enabled in the Nearby Connections SDK. */
+@property(nonatomic, class, readonly) BOOL sharedPeripheralManagerEnabled;
+
+/** Checks whether single copy read/write is enabled in the Nearby Connections SDK. */
+@property(nonatomic, class, readonly) BOOL singleCopyEnabled;
+
+/** Checks whether BLE server socket deadlock is fixed in the Nearby Connections SDK. */
+@property(nonatomic, class, readonly) BOOL fixBleServerSocketDeadlockEnabled;
+
 @end

internal/platform/implementation/apple/Flags/GNCFeatureFlags.mm

@@ -42,4 +42,21 @@
           kRefactorBleL2cap);
 }
 
++ (BOOL)sharedPeripheralManagerEnabled {
+  return nearby::NearbyFlags::GetInstance().GetBoolFlag(
+      nearby::connections::config_package_nearby::nearby_connections_feature::
+          kEnableSharedPeripheralManager);
+}
+
++ (BOOL)singleCopyEnabled {
+  return nearby::NearbyFlags::GetInstance().GetBoolFlag(
+      nearby::connections::config_package_nearby::nearby_connections_feature::kEnableSingleCopy);
+}
+
++ (BOOL)fixBleServerSocketDeadlockEnabled {
+  return nearby::NearbyFlags::GetInstance().GetBoolFlag(
+      nearby::connections::config_package_nearby::nearby_connections_feature::
+          kFixBleServerSocketDeadlock);
+}
+
 @end

internal/platform/implementation/apple/Flags/Tests/GNCFeatureFlagsTest.mm

@@ -34,6 +34,13 @@
   nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
       nearby::connections::config_package_nearby::nearby_connections_feature::kEnableBleL2cap,
       false);
+  nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+      nearby::connections::config_package_nearby::nearby_connections_feature::kRefactorBleL2cap,
+      false);
+  nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+      nearby::connections::config_package_nearby::nearby_connections_feature::
+          kEnableSharedPeripheralManager,
+      false);
 
   [super tearDown];
 }
@@ -78,4 +85,34 @@
   XCTAssertFalse([GNCFeatureFlags bleL2capEnabled]);
 }
 
+- (void)testRefactorBleL2capEnabled_WhenFlagIsTrue {
+  nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+      nearby::connections::config_package_nearby::nearby_connections_feature::kRefactorBleL2cap,
+      YES);
+  XCTAssertTrue([GNCFeatureFlags refactorBleL2capEnabled]);
+}
+
+- (void)testRefactorBleL2capEnabled_WhenFlagIsFalse {
+  nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+      nearby::connections::config_package_nearby::nearby_connections_feature::kRefactorBleL2cap,
+      NO);
+  XCTAssertFalse([GNCFeatureFlags refactorBleL2capEnabled]);
+}
+
+- (void)testSharedPeripheralManagerEnabled_WhenFlagIsTrue {
+  nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+      nearby::connections::config_package_nearby::nearby_connections_feature::
+          kEnableSharedPeripheralManager,
+      YES);
+  XCTAssertTrue([GNCFeatureFlags sharedPeripheralManagerEnabled]);
+}
+
+- (void)testSharedPeripheralManagerEnabled_WhenFlagIsFalse {
+  nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+      nearby::connections::config_package_nearby::nearby_connections_feature::
+          kEnableSharedPeripheralManager,
+      NO);
+  XCTAssertFalse([GNCFeatureFlags sharedPeripheralManagerEnabled]);
+}
+
 @end

internal/platform/implementation/apple/Mediums/BLE/BUILD

@@ -39,6 +39,7 @@ objc_library(
         "GNCMConnection.m",
         "GNCPeripheral.m",
         "GNCPeripheralManager.m",
+        "GNCPeripheralManagerMultiplexer.m",
         "NSData+GNCBase85.mm",
         "NSData+GNCWebSafeBase64.m",
     ],
@@ -59,6 +60,7 @@ objc_library(
         "GNCMConnection.h",
         "GNCPeripheral.h",
         "GNCPeripheralManager.h",
+        "GNCPeripheralManagerMultiplexer.h",
         "NSData+GNCBase85.h",
         "NSData+GNCWebSafeBase64.h",
     ],

internal/platform/implementation/apple/Mediums/BLE/GNCBLEGATTServer.h

@@ -15,6 +15,8 @@
 #import <CoreBluetooth/CoreBluetooth.h>
 #import <Foundation/Foundation.h>
 
+#import "internal/platform/implementation/apple/Mediums/BLE/GNCPeripheralManager.h"
+
 @class GNCBLEGATTCharacteristic;
 
 NS_ASSUME_NONNULL_BEGIN
@@ -57,7 +59,18 @@ typedef void (^GNCStopAdvertisingCompletionHandler)(NSError *_Nullable error);
  *
  * @note The public APIs of this class are thread safe.
  */
-@interface GNCBLEGATTServer : NSObject
+@interface GNCBLEGATTServer : NSObject <GNCPeripheralManagerDelegate>
+
+/**
+ * Initializes the GATT server.
+ *
+ * @param peripheralManager The peripheral manager to use.
+ * @param queue The queue to use for delegate callbacks and internal operations.
+ */
+- (instancetype)initWithPeripheralManager:(nullable id<GNCPeripheralManager>)peripheralManager
+                                    queue:(nullable dispatch_queue_t)queue;
+
+- (instancetype)init NS_UNAVAILABLE;
 
 /**
  * Creates a characteristic and adds it to the GATT server.

internal/platform/implementation/apple/Mediums/BLE/GNCBLEGATTServer.m

@@ -59,34 +59,37 @@ static const int kMaxAdvertisementLengthOnIOS = 23;
   NSDictionary<NSString *, id> *_advertisementData;
 }
 
-- (instancetype)init {
+- (instancetype)initWithPeripheralManager:(nullable id<GNCPeripheralManager>)peripheralManager
+                                    queue:(nullable dispatch_queue_t)queue {
   self = [super init];
   if (self) {
-    _queue = dispatch_queue_create(kGNCBLEGATTServerQueueLabel, DISPATCH_QUEUE_SERIAL);
-    _peripheralManager = [[CBPeripheralManager alloc] initWithDelegate:nil queue:_queue];
-    // Set for @c GNCPeripheralManager to be able to forward callbacks.
-    _peripheralManager.peripheralDelegate = self;
+    _queue = queue ?: dispatch_queue_create(kGNCBLEGATTServerQueueLabel, DISPATCH_QUEUE_SERIAL);
     _services = [[NSMutableDictionary alloc] init];
     _pendingCharacteristics = [[NSMutableDictionary alloc] init];
     _characteristicValues = [[NSMutableDictionary alloc] init];
     _advertisementData = nil;
-  }
-  return self;
-}
 
-// This is private and should only be used for tests. The provided peripheral manager must call
-// delegate methods on the main queue.
-- (instancetype)initWithPeripheralManager:(nullable id<GNCPeripheralManager>)peripheralManager {
-  self = [super init];
-  if (self) {
-    _queue = dispatch_get_main_queue();
-    _peripheralManager = peripheralManager;
-    // Set for @c GNCPeripheralManager to be able to forward callbacks.
-    _peripheralManager.peripheralDelegate = self;
-    _services = [[NSMutableDictionary alloc] init];
-    _pendingCharacteristics = [[NSMutableDictionary alloc] init];
-    _characteristicValues = [[NSMutableDictionary alloc] init];
-    _advertisementData = nil;
+    if (GNCFeatureFlags.sharedPeripheralManagerEnabled) {
+      if (!peripheralManager) {
+        // In shared mode, the peripheral manager must be injected.
+        [NSException raise:NSInvalidArgumentException
+                    format:@"Peripheral manager cannot be nil when shared manager is enabled."];
+      }
+      _peripheralManager = peripheralManager;
+      // In shared mode, do NOT set the delegate. The Multiplexer handles callbacks.
+    } else {
+      // Legacy mode: Create a new manager if one isn't provided.
+      if (!peripheralManager) {
+        peripheralManager = [[CBPeripheralManager alloc]
+            initWithDelegate:nil
+                       queue:_queue
+                     options:@{CBPeripheralManagerOptionShowPowerAlertKey : @NO}];
+      }
+      _peripheralManager = peripheralManager;
+      // In legacy mode, we own the manager (or use the injected one as if we own it) and set the
+      // delegate.
+      _peripheralManager.peripheralDelegate = self;
+    }
   }
   return self;
 }
@@ -342,6 +345,12 @@ static const int kMaxAdvertisementLengthOnIOS = 23;
 - (void)gnc_peripheralManager:(id<GNCPeripheralManager>)peripheral
         didReceiveReadRequest:(CBATTRequest *)request {
   dispatch_assert_queue(_queue);
+  if (!_services[request.characteristic.service.UUID]) {
+    // This server does not own the requested service. Ignore the request to allow other listeners
+    // (or future listeners) to handle it.
+    return;
+  }
+
   NSData *value =
       _characteristicValues[request.characteristic.service.UUID][request.characteristic.UUID];
   if (!value) {

internal/platform/implementation/apple/Mediums/BLE/GNCBLEL2CAPServer.h

@@ -15,6 +15,8 @@
 #import <CoreBluetooth/CoreBluetooth.h>
 #import <Foundation/Foundation.h>
 
+#import "internal/platform/implementation/apple/Mediums/BLE/GNCPeripheralManager.h"
+
 @class GNCBLEL2CAPStream;
 @protocol GNCPeripheralManager;
 
@@ -42,7 +44,7 @@ typedef void (^GNCOpenL2CAPServerChannelOpendCompletionHandler)(GNCBLEL2CAPStrea
  *
  * @note The public APIs of this class are thread safe.
  */
-@interface GNCBLEL2CAPServer : NSObject
+@interface GNCBLEL2CAPServer : NSObject <GNCPeripheralManagerDelegate>
 
 // Represents a PSM (Protocol/Service Multiplexer) value for an L2CAP channel.
 @property(atomic, readonly) CBL2CAPPSM PSM;
@@ -57,6 +59,8 @@ typedef void (^GNCOpenL2CAPServerChannelOpendCompletionHandler)(GNCBLEL2CAPStrea
 - (instancetype)initWithPeripheralManager:(nullable id<GNCPeripheralManager>)peripheralManager
                                     queue:(nullable dispatch_queue_t)queue;
 
+- (instancetype)init NS_UNAVAILABLE;
+
 /**
  * Starts listening for an L2CAP channel.
  *

internal/platform/implementation/apple/Mediums/BLE/GNCBLEL2CAPServer.m

@@ -17,6 +17,7 @@
 #import <CoreBluetooth/CoreBluetooth.h>
 #import <Foundation/Foundation.h>
 
+#import "internal/platform/implementation/apple/Flags/GNCFeatureFlags.h"
 #import "internal/platform/implementation/apple/Log/GNCLogger.h"
 #import "internal/platform/implementation/apple/Mediums/BLE/GNCBLEError.h"
 #import "internal/platform/implementation/apple/Mediums/BLE/GNCBLEL2CAPStream.h"
@@ -43,21 +44,25 @@ static char *const kGNCBLEL2CAPServerQueueLabel = "com.google.nearby.GNCBLEL2CAP
   BOOL _alreadyStartedWhenPeripheralPoweredOff;
 }
 
-- (instancetype)init {
-  return [self initWithPeripheralManager:nil queue:nil];
-}
-
-// This is private and should only be used for tests. The provided peripheral manager must call
-// delegate methods on the main queue.
 - (instancetype)initWithPeripheralManager:(nullable id<GNCPeripheralManager>)peripheralManager
                                     queue:(nullable dispatch_queue_t)queue {
   self = [super init];
   if (self) {
     _queue = queue ?: dispatch_queue_create(kGNCBLEL2CAPServerQueueLabel, DISPATCH_QUEUE_SERIAL);
-    if (peripheralManager) {
+    if (GNCFeatureFlags.sharedPeripheralManagerEnabled) {
+      if (!peripheralManager) {
+        // In shared mode, the peripheral manager must be injected.
+        [NSException raise:NSInvalidArgumentException
+                    format:@"Peripheral manager cannot be nil when shared manager is enabled."];
+      }
       _peripheralManager = peripheralManager;
-      // Set for @c GNCPeripheralManager to be able to forward callbacks.
-      _peripheralManager.peripheralDelegate = self;
+      // In shared mode, do NOT set the delegate. The Multiplexer handles callbacks.
+    } else {
+      if (peripheralManager) {
+        _peripheralManager = peripheralManager;
+        // Set for @c GNCPeripheralManager to be able to forward callbacks.
+        _peripheralManager.peripheralDelegate = self;
+      }
     }
   }
   return self;
@@ -70,22 +75,42 @@ static char *const kGNCBLEL2CAPServerQueueLabel = "com.google.nearby.GNCBLEL2CAP
                                         channelOpenedCompletionHandler {
   _psmPublishedCompletionHandler = [psmPublishedCompletionHandler copy];
   _channelOpenedCompletionHandler = [channelOpenedCompletionHandler copy];
-  if (!_queue) {
-    _psmPublishedCompletionHandler(0, [NSError errorWithDomain:GNCBLEErrorDomain
-                                                          code:GNCBLEErrorL2CAPListeningOnQueueNil
-                                                      userInfo:nil]);
-    return;
-  }
-  if (!_peripheralManager) {
-    // Lazy initialization to avoid system dialog on app startup before pairing.
-    _peripheralManager = [[CBPeripheralManager alloc] initWithDelegate:nil
-                                                                 queue:_queue
-                                                               options:nil];
+  if (GNCFeatureFlags.sharedPeripheralManagerEnabled) {
+    if (!_queue) {
+      if (_psmPublishedCompletionHandler) {
+        _psmPublishedCompletionHandler(0,
+                                       [NSError errorWithDomain:GNCBLEErrorDomain
+                                                           code:GNCBLEErrorL2CAPListeningOnQueueNil
+                                                       userInfo:nil]);
+      }
+      return;
+    }
+    if (!_peripheralManager) {
+      GNCLoggerError(@"[NEARBY] Peripheral manager must not be nil.");
+      return;
+    }
+  } else {
+    if (!_queue) {
+      _psmPublishedCompletionHandler(0, [NSError errorWithDomain:GNCBLEErrorDomain
+                                                            code:GNCBLEErrorL2CAPListeningOnQueueNil
+                                                        userInfo:nil]);
+      return;
+    }
+    if (!_peripheralManager) {
+      // Lazy initialization to avoid system dialog on app startup before pairing.
+      _peripheralManager = [[CBPeripheralManager alloc] initWithDelegate:nil
+                                                                   queue:_queue
+                                                                 options:nil];
 
-    // Set for @c GNCPeripheralManager to be able to forward callbacks.
-    _peripheralManager.peripheralDelegate = self;
+      // Set for @c GNCPeripheralManager to be able to forward callbacks.
+      _peripheralManager.peripheralDelegate = self;
+    }
   }
 
+  if (_PSM > 0) {
+    GNCLoggerInfo((@"[NEARBY] Unpublish L2CAP channel with PSM: %@"), @(_PSM));
+    [_peripheralManager unpublishL2CAPChannel:_PSM];
+  }
   if (_peripheralManager.state == CBManagerStatePoweredOn) {
     // Bluetooth link is already encrypted, however encryption is not required here to avoid getting
     // insufficient authentication errors due to initialization order.

internal/platform/implementation/apple/Mediums/BLE/GNCBLEMedium.h

@@ -106,15 +106,6 @@ typedef void (^GNCGATTConnectionCompletionHandler)(GNCBLEGATTClient *_Nullable c
  */
 - (instancetype)init;
 
-/**
- * Initializes the BLE medium with a custom central manager.
- *
- * @param centralManager The central manager to use for BLE operations.
- * @param queue The queue to use for all internal operations.
- */
-- (instancetype)initWithCentralManager:(id<GNCCentralManager>)centralManager
-                                 queue:(nullable dispatch_queue_t)queue;
-
 /** The hardware supports BOTH advertising extensions and extended scans. */
 @property(nonatomic, readonly) BOOL supportsExtendedAdvertisements;
 

internal/platform/implementation/apple/Mediums/BLE/GNCBLEMedium.m

@@ -22,10 +22,10 @@
 #import "internal/platform/implementation/apple/Mediums/BLE/GNCBLEError.h"
 #import "internal/platform/implementation/apple/Mediums/BLE/GNCBLEGATTClient.h"
 #import "internal/platform/implementation/apple/Mediums/BLE/GNCBLEGATTServer.h"
-#import "internal/platform/implementation/apple/Mediums/BLE/GNCBLEL2CAPClient.h"
 #import "internal/platform/implementation/apple/Mediums/BLE/GNCBLEL2CAPServer.h"
 #import "internal/platform/implementation/apple/Mediums/BLE/GNCCentralManager.h"
 #import "internal/platform/implementation/apple/Mediums/BLE/GNCPeripheral.h"
+#import "internal/platform/implementation/apple/Mediums/BLE/GNCPeripheralManagerMultiplexer.h"
 #import "internal/platform/implementation/apple/Mediums/BLE/NSData+GNCBase85.h"
 #import "internal/platform/implementation/apple/Mediums/BLE/NSData+GNCWebSafeBase64.h"
 
@@ -40,22 +40,17 @@ static NSError *AlreadyScanningError() {
   return [NSError errorWithDomain:GNCBLEErrorDomain code:GNCBLEErrorAlreadyScanning userInfo:nil];
 }
 
-static GNCBLEL2CAPServer *_Nonnull CreateL2CapServer(
-    id<GNCPeripheralManager> _Nullable peripheralManager) {
-  if (!peripheralManager) {
-    return [[GNCBLEL2CAPServer alloc] init];
-  } else {
-    return [[GNCBLEL2CAPServer alloc] initWithPeripheralManager:peripheralManager
-                                                          queue:dispatch_get_main_queue()];
-  }
-}
-
 @interface GNCBLEMedium () <GNCCentralManagerDelegate, CBCentralManagerDelegate>
+- (instancetype)initWithCentralManager:(id<GNCCentralManager>)centralManager
+                     peripheralManager:(nullable id<GNCPeripheralManager>)peripheralManager
+                                 queue:(dispatch_queue_t)queue;
 @end
 
 @implementation GNCBLEMedium {
   dispatch_queue_t _queue;
   id<GNCCentralManager> _centralManager;
+  id<GNCPeripheralManager> _peripheralManager;
+  GNCPeripheralManagerMultiplexer *_multiplexer;
 
   // The active GATT server, or @nil if one hasn't been started yet.
   GNCBLEGATTServer *_server;
@@ -99,21 +94,31 @@ static GNCBLEL2CAPServer *_Nonnull CreateL2CapServer(
 - (instancetype)init {
   dispatch_queue_t queue = dispatch_queue_create(kBLEMediumQueueLabel, DISPATCH_QUEUE_SERIAL);
   CBCentralManager *centralManager =
-      [[CBCentralManager alloc] initWithDelegate:self
+      [[CBCentralManager alloc] initWithDelegate:nil
                                            queue:queue
                                          options:@{CBCentralManagerOptionShowPowerAlertKey : @NO}];
-  return [self initWithCentralManager:centralManager queue:queue];
+  CBPeripheralManager *peripheralManager = [[CBPeripheralManager alloc] initWithDelegate:nil
+                                                                                   queue:queue];
+  return [self initWithCentralManager:centralManager
+                    peripheralManager:peripheralManager
+                                queue:queue];
 }
 
 // This is private and should only be used for tests. The provided central manager must call
 // delegate methods on the main queue.
 - (instancetype)initWithCentralManager:(id<GNCCentralManager>)centralManager
-                                 queue:(nullable dispatch_queue_t)queue {
+                     peripheralManager:(nullable id<GNCPeripheralManager>)peripheralManager
+                                 queue:(dispatch_queue_t)queue {
   self = [super init];
   if (self) {
-    _queue = queue ?: dispatch_get_main_queue();
+    _queue = queue;
     _centralManager = centralManager;
     _centralManager.centralDelegate = self;
+    _peripheralManager = peripheralManager;
+    if (GNCFeatureFlags.sharedPeripheralManagerEnabled && _peripheralManager) {
+      _multiplexer = [[GNCPeripheralManagerMultiplexer alloc] initWithCallbackQueue:_queue];
+      _peripheralManager.peripheralDelegate = _multiplexer;
+    }
     _gattConnectionCompletionHandlers = [NSMutableDictionary dictionary];
     _gattDisconnectionHandlers = [NSMutableDictionary dictionary];
     _scanningServiceUUIDs = [NSMutableArray array];
@@ -160,11 +165,27 @@ static GNCBLEL2CAPServer *_Nonnull CreateL2CapServer(
   return NO;
 }
 
+- (void)dealloc {
+  [_centralManager stopScan];
+  _centralManager.centralDelegate = nil;
+
+  [_peripheralManager stopAdvertising];
+  _peripheralManager.peripheralDelegate = nil;
+}
+
 - (void)startAdvertisingData:(NSDictionary<CBUUID *, NSData *> *)serviceData
            completionHandler:(nullable GNCStartAdvertisingCompletionHandler)completionHandler {
   dispatch_async(_queue, ^{
     if (!_server) {
-      _server = [[GNCBLEGATTServer alloc] init];
+      if (GNCFeatureFlags.sharedPeripheralManagerEnabled) {
+        _server = [[GNCBLEGATTServer alloc] initWithPeripheralManager:_peripheralManager
+                                                                queue:_queue];
+        [_multiplexer addListener:_server];
+      } else {
+        // In legacy mode, we pass nil (or a separate manager) and do NOT add to multiplexer.
+        // GNCBLEGATTServer will create its own internal manager.
+        _server = [[GNCBLEGATTServer alloc] initWithPeripheralManager:nil queue:nil];
+      }
     }
     [_server startAdvertisingData:serviceData completionHandler:completionHandler];
   });
@@ -206,7 +227,7 @@ static GNCBLEL2CAPServer *_Nonnull CreateL2CapServer(
     [_scanningServiceUUIDs addObjectsFromArray:serviceUUIDs];
     _advertisementFoundHandler = advertisementFoundHandler;
 
-    [self internalStartScanningIfPoweredOn];
+    [self updateScanningState];
     if (completionHandler) {
       completionHandler(nil);
     }
@@ -227,7 +248,7 @@ static GNCBLEL2CAPServer *_Nonnull CreateL2CapServer(
 
 - (void)resumeMediumScanning:(nullable GNCStartScanningCompletionHandler)completionHandler {
   dispatch_async(_queue, ^{
-    [self internalStartScanningIfPoweredOn];
+    [self updateScanningState];
     if (completionHandler) {
       completionHandler(nil);
     }
@@ -238,7 +259,13 @@ static GNCBLEL2CAPServer *_Nonnull CreateL2CapServer(
     (nullable GNCGATTServerCompletionHandler)completionHandler {
   dispatch_async(_queue, ^{
     if (!_server) {
-      _server = [[GNCBLEGATTServer alloc] init];
+      if (GNCFeatureFlags.sharedPeripheralManagerEnabled) {
+        _server = [[GNCBLEGATTServer alloc] initWithPeripheralManager:_peripheralManager
+                                                                queue:_queue];
+        [_multiplexer addListener:_server];
+      } else {
+        _server = [[GNCBLEGATTServer alloc] initWithPeripheralManager:nil queue:nil];
+      }
     }
     if (completionHandler) {
       completionHandler(_server, nil);
@@ -284,7 +311,22 @@ static GNCBLEL2CAPServer *_Nonnull CreateL2CapServer(
                                            (nullable id<GNCPeripheralManager>)peripheralManager {
   dispatch_async(_queue, ^{
     if (!_l2capServer) {
-      _l2capServer = CreateL2CapServer(peripheralManager);
+      if (GNCFeatureFlags.sharedPeripheralManagerEnabled) {
+        _l2capServer = [[GNCBLEL2CAPServer alloc]
+            initWithPeripheralManager:peripheralManager ?: _peripheralManager
+                                queue:peripheralManager ? dispatch_get_main_queue() : _queue];
+        // Only add to multiplexer if we are using the internal shared manager.
+        // If a specific manager was passed in (e.g. for testing?), we might still need logic here.
+        // But typically `peripheralManager` is nil in prod.
+        if (peripheralManager == nil || peripheralManager == _peripheralManager) {
+          [_multiplexer addListener:_l2capServer];
+        }
+      } else {
+        // Legacy mode
+        _l2capServer = [[GNCBLEL2CAPServer alloc]
+            initWithPeripheralManager:peripheralManager  // Likely nil, so Server creates new one
+                                queue:peripheralManager ? dispatch_get_main_queue() : nil];
+      }
     }
     [_l2capServer
         startListeningChannelWithPSMPublishedCompletionHandler:psmPublishedCompletionHandler
@@ -335,7 +377,7 @@ static GNCBLEL2CAPServer *_Nonnull CreateL2CapServer(
 
 #pragma mark - Internal
 
-- (void)internalStartScanningIfPoweredOn {
+- (void)updateScanningState {
   dispatch_assert_queue(_queue);
   // Scanning can only be done when powered on and must be restarted if bluetooth is turned off
   // then back on. This will be called anytime the central manager's state changes, so
@@ -463,7 +505,7 @@ static GNCBLEL2CAPServer *_Nonnull CreateL2CapServer(
     return;
   }
   dispatch_assert_queue(_queue);
-  [self internalStartScanningIfPoweredOn];
+  [self updateScanningState];
 }
 
 - (void)gnc_centralManager:(id<GNCCentralManager>)central
@@ -480,6 +522,7 @@ static GNCBLEL2CAPServer *_Nonnull CreateL2CapServer(
       didConnectPeripheral:(id<GNCPeripheral>)peripheral {
   dispatch_assert_queue(_queue);
   [self cancelConnectionTimeout];
+
   if (_l2capPSM > 0) {
     [self internalOpenL2CAPChannel:peripheral];
     return;
@@ -525,6 +568,7 @@ static GNCBLEL2CAPServer *_Nonnull CreateL2CapServer(
     didDisconnectPeripheral:(id<GNCPeripheral>)peripheral
                       error:(nullable NSError *)error {
   dispatch_assert_queue(_queue);
+
   GNCGATTDisconnectionHandler handler = _gattDisconnectionHandlers[peripheral.identifier];
   _gattDisconnectionHandlers[peripheral.identifier] = nil;
   if (handler) {

internal/platform/implementation/apple/Mediums/BLE/GNCCentralManager.m

@@ -22,8 +22,10 @@ NS_ASSUME_NONNULL_BEGIN
 @implementation CBCentralManager (GNCCentralManagerAdditions)
 
 - (void)setCentralDelegate:(nullable id<GNCCentralManagerDelegate>)centralDelegate {
-  NSAssert([centralDelegate conformsToProtocol:@protocol(CBCentralManagerDelegate)],
-           @"centralDelegate must conform to protocol CBCentralManagerDelegate");
+  if (centralDelegate) {
+    NSAssert([centralDelegate conformsToProtocol:@protocol(CBCentralManagerDelegate)],
+             @"centralDelegate must conform to protocol CBCentralManagerDelegate");
+  }
   self.delegate = (id<CBCentralManagerDelegate>)centralDelegate;
 }
 

internal/platform/implementation/apple/Mediums/BLE/GNCMBleUtils.h

@@ -90,9 +90,11 @@ NSData *_Nullable GNCMGenerateBLEL2CAPPacket(GNCMBLEL2CAPCommand command, NSData
 
 /**
  * Calls the completion handler with (a) YES if the GNSSocket connected, or (b) NO if it failed to
- * connect for any reason. The completion handler is called on the main queue.
+ * connect for any reason. The completion handler is called on the given queue. If the queue is nil,
+ * the completion handler is called on the main queue.
  */
-void GNCMWaitForConnection(GNSSocket *socket, GNCMBoolHandler completion);
+void GNCMWaitForConnection(GNSSocket *socket, dispatch_queue_t _Nullable queue,
+                           GNCMBoolHandler completion);
 
 #ifdef __cplusplus
 }  // extern "C"

internal/platform/implementation/apple/Mediums/BLE/GNCMBleUtils.mm

@@ -235,18 +235,20 @@ NSData *_Nullable GNCMGenerateBLEL2CAPPacket(GNCMBLEL2CAPCommand command, NSData
 
 @end
 
-void GNCMWaitForConnection(GNSSocket *socket, GNCMBoolHandler completion) {
+void GNCMWaitForConnection(GNSSocket *socket, dispatch_queue_t _Nullable queue,
+                           GNCMBoolHandler completion) {
   // This function passes YES to the completion when the socket has successfully connected, and
   // otherwise passes NO to the completion after a timeout of several seconds.  We shouldn't retain
   // the completion after it's been called, so store it in a __block variable and nil it out once
   // the socket has connected.
   __block GNCMBoolHandler completionRef = completion;
+  dispatch_queue_t targetQueue = queue ?: dispatch_get_main_queue();
 
   // The delegate listens for the socket connection callbacks.  It's retained by the block passed to
   // dispatch_after below, so it will live long enough to do its job.
   GNCMBleSocketDelegate *delegate =
       [GNCMBleSocketDelegate delegateWithConnectedHandler:^(BOOL didConnect) {
-        dispatch_async(dispatch_get_main_queue(), ^{
+        dispatch_async(targetQueue, ^{
           if (completionRef) completionRef(didConnect);
           completionRef = nil;
         });
@@ -254,9 +256,10 @@ void GNCMWaitForConnection(GNSSocket *socket, GNCMBoolHandler completion) {
   socket.delegate = delegate;
   dispatch_after(
       dispatch_time(DISPATCH_TIME_NOW, (int64_t)(kBleSocketConnectionTimeout * NSEC_PER_SEC)),
-      dispatch_get_main_queue(), ^{
+      targetQueue, ^{
         (void)delegate;  // make sure it's retained until the timeout
         if (completionRef) completionRef(NO);
+        completionRef = nil;
       });
 }
 

internal/platform/implementation/apple/Mediums/BLE/GNCPeripheralManagerMultiplexer.h

@@ -0,0 +1,49 @@
+// Copyright 2026 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#import "internal/platform/implementation/apple/Mediums/BLE/GNCPeripheralManager.h"
+
+NS_ASSUME_NONNULL_BEGIN
+
+/**
+ * A multiplexer that forwards @c CBPeripheralManagerDelegate and @c GNCPeripheralManagerDelegate
+ */
+@interface GNCPeripheralManagerMultiplexer : NSObject <GNCPeripheralManagerDelegate>
+
+/**
+ * Initializes the multiplexer.
+ *
+ * @param callbackQueue The queue to use for forwarding delegate callbacks.
+ */
+- (instancetype)initWithCallbackQueue:(dispatch_queue_t)callbackQueue NS_DESIGNATED_INITIALIZER;
+
+- (instancetype)init NS_UNAVAILABLE;
+
+/**
+ * Adds a listener to the multiplexer. Listeners are held weakly.
+ *
+ * @param listener The listener to add.
+ */
+- (void)addListener:(id<GNCPeripheralManagerDelegate>)listener;
+
+/**
+ * Removes a listener from the multiplexer.
+ *
+ * @param listener The listener to remove.
+ */
+- (void)removeListener:(id<GNCPeripheralManagerDelegate>)listener;
+
+@end
+
+NS_ASSUME_NONNULL_END

internal/platform/implementation/apple/Mediums/BLE/GNCPeripheralManagerMultiplexer.m

@@ -0,0 +1,194 @@
+// Copyright 2026 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#import "internal/platform/implementation/apple/Mediums/BLE/GNCPeripheralManagerMultiplexer.h"
+
+#import <CoreBluetooth/CoreBluetooth.h>
+#import <Foundation/Foundation.h>
+
+#import "internal/platform/implementation/apple/Mediums/BLE/GNCPeripheralManager.h"
+
+NS_ASSUME_NONNULL_BEGIN
+
+@implementation GNCPeripheralManagerMultiplexer {
+  NSHashTable<id<GNCPeripheralManagerDelegate>> *_listeners;
+  dispatch_queue_t _callbackQueue;
+  dispatch_queue_t _syncQueue;
+}
+
+- (instancetype)initWithCallbackQueue:(dispatch_queue_t)callbackQueue {
+  self = [super init];
+  if (self) {
+    _listeners = [NSHashTable weakObjectsHashTable];
+    _callbackQueue = callbackQueue;
+    _syncQueue = dispatch_queue_create("com.google.nearby.GNCPeripheralManagerMultiplexerSync",
+                                       DISPATCH_QUEUE_SERIAL);
+  }
+  return self;
+}
+
+- (instancetype)init {
+  return [self initWithCallbackQueue:dispatch_get_main_queue()];
+}
+
+- (void)addListener:(id<GNCPeripheralManagerDelegate>)listener {
+  dispatch_async(_syncQueue, ^{
+    [self->_listeners addObject:listener];
+  });
+}
+
+- (void)removeListener:(id<GNCPeripheralManagerDelegate>)listener {
+  dispatch_async(_syncQueue, ^{
+    [self->_listeners removeObject:listener];
+  });
+}
+
+- (NSArray<id<GNCPeripheralManagerDelegate>> *)allListeners {
+  __block NSArray<id<GNCPeripheralManagerDelegate>> *listeners;
+  dispatch_sync(_syncQueue, ^{
+    listeners = [self->_listeners allObjects];
+  });
+  return listeners;
+}
+
+#pragma mark - GNCPeripheralManagerDelegate
+
+- (void)gnc_peripheralManagerDidUpdateState:(id<GNCPeripheralManager>)peripheral {
+  NSArray<id<GNCPeripheralManagerDelegate>> *listeners = [self allListeners];
+  dispatch_async(_callbackQueue, ^{
+    for (id<GNCPeripheralManagerDelegate> listener in listeners) {
+      [listener gnc_peripheralManagerDidUpdateState:peripheral];
+    }
+  });
+}
+
+- (void)gnc_peripheralManagerDidStartAdvertising:(id<GNCPeripheralManager>)peripheral
+                                           error:(nullable NSError *)error {
+  NSArray<id<GNCPeripheralManagerDelegate>> *listeners = [self allListeners];
+  dispatch_async(_callbackQueue, ^{
+    for (id<GNCPeripheralManagerDelegate> listener in listeners) {
+      if ([listener respondsToSelector:@selector(gnc_peripheralManagerDidStartAdvertising:error:)]) {
+        [listener gnc_peripheralManagerDidStartAdvertising:peripheral error:error];
+      }
+    }
+  });
+}
+
+- (void)gnc_peripheralManager:(id<GNCPeripheralManager>)peripheral
+                didAddService:(CBService *)service
+                        error:(nullable NSError *)error {
+  NSArray<id<GNCPeripheralManagerDelegate>> *listeners = [self allListeners];
+  dispatch_async(_callbackQueue, ^{
+    for (id<GNCPeripheralManagerDelegate> listener in listeners) {
+      if ([listener respondsToSelector:@selector(gnc_peripheralManager:didAddService:error:)]) {
+        [listener gnc_peripheralManager:peripheral didAddService:service error:error];
+      }
+    }
+  });
+}
+
+- (void)gnc_peripheralManager:(id<GNCPeripheralManager>)peripheral
+        didReceiveReadRequest:(CBATTRequest *)request {
+  NSArray<id<GNCPeripheralManagerDelegate>> *listeners = [self allListeners];
+  dispatch_async(_callbackQueue, ^{
+    for (id<GNCPeripheralManagerDelegate> listener in listeners) {
+      if ([listener respondsToSelector:@selector(gnc_peripheralManager:didReceiveReadRequest:)]) {
+        [listener gnc_peripheralManager:peripheral didReceiveReadRequest:request];
+      }
+    }
+  });
+}
+
+- (void)gnc_peripheralManager:(id<GNCPeripheralManager>)peripheral
+       didPublishL2CAPChannel:(CBL2CAPPSM)PSM
+                        error:(nullable NSError *)error {
+  NSArray<id<GNCPeripheralManagerDelegate>> *listeners = [self allListeners];
+  dispatch_async(_callbackQueue, ^{
+    for (id<GNCPeripheralManagerDelegate> listener in listeners) {
+      if ([listener respondsToSelector:@selector(gnc_peripheralManager:didPublishL2CAPChannel:error:)]) {
+        [listener gnc_peripheralManager:peripheral didPublishL2CAPChannel:PSM error:error];
+      }
+    }
+  });
+}
+
+- (void)gnc_peripheralManager:(id<GNCPeripheralManager>)peripheral
+     didUnpublishL2CAPChannel:(CBL2CAPPSM)PSM
+                        error:(NSError *)error {
+  NSArray<id<GNCPeripheralManagerDelegate>> *listeners = [self allListeners];
+  dispatch_async(_callbackQueue, ^{
+    for (id<GNCPeripheralManagerDelegate> listener in listeners) {
+      if ([listener respondsToSelector:@selector(gnc_peripheralManager:didUnpublishL2CAPChannel:error:)]) {
+        [listener gnc_peripheralManager:peripheral didUnpublishL2CAPChannel:PSM error:error];
+      }
+    }
+  });
+}
+
+- (void)gnc_peripheralManager:(id<GNCPeripheralManager>)peripheral
+          didOpenL2CAPChannel:(nullable CBL2CAPChannel *)channel
+                        error:(nullable NSError *)error {
+  NSArray<id<GNCPeripheralManagerDelegate>> *listeners = [self allListeners];
+  dispatch_async(_callbackQueue, ^{
+    for (id<GNCPeripheralManagerDelegate> listener in listeners) {
+      if ([listener respondsToSelector:@selector(gnc_peripheralManager:didOpenL2CAPChannel:error:)]) {
+        [listener gnc_peripheralManager:peripheral didOpenL2CAPChannel:channel error:error];
+      }
+    }
+  });
+}
+
+#pragma mark - CBPeripheralManagerDelegate
+
+- (void)peripheralManagerDidUpdateState:(CBPeripheralManager *)peripheral {
+  [self gnc_peripheralManagerDidUpdateState:peripheral];
+}
+
+- (void)peripheralManagerDidStartAdvertising:(CBPeripheralManager *)peripheral
+                                       error:(nullable NSError *)error {
+  [self gnc_peripheralManagerDidStartAdvertising:peripheral error:error];
+}
+
+- (void)peripheralManager:(CBPeripheralManager *)peripheral
+            didAddService:(CBService *)service
+                    error:(nullable NSError *)error {
+  [self gnc_peripheralManager:peripheral didAddService:service error:error];
+}
+
+- (void)peripheralManager:(CBPeripheralManager *)peripheral
+    didReceiveReadRequest:(CBATTRequest *)request {
+  [self gnc_peripheralManager:peripheral didReceiveReadRequest:request];
+}
+
+- (void)peripheralManager:(CBPeripheralManager *)peripheral
+    didPublishL2CAPChannel:(CBL2CAPPSM)PSM
+                     error:(nullable NSError *)error {
+  [self gnc_peripheralManager:peripheral didPublishL2CAPChannel:PSM error:error];
+}
+
+- (void)peripheralManager:(CBPeripheralManager *)peripheral
+    didUnpublishL2CAPChannel:(CBL2CAPPSM)PSM
+                       error:(nullable NSError *)error {
+  [self gnc_peripheralManager:peripheral didUnpublishL2CAPChannel:PSM error:error];
+}
+
+- (void)peripheralManager:(CBPeripheralManager *)peripheral
+      didOpenL2CAPChannel:(nullable CBL2CAPChannel *)channel
+                    error:(nullable NSError *)error {
+  [self gnc_peripheralManager:peripheral didOpenL2CAPChannel:channel error:error];
+}
+
+@end
+
+NS_ASSUME_NONNULL_END

internal/platform/implementation/apple/Mediums/BLE/Sockets/BUILD

@@ -30,9 +30,6 @@ objc_library(
     ]) + [
         "Source/GNSCentral.h",
     ],
-    copts = [
-        "-Wno-enum-compare",  # TODO(b/418286948): Remove this when the error is fixed.
-    ],
     deps = [
         ":Shared",
         "//internal/platform/implementation/apple/Log:GNCLogger",
@@ -51,9 +48,6 @@ objc_library(
     ]) + [
         "Source/GNSPeripheral.h",
     ],
-    copts = [
-        "-Wno-enum-compare",  # TODO(b/418286948): Remove this when the error is fixed.
-    ],
     deps = [
         ":Shared",
         "//internal/platform/implementation/apple/Log:GNCLogger",

internal/platform/implementation/apple/Mediums/BLE/Sockets/Source/Peripheral/GNSPeripheralManager.m

@@ -371,7 +371,7 @@ static NSTimeInterval gKBTCrashLoopMaxTimeBetweenResetting = 15.f;
 }
 
 - (void)updateBTCrashLoopHeuristic {
-  NSAssert(_cbPeripheralManager.state == CBCentralManagerStateResetting, @"Unexpected CB state %@",
+  NSAssert(_cbPeripheralManager.state == CBManagerStateResetting, @"Unexpected CB state %@",
            CBManagerStateString(_cbPeripheralManager.state));
   NSDate *now = [NSDate date];
   if ([now timeIntervalSinceDate:_btCrashLastResettingDate] >

internal/platform/implementation/apple/Mediums/BLE/Tests/BUILD

@@ -26,13 +26,13 @@ objc_library(
     srcs = [
         "GNCBLEGATTCharacteristicTest.mm",
         "GNCBLEGATTClientTest.m",
-        "GNCBLEGATTServerTest.m",
+        "GNCBLEGATTServerTest.mm",
         "GNCBLEL2CAPClientTest.m",
         "GNCBLEL2CAPConnectionTest.m",
         "GNCBLEL2CAPFakeInputOutputStream.m",
-        "GNCBLEL2CAPServerTest.m",
+        "GNCBLEL2CAPServerTest.mm",
         "GNCBLEL2CAPStreamTest.m",
-        "GNCBLEMediumTest.m",
+        "GNCBLEMediumTest.mm",
         "GNCFakeBLEGATTServer.m",
         "GNCFakeBLEMedium.m",
         "GNCFakeCBL2CAPChannel.m",
@@ -44,6 +44,7 @@ objc_library(
         "GNCMBleUtilsTest.m",
         "GNCMConnectionsTest.m",
         "GNCMFakeConnection.mm",
+        "GNCPeripheralManagerMultiplexerTest.m",
         "GNCPeripheralManagerTest.m",
         "GNCPeripheralTest.m",
         "NSData+GNCBase85Test.m",
@@ -66,6 +67,8 @@ objc_library(
         "GNCMFakeConnection.h",
     ],
     deps = [
+        "//connections/implementation/flags:connections_flags",
+        "//internal/flags:nearby_flags",
         "//internal/platform/implementation/apple",  # buildcleaner: keep
         "//internal/platform/implementation/apple/Mediums/BLE",
         "//internal/platform/implementation/apple/Mediums/BLE/Sockets:Shared",

internal/platform/implementation/apple/Mediums/BLE/Tests/GNCBLEGATTServerTest.mm

@@ -22,6 +22,9 @@
 #import "internal/platform/implementation/apple/Mediums/BLE/Tests/GNCBLEGATTServer+Testing.h"
 #import "internal/platform/implementation/apple/Mediums/BLE/Tests/GNCFakePeripheralManager.h"
 
+#include "connections/implementation/flags/nearby_connections_feature_flags.h"
+#include "internal/flags/nearby_flags.h"
+
 static NSString *const kServiceUUID1 = @"0000FEF3-0000-1000-8000-00805F9B34FB";
 static NSString *const kServiceUUID2 = @"0000FEF4-0000-1000-8000-00805F9B34FB";
 static NSString *const kCharacteristicUUID1 = @"00000000-0000-3000-8000-000000000000";
@@ -34,11 +37,60 @@ static NSString *const kCharacteristicUUID2 = @"00000000-0000-3000-8000-00000000
 
 #pragma mark - Create Characteristic
 
-- (void)testCreateCharacteristic {
-  GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+- (void)tearDown {
+  nearby::NearbyFlags::GetInstance().ResetOverridedValues();
+  [super tearDown];
+}
 
-  GNCBLEGATTServer *gattServer =
-      [[GNCBLEGATTServer alloc] initWithPeripheralManager:fakePeripheralManager];
+- (void)testInit_setsDelegateCorrectlyBasedOnFlag {
+  for (NSNumber *enabled in @[ @NO, @YES ]) {
+    nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+        nearby::connections::config_package_nearby::nearby_connections_feature::
+            kEnableSharedPeripheralManager,
+        enabled.boolValue);
+
+    GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+    GNCBLEGATTServer *server =
+        [[GNCBLEGATTServer alloc] initWithPeripheralManager:fakePeripheralManager
+                                                      queue:dispatch_get_main_queue()];
+
+    if (enabled.boolValue) {
+      // In shared mode, functionality is delegated to the multiplexer, so the server should NOT
+      // self-assign as delegate.
+      XCTAssertNil(fakePeripheralManager.peripheralDelegate);
+    } else {
+      // In legacy mode, the server owns the manager and sets itself as delegate.
+      XCTAssertEqual(fakePeripheralManager.peripheralDelegate, server);
+    }
+  }
+}
+
+- (void)testInit_throwsWithNilManagerWhenFlagEnabled {
+  nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+      nearby::connections::config_package_nearby::nearby_connections_feature::
+          kEnableSharedPeripheralManager,
+      true);
+
+  XCTAssertThrowsSpecificNamed(
+      [[GNCBLEGATTServer alloc] initWithPeripheralManager:(id<GNCPeripheralManager>)nil
+                                                    queue:dispatch_get_main_queue()],
+      NSException, NSInvalidArgumentException);
+}
+
+- (void)testCreateCharacteristic {
+  for (NSNumber *enabled in @[ @NO, @YES ]) {
+    nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+        nearby::connections::config_package_nearby::nearby_connections_feature::
+            kEnableSharedPeripheralManager,
+        enabled.boolValue);
+    GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+
+    GNCBLEGATTServer *gattServer =
+        [[GNCBLEGATTServer alloc] initWithPeripheralManager:fakePeripheralManager
+                                                      queue:dispatch_get_main_queue()];
+    if (enabled.boolValue) {
+      fakePeripheralManager.peripheralDelegate = gattServer;
+    }
 
   [fakePeripheralManager simulatePeripheralManagerDidUpdateState:CBManagerStatePoweredOn];
 
@@ -62,13 +114,23 @@ static NSString *const kCharacteristicUUID2 = @"00000000-0000-3000-8000-00000000
                       }];
 
   [self waitForExpectations:@[ expectation ] timeout:3];
+  }
 }
 
 - (void)testCreateMultipleCharacteristicsForOneService {
-  GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+  for (NSNumber *enabled in @[ @NO, @YES ]) {
+    nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+        nearby::connections::config_package_nearby::nearby_connections_feature::
+            kEnableSharedPeripheralManager,
+        enabled.boolValue);
+    GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
 
-  GNCBLEGATTServer *gattServer =
-      [[GNCBLEGATTServer alloc] initWithPeripheralManager:fakePeripheralManager];
+    GNCBLEGATTServer *gattServer =
+        [[GNCBLEGATTServer alloc] initWithPeripheralManager:fakePeripheralManager
+                                                      queue:dispatch_get_main_queue()];
+    if (enabled.boolValue) {
+      fakePeripheralManager.peripheralDelegate = gattServer;
+    }
 
   [fakePeripheralManager simulatePeripheralManagerDidUpdateState:CBManagerStatePoweredOn];
 
@@ -105,13 +167,23 @@ static NSString *const kCharacteristicUUID2 = @"00000000-0000-3000-8000-00000000
   [self waitForExpectations:@[ expectation1, expectation2 ] timeout:3];
   XCTAssertEqual(fakePeripheralManager.services.count, 1);
   XCTAssertEqual(fakePeripheralManager.services[0].characteristics.count, 2);
+  }
 }
 
 - (void)testCreateDuplicateCharacteristics {
-  GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+  for (NSNumber *enabled in @[ @NO, @YES ]) {
+    nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+        nearby::connections::config_package_nearby::nearby_connections_feature::
+            kEnableSharedPeripheralManager,
+        enabled.boolValue);
+    GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
 
-  GNCBLEGATTServer *gattServer =
-      [[GNCBLEGATTServer alloc] initWithPeripheralManager:fakePeripheralManager];
+    GNCBLEGATTServer *gattServer =
+        [[GNCBLEGATTServer alloc] initWithPeripheralManager:fakePeripheralManager
+                                                      queue:dispatch_get_main_queue()];
+    if (enabled.boolValue) {
+      fakePeripheralManager.peripheralDelegate = gattServer;
+    }
 
   [fakePeripheralManager simulatePeripheralManagerDidUpdateState:CBManagerStatePoweredOn];
 
@@ -140,13 +212,23 @@ static NSString *const kCharacteristicUUID2 = @"00000000-0000-3000-8000-00000000
   [self waitForExpectations:@[ expectation ] timeout:3];
   XCTAssertEqual(fakePeripheralManager.services.count, 1);
   XCTAssertEqual(fakePeripheralManager.services[0].characteristics.count, 1);
+  }
 }
 
 - (void)testCreateDuplicatePendingCharacteristics {
-  GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+  for (NSNumber *enabled in @[ @NO, @YES ]) {
+    nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+        nearby::connections::config_package_nearby::nearby_connections_feature::
+            kEnableSharedPeripheralManager,
+        enabled.boolValue);
+    GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
 
-  GNCBLEGATTServer *gattServer =
-      [[GNCBLEGATTServer alloc] initWithPeripheralManager:fakePeripheralManager];
+    GNCBLEGATTServer *gattServer =
+        [[GNCBLEGATTServer alloc] initWithPeripheralManager:fakePeripheralManager
+                                                      queue:dispatch_get_main_queue()];
+    if (enabled.boolValue) {
+      fakePeripheralManager.peripheralDelegate = gattServer;
+    }
 
   XCTestExpectation *expectation =
       [[XCTestExpectation alloc] initWithDescription:@"Create characteristic."];
@@ -171,13 +253,23 @@ static NSString *const kCharacteristicUUID2 = @"00000000-0000-3000-8000-00000000
                               }];
 
   [self waitForExpectations:@[ expectation ] timeout:3];
+  }
 }
 
 - (void)testCreateCharacteristicNotPoweredOn {
-  GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+  for (NSNumber *enabled in @[ @NO, @YES ]) {
+    nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+        nearby::connections::config_package_nearby::nearby_connections_feature::
+            kEnableSharedPeripheralManager,
+        enabled.boolValue);
+    GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
 
-  GNCBLEGATTServer *gattServer =
-      [[GNCBLEGATTServer alloc] initWithPeripheralManager:fakePeripheralManager];
+    GNCBLEGATTServer *gattServer =
+        [[GNCBLEGATTServer alloc] initWithPeripheralManager:fakePeripheralManager
+                                                      queue:dispatch_get_main_queue()];
+    if (enabled.boolValue) {
+      fakePeripheralManager.peripheralDelegate = gattServer;
+    }
 
   XCTestExpectation *expectation =
       [[XCTestExpectation alloc] initWithDescription:@"Create characteristic."];
@@ -198,13 +290,23 @@ static NSString *const kCharacteristicUUID2 = @"00000000-0000-3000-8000-00000000
                               }];
 
   [self waitForExpectations:@[ expectation ] timeout:3];
+  }
 }
 
 - (void)testCreateCharacteristicServiceFailure {
-  GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+  for (NSNumber *enabled in @[ @NO, @YES ]) {
+    nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+        nearby::connections::config_package_nearby::nearby_connections_feature::
+            kEnableSharedPeripheralManager,
+        enabled.boolValue);
+    GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
 
-  GNCBLEGATTServer *gattServer =
-      [[GNCBLEGATTServer alloc] initWithPeripheralManager:fakePeripheralManager];
+    GNCBLEGATTServer *gattServer =
+        [[GNCBLEGATTServer alloc] initWithPeripheralManager:fakePeripheralManager
+                                                      queue:dispatch_get_main_queue()];
+    if (enabled.boolValue) {
+      fakePeripheralManager.peripheralDelegate = gattServer;
+    }
 
   fakePeripheralManager.didAddServiceError = [NSError errorWithDomain:@"fake" code:0 userInfo:nil];
   [fakePeripheralManager simulatePeripheralManagerDidUpdateState:CBManagerStatePoweredOn];
@@ -228,15 +330,25 @@ static NSString *const kCharacteristicUUID2 = @"00000000-0000-3000-8000-00000000
                               }];
 
   [self waitForExpectations:@[ expectation ] timeout:3];
+  }
 }
 
 #pragma mark - Read Request
 
 - (void)testReadRequest {
-  GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+  for (NSNumber *enabled in @[ @NO, @YES ]) {
+    nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+        nearby::connections::config_package_nearby::nearby_connections_feature::
+            kEnableSharedPeripheralManager,
+        enabled.boolValue);
+    GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
 
-  GNCBLEGATTServer *gattServer =
-      [[GNCBLEGATTServer alloc] initWithPeripheralManager:fakePeripheralManager];
+    GNCBLEGATTServer *gattServer =
+        [[GNCBLEGATTServer alloc] initWithPeripheralManager:fakePeripheralManager
+                                                      queue:dispatch_get_main_queue()];
+    if (enabled.boolValue) {
+      fakePeripheralManager.peripheralDelegate = gattServer;
+    }
 
   [fakePeripheralManager simulatePeripheralManagerDidUpdateState:CBManagerStatePoweredOn];
 
@@ -265,14 +377,24 @@ static NSString *const kCharacteristicUUID2 = @"00000000-0000-3000-8000-00000000
                                                 characteristic:characteristicUUID];
 
   [self waitForExpectations:@[ fakePeripheralManager.respondToRequestSuccessExpectation ]
-                    timeout:0];
+                    timeout:3];
+  }
 }
 
-- (void)testReadRequestInvalidService {
-  GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+- (void)testReadRequestInvalidCharacteristic {
+  for (NSNumber *enabled in @[ @NO, @YES ]) {
+    nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+        nearby::connections::config_package_nearby::nearby_connections_feature::
+            kEnableSharedPeripheralManager,
+        enabled.boolValue);
+    GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
 
-  GNCBLEGATTServer *gattServer =
-      [[GNCBLEGATTServer alloc] initWithPeripheralManager:fakePeripheralManager];
+    GNCBLEGATTServer *gattServer =
+        [[GNCBLEGATTServer alloc] initWithPeripheralManager:fakePeripheralManager
+                                                      queue:dispatch_get_main_queue()];
+    if (enabled.boolValue) {
+      fakePeripheralManager.peripheralDelegate = gattServer;
+    }
 
   [fakePeripheralManager simulatePeripheralManagerDidUpdateState:CBManagerStatePoweredOn];
 
@@ -296,73 +418,106 @@ static NSString *const kCharacteristicUUID2 = @"00000000-0000-3000-8000-00000000
 
   [self waitForExpectations:@[ expectation ] timeout:3];
 
+  CBUUID *invalidCharacteristicUUID = [CBUUID UUIDWithString:kCharacteristicUUID2];
+
+  [fakePeripheralManager
+      simulatePeripheralManagerDidReceiveReadRequestForService:serviceUUID
+                                                characteristic:invalidCharacteristicUUID];
+
+  [self waitForExpectations:@[ fakePeripheralManager.respondToRequestErrorExpectation ] timeout:3];
+  }
+}
+
+- (void)testReadRequestInvalidService {
+  for (NSNumber *enabled in @[ @NO, @YES ]) {
+    nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+        nearby::connections::config_package_nearby::nearby_connections_feature::
+            kEnableSharedPeripheralManager,
+        enabled.boolValue);
+    GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+
+    GNCBLEGATTServer *gattServer =
+        [[GNCBLEGATTServer alloc] initWithPeripheralManager:fakePeripheralManager
+                                                      queue:dispatch_get_main_queue()];
+    if (enabled.boolValue) {
+      fakePeripheralManager.peripheralDelegate = gattServer;
+    }
+
+  [fakePeripheralManager simulatePeripheralManagerDidUpdateState:CBManagerStatePoweredOn];
+
+  XCTestExpectation *expectation =
+      [[XCTestExpectation alloc] initWithDescription:@"Create characteristic."];
+
+  CBUUID *serviceUUID = [CBUUID UUIDWithString:kServiceUUID1];
+  CBUUID *characteristicUUID = [CBUUID UUIDWithString:kCharacteristicUUID1];
+  [gattServer createCharacteristicWithServiceID:serviceUUID
+                             characteristicUUID:characteristicUUID
+                                    permissions:CBAttributePermissionsReadable
+                                     properties:CBCharacteristicPropertyRead
+                              completionHandler:^(GNCBLEGATTCharacteristic *characteristic,
+                                                  NSError *error) {
+                                [expectation fulfill];
+                              }];
+
+  [self waitForExpectations:@[ expectation ] timeout:3];
+
   CBUUID *invalidServiceUUID = [CBUUID UUIDWithString:kServiceUUID2];
 
+  // Expectation that we *should not* receive a response.
+  fakePeripheralManager.respondToRequestSuccessExpectation.inverted = YES;
+  fakePeripheralManager.respondToRequestErrorExpectation.inverted = YES;
+
   [fakePeripheralManager
       simulatePeripheralManagerDidReceiveReadRequestForService:invalidServiceUUID
                                                 characteristic:characteristicUUID];
 
-  [self waitForExpectations:@[ fakePeripheralManager.respondToRequestErrorExpectation ] timeout:0];
-}
-
-- (void)testReadRequestInvalidCharacteristic {
-  GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
-
-  GNCBLEGATTServer *gattServer =
-      [[GNCBLEGATTServer alloc] initWithPeripheralManager:fakePeripheralManager];
-
-  [fakePeripheralManager simulatePeripheralManagerDidUpdateState:CBManagerStatePoweredOn];
-
-  XCTestExpectation *expectation =
-      [[XCTestExpectation alloc] initWithDescription:@"Create and update characteristic."];
-
-  CBUUID *serviceUUID = [CBUUID UUIDWithString:kServiceUUID1];
-  CBUUID *characteristicUUID = [CBUUID UUIDWithString:kCharacteristicUUID1];
-  [gattServer createCharacteristicWithServiceID:serviceUUID
-                             characteristicUUID:characteristicUUID
-                                    permissions:CBAttributePermissionsReadable
-                                     properties:CBCharacteristicPropertyRead
-                              completionHandler:^(GNCBLEGATTCharacteristic *characteristic,
-                                                  NSError *error) {
-                                [gattServer updateCharacteristic:characteristic
-                                                           value:[NSData data]
-                                               completionHandler:^(NSError *error) {
-                                                 [expectation fulfill];
-                                               }];
-                              }];
-
-  [self waitForExpectations:@[ expectation ] timeout:3];
-
-  CBUUID *invalidCharacteristicUUID =
-      [CBUUID UUIDWithString:kCharacteristicUUID2];
-
-  [fakePeripheralManager
-      simulatePeripheralManagerDidReceiveReadRequestForService:serviceUUID
-                                                characteristic:invalidCharacteristicUUID];
-
-  [self waitForExpectations:@[ fakePeripheralManager.respondToRequestErrorExpectation ] timeout:0];
+  [self waitForExpectations:@[
+    fakePeripheralManager.respondToRequestSuccessExpectation,
+    fakePeripheralManager.respondToRequestErrorExpectation
+  ]
+                    timeout:3];
+  }
 }
 
 #pragma mark - Stop
 
 - (void)testStop {
-  GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+  for (NSNumber *enabled in @[ @NO, @YES ]) {
+    nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+        nearby::connections::config_package_nearby::nearby_connections_feature::
+            kEnableSharedPeripheralManager,
+        enabled.boolValue);
+    GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
 
-  GNCBLEGATTServer *gattServer =
-      [[GNCBLEGATTServer alloc] initWithPeripheralManager:fakePeripheralManager];
+    GNCBLEGATTServer *gattServer =
+        [[GNCBLEGATTServer alloc] initWithPeripheralManager:fakePeripheralManager
+                                                      queue:dispatch_get_main_queue()];
+    if (enabled.boolValue) {
+      fakePeripheralManager.peripheralDelegate = gattServer;
+    }
 
-  [gattServer stop];
+    [gattServer stop];
 
-  XCTAssertEqual(fakePeripheralManager.services.count, 0);
+    XCTAssertEqual(fakePeripheralManager.services.count, 0);
+  }
 }
 
 #pragma mark - Start Advertising
 
 - (void)testStartAdvertisingNoServiceData {
-  GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+  for (NSNumber *enabled in @[ @NO, @YES ]) {
+    nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+        nearby::connections::config_package_nearby::nearby_connections_feature::
+            kEnableSharedPeripheralManager,
+        enabled.boolValue);
+    GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
 
-  GNCBLEGATTServer *gattServer =
-      [[GNCBLEGATTServer alloc] initWithPeripheralManager:fakePeripheralManager];
+    GNCBLEGATTServer *gattServer =
+        [[GNCBLEGATTServer alloc] initWithPeripheralManager:fakePeripheralManager
+                                                      queue:dispatch_get_main_queue()];
+    if (enabled.boolValue) {
+      fakePeripheralManager.peripheralDelegate = gattServer;
+    }
 
   [fakePeripheralManager simulatePeripheralManagerDidUpdateState:CBManagerStatePoweredOn];
 
@@ -377,13 +532,23 @@ static NSString *const kCharacteristicUUID2 = @"00000000-0000-3000-8000-00000000
                  }];
 
   [self waitForExpectations:@[ expectation ] timeout:3];
+  }
 }
 
 - (void)testStartAdvertisingEmptyServiceData {
-  GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+  for (NSNumber *enabled in @[ @NO, @YES ]) {
+    nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+        nearby::connections::config_package_nearby::nearby_connections_feature::
+            kEnableSharedPeripheralManager,
+        enabled.boolValue);
+    GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
 
-  GNCBLEGATTServer *gattServer =
-      [[GNCBLEGATTServer alloc] initWithPeripheralManager:fakePeripheralManager];
+    GNCBLEGATTServer *gattServer =
+        [[GNCBLEGATTServer alloc] initWithPeripheralManager:fakePeripheralManager
+                                                      queue:dispatch_get_main_queue()];
+    if (enabled.boolValue) {
+      fakePeripheralManager.peripheralDelegate = gattServer;
+    }
 
   [fakePeripheralManager simulatePeripheralManagerDidUpdateState:CBManagerStatePoweredOn];
 
@@ -402,13 +567,23 @@ static NSString *const kCharacteristicUUID2 = @"00000000-0000-3000-8000-00000000
                  }];
 
   [self waitForExpectations:@[ expectation ] timeout:3];
+  }
 }
 
 - (void)testStartAdvertisingShortServiceData {
-  GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+  for (NSNumber *enabled in @[ @NO, @YES ]) {
+    nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+        nearby::connections::config_package_nearby::nearby_connections_feature::
+            kEnableSharedPeripheralManager,
+        enabled.boolValue);
+    GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
 
-  GNCBLEGATTServer *gattServer =
-      [[GNCBLEGATTServer alloc] initWithPeripheralManager:fakePeripheralManager];
+    GNCBLEGATTServer *gattServer =
+        [[GNCBLEGATTServer alloc] initWithPeripheralManager:fakePeripheralManager
+                                                      queue:dispatch_get_main_queue()];
+    if (enabled.boolValue) {
+      fakePeripheralManager.peripheralDelegate = gattServer;
+    }
 
   [fakePeripheralManager simulatePeripheralManagerDidUpdateState:CBManagerStatePoweredOn];
 
@@ -429,13 +604,23 @@ static NSString *const kCharacteristicUUID2 = @"00000000-0000-3000-8000-00000000
                  }];
 
   [self waitForExpectations:@[ expectation ] timeout:3];
+  }
 }
 
 - (void)testStartAdvertising20ByteServiceData {
-  GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+  for (NSNumber *enabled in @[ @NO, @YES ]) {
+    nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+        nearby::connections::config_package_nearby::nearby_connections_feature::
+            kEnableSharedPeripheralManager,
+        enabled.boolValue);
+    GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
 
-  GNCBLEGATTServer *gattServer =
-      [[GNCBLEGATTServer alloc] initWithPeripheralManager:fakePeripheralManager];
+    GNCBLEGATTServer *gattServer =
+        [[GNCBLEGATTServer alloc] initWithPeripheralManager:fakePeripheralManager
+                                                      queue:dispatch_get_main_queue()];
+    if (enabled.boolValue) {
+      fakePeripheralManager.peripheralDelegate = gattServer;
+    }
 
   [fakePeripheralManager simulatePeripheralManagerDidUpdateState:CBManagerStatePoweredOn];
 
@@ -457,13 +642,23 @@ static NSString *const kCharacteristicUUID2 = @"00000000-0000-3000-8000-00000000
                  }];
 
   [self waitForExpectations:@[ expectation ] timeout:3];
+  }
 }
 
 - (void)testStartAdvertisingLongServiceData {
-  GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+  for (NSNumber *enabled in @[ @NO, @YES ]) {
+    nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+        nearby::connections::config_package_nearby::nearby_connections_feature::
+            kEnableSharedPeripheralManager,
+        enabled.boolValue);
+    GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
 
-  GNCBLEGATTServer *gattServer =
-      [[GNCBLEGATTServer alloc] initWithPeripheralManager:fakePeripheralManager];
+    GNCBLEGATTServer *gattServer =
+        [[GNCBLEGATTServer alloc] initWithPeripheralManager:fakePeripheralManager
+                                                      queue:dispatch_get_main_queue()];
+    if (enabled.boolValue) {
+      fakePeripheralManager.peripheralDelegate = gattServer;
+    }
 
   [fakePeripheralManager simulatePeripheralManagerDidUpdateState:CBManagerStatePoweredOn];
 
@@ -482,13 +677,23 @@ static NSString *const kCharacteristicUUID2 = @"00000000-0000-3000-8000-00000000
          }];
 
   [self waitForExpectations:@[ expectation ] timeout:3];
+  }
 }
 
 - (void)testStartAdvertisingWithEmojiServiceData {
-  GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+  for (NSNumber *enabled in @[ @NO, @YES ]) {
+    nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+        nearby::connections::config_package_nearby::nearby_connections_feature::
+            kEnableSharedPeripheralManager,
+        enabled.boolValue);
+    GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
 
-  GNCBLEGATTServer *gattServer =
-      [[GNCBLEGATTServer alloc] initWithPeripheralManager:fakePeripheralManager];
+    GNCBLEGATTServer *gattServer =
+        [[GNCBLEGATTServer alloc] initWithPeripheralManager:fakePeripheralManager
+                                                      queue:dispatch_get_main_queue()];
+    if (enabled.boolValue) {
+      fakePeripheralManager.peripheralDelegate = gattServer;
+    }
 
   [fakePeripheralManager simulatePeripheralManagerDidUpdateState:CBManagerStatePoweredOn];
 
@@ -510,13 +715,23 @@ static NSString *const kCharacteristicUUID2 = @"00000000-0000-3000-8000-00000000
          }];
 
   [self waitForExpectations:@[ expectation ] timeout:3];
+  }
 }
 
 - (void)testStartAdvertisingMultipleServices {
-  GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+  for (NSNumber *enabled in @[ @NO, @YES ]) {
+    nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+        nearby::connections::config_package_nearby::nearby_connections_feature::
+            kEnableSharedPeripheralManager,
+        enabled.boolValue);
+    GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
 
-  GNCBLEGATTServer *gattServer =
-      [[GNCBLEGATTServer alloc] initWithPeripheralManager:fakePeripheralManager];
+    GNCBLEGATTServer *gattServer =
+        [[GNCBLEGATTServer alloc] initWithPeripheralManager:fakePeripheralManager
+                                                      queue:dispatch_get_main_queue()];
+    if (enabled.boolValue) {
+      fakePeripheralManager.peripheralDelegate = gattServer;
+    }
 
   [fakePeripheralManager simulatePeripheralManagerDidUpdateState:CBManagerStatePoweredOn];
 
@@ -536,13 +751,23 @@ static NSString *const kCharacteristicUUID2 = @"00000000-0000-3000-8000-00000000
                  }];
 
   [self waitForExpectations:@[ expectation ] timeout:3];
+  }
 }
 
 - (void)testStartAdvertisingNotPoweredOn {
-  GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+  for (NSNumber *enabled in @[ @NO, @YES ]) {
+    nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+        nearby::connections::config_package_nearby::nearby_connections_feature::
+            kEnableSharedPeripheralManager,
+        enabled.boolValue);
+    GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
 
-  GNCBLEGATTServer *gattServer =
-      [[GNCBLEGATTServer alloc] initWithPeripheralManager:fakePeripheralManager];
+    GNCBLEGATTServer *gattServer =
+        [[GNCBLEGATTServer alloc] initWithPeripheralManager:fakePeripheralManager
+                                                      queue:dispatch_get_main_queue()];
+    if (enabled.boolValue) {
+      fakePeripheralManager.peripheralDelegate = gattServer;
+    }
 
   XCTestExpectation *expectation =
       [[XCTestExpectation alloc] initWithDescription:@"Start advertising."];
@@ -556,13 +781,23 @@ static NSString *const kCharacteristicUUID2 = @"00000000-0000-3000-8000-00000000
                  }];
 
   [self waitForExpectations:@[ expectation ] timeout:3];
+  }
 }
 
 - (void)testStartAdvertisingStartFailure {
-  GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+  for (NSNumber *enabled in @[ @NO, @YES ]) {
+    nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+        nearby::connections::config_package_nearby::nearby_connections_feature::
+            kEnableSharedPeripheralManager,
+        enabled.boolValue);
+    GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
 
-  GNCBLEGATTServer *gattServer =
-      [[GNCBLEGATTServer alloc] initWithPeripheralManager:fakePeripheralManager];
+    GNCBLEGATTServer *gattServer =
+        [[GNCBLEGATTServer alloc] initWithPeripheralManager:fakePeripheralManager
+                                                      queue:dispatch_get_main_queue()];
+    if (enabled.boolValue) {
+      fakePeripheralManager.peripheralDelegate = gattServer;
+    }
 
   fakePeripheralManager.didStartAdvertisingError = [NSError errorWithDomain:@"fake"
                                                                        code:0
@@ -581,13 +816,23 @@ static NSString *const kCharacteristicUUID2 = @"00000000-0000-3000-8000-00000000
                  }];
 
   [self waitForExpectations:@[ expectation ] timeout:3];
+  }
 }
 
 - (void)testStartAdvertisingAlreadyAdvertising {
-  GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+  for (NSNumber *enabled in @[ @NO, @YES ]) {
+    nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+        nearby::connections::config_package_nearby::nearby_connections_feature::
+            kEnableSharedPeripheralManager,
+        enabled.boolValue);
+    GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
 
-  GNCBLEGATTServer *gattServer =
-      [[GNCBLEGATTServer alloc] initWithPeripheralManager:fakePeripheralManager];
+    GNCBLEGATTServer *gattServer =
+        [[GNCBLEGATTServer alloc] initWithPeripheralManager:fakePeripheralManager
+                                                      queue:dispatch_get_main_queue()];
+    if (enabled.boolValue) {
+      fakePeripheralManager.peripheralDelegate = gattServer;
+    }
 
   fakePeripheralManager.didStartAdvertisingError = [NSError errorWithDomain:@"fake"
                                                                        code:0
@@ -608,13 +853,23 @@ static NSString *const kCharacteristicUUID2 = @"00000000-0000-3000-8000-00000000
                  }];
 
   [self waitForExpectations:@[ expectation ] timeout:3];
+  }
 }
 
 - (void)testStartStopStartAdvertising {
-  GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+  for (NSNumber *enabled in @[ @NO, @YES ]) {
+    nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+        nearby::connections::config_package_nearby::nearby_connections_feature::
+            kEnableSharedPeripheralManager,
+        enabled.boolValue);
+    GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
 
-  GNCBLEGATTServer *gattServer =
-      [[GNCBLEGATTServer alloc] initWithPeripheralManager:fakePeripheralManager];
+    GNCBLEGATTServer *gattServer =
+        [[GNCBLEGATTServer alloc] initWithPeripheralManager:fakePeripheralManager
+                                                      queue:dispatch_get_main_queue()];
+    if (enabled.boolValue) {
+      fakePeripheralManager.peripheralDelegate = gattServer;
+    }
 
   [fakePeripheralManager simulatePeripheralManagerDidUpdateState:CBManagerStatePoweredOn];
 
@@ -648,6 +903,9 @@ static NSString *const kCharacteristicUUID2 = @"00000000-0000-3000-8000-00000000
                  }];
 
   [self waitForExpectations:@[ expectation ] timeout:3];
+  }
 }
 
 @end
+
+

internal/platform/implementation/apple/Mediums/BLE/Tests/GNCBLEL2CAPServerTest.m

@@ -1,329 +0,0 @@
-// Copyright 2025 Google LLC
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     https://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-#import "internal/platform/implementation/apple/Mediums/BLE/GNCBLEL2CAPServer.h"
-
-#import <CoreBluetooth/CoreBluetooth.h>
-#import <Foundation/Foundation.h>
-#import <XCTest/XCTest.h>
-
-#import "internal/platform/implementation/apple/Mediums/BLE/Tests/GNCBLEL2CAPServer+Testing.h"
-#import "internal/platform/implementation/apple/Mediums/BLE/Tests/GNCFakePeripheralManager.h"
-
-static const NSTimeInterval kTestTimeout = 1.0;
-
-@interface GNCBLEL2CAPServerTest : XCTestCase
-@end
-
-@implementation GNCBLEL2CAPServerTest
-
-#pragma mark Tests
-
-- (void)testInit {
-  GNCBLEL2CAPServer *l2capServer = [[GNCBLEL2CAPServer alloc] init];
-  XCTAssertNotNil(l2capServer);
-  XCTAssertNil([l2capServer valueForKey:@"_peripheralManager"]);
-}
-
-- (void)testPublishL2CAPChannelAndOpenChannelWhenStartListeningChannel {
-  GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
-  GNCBLEL2CAPServer *l2capServer =
-      [[GNCBLEL2CAPServer alloc] initWithPeripheralManager:fakePeripheralManager
-                                                     queue:dispatch_get_main_queue()];
-  XCTestExpectation *psmPublishedExpectation =
-      [[XCTestExpectation alloc] initWithDescription:@"PSM published."];
-  XCTestExpectation *channelOpenedexpectation =
-      [[XCTestExpectation alloc] initWithDescription:@"Channel opened."];
-  [fakePeripheralManager simulatePeripheralManagerDidUpdateState:CBManagerStatePoweredOn];
-
-  [l2capServer
-      startListeningChannelWithPSMPublishedCompletionHandler:^(uint16_t PSM,
-                                                               NSError *_Nullable error) {
-        XCTAssertEqual(error, nil);
-        XCTAssertEqual(PSM, fakePeripheralManager.PSM);
-        [psmPublishedExpectation fulfill];
-      }
-      channelOpenedCompletionHandler:^(GNCBLEL2CAPStream *_Nullable stream,
-                                       NSError *_Nullable error) {
-        XCTAssertNil(error);
-        XCTAssertNotNil(stream);
-        [channelOpenedexpectation fulfill];
-      }];
-  [self waitForExpectations:@[ psmPublishedExpectation, channelOpenedexpectation ]
-                    timeout:kTestTimeout];
-  XCTAssertNotNil([l2capServer valueForKey:@"l2CAPChannel"]);
-  XCTAssertNotNil([l2capServer valueForKey:@"l2CAPStream"]);
-}
-
-- (void)testFailedToPublishL2CAPChannel {
-  GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
-  fakePeripheralManager.didPublishL2CAPChannelError = [NSError errorWithDomain:@"fake"
-                                                                          code:0
-                                                                      userInfo:nil];
-  GNCBLEL2CAPServer *l2capServer =
-      [[GNCBLEL2CAPServer alloc] initWithPeripheralManager:fakePeripheralManager
-                                                     queue:dispatch_get_main_queue()];
-  XCTestExpectation *psmPublishedExpectation =
-      [[XCTestExpectation alloc] initWithDescription:@"PSM published with error."];
-  [fakePeripheralManager simulatePeripheralManagerDidUpdateState:CBManagerStatePoweredOn];
-
-  [l2capServer
-      startListeningChannelWithPSMPublishedCompletionHandler:^(uint16_t PSM,
-                                                               NSError *_Nullable error) {
-        XCTAssertEqual(error, fakePeripheralManager.didPublishL2CAPChannelError);
-        XCTAssertEqual(PSM, 0);
-        [psmPublishedExpectation fulfill];
-      }
-                              channelOpenedCompletionHandler:^(GNCBLEL2CAPStream *_Nullable stream,
-                                                               NSError *_Nullable error){
-                              }];
-  [self waitForExpectations:@[ psmPublishedExpectation ] timeout:kTestTimeout];
-}
-
-- (void)testPoweredOffUnpublishesChannel {
-  GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
-  GNCBLEL2CAPServer *l2capServer =
-      [[GNCBLEL2CAPServer alloc] initWithPeripheralManager:fakePeripheralManager
-                                                     queue:dispatch_get_main_queue()];
-  [fakePeripheralManager simulatePeripheralManagerDidUpdateState:CBManagerStatePoweredOn];
-
-  [l2capServer
-      startListeningChannelWithPSMPublishedCompletionHandler:^(uint16_t PSM,
-                                                               NSError *_Nullable error) {
-        XCTAssertEqual(error, nil);
-        XCTAssertEqual(PSM, fakePeripheralManager.PSM);
-      }
-                              channelOpenedCompletionHandler:^(GNCBLEL2CAPStream *_Nullable stream,
-                                                               NSError *_Nullable error){
-                              }];
-
-  [fakePeripheralManager simulatePeripheralManagerDidUpdateState:CBManagerStatePoweredOff];
-
-  [self waitForExpectations:@[ fakePeripheralManager.unpublishExpectation ] timeout:kTestTimeout];
-}
-
-- (void)testPeripheralManagerDidUpdateStatePoweredOffUnpublishesChannel {
-  GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
-  GNCBLEL2CAPServer *l2capServer =
-      [[GNCBLEL2CAPServer alloc] initWithPeripheralManager:fakePeripheralManager
-                                                     queue:dispatch_get_main_queue()];
-  fakePeripheralManager.state = CBManagerStatePoweredOn;
-  [(id<CBPeripheralManagerDelegate>)l2capServer
-      peripheralManagerDidUpdateState:(CBPeripheralManager *)fakePeripheralManager];
-
-  [l2capServer
-      startListeningChannelWithPSMPublishedCompletionHandler:^(uint16_t PSM,
-                                                               NSError *_Nullable error) {
-        XCTAssertEqual(error, nil);
-        XCTAssertEqual(PSM, fakePeripheralManager.PSM);
-      }
-                              channelOpenedCompletionHandler:^(GNCBLEL2CAPStream *_Nullable stream,
-                                                               NSError *_Nullable error){
-                              }];
-
-  fakePeripheralManager.state = CBManagerStatePoweredOff;
-  [(id<CBPeripheralManagerDelegate>)l2capServer
-      peripheralManagerDidUpdateState:(CBPeripheralManager *)fakePeripheralManager];
-
-  [self waitForExpectations:@[ fakePeripheralManager.unpublishExpectation ] timeout:kTestTimeout];
-}
-
-- (void)testStartPeripheralManagerInitiallyOff {
-  GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
-  GNCBLEL2CAPServer *l2capServer =
-      [[GNCBLEL2CAPServer alloc] initWithPeripheralManager:fakePeripheralManager
-                                                     queue:dispatch_get_main_queue()];
-  XCTestExpectation *psmPublishedExpectation =
-      [[XCTestExpectation alloc] initWithDescription:@"PSM published."];
-  XCTestExpectation *channelOpenedexpectation =
-      [[XCTestExpectation alloc] initWithDescription:@"Channel opened."];
-
-  [l2capServer
-      startListeningChannelWithPSMPublishedCompletionHandler:^(uint16_t PSM,
-                                                               NSError *_Nullable error) {
-        XCTAssertEqual(error, nil);
-        XCTAssertEqual(PSM, fakePeripheralManager.PSM);
-        [psmPublishedExpectation fulfill];
-      }
-      channelOpenedCompletionHandler:^(GNCBLEL2CAPStream *_Nullable stream,
-                                       NSError *_Nullable error) {
-        [channelOpenedexpectation fulfill];
-      }];
-
-  [fakePeripheralManager simulatePeripheralManagerDidUpdateState:CBManagerStatePoweredOn];
-  [self waitForExpectations:@[ psmPublishedExpectation, channelOpenedexpectation ]
-                    timeout:kTestTimeout];
-}
-
-- (void)testClose {
-  GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
-  GNCBLEL2CAPServer *l2capServer =
-      [[GNCBLEL2CAPServer alloc] initWithPeripheralManager:fakePeripheralManager
-                                                     queue:dispatch_get_main_queue()];
-  [fakePeripheralManager simulatePeripheralManagerDidUpdateState:CBManagerStatePoweredOn];
-
-  [l2capServer
-      startListeningChannelWithPSMPublishedCompletionHandler:^(uint16_t PSM,
-                                                               NSError *_Nullable error) {
-        XCTAssertEqual(error, nil);
-        XCTAssertEqual(PSM, fakePeripheralManager.PSM);
-      }
-                              channelOpenedCompletionHandler:^(GNCBLEL2CAPStream *_Nullable stream,
-                                                               NSError *_Nullable error){
-                              }];
-
-  [l2capServer close];
-
-  XCTAssertEqual([l2capServer PSM], 0);
-}
-
-- (void)testCloseDoesNotUnpublishesChannelIfNotConnected {
-  GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
-  fakePeripheralManager.unpublishExpectation.inverted = YES;
-  GNCBLEL2CAPServer *l2capServer =
-      [[GNCBLEL2CAPServer alloc] initWithPeripheralManager:fakePeripheralManager
-                                                     queue:dispatch_get_main_queue()];
-
-  [l2capServer close];
-
-  [self waitForExpectations:@[ fakePeripheralManager.unpublishExpectation ] timeout:kTestTimeout];
-}
-
-- (void)testFailedToOpenL2CAPChannel {
-  GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
-  fakePeripheralManager.didOpenL2CAPChannelError = [NSError errorWithDomain:@"fake"
-                                                                       code:0
-                                                                   userInfo:nil];
-  GNCBLEL2CAPServer *l2capServer =
-      [[GNCBLEL2CAPServer alloc] initWithPeripheralManager:fakePeripheralManager
-                                                     queue:dispatch_get_main_queue()];
-  XCTestExpectation *channelOpenedexpectation =
-      [[XCTestExpectation alloc] initWithDescription:@"Channel opened."];
-  [fakePeripheralManager simulatePeripheralManagerDidUpdateState:CBManagerStatePoweredOn];
-
-  [l2capServer
-      startListeningChannelWithPSMPublishedCompletionHandler:^(uint16_t PSM,
-                                                               NSError *_Nullable error) {
-        XCTAssertEqual(error, nil);
-        XCTAssertEqual(PSM, fakePeripheralManager.PSM);
-      }
-      channelOpenedCompletionHandler:^(GNCBLEL2CAPStream *_Nullable stream,
-                                       NSError *_Nullable error) {
-        XCTAssertNil(stream);
-        XCTAssertEqual(error, fakePeripheralManager.didOpenL2CAPChannelError);
-        [channelOpenedexpectation fulfill];
-      }];
-  [self waitForExpectations:@[ channelOpenedexpectation ] timeout:kTestTimeout];
-  XCTAssertNil([l2capServer valueForKey:@"l2CAPChannel"]);
-  XCTAssertNil([l2capServer valueForKey:@"l2CAPStream"]);
-}
-
-- (void)testPeripheralManagerDidUnpublishL2CAPChannel {
-  GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
-  GNCBLEL2CAPServer *l2capServer =
-      [[GNCBLEL2CAPServer alloc] initWithPeripheralManager:fakePeripheralManager
-                                                     queue:dispatch_get_main_queue()];
-  [fakePeripheralManager simulatePeripheralManagerDidUpdateState:CBManagerStatePoweredOn];
-  [l2capServer
-      startListeningChannelWithPSMPublishedCompletionHandler:^(uint16_t PSM,
-                                                               NSError *_Nullable error) {
-      }
-                              channelOpenedCompletionHandler:^(GNCBLEL2CAPStream *_Nullable stream,
-                                                               NSError *_Nullable error){
-                              }];
-
-  [(id<CBPeripheralManagerDelegate>)l2capServer
-             peripheralManager:(CBPeripheralManager *)fakePeripheralManager
-      didUnpublishL2CAPChannel:l2capServer.PSM
-                         error:[NSError errorWithDomain:@"fake" code:0 userInfo:nil]];
-
-  XCTAssertEqual(l2capServer.PSM, 0);
-}
-
-- (void)testCloseL2CAPChannel {
-  GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
-  GNCBLEL2CAPServer *l2capServer =
-      [[GNCBLEL2CAPServer alloc] initWithPeripheralManager:fakePeripheralManager
-                                                     queue:dispatch_get_main_queue()];
-  XCTestExpectation *channelOpenedexpectation =
-      [[XCTestExpectation alloc] initWithDescription:@"Channel opened."];
-  [fakePeripheralManager simulatePeripheralManagerDidUpdateState:CBManagerStatePoweredOn];
-  [l2capServer
-      startListeningChannelWithPSMPublishedCompletionHandler:^(uint16_t PSM,
-                                                               NSError *_Nullable error) {
-      }
-      channelOpenedCompletionHandler:^(GNCBLEL2CAPStream *_Nullable stream,
-                                       NSError *_Nullable error) {
-        [channelOpenedexpectation fulfill];
-      }];
-  [self waitForExpectations:@[ channelOpenedexpectation ] timeout:kTestTimeout];
-
-  [l2capServer closeL2CAPChannel];
-
-  XCTAssertNil([l2capServer valueForKey:@"l2CAPChannel"]);
-  XCTAssertNil([l2capServer valueForKey:@"l2CAPStream"]);
-}
-
-- (void)testPeripheralManagerDidPublishL2CAPChannel {
-  GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
-  GNCBLEL2CAPServer *l2capServer =
-      [[GNCBLEL2CAPServer alloc] initWithPeripheralManager:fakePeripheralManager
-                                                     queue:dispatch_get_main_queue()];
-  XCTestExpectation *expectation =
-      [[XCTestExpectation alloc] initWithDescription:@"completion called"];
-  [l2capServer
-      startListeningChannelWithPSMPublishedCompletionHandler:^(uint16_t PSM,
-                                                               NSError *_Nullable error) {
-        XCTAssertEqual(PSM, 1);
-        XCTAssertNil(error);
-        [expectation fulfill];
-      }
-                              channelOpenedCompletionHandler:^(GNCBLEL2CAPStream *_Nullable stream,
-                                                               NSError *_Nullable error){
-                              }];
-  [(id<CBPeripheralManagerDelegate>)l2capServer
-           peripheralManager:(CBPeripheralManager *)fakePeripheralManager
-      didPublishL2CAPChannel:1
-                       error:nil];
-  [self waitForExpectations:@[ expectation ] timeout:kTestTimeout];
-  XCTAssertEqual(l2capServer.PSM, 1);
-}
-
-- (void)testPeripheralManagerDidPublishL2CAPChannelWithError {
-  GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
-  GNCBLEL2CAPServer *l2capServer =
-      [[GNCBLEL2CAPServer alloc] initWithPeripheralManager:fakePeripheralManager
-                                                     queue:dispatch_get_main_queue()];
-  XCTestExpectation *expectation =
-      [[XCTestExpectation alloc] initWithDescription:@"completion called"];
-  NSError *publishError = [NSError errorWithDomain:@"test" code:0 userInfo:nil];
-  [l2capServer
-      startListeningChannelWithPSMPublishedCompletionHandler:^(uint16_t PSM,
-                                                               NSError *_Nullable error) {
-        XCTAssertEqual(PSM, 0);
-        XCTAssertEqualObjects(error, publishError);
-        [expectation fulfill];
-      }
-                              channelOpenedCompletionHandler:^(GNCBLEL2CAPStream *_Nullable stream,
-                                                               NSError *_Nullable error){
-                              }];
-  [(id<CBPeripheralManagerDelegate>)l2capServer
-           peripheralManager:(CBPeripheralManager *)fakePeripheralManager
-      didPublishL2CAPChannel:0
-                       error:publishError];
-  [self waitForExpectations:@[ expectation ] timeout:kTestTimeout];
-  XCTAssertEqual(l2capServer.PSM, 0);
-}
-
-@end

internal/platform/implementation/apple/Mediums/BLE/Tests/GNCBLEL2CAPServerTest.mm

@@ -0,0 +1,485 @@
+// Copyright 2025 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#import "internal/platform/implementation/apple/Mediums/BLE/GNCBLEL2CAPServer.h"
+
+#import <CoreBluetooth/CoreBluetooth.h>
+#import <Foundation/Foundation.h>
+#import <XCTest/XCTest.h>
+
+#import "internal/platform/implementation/apple/Mediums/BLE/Tests/GNCBLEL2CAPServer+Testing.h"
+#import "internal/platform/implementation/apple/Mediums/BLE/Tests/GNCFakePeripheralManager.h"
+
+#include "connections/implementation/flags/nearby_connections_feature_flags.h"
+#include "internal/flags/nearby_flags.h"
+
+static const NSTimeInterval kTestTimeout = 1.0;
+
+@interface GNCBLEL2CAPServerTest : XCTestCase
+@end
+
+@implementation GNCBLEL2CAPServerTest
+
+#pragma mark Tests
+
+- (void)tearDown {
+  nearby::NearbyFlags::GetInstance().ResetOverridedValues();
+  [super tearDown];
+}
+
+- (void)testInit_setsDelegateCorrectlyBasedOnFlag {
+  for (NSNumber *enabled in @[ @NO, @YES ]) {
+    nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+        nearby::connections::config_package_nearby::nearby_connections_feature::
+            kEnableSharedPeripheralManager,
+        enabled.boolValue);
+
+    GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+    GNCBLEL2CAPServer *server =
+        [[GNCBLEL2CAPServer alloc] initWithPeripheralManager:fakePeripheralManager
+                                                       queue:dispatch_get_main_queue()];
+
+    if (enabled.boolValue) {
+      // In shared mode, functionality is delegated to the multiplexer, so the server should NOT
+      // self-assign as delegate.
+      XCTAssertNil(fakePeripheralManager.peripheralDelegate);
+    } else {
+      // In legacy mode, the server owns the manager and sets itself as delegate.
+      XCTAssertEqual(fakePeripheralManager.peripheralDelegate, server);
+    }
+  }
+}
+
+- (void)testInit_throwsWithNilManagerWhenFlagEnabled {
+  nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+      nearby::connections::config_package_nearby::nearby_connections_feature::
+          kEnableSharedPeripheralManager,
+      true);
+
+  XCTAssertThrowsSpecificNamed(
+      [[GNCBLEL2CAPServer alloc] initWithPeripheralManager:(id<GNCPeripheralManager>)nil
+                                                     queue:dispatch_get_main_queue()],
+      NSException, NSInvalidArgumentException);
+}
+
+- (void)testPublishL2CAPChannelAndOpenChannelWhenStartListeningChannel {
+  for (NSNumber *enabled in @[ @NO, @YES ]) {
+    nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+        nearby::connections::config_package_nearby::nearby_connections_feature::
+            kEnableSharedPeripheralManager,
+        enabled.boolValue);
+    GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+    GNCBLEL2CAPServer *l2capServer =
+        [[GNCBLEL2CAPServer alloc] initWithPeripheralManager:fakePeripheralManager
+                                                       queue:dispatch_get_main_queue()];
+    if (enabled.boolValue) {
+      fakePeripheralManager.peripheralDelegate = l2capServer;
+    }
+
+    XCTestExpectation *psmPublishedExpectation =
+        [[XCTestExpectation alloc] initWithDescription:@"PSM published."];
+    XCTestExpectation *channelOpenedexpectation =
+        [[XCTestExpectation alloc] initWithDescription:@"Channel opened."];
+    [fakePeripheralManager simulatePeripheralManagerDidUpdateState:CBManagerStatePoweredOn];
+
+    [l2capServer
+        startListeningChannelWithPSMPublishedCompletionHandler:^(uint16_t PSM,
+                                                                 NSError *_Nullable error) {
+          XCTAssertEqual(error, nil);
+          XCTAssertEqual(PSM, fakePeripheralManager.PSM);
+          [psmPublishedExpectation fulfill];
+        }
+        channelOpenedCompletionHandler:^(GNCBLEL2CAPStream *_Nullable stream,
+                                         NSError *_Nullable error) {
+          XCTAssertNil(error);
+          XCTAssertNotNil(stream);
+          [channelOpenedexpectation fulfill];
+        }];
+    [self waitForExpectations:@[ psmPublishedExpectation, channelOpenedexpectation ]
+                      timeout:kTestTimeout];
+    XCTAssertNotNil([l2capServer valueForKey:@"l2CAPChannel"]);
+    XCTAssertNotNil([l2capServer valueForKey:@"l2CAPStream"]);
+  }
+}
+
+- (void)testFailedToPublishL2CAPChannel {
+  for (NSNumber *enabled in @[ @NO, @YES ]) {
+    nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+        nearby::connections::config_package_nearby::nearby_connections_feature::
+            kEnableSharedPeripheralManager,
+        enabled.boolValue);
+    GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+    fakePeripheralManager.didPublishL2CAPChannelError = [NSError errorWithDomain:@"fake"
+                                                                            code:0
+                                                                        userInfo:nil];
+    GNCBLEL2CAPServer *l2capServer =
+        [[GNCBLEL2CAPServer alloc] initWithPeripheralManager:fakePeripheralManager
+                                                       queue:dispatch_get_main_queue()];
+    if (enabled.boolValue) {
+      fakePeripheralManager.peripheralDelegate = l2capServer;
+    }
+
+    XCTestExpectation *psmPublishedExpectation =
+        [[XCTestExpectation alloc] initWithDescription:@"PSM published with error."];
+    [fakePeripheralManager simulatePeripheralManagerDidUpdateState:CBManagerStatePoweredOn];
+
+    [l2capServer
+        startListeningChannelWithPSMPublishedCompletionHandler:^(uint16_t PSM,
+                                                                 NSError *_Nullable error) {
+          XCTAssertEqual(error, fakePeripheralManager.didPublishL2CAPChannelError);
+          XCTAssertEqual(PSM, 0);
+          [psmPublishedExpectation fulfill];
+        }
+                                channelOpenedCompletionHandler:^(GNCBLEL2CAPStream *_Nullable stream,
+                                                                 NSError *_Nullable error){
+                                }];
+    [self waitForExpectations:@[ psmPublishedExpectation ] timeout:kTestTimeout];
+  }
+}
+
+- (void)testPoweredOffUnpublishesChannel {
+  for (NSNumber *enabled in @[ @NO, @YES ]) {
+    nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+        nearby::connections::config_package_nearby::nearby_connections_feature::
+            kEnableSharedPeripheralManager,
+        enabled.boolValue);
+    GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+    GNCBLEL2CAPServer *l2capServer =
+        [[GNCBLEL2CAPServer alloc] initWithPeripheralManager:fakePeripheralManager
+                                                       queue:dispatch_get_main_queue()];
+    if (enabled.boolValue) {
+      fakePeripheralManager.peripheralDelegate = l2capServer;
+    }
+
+    [fakePeripheralManager simulatePeripheralManagerDidUpdateState:CBManagerStatePoweredOn];
+
+    [l2capServer
+        startListeningChannelWithPSMPublishedCompletionHandler:^(uint16_t PSM,
+                                                                 NSError *_Nullable error) {
+          XCTAssertEqual(error, nil);
+          XCTAssertEqual(PSM, fakePeripheralManager.PSM);
+        }
+                                channelOpenedCompletionHandler:^(GNCBLEL2CAPStream *_Nullable stream,
+                                                                 NSError *_Nullable error){
+                                }];
+
+    [fakePeripheralManager simulatePeripheralManagerDidUpdateState:CBManagerStatePoweredOff];
+
+    [self waitForExpectations:@[ fakePeripheralManager.unpublishExpectation ] timeout:kTestTimeout];
+  }
+}
+
+- (void)testPeripheralManagerDidUpdateStatePoweredOffUnpublishesChannel {
+  for (NSNumber *enabled in @[ @NO, @YES ]) {
+    nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+        nearby::connections::config_package_nearby::nearby_connections_feature::
+            kEnableSharedPeripheralManager,
+        enabled.boolValue);
+    GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+    GNCBLEL2CAPServer *l2capServer =
+        [[GNCBLEL2CAPServer alloc] initWithPeripheralManager:fakePeripheralManager
+                                                       queue:dispatch_get_main_queue()];
+    if (enabled.boolValue) {
+      fakePeripheralManager.peripheralDelegate = l2capServer;
+    }
+    fakePeripheralManager.state = CBManagerStatePoweredOn;
+    [(id<CBPeripheralManagerDelegate>)l2capServer
+        peripheralManagerDidUpdateState:(CBPeripheralManager *)fakePeripheralManager];
+
+    [l2capServer
+        startListeningChannelWithPSMPublishedCompletionHandler:^(uint16_t PSM,
+                                                                 NSError *_Nullable error) {
+          XCTAssertEqual(error, nil);
+          XCTAssertEqual(PSM, fakePeripheralManager.PSM);
+        }
+                                channelOpenedCompletionHandler:^(GNCBLEL2CAPStream *_Nullable stream,
+                                                                 NSError *_Nullable error){
+                                }];
+
+    fakePeripheralManager.state = CBManagerStatePoweredOff;
+    [(id<CBPeripheralManagerDelegate>)l2capServer
+        peripheralManagerDidUpdateState:(CBPeripheralManager *)fakePeripheralManager];
+
+    [self waitForExpectations:@[ fakePeripheralManager.unpublishExpectation ] timeout:kTestTimeout];
+  }
+}
+
+- (void)testStartPeripheralManagerInitiallyOff {
+  for (NSNumber *enabled in @[ @NO, @YES ]) {
+    nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+        nearby::connections::config_package_nearby::nearby_connections_feature::
+            kEnableSharedPeripheralManager,
+        enabled.boolValue);
+    GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+    GNCBLEL2CAPServer *l2capServer =
+        [[GNCBLEL2CAPServer alloc] initWithPeripheralManager:fakePeripheralManager
+                                                       queue:dispatch_get_main_queue()];
+    if (enabled.boolValue) {
+      fakePeripheralManager.peripheralDelegate = l2capServer;
+    }
+
+    XCTestExpectation *psmPublishedExpectation =
+        [[XCTestExpectation alloc] initWithDescription:@"PSM published."];
+    XCTestExpectation *channelOpenedexpectation =
+        [[XCTestExpectation alloc] initWithDescription:@"Channel opened."];
+
+    [l2capServer
+        startListeningChannelWithPSMPublishedCompletionHandler:^(uint16_t PSM,
+                                                                 NSError *_Nullable error) {
+          XCTAssertEqual(error, nil);
+          XCTAssertEqual(PSM, fakePeripheralManager.PSM);
+          [psmPublishedExpectation fulfill];
+        }
+        channelOpenedCompletionHandler:^(GNCBLEL2CAPStream *_Nullable stream,
+                                         NSError *_Nullable error) {
+          [channelOpenedexpectation fulfill];
+        }];
+
+    [fakePeripheralManager simulatePeripheralManagerDidUpdateState:CBManagerStatePoweredOn];
+    [self waitForExpectations:@[ psmPublishedExpectation, channelOpenedexpectation ]
+                      timeout:kTestTimeout];
+  }
+}
+
+- (void)testClose {
+  for (NSNumber *enabled in @[ @NO, @YES ]) {
+    nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+        nearby::connections::config_package_nearby::nearby_connections_feature::
+            kEnableSharedPeripheralManager,
+        enabled.boolValue);
+    GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+    GNCBLEL2CAPServer *l2capServer =
+        [[GNCBLEL2CAPServer alloc] initWithPeripheralManager:fakePeripheralManager
+                                                       queue:dispatch_get_main_queue()];
+    if (enabled.boolValue) {
+      fakePeripheralManager.peripheralDelegate = l2capServer;
+    }
+
+    [fakePeripheralManager simulatePeripheralManagerDidUpdateState:CBManagerStatePoweredOn];
+
+    [l2capServer
+        startListeningChannelWithPSMPublishedCompletionHandler:^(uint16_t PSM,
+                                                                 NSError *_Nullable error) {
+          XCTAssertEqual(error, nil);
+          XCTAssertEqual(PSM, fakePeripheralManager.PSM);
+        }
+                                channelOpenedCompletionHandler:^(GNCBLEL2CAPStream *_Nullable stream,
+                                                                 NSError *_Nullable error){
+                                }];
+
+    [l2capServer close];
+
+    XCTAssertEqual([l2capServer PSM], 0);
+  }
+}
+
+- (void)testCloseDoesNotUnpublishesChannelIfNotConnected {
+  for (NSNumber *enabled in @[ @NO, @YES ]) {
+    nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+        nearby::connections::config_package_nearby::nearby_connections_feature::
+            kEnableSharedPeripheralManager,
+        enabled.boolValue);
+    GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+    fakePeripheralManager.unpublishExpectation.inverted = YES;
+    GNCBLEL2CAPServer *l2capServer =
+        [[GNCBLEL2CAPServer alloc] initWithPeripheralManager:fakePeripheralManager
+                                                       queue:dispatch_get_main_queue()];
+    if (enabled.boolValue) {
+      fakePeripheralManager.peripheralDelegate = l2capServer;
+    }
+
+    [l2capServer close];
+
+    [self waitForExpectations:@[ fakePeripheralManager.unpublishExpectation ] timeout:kTestTimeout];
+  }
+}
+
+- (void)testFailedToOpenL2CAPChannel {
+  for (NSNumber *enabled in @[ @NO, @YES ]) {
+    nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+        nearby::connections::config_package_nearby::nearby_connections_feature::
+            kEnableSharedPeripheralManager,
+        enabled.boolValue);
+    GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+    fakePeripheralManager.didOpenL2CAPChannelError = [NSError errorWithDomain:@"fake"
+                                                                         code:0
+                                                                     userInfo:nil];
+    GNCBLEL2CAPServer *l2capServer =
+        [[GNCBLEL2CAPServer alloc] initWithPeripheralManager:fakePeripheralManager
+                                                       queue:dispatch_get_main_queue()];
+    if (enabled.boolValue) {
+      fakePeripheralManager.peripheralDelegate = l2capServer;
+    }
+
+    XCTestExpectation *channelOpenedexpectation =
+        [[XCTestExpectation alloc] initWithDescription:@"Channel opened."];
+    [fakePeripheralManager simulatePeripheralManagerDidUpdateState:CBManagerStatePoweredOn];
+
+    [l2capServer
+        startListeningChannelWithPSMPublishedCompletionHandler:^(uint16_t PSM,
+                                                                 NSError *_Nullable error) {
+          XCTAssertEqual(error, nil);
+          XCTAssertEqual(PSM, fakePeripheralManager.PSM);
+        }
+        channelOpenedCompletionHandler:^(GNCBLEL2CAPStream *_Nullable stream,
+                                         NSError *_Nullable error) {
+          XCTAssertNil(stream);
+          XCTAssertEqual(error, fakePeripheralManager.didOpenL2CAPChannelError);
+          [channelOpenedexpectation fulfill];
+        }];
+    [self waitForExpectations:@[ channelOpenedexpectation ] timeout:kTestTimeout];
+    XCTAssertNil([l2capServer valueForKey:@"l2CAPChannel"]);
+    XCTAssertNil([l2capServer valueForKey:@"l2CAPStream"]);
+  }
+}
+
+- (void)testPeripheralManagerDidUnpublishL2CAPChannel {
+  for (NSNumber *enabled in @[ @NO, @YES ]) {
+    nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+        nearby::connections::config_package_nearby::nearby_connections_feature::
+            kEnableSharedPeripheralManager,
+        enabled.boolValue);
+    GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+    GNCBLEL2CAPServer *l2capServer =
+        [[GNCBLEL2CAPServer alloc] initWithPeripheralManager:fakePeripheralManager
+                                                       queue:dispatch_get_main_queue()];
+    if (enabled.boolValue) {
+      fakePeripheralManager.peripheralDelegate = l2capServer;
+    }
+
+    [fakePeripheralManager simulatePeripheralManagerDidUpdateState:CBManagerStatePoweredOn];
+    [l2capServer
+        startListeningChannelWithPSMPublishedCompletionHandler:^(uint16_t PSM,
+                                                                 NSError *_Nullable error) {
+        }
+                                channelOpenedCompletionHandler:^(GNCBLEL2CAPStream *_Nullable stream,
+                                                                 NSError *_Nullable error){
+                                }];
+
+    [(id<CBPeripheralManagerDelegate>)l2capServer
+               peripheralManager:(CBPeripheralManager *)fakePeripheralManager
+        didUnpublishL2CAPChannel:l2capServer.PSM
+                           error:[NSError errorWithDomain:@"fake" code:0 userInfo:nil]];
+
+    XCTAssertEqual(l2capServer.PSM, 0);
+  }
+}
+
+- (void)testCloseL2CAPChannel {
+  for (NSNumber *enabled in @[ @NO, @YES ]) {
+    nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+        nearby::connections::config_package_nearby::nearby_connections_feature::
+            kEnableSharedPeripheralManager,
+        enabled.boolValue);
+    GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+    GNCBLEL2CAPServer *l2capServer =
+        [[GNCBLEL2CAPServer alloc] initWithPeripheralManager:fakePeripheralManager
+                                                       queue:dispatch_get_main_queue()];
+    if (enabled.boolValue) {
+      fakePeripheralManager.peripheralDelegate = l2capServer;
+    }
+
+    XCTestExpectation *channelOpenedexpectation =
+        [[XCTestExpectation alloc] initWithDescription:@"Channel opened."];
+    [fakePeripheralManager simulatePeripheralManagerDidUpdateState:CBManagerStatePoweredOn];
+    [l2capServer
+        startListeningChannelWithPSMPublishedCompletionHandler:^(uint16_t PSM,
+                                                                 NSError *_Nullable error) {
+        }
+        channelOpenedCompletionHandler:^(GNCBLEL2CAPStream *_Nullable stream,
+                                         NSError *_Nullable error) {
+          [channelOpenedexpectation fulfill];
+        }];
+    [self waitForExpectations:@[ channelOpenedexpectation ] timeout:kTestTimeout];
+
+    [l2capServer closeL2CAPChannel];
+
+    XCTAssertNil([l2capServer valueForKey:@"l2CAPChannel"]);
+    XCTAssertNil([l2capServer valueForKey:@"l2CAPStream"]);
+  }
+}
+
+- (void)testPeripheralManagerDidPublishL2CAPChannel {
+  for (NSNumber *enabled in @[ @NO, @YES ]) {
+    nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+        nearby::connections::config_package_nearby::nearby_connections_feature::
+            kEnableSharedPeripheralManager,
+        enabled.boolValue);
+    GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+    GNCBLEL2CAPServer *l2capServer =
+        [[GNCBLEL2CAPServer alloc] initWithPeripheralManager:fakePeripheralManager
+                                                       queue:dispatch_get_main_queue()];
+    if (enabled.boolValue) {
+      fakePeripheralManager.peripheralDelegate = l2capServer;
+    }
+
+    XCTestExpectation *expectation =
+        [[XCTestExpectation alloc] initWithDescription:@"completion called"];
+    [l2capServer
+        startListeningChannelWithPSMPublishedCompletionHandler:^(uint16_t PSM,
+                                                                 NSError *_Nullable error) {
+          XCTAssertEqual(PSM, 1);
+          XCTAssertNil(error);
+          [expectation fulfill];
+        }
+                                channelOpenedCompletionHandler:^(GNCBLEL2CAPStream *_Nullable stream,
+                                                                 NSError *_Nullable error){
+                                }];
+    [(id<CBPeripheralManagerDelegate>)l2capServer
+             peripheralManager:(CBPeripheralManager *)fakePeripheralManager
+        didPublishL2CAPChannel:1
+                         error:nil];
+    [self waitForExpectations:@[ expectation ] timeout:kTestTimeout];
+    XCTAssertEqual(l2capServer.PSM, 1);
+  }
+}
+
+- (void)testPeripheralManagerDidPublishL2CAPChannelWithError {
+  for (NSNumber *enabled in @[ @NO, @YES ]) {
+    nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+        nearby::connections::config_package_nearby::nearby_connections_feature::
+            kEnableSharedPeripheralManager,
+        enabled.boolValue);
+    GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+    GNCBLEL2CAPServer *l2capServer =
+        [[GNCBLEL2CAPServer alloc] initWithPeripheralManager:fakePeripheralManager
+                                                       queue:dispatch_get_main_queue()];
+    if (enabled.boolValue) {
+      fakePeripheralManager.peripheralDelegate = l2capServer;
+    }
+
+    XCTestExpectation *expectation =
+        [[XCTestExpectation alloc] initWithDescription:@"completion called"];
+    NSError *publishError = [NSError errorWithDomain:@"test" code:0 userInfo:nil];
+    [l2capServer
+        startListeningChannelWithPSMPublishedCompletionHandler:^(uint16_t PSM,
+                                                                 NSError *_Nullable error) {
+          XCTAssertEqual(PSM, 0);
+          XCTAssertEqualObjects(error, publishError);
+          [expectation fulfill];
+        }
+                                channelOpenedCompletionHandler:^(GNCBLEL2CAPStream *_Nullable stream,
+                                                                 NSError *_Nullable error){
+                                }];
+    [(id<CBPeripheralManagerDelegate>)l2capServer
+             peripheralManager:(CBPeripheralManager *)fakePeripheralManager
+        didPublishL2CAPChannel:0
+                         error:publishError];
+    [self waitForExpectations:@[ expectation ] timeout:kTestTimeout];
+    XCTAssertEqual(l2capServer.PSM, 0);
+  }
+}
+
+@end
+

internal/platform/implementation/apple/Mediums/BLE/Tests/GNCBLEMedium+Testing.h

@@ -24,16 +24,19 @@ NS_ASSUME_NONNULL_BEGIN
 @interface GNCBLEMedium (Testing)
 
 /**
- * Creates a BLE Medium with a provided central manager.
+ * Creates a BLE Medium with a provided central manager and peripheral manager.
  *
- * This is only exposed for testing and can be used to inject a fake central manager.
+ * This is only exposed for tests and can be used to inject a fake central manager and
+ * peripheral manager.
  *
  * @param centralManager The central manager instance.
+ * @param peripheralManager The peripheral manager instance.
  * @param queue The queue to run on, this must match the queue that the central manager's delegate
- *              is running on. Defaults to the main queue when @c nil.
+ *              is running on.
  */
 - (instancetype)initWithCentralManager:(id<GNCCentralManager>)centralManager
-                                 queue:(nullable dispatch_queue_t)queue;
+                     peripheralManager:(nullable id<GNCPeripheralManager>)peripheralManager
+                                 queue:(dispatch_queue_t)queue;
 
 - (NSDictionary<CBUUID *, NSData *> *)decodeAdvertisementData:
     (NSDictionary<NSString *, id> *)advertisementData;

internal/platform/implementation/apple/Mediums/BLE/Tests/GNCBLEMediumTest.m

@@ -1,404 +0,0 @@
-// Copyright 2023 Google LLC
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     https://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-#import "internal/platform/implementation/apple/Mediums/BLE/GNCBLEMedium.h"
-
-#import <CoreBluetooth/CoreBluetooth.h>
-#import <Foundation/Foundation.h>
-#import <XCTest/XCTest.h>
-
-#import "internal/platform/implementation/apple/Mediums/BLE/GNCBLEGATTClient.h"
-#import "internal/platform/implementation/apple/Mediums/BLE/GNCBLEGATTServer.h"
-#import "internal/platform/implementation/apple/Mediums/BLE/GNCPeripheral.h"
-#import "internal/platform/implementation/apple/Mediums/BLE/Tests/GNCBLEL2CAPClient+Testing.h"
-#import "internal/platform/implementation/apple/Mediums/BLE/Tests/GNCBLEMedium+Testing.h"
-#import "internal/platform/implementation/apple/Mediums/BLE/Tests/GNCFakeCentralManager.h"
-#import "internal/platform/implementation/apple/Mediums/BLE/Tests/GNCFakePeripheral.h"
-#import "internal/platform/implementation/apple/Mediums/BLE/Tests/GNCFakePeripheralManager.h"
-
-static NSString *const kServiceUUID = @"0000FEF3-0000-1000-8000-00805F9B34FB";
-
-@interface GNCBLEMediumTest : XCTestCase
-@end
-
-@implementation GNCBLEMediumTest
-
-#pragma mark - Supports Extended Advertisements
-
-- (void)testSupportsExtendedAdvertisements {
-  GNCFakeCentralManager *fakeCentralManager = [[GNCFakeCentralManager alloc] init];
-
-  GNCBLEMedium *medium = [[GNCBLEMedium alloc] initWithCentralManager:fakeCentralManager queue:nil];
-
-  XCTAssertFalse([medium supportsExtendedAdvertisements]);
-}
-
-#pragma mark - Start Scanning
-
-- (void)testStartScanning {
-  GNCFakeCentralManager *fakeCentralManager = [[GNCFakeCentralManager alloc] init];
-  GNCBLEMedium *medium = [[GNCBLEMedium alloc] initWithCentralManager:fakeCentralManager queue:nil];
-  XCTestExpectation *startScanningExpectation =
-      [[XCTestExpectation alloc] initWithDescription:@"Start scanning."];
-  XCTestExpectation *advertisementFoundExpectation =
-      [[XCTestExpectation alloc] initWithDescription:@"Advertisement found."];
-  CBUUID *serviceUUID = [CBUUID UUIDWithString:kServiceUUID];
-
-  [fakeCentralManager simulateCentralManagerDidUpdateState:CBManagerStatePoweredOn];
-
-  [medium startScanningForService:serviceUUID
-      advertisementFoundHandler:^(id<GNCPeripheral> peripheral,
-                                  NSDictionary<CBUUID *, NSData *> *data) {
-        NSDictionary<CBUUID *, NSData *> *expected = @{
-          serviceUUID : [@"test" dataUsingEncoding:NSUTF8StringEncoding],
-        };
-        XCTAssertEqualObjects(expected, data);
-        [advertisementFoundExpectation fulfill];
-      }
-      completionHandler:^(NSError *error) {
-        XCTAssertNil(error);
-        [startScanningExpectation fulfill];
-      }];
-
-  [self waitForExpectations:@[ startScanningExpectation ] timeout:3];
-
-  XCTAssertEqualObjects(@[ serviceUUID ], fakeCentralManager.serviceUUIDs);
-
-  [fakeCentralManager
-      simulateCentralManagerDidDiscoverPeripheral:[[GNCFakePeripheral alloc] init]
-                                advertisementData:@{
-                                  CBAdvertisementDataLocalNameKey : @"dGVzdA",
-                                  CBAdvertisementDataServiceUUIDsKey : @[ serviceUUID ],
-                                }];
-
-  [self waitForExpectations:@[ advertisementFoundExpectation ] timeout:3];
-}
-
-- (void)testAlreadyScanning {
-  GNCFakeCentralManager *fakeCentralManager = [[GNCFakeCentralManager alloc] init];
-  GNCBLEMedium *medium = [[GNCBLEMedium alloc] initWithCentralManager:fakeCentralManager queue:nil];
-  XCTestExpectation *expectation =
-      [[XCTestExpectation alloc] initWithDescription:@"Start scanning."];
-
-  [medium startScanningForService:[CBUUID UUIDWithString:kServiceUUID]
-        advertisementFoundHandler:^(id<GNCPeripheral> peripheral,
-                                    NSDictionary<CBUUID *, NSData *> *data) {
-        }
-                completionHandler:nil];
-
-  [medium startScanningForService:[CBUUID UUIDWithString:kServiceUUID]
-      advertisementFoundHandler:^(id<GNCPeripheral> peripheral,
-                                  NSDictionary<CBUUID *, NSData *> *data) {
-      }
-      completionHandler:^(NSError *error) {
-        XCTAssertNotNil(error);
-        [expectation fulfill];
-      }];
-
-  [self waitForExpectations:@[ expectation ] timeout:3];
-}
-
-- (void)testStartStopStartScanning {
-  GNCFakeCentralManager *fakeCentralManager = [[GNCFakeCentralManager alloc] init];
-  GNCBLEMedium *medium = [[GNCBLEMedium alloc] initWithCentralManager:fakeCentralManager queue:nil];
-  XCTestExpectation *expectation =
-      [[XCTestExpectation alloc] initWithDescription:@"Start scanning."];
-
-  CBUUID *serviceUUID = [CBUUID UUIDWithString:kServiceUUID];
-
-  [medium startScanningForService:serviceUUID
-      advertisementFoundHandler:^(id<GNCPeripheral> peripheral,
-                                  NSDictionary<CBUUID *, NSData *> *data) {
-      }
-      completionHandler:^(NSError *error) {
-        XCTAssertNil(error);
-        [medium stopScanningWithCompletionHandler:^(NSError *error) {
-          XCTAssertNil(error);
-          [medium startScanningForService:serviceUUID
-              advertisementFoundHandler:^(id<GNCPeripheral> peripheral,
-                                          NSDictionary<CBUUID *, NSData *> *data) {
-              }
-              completionHandler:^(NSError *error) {
-                XCTAssertNil(error);
-                [expectation fulfill];
-              }];
-        }];
-      }];
-
-  [self waitForExpectations:@[ expectation ] timeout:3];
-}
-
-#pragma mark - Decode Advertisement Data
-
-- (void)testDecodeAndroidStyleAdvertisementData {
-  GNCFakeCentralManager *fakeCentralManager = [[GNCFakeCentralManager alloc] init];
-  GNCBLEMedium *medium = [[GNCBLEMedium alloc] initWithCentralManager:fakeCentralManager queue:nil];
-  CBUUID *serviceUUID = [CBUUID UUIDWithString:kServiceUUID];
-
-  NSDictionary<CBUUID *, NSData *> *expected = @{
-    serviceUUID : [@"test" dataUsingEncoding:NSUTF8StringEncoding],
-  };
-
-  NSDictionary<NSString *, id> *data = @{
-    CBAdvertisementDataServiceDataKey : @{
-      serviceUUID : [@"test" dataUsingEncoding:NSUTF8StringEncoding],
-    },
-  };
-  NSDictionary<CBUUID *, NSData *> *actual = [medium decodeAdvertisementData:data];
-
-  XCTAssertEqualObjects(expected, actual);
-}
-
-- (void)testDecodeAndroidStyleAdvertisementDataWithLocalName {
-  GNCFakeCentralManager *fakeCentralManager = [[GNCFakeCentralManager alloc] init];
-  GNCBLEMedium *medium = [[GNCBLEMedium alloc] initWithCentralManager:fakeCentralManager queue:nil];
-  CBUUID *serviceUUID = [CBUUID UUIDWithString:kServiceUUID];
-
-  NSDictionary<CBUUID *, NSData *> *expected = @{
-    serviceUUID : [@"test" dataUsingEncoding:NSUTF8StringEncoding],
-  };
-
-  NSDictionary<NSString *, id> *data = @{
-    CBAdvertisementDataLocalNameKey : @"Nearby",  // Just happens to be base64 decodable.
-    CBAdvertisementDataServiceUUIDsKey : @[ serviceUUID ],
-    CBAdvertisementDataServiceDataKey : @{
-      serviceUUID : [@"test" dataUsingEncoding:NSUTF8StringEncoding],
-    },
-  };
-  NSDictionary<CBUUID *, NSData *> *actual = [medium decodeAdvertisementData:data];
-
-  XCTAssertEqualObjects(expected, actual);
-}
-
-- (void)testDecodeAppleStyleAdvertisementData {
-  GNCFakeCentralManager *fakeCentralManager = [[GNCFakeCentralManager alloc] init];
-  GNCBLEMedium *medium = [[GNCBLEMedium alloc] initWithCentralManager:fakeCentralManager queue:nil];
-  CBUUID *serviceUUID = [CBUUID UUIDWithString:kServiceUUID];
-
-  NSDictionary<CBUUID *, NSData *> *expected = @{
-    serviceUUID : [@"test" dataUsingEncoding:NSUTF8StringEncoding],
-  };
-
-  NSDictionary<NSString *, id> *data = @{
-    CBAdvertisementDataLocalNameKey : @"dGVzdA",
-    CBAdvertisementDataServiceUUIDsKey : @[ serviceUUID ],
-  };
-  NSDictionary<CBUUID *, NSData *> *actual = [medium decodeAdvertisementData:data];
-
-  XCTAssertEqualObjects(expected, actual);
-}
-
-- (void)testDecodeInvalidAdvertisementData {
-  GNCFakeCentralManager *fakeCentralManager = [[GNCFakeCentralManager alloc] init];
-  GNCBLEMedium *medium = [[GNCBLEMedium alloc] initWithCentralManager:fakeCentralManager queue:nil];
-  CBUUID *serviceUUID = [CBUUID UUIDWithString:kServiceUUID];
-
-  NSDictionary<NSString *, id> *data = @{
-    CBAdvertisementDataLocalNameKey : @"!@#$",
-    CBAdvertisementDataServiceUUIDsKey : @[ serviceUUID ],
-  };
-  NSDictionary<CBUUID *, NSData *> *actual = [medium decodeAdvertisementData:data];
-
-  XCTAssertEqualObjects(@{}, actual);
-}
-
-- (void)testDecodeEmptyAdvertisementData {
-  GNCFakeCentralManager *fakeCentralManager = [[GNCFakeCentralManager alloc] init];
-  GNCBLEMedium *medium = [[GNCBLEMedium alloc] initWithCentralManager:fakeCentralManager queue:nil];
-
-  NSDictionary<CBUUID *, NSData *> *actual = [medium decodeAdvertisementData:@{}];
-
-  XCTAssertEqualObjects(@{}, actual);
-}
-
-#pragma mark - Start GATT Server
-
-- (void)testStartGATTServer {
-  GNCFakeCentralManager *fakeCentralManager = [[GNCFakeCentralManager alloc] init];
-  GNCBLEMedium *medium = [[GNCBLEMedium alloc] initWithCentralManager:fakeCentralManager queue:nil];
-  XCTestExpectation *expectation =
-      [[XCTestExpectation alloc] initWithDescription:@"Start GATT server."];
-
-  [medium startGATTServerWithCompletionHandler:^(GNCBLEGATTServer *server, NSError *error) {
-    XCTAssertNotNil(server);
-    XCTAssertNil(error);
-    [expectation fulfill];
-  }];
-
-  [self waitForExpectations:@[ expectation ] timeout:3];
-}
-
-#pragma mark - Start Advertising
-
-- (void)testStartAdvertising {
-  GNCFakeCentralManager *fakeCentralManager = [[GNCFakeCentralManager alloc] init];
-  GNCBLEMedium *medium = [[GNCBLEMedium alloc] initWithCentralManager:fakeCentralManager queue:nil];
-  XCTestExpectation *expectation =
-      [[XCTestExpectation alloc] initWithDescription:@"Start advertising."];
-
-  // Start advertising is fully covered with @c GNCBLEGATTServer tests. We are passing invalid
-  // advertising data here so we can test code paths relevant to @c GNCBLEMedium, but bail early
-  // enough to avoid making actual CoreBluetooth calls.
-  [medium startAdvertisingData:@{}
-             completionHandler:^(NSError *error) {
-               XCTAssertNotNil(error);
-               [expectation fulfill];
-             }];
-
-  [self waitForExpectations:@[ expectation ] timeout:3];
-}
-
-- (void)testStopAdvertising {
-  GNCFakeCentralManager *fakeCentralManager = [[GNCFakeCentralManager alloc] init];
-  GNCBLEMedium *medium = [[GNCBLEMedium alloc] initWithCentralManager:fakeCentralManager queue:nil];
-  XCTestExpectation *expectation =
-      [[XCTestExpectation alloc] initWithDescription:@"Stop advertising."];
-
-  // Stop advertising is fully covered with @c GNCBLEGATTServer tests. We are only testing stopping
-  // without having started which tests the code paths relevant to @c GNCBLEMedium.
-  [medium stopAdvertisingWithCompletionHandler:^(NSError *error) {
-    XCTAssertNil(error);
-    [expectation fulfill];
-  }];
-
-  [self waitForExpectations:@[ expectation ] timeout:3];
-}
-
-#pragma mark - Open L2CAP Channel
-
-- (void)testOpenL2CAPServerSocket {
-  GNCFakeCentralManager *fakeCentralManager = [[GNCFakeCentralManager alloc] init];
-  GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
-  GNCBLEMedium *medium = [[GNCBLEMedium alloc] initWithCentralManager:fakeCentralManager queue:nil];
-  XCTestExpectation *psmPublishedexpectation =
-      [[XCTestExpectation alloc] initWithDescription:@"PSM published."];
-  XCTestExpectation *channelOpenedexpectation =
-      [[XCTestExpectation alloc] initWithDescription:@"Channel opened."];
-
-  [fakePeripheralManager simulatePeripheralManagerDidUpdateState:CBManagerStatePoweredOn];
-
-  // Open L2CAP server is fully covered with @c GNCBLEL2CAPServer tests.
-  [medium
-      openL2CAPServerWithPSMPublishedCompletionHandler:^(uint16_t PSM, NSError *error) {
-        XCTAssertEqual(PSM, fakePeripheralManager.PSM);
-        XCTAssertNil(error);
-        [psmPublishedexpectation fulfill];
-      }
-      channelOpenedCompletionHandler:^(GNCBLEL2CAPStream *stream, NSError *error) {
-        XCTAssertNil(error);
-        [channelOpenedexpectation fulfill];
-      }
-      peripheralManager:fakePeripheralManager];
-
-  [self waitForExpectations:@[ psmPublishedexpectation ] timeout:0.1];
-  [self waitForExpectations:@[ channelOpenedexpectation ] timeout:0.5];
-}
-
-- (void)testSuccessfulOpenL2CAPChannel {
-  GNCFakeCentralManager *fakeCentralManager = [[GNCFakeCentralManager alloc] init];
-  GNCBLEMedium *medium = [[GNCBLEMedium alloc] initWithCentralManager:fakeCentralManager queue:nil];
-  XCTestExpectation *expectation =
-      [[XCTestExpectation alloc] initWithDescription:@"Open L2CAP channel."];
-
-  GNCFakePeripheral *fakePeripheral = [[GNCFakePeripheral alloc] init];
-  GNCBLEL2CAPClient *l2capClient =
-      [[GNCBLEL2CAPClient alloc] initWithQueue:nil
-                   requestDisconnectionHandler:^(id<GNCPeripheral> _Nonnull peripheral){
-                   }];
-  [medium setL2CAPClient:l2capClient];
-  [medium openL2CAPChannelWithPSM:123
-                       peripheral:fakePeripheral
-                completionHandler:^(GNCBLEL2CAPStream *_Nullable stream, NSError *_Nullable error) {
-                  [expectation fulfill];
-                }];
-
-  [self waitForExpectations:@[ expectation ] timeout:3];
-}
-
-#pragma mark - Connect
-
-- (void)testSuccessfulConnect {
-  GNCFakeCentralManager *fakeCentralManager = [[GNCFakeCentralManager alloc] init];
-  GNCBLEMedium *medium = [[GNCBLEMedium alloc] initWithCentralManager:fakeCentralManager queue:nil];
-  XCTestExpectation *expectation = [[XCTestExpectation alloc] initWithDescription:@"Connect."];
-
-  [medium connectToGATTServerForPeripheral:[[GNCFakePeripheral alloc] init]
-                      disconnectionHandler:nil
-                         completionHandler:^(GNCBLEGATTClient *client, NSError *error) {
-                           XCTAssertNotNil(client);
-                           XCTAssertNil(error);
-                           [expectation fulfill];
-                         }];
-
-  [self waitForExpectations:@[ expectation ] timeout:3];
-}
-
-- (void)testFailedConnect {
-  GNCFakeCentralManager *fakeCentralManager = [[GNCFakeCentralManager alloc] init];
-  GNCBLEMedium *medium = [[GNCBLEMedium alloc] initWithCentralManager:fakeCentralManager queue:nil];
-  XCTestExpectation *expectation = [[XCTestExpectation alloc] initWithDescription:@"Connect."];
-
-  fakeCentralManager.didFailToConnectPeripheralError = [NSError errorWithDomain:@"fake"
-                                                                           code:0
-                                                                       userInfo:nil];
-
-  [medium connectToGATTServerForPeripheral:[[GNCFakePeripheral alloc] init]
-                      disconnectionHandler:nil
-                         completionHandler:^(GNCBLEGATTClient *client, NSError *error) {
-                           XCTAssertNil(client);
-                           XCTAssertNotNil(error);
-                           [expectation fulfill];
-                         }];
-
-  [self waitForExpectations:@[ expectation ] timeout:3];
-}
-
-- (void)testDisconnect {
-  GNCFakeCentralManager *fakeCentralManager = [[GNCFakeCentralManager alloc] init];
-  GNCBLEMedium *medium = [[GNCBLEMedium alloc] initWithCentralManager:fakeCentralManager queue:nil];
-  XCTestExpectation *disconnectExpectation =
-      [[XCTestExpectation alloc] initWithDescription:@"Disconnect."];
-
-  GNCFakePeripheral *peripheral = [[GNCFakePeripheral alloc] init];
-
-  [medium connectToGATTServerForPeripheral:peripheral
-      disconnectionHandler:^() {
-        [disconnectExpectation fulfill];
-      }
-      completionHandler:^(GNCBLEGATTClient *client, NSError *error) {
-        XCTAssertNotNil(client);
-        XCTAssertNil(error);
-        [client disconnect];
-      }];
-
-  [self waitForExpectations:@[ disconnectExpectation ] timeout:3];
-}
-
-- (void)testRetrievePeripheralWithIdentifier_exists {
-  GNCFakeCentralManager *fakeCentralManager = [[GNCFakeCentralManager alloc] init];
-  GNCBLEMedium *medium = [[GNCBLEMedium alloc] initWithCentralManager:fakeCentralManager queue:nil];
-  XCTAssertNotNil(
-      [medium retrievePeripheralWithIdentifier:
-                  [[NSUUID alloc] initWithUUIDString:@"11111111-1111-1111-1111-111111111111"]]);
-}
-
-- (void)testRetrievePeripheralWithIdentifier_doesNotExist {
-  GNCFakeCentralManager *fakeCentralManager = [[GNCFakeCentralManager alloc] init];
-  GNCBLEMedium *medium = [[GNCBLEMedium alloc] initWithCentralManager:fakeCentralManager queue:nil];
-  XCTAssertNil(
-      [medium retrievePeripheralWithIdentifier:
-                  [[NSUUID alloc] initWithUUIDString:@"11111111-1111-1111-1111-111111111112"]]);
-}
-
-@end

internal/platform/implementation/apple/Mediums/BLE/Tests/GNCBLEMediumTest.mm

@@ -0,0 +1,621 @@
+// Copyright 2023 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#import "internal/platform/implementation/apple/Mediums/BLE/GNCBLEMedium.h"
+
+#import <CoreBluetooth/CoreBluetooth.h>
+#import <Foundation/Foundation.h>
+#import <XCTest/XCTest.h>
+
+#import "internal/platform/implementation/apple/Mediums/BLE/GNCBLEGATTClient.h"
+#import "internal/platform/implementation/apple/Mediums/BLE/GNCBLEGATTServer.h"
+#import "internal/platform/implementation/apple/Mediums/BLE/GNCPeripheral.h"
+#import "internal/platform/implementation/apple/Mediums/BLE/Tests/GNCBLEL2CAPClient+Testing.h"
+#import "internal/platform/implementation/apple/Mediums/BLE/Tests/GNCBLEMedium+Testing.h"
+#import "internal/platform/implementation/apple/Mediums/BLE/Tests/GNCFakeCentralManager.h"
+#import "internal/platform/implementation/apple/Mediums/BLE/Tests/GNCFakePeripheral.h"
+#import "internal/platform/implementation/apple/Mediums/BLE/Tests/GNCFakePeripheralManager.h"
+
+#include "connections/implementation/flags/nearby_connections_feature_flags.h"
+#include "internal/flags/nearby_flags.h"
+
+static NSString *const kServiceUUID = @"0000FEF3-0000-1000-8000-00805F9B34FB";
+
+@interface GNCBLEMediumTest : XCTestCase
+@end
+
+@implementation GNCBLEMediumTest
+
+- (void)tearDown {
+  nearby::NearbyFlags::GetInstance().ResetOverridedValues();
+  [super tearDown];
+}
+
+- (void)testInit_allocatesMultiplexerWhenFlagEnabled {
+  for (NSNumber *enabled in @[ @NO, @YES ]) {
+    nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+        nearby::connections::config_package_nearby::nearby_connections_feature::
+            kEnableSharedPeripheralManager,
+        enabled.boolValue);
+    GNCFakeCentralManager *fakeCentralManager = [[GNCFakeCentralManager alloc] init];
+    GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+
+    GNCBLEMedium *medium = [[GNCBLEMedium alloc] initWithCentralManager:fakeCentralManager
+                                                      peripheralManager:fakePeripheralManager
+                                                                  queue:dispatch_get_main_queue()];
+
+    id multiplexer = [medium valueForKey:@"_multiplexer"];
+    if (enabled.boolValue) {
+      XCTAssertNotNil(multiplexer);
+      XCTAssertEqual(fakePeripheralManager.peripheralDelegate, multiplexer);
+    } else {
+      XCTAssertNil(multiplexer);
+      XCTAssertNil(fakePeripheralManager.peripheralDelegate);
+    }
+  }
+}
+
+#pragma mark - Supports Extended Advertisements
+
+- (void)testSupportsExtendedAdvertisements {
+  for (NSNumber *enabled in @[ @NO, @YES ]) {
+    nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+        nearby::connections::config_package_nearby::nearby_connections_feature::
+            kEnableSharedPeripheralManager,
+        enabled.boolValue);
+    GNCFakeCentralManager *fakeCentralManager = [[GNCFakeCentralManager alloc] init];
+    GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+
+    GNCBLEMedium *medium = [[GNCBLEMedium alloc] initWithCentralManager:fakeCentralManager
+                                                      peripheralManager:fakePeripheralManager
+                                                                  queue:dispatch_get_main_queue()];
+
+    XCTAssertFalse([medium supportsExtendedAdvertisements]);
+  }
+}
+
+#pragma mark - Start Scanning
+
+- (void)testStartScanning {
+  for (NSNumber *enabled in @[ @NO, @YES ]) {
+    nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+        nearby::connections::config_package_nearby::nearby_connections_feature::
+            kEnableSharedPeripheralManager,
+        enabled.boolValue);
+    GNCFakeCentralManager *fakeCentralManager = [[GNCFakeCentralManager alloc] init];
+    GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+    GNCBLEMedium *medium = [[GNCBLEMedium alloc] initWithCentralManager:fakeCentralManager
+                                                      peripheralManager:fakePeripheralManager
+                                                                  queue:dispatch_get_main_queue()];
+    XCTestExpectation *startScanningExpectation =
+        [[XCTestExpectation alloc] initWithDescription:@"Start scanning."];
+    XCTestExpectation *advertisementFoundExpectation =
+        [[XCTestExpectation alloc] initWithDescription:@"Advertisement found."];
+    CBUUID *serviceUUID = [CBUUID UUIDWithString:kServiceUUID];
+
+    [fakeCentralManager simulateCentralManagerDidUpdateState:CBManagerStatePoweredOn];
+
+    [medium startScanningForService:serviceUUID
+        advertisementFoundHandler:^(id<GNCPeripheral> peripheral,
+                                    NSDictionary<CBUUID *, NSData *> *data) {
+          NSDictionary<CBUUID *, NSData *> *expected = @{
+            serviceUUID : [@"test" dataUsingEncoding:NSUTF8StringEncoding],
+          };
+          XCTAssertEqualObjects(expected, data);
+          [advertisementFoundExpectation fulfill];
+        }
+        completionHandler:^(NSError *error) {
+          XCTAssertNil(error);
+          [startScanningExpectation fulfill];
+        }];
+
+    [self waitForExpectations:@[ startScanningExpectation ] timeout:3];
+
+    XCTAssertEqualObjects(@[ serviceUUID ], fakeCentralManager.serviceUUIDs);
+
+    [fakeCentralManager
+        simulateCentralManagerDidDiscoverPeripheral:[[GNCFakePeripheral alloc] init]
+                                  advertisementData:@{
+                                    CBAdvertisementDataLocalNameKey : @"dGVzdA",
+                                    CBAdvertisementDataServiceUUIDsKey : @[ serviceUUID ],
+                                  }];
+
+    [self waitForExpectations:@[ advertisementFoundExpectation ] timeout:3];
+  }
+}
+
+- (void)testAlreadyScanning {
+  for (NSNumber *enabled in @[ @NO, @YES ]) {
+    nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+        nearby::connections::config_package_nearby::nearby_connections_feature::
+            kEnableSharedPeripheralManager,
+        enabled.boolValue);
+    GNCFakeCentralManager *fakeCentralManager = [[GNCFakeCentralManager alloc] init];
+    GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+    GNCBLEMedium *medium = [[GNCBLEMedium alloc] initWithCentralManager:fakeCentralManager
+                                                      peripheralManager:fakePeripheralManager
+                                                                  queue:dispatch_get_main_queue()];
+    XCTestExpectation *expectation =
+        [[XCTestExpectation alloc] initWithDescription:@"Start scanning."];
+
+    [medium startScanningForService:[CBUUID UUIDWithString:kServiceUUID]
+          advertisementFoundHandler:^(id<GNCPeripheral> peripheral,
+                                      NSDictionary<CBUUID *, NSData *> *data) {
+          }
+                  completionHandler:nil];
+
+    [medium startScanningForService:[CBUUID UUIDWithString:kServiceUUID]
+        advertisementFoundHandler:^(id<GNCPeripheral> peripheral,
+                                    NSDictionary<CBUUID *, NSData *> *data) {
+        }
+        completionHandler:^(NSError *error) {
+          XCTAssertNotNil(error);
+          [expectation fulfill];
+        }];
+
+    [self waitForExpectations:@[ expectation ] timeout:3];
+  }
+}
+
+- (void)testStartStopStartScanning {
+  for (NSNumber *enabled in @[ @NO, @YES ]) {
+    nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+        nearby::connections::config_package_nearby::nearby_connections_feature::
+            kEnableSharedPeripheralManager,
+        enabled.boolValue);
+    GNCFakeCentralManager *fakeCentralManager = [[GNCFakeCentralManager alloc] init];
+    GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+    GNCBLEMedium *medium = [[GNCBLEMedium alloc] initWithCentralManager:fakeCentralManager
+                                                      peripheralManager:fakePeripheralManager
+                                                                  queue:dispatch_get_main_queue()];
+    XCTestExpectation *expectation =
+        [[XCTestExpectation alloc] initWithDescription:@"Start scanning."];
+
+    CBUUID *serviceUUID = [CBUUID UUIDWithString:kServiceUUID];
+
+    [medium startScanningForService:serviceUUID
+        advertisementFoundHandler:^(id<GNCPeripheral> peripheral,
+                                    NSDictionary<CBUUID *, NSData *> *data) {
+        }
+        completionHandler:^(NSError *error) {
+          XCTAssertNil(error);
+          [medium stopScanningWithCompletionHandler:^(NSError *error) {
+            XCTAssertNil(error);
+            [medium startScanningForService:serviceUUID
+                advertisementFoundHandler:^(id<GNCPeripheral> peripheral,
+                                            NSDictionary<CBUUID *, NSData *> *data) {
+                }
+                completionHandler:^(NSError *error) {
+                  XCTAssertNil(error);
+                  [expectation fulfill];
+                }];
+          }];
+        }];
+
+    [self waitForExpectations:@[ expectation ] timeout:3];
+  }
+}
+
+#pragma mark - Decode Advertisement Data
+
+- (void)testDecodeAndroidStyleAdvertisementData {
+  for (NSNumber *enabled in @[ @NO, @YES ]) {
+    nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+        nearby::connections::config_package_nearby::nearby_connections_feature::
+            kEnableSharedPeripheralManager,
+        enabled.boolValue);
+    GNCFakeCentralManager *fakeCentralManager = [[GNCFakeCentralManager alloc] init];
+    GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+    GNCBLEMedium *medium = [[GNCBLEMedium alloc] initWithCentralManager:fakeCentralManager
+                                                      peripheralManager:fakePeripheralManager
+                                                                  queue:dispatch_get_main_queue()];
+    CBUUID *serviceUUID = [CBUUID UUIDWithString:kServiceUUID];
+
+    NSDictionary<CBUUID *, NSData *> *expected = @{
+      serviceUUID : [@"test" dataUsingEncoding:NSUTF8StringEncoding],
+    };
+
+    NSDictionary<NSString *, id> *data = @{
+      CBAdvertisementDataServiceDataKey : @{
+        serviceUUID : [@"test" dataUsingEncoding:NSUTF8StringEncoding],
+      },
+    };
+    NSDictionary<CBUUID *, NSData *> *actual = [medium decodeAdvertisementData:data];
+
+    XCTAssertEqualObjects(expected, actual);
+  }
+}
+
+- (void)testDecodeAndroidStyleAdvertisementDataWithLocalName {
+  for (NSNumber *enabled in @[ @NO, @YES ]) {
+    nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+        nearby::connections::config_package_nearby::nearby_connections_feature::
+            kEnableSharedPeripheralManager,
+        enabled.boolValue);
+    GNCFakeCentralManager *fakeCentralManager = [[GNCFakeCentralManager alloc] init];
+    GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+    GNCBLEMedium *medium = [[GNCBLEMedium alloc] initWithCentralManager:fakeCentralManager
+                                                      peripheralManager:fakePeripheralManager
+                                                                  queue:dispatch_get_main_queue()];
+    CBUUID *serviceUUID = [CBUUID UUIDWithString:kServiceUUID];
+
+    NSDictionary<CBUUID *, NSData *> *expected = @{
+      serviceUUID : [@"test" dataUsingEncoding:NSUTF8StringEncoding],
+    };
+
+    NSDictionary<NSString *, id> *data = @{
+      CBAdvertisementDataLocalNameKey : @"Nearby",  // Just happens to be base64 decodable.
+      CBAdvertisementDataServiceUUIDsKey : @[ serviceUUID ],
+      CBAdvertisementDataServiceDataKey : @{
+        serviceUUID : [@"test" dataUsingEncoding:NSUTF8StringEncoding],
+      },
+    };
+    NSDictionary<CBUUID *, NSData *> *actual = [medium decodeAdvertisementData:data];
+
+    XCTAssertEqualObjects(expected, actual);
+  }
+}
+
+- (void)testDecodeAppleStyleAdvertisementData {
+  for (NSNumber *enabled in @[ @NO, @YES ]) {
+    nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+        nearby::connections::config_package_nearby::nearby_connections_feature::
+            kEnableSharedPeripheralManager,
+        enabled.boolValue);
+    GNCFakeCentralManager *fakeCentralManager = [[GNCFakeCentralManager alloc] init];
+    GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+    GNCBLEMedium *medium = [[GNCBLEMedium alloc] initWithCentralManager:fakeCentralManager
+                                                      peripheralManager:fakePeripheralManager
+                                                                  queue:dispatch_get_main_queue()];
+    CBUUID *serviceUUID = [CBUUID UUIDWithString:kServiceUUID];
+
+    NSDictionary<CBUUID *, NSData *> *expected = @{
+      serviceUUID : [@"test" dataUsingEncoding:NSUTF8StringEncoding],
+    };
+
+    NSDictionary<NSString *, id> *data = @{
+      CBAdvertisementDataLocalNameKey : @"dGVzdA",
+      CBAdvertisementDataServiceUUIDsKey : @[ serviceUUID ],
+    };
+    NSDictionary<CBUUID *, NSData *> *actual = [medium decodeAdvertisementData:data];
+
+    XCTAssertEqualObjects(expected, actual);
+  }
+}
+
+- (void)testDecodeInvalidAdvertisementData {
+  for (NSNumber *enabled in @[ @NO, @YES ]) {
+    nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+        nearby::connections::config_package_nearby::nearby_connections_feature::
+            kEnableSharedPeripheralManager,
+        enabled.boolValue);
+    GNCFakeCentralManager *fakeCentralManager = [[GNCFakeCentralManager alloc] init];
+    GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+    GNCBLEMedium *medium = [[GNCBLEMedium alloc] initWithCentralManager:fakeCentralManager
+                                                      peripheralManager:fakePeripheralManager
+                                                                  queue:dispatch_get_main_queue()];
+    CBUUID *serviceUUID = [CBUUID UUIDWithString:kServiceUUID];
+
+    NSDictionary<NSString *, id> *data = @{
+      CBAdvertisementDataLocalNameKey : @"!@#$",
+      CBAdvertisementDataServiceUUIDsKey : @[ serviceUUID ],
+    };
+    NSDictionary<CBUUID *, NSData *> *actual = [medium decodeAdvertisementData:data];
+
+    XCTAssertEqualObjects(@{}, actual);
+  }
+}
+
+- (void)testDecodeEmptyAdvertisementData {
+  for (NSNumber *enabled in @[ @NO, @YES ]) {
+    nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+        nearby::connections::config_package_nearby::nearby_connections_feature::
+            kEnableSharedPeripheralManager,
+        enabled.boolValue);
+    GNCFakeCentralManager *fakeCentralManager = [[GNCFakeCentralManager alloc] init];
+    GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+    GNCBLEMedium *medium = [[GNCBLEMedium alloc] initWithCentralManager:fakeCentralManager
+                                                      peripheralManager:fakePeripheralManager
+                                                                  queue:dispatch_get_main_queue()];
+
+    NSDictionary<CBUUID *, NSData *> *actual = [medium decodeAdvertisementData:@{}];
+
+    XCTAssertEqualObjects(@{}, actual);
+  }
+}
+
+#pragma mark - Start GATT Server
+
+- (void)testStartGATTServer {
+  for (NSNumber *enabled in @[ @NO, @YES ]) {
+    nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+        nearby::connections::config_package_nearby::nearby_connections_feature::
+            kEnableSharedPeripheralManager,
+        enabled.boolValue);
+    GNCFakeCentralManager *fakeCentralManager = [[GNCFakeCentralManager alloc] init];
+    GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+    GNCBLEMedium *medium = [[GNCBLEMedium alloc] initWithCentralManager:fakeCentralManager
+                                                      peripheralManager:fakePeripheralManager
+                                                                  queue:dispatch_get_main_queue()];
+    XCTestExpectation *expectation =
+        [[XCTestExpectation alloc] initWithDescription:@"Start GATT server."];
+
+    [medium startGATTServerWithCompletionHandler:^(GNCBLEGATTServer *server, NSError *error) {
+      XCTAssertNotNil(server);
+      XCTAssertNil(error);
+
+      // Verify internal structure based on flag
+      id mediumManager = [medium valueForKey:@"_peripheralManager"];
+      id serverManager = [server valueForKey:@"_peripheralManager"];
+
+      if (enabled.boolValue) {
+        XCTAssertEqual(mediumManager, serverManager);
+        id multiplexer = [medium valueForKey:@"_multiplexer"];
+        XCTAssertEqual([mediumManager peripheralDelegate], multiplexer);
+      } else {
+        XCTAssertNotEqual(mediumManager, serverManager);
+        id manager = [server valueForKey:@"_peripheralManager"];
+        XCTAssertEqual([manager peripheralDelegate], server);
+      }
+
+      [expectation fulfill];
+    }];
+
+    [self waitForExpectations:@[ expectation ] timeout:3];
+  }
+}
+
+#pragma mark - Start Advertising
+
+- (void)testStartAdvertising {
+  for (NSNumber *enabled in @[ @NO, @YES ]) {
+    nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+        nearby::connections::config_package_nearby::nearby_connections_feature::
+            kEnableSharedPeripheralManager,
+        enabled.boolValue);
+    GNCFakeCentralManager *fakeCentralManager = [[GNCFakeCentralManager alloc] init];
+    GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+    GNCBLEMedium *medium = [[GNCBLEMedium alloc] initWithCentralManager:fakeCentralManager
+                                                      peripheralManager:fakePeripheralManager
+                                                                  queue:dispatch_get_main_queue()];
+    XCTestExpectation *expectation =
+        [[XCTestExpectation alloc] initWithDescription:@"Start advertising."];
+
+    // Start advertising is fully covered with @c GNCBLEGATTServer tests. We are passing invalid
+    // advertising data here so we can test code paths relevant to @c GNCBLEMedium, but bail early
+    // enough to avoid making actual CoreBluetooth calls.
+    [medium startAdvertisingData:@{}
+               completionHandler:^(NSError *error) {
+                 XCTAssertNotNil(error);
+                 [expectation fulfill];
+               }];
+
+    [self waitForExpectations:@[ expectation ] timeout:3];
+  }
+}
+
+- (void)testStopAdvertising {
+  for (NSNumber *enabled in @[ @NO, @YES ]) {
+    nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+        nearby::connections::config_package_nearby::nearby_connections_feature::
+            kEnableSharedPeripheralManager,
+        enabled.boolValue);
+    GNCFakeCentralManager *fakeCentralManager = [[GNCFakeCentralManager alloc] init];
+    GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+    GNCBLEMedium *medium = [[GNCBLEMedium alloc] initWithCentralManager:fakeCentralManager
+                                                      peripheralManager:fakePeripheralManager
+                                                                  queue:dispatch_get_main_queue()];
+    XCTestExpectation *expectation =
+        [[XCTestExpectation alloc] initWithDescription:@"Stop advertising."];
+
+    // Stop advertising is fully covered with @c GNCBLEGATTServer tests. We are only testing stopping
+    // without having started which tests the code paths relevant to @c GNCBLEMedium.
+    [medium stopAdvertisingWithCompletionHandler:^(NSError *error) {
+      XCTAssertNil(error);
+      [expectation fulfill];
+    }];
+
+    [self waitForExpectations:@[ expectation ] timeout:3];
+  }
+}
+
+#pragma mark - Open L2CAP Channel
+
+- (void)testOpenL2CAPServerSocket {
+  for (NSNumber *enabled in @[ @NO, @YES ]) {
+    nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+        nearby::connections::config_package_nearby::nearby_connections_feature::
+            kEnableSharedPeripheralManager,
+        enabled.boolValue);
+    GNCFakeCentralManager *fakeCentralManager = [[GNCFakeCentralManager alloc] init];
+    GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+    GNCBLEMedium *medium = [[GNCBLEMedium alloc] initWithCentralManager:fakeCentralManager
+                                                      peripheralManager:fakePeripheralManager
+                                                                  queue:dispatch_get_main_queue()];
+    XCTestExpectation *psmPublishedexpectation =
+        [[XCTestExpectation alloc] initWithDescription:@"PSM published."];
+    XCTestExpectation *channelOpenedexpectation =
+        [[XCTestExpectation alloc] initWithDescription:@"Channel opened."];
+
+    [fakePeripheralManager simulatePeripheralManagerDidUpdateState:CBManagerStatePoweredOn];
+
+    // Open L2CAP server is fully covered with @c GNCBLEL2CAPServer tests.
+    [medium
+        openL2CAPServerWithPSMPublishedCompletionHandler:^(uint16_t PSM, NSError *error) {
+          XCTAssertEqual(PSM, fakePeripheralManager.PSM);
+          XCTAssertNil(error);
+          [psmPublishedexpectation fulfill];
+        }
+        channelOpenedCompletionHandler:^(GNCBLEL2CAPStream *stream, NSError *error) {
+          XCTAssertNil(error);
+          [channelOpenedexpectation fulfill];
+        }
+        peripheralManager:fakePeripheralManager];
+
+    [self waitForExpectations:@[ psmPublishedexpectation ] timeout:0.1];
+    [self waitForExpectations:@[ channelOpenedexpectation ] timeout:0.5];
+  }
+}
+
+- (void)testSuccessfulOpenL2CAPChannel {
+  for (NSNumber *enabled in @[ @NO, @YES ]) {
+    nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+        nearby::connections::config_package_nearby::nearby_connections_feature::
+            kEnableSharedPeripheralManager,
+        enabled.boolValue);
+    GNCFakeCentralManager *fakeCentralManager = [[GNCFakeCentralManager alloc] init];
+    GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+    GNCBLEMedium *medium = [[GNCBLEMedium alloc] initWithCentralManager:fakeCentralManager
+                                                      peripheralManager:fakePeripheralManager
+                                                                  queue:dispatch_get_main_queue()];
+    XCTestExpectation *expectation =
+        [[XCTestExpectation alloc] initWithDescription:@"Open L2CAP channel."];
+
+    GNCFakePeripheral *fakePeripheral = [[GNCFakePeripheral alloc] init];
+    GNCBLEL2CAPClient *l2capClient =
+        [[GNCBLEL2CAPClient alloc] initWithQueue:nil
+                     requestDisconnectionHandler:^(id<GNCPeripheral> _Nonnull peripheral){
+                     }];
+    [medium setL2CAPClient:l2capClient];
+    [medium openL2CAPChannelWithPSM:123
+                         peripheral:fakePeripheral
+                  completionHandler:^(GNCBLEL2CAPStream *_Nullable stream, NSError *_Nullable error) {
+                    [expectation fulfill];
+                  }];
+
+    [self waitForExpectations:@[ expectation ] timeout:3];
+  }
+}
+
+#pragma mark - Connect
+
+- (void)testSuccessfulConnect {
+  for (NSNumber *enabled in @[ @NO, @YES ]) {
+    nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+        nearby::connections::config_package_nearby::nearby_connections_feature::
+            kEnableSharedPeripheralManager,
+        enabled.boolValue);
+    GNCFakeCentralManager *fakeCentralManager = [[GNCFakeCentralManager alloc] init];
+    GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+    GNCBLEMedium *medium = [[GNCBLEMedium alloc] initWithCentralManager:fakeCentralManager
+                                                      peripheralManager:fakePeripheralManager
+                                                                  queue:dispatch_get_main_queue()];
+    XCTestExpectation *expectation = [[XCTestExpectation alloc] initWithDescription:@"Connect."];
+
+    [medium connectToGATTServerForPeripheral:[[GNCFakePeripheral alloc] init]
+                        disconnectionHandler:nil
+                           completionHandler:^(GNCBLEGATTClient *client, NSError *error) {
+                             XCTAssertNotNil(client);
+                             XCTAssertNil(error);
+                             [expectation fulfill];
+                           }];
+
+    [self waitForExpectations:@[ expectation ] timeout:3];
+  }
+}
+
+- (void)testFailedConnect {
+  for (NSNumber *enabled in @[ @NO, @YES ]) {
+    nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+        nearby::connections::config_package_nearby::nearby_connections_feature::
+            kEnableSharedPeripheralManager,
+        enabled.boolValue);
+    GNCFakeCentralManager *fakeCentralManager = [[GNCFakeCentralManager alloc] init];
+    GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+    GNCBLEMedium *medium = [[GNCBLEMedium alloc] initWithCentralManager:fakeCentralManager
+                                                      peripheralManager:fakePeripheralManager
+                                                                  queue:dispatch_get_main_queue()];
+    XCTestExpectation *expectation = [[XCTestExpectation alloc] initWithDescription:@"Connect."];
+
+    fakeCentralManager.didFailToConnectPeripheralError = [NSError errorWithDomain:@"fake"
+                                                                             code:0
+                                                                         userInfo:nil];
+
+    [medium connectToGATTServerForPeripheral:[[GNCFakePeripheral alloc] init]
+                        disconnectionHandler:nil
+                           completionHandler:^(GNCBLEGATTClient *client, NSError *error) {
+                             XCTAssertNil(client);
+                             XCTAssertNotNil(error);
+                             [expectation fulfill];
+                           }];
+
+    [self waitForExpectations:@[ expectation ] timeout:3];
+  }
+}
+
+- (void)testDisconnect {
+  for (NSNumber *enabled in @[ @NO, @YES ]) {
+    nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+        nearby::connections::config_package_nearby::nearby_connections_feature::
+            kEnableSharedPeripheralManager,
+        enabled.boolValue);
+    GNCFakeCentralManager *fakeCentralManager = [[GNCFakeCentralManager alloc] init];
+    GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+    GNCBLEMedium *medium = [[GNCBLEMedium alloc] initWithCentralManager:fakeCentralManager
+                                                      peripheralManager:fakePeripheralManager
+                                                                  queue:dispatch_get_main_queue()];
+    XCTestExpectation *disconnectExpectation =
+        [[XCTestExpectation alloc] initWithDescription:@"Disconnect."];
+
+    GNCFakePeripheral *peripheral = [[GNCFakePeripheral alloc] init];
+
+    [medium connectToGATTServerForPeripheral:peripheral
+        disconnectionHandler:^() {
+          [disconnectExpectation fulfill];
+        }
+        completionHandler:^(GNCBLEGATTClient *client, NSError *error) {
+          XCTAssertNotNil(client);
+          XCTAssertNil(error);
+          [client disconnect];
+        }];
+
+    [self waitForExpectations:@[ disconnectExpectation ] timeout:3];
+  }
+}
+
+- (void)testRetrievePeripheralWithIdentifier_exists {
+  for (NSNumber *enabled in @[ @NO, @YES ]) {
+    nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+        nearby::connections::config_package_nearby::nearby_connections_feature::
+            kEnableSharedPeripheralManager,
+        enabled.boolValue);
+    GNCFakeCentralManager *fakeCentralManager = [[GNCFakeCentralManager alloc] init];
+    GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+    GNCBLEMedium *medium = [[GNCBLEMedium alloc] initWithCentralManager:fakeCentralManager
+                                                      peripheralManager:fakePeripheralManager
+                                                                  queue:dispatch_get_main_queue()];
+    XCTAssertNotNil(
+        [medium retrievePeripheralWithIdentifier:
+                    [[NSUUID alloc] initWithUUIDString:@"11111111-1111-1111-1111-111111111111"]]);
+  }
+}
+
+- (void)testRetrievePeripheralWithIdentifier_doesNotExist {
+  for (NSNumber *enabled in @[ @NO, @YES ]) {
+    nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+        nearby::connections::config_package_nearby::nearby_connections_feature::
+            kEnableSharedPeripheralManager,
+        enabled.boolValue);
+    GNCFakeCentralManager *fakeCentralManager = [[GNCFakeCentralManager alloc] init];
+    GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+    GNCBLEMedium *medium = [[GNCBLEMedium alloc] initWithCentralManager:fakeCentralManager
+                                                      peripheralManager:fakePeripheralManager
+                                                                  queue:dispatch_get_main_queue()];
+    XCTAssertNil(
+        [medium retrievePeripheralWithIdentifier:
+                    [[NSUUID alloc] initWithUUIDString:@"11111111-1111-1111-1111-111111111112"]]);
+  }
+}
+
+@end

internal/platform/implementation/apple/Mediums/BLE/Tests/GNCFakeCBL2CAPChannel.h

@@ -29,7 +29,7 @@ NS_ASSUME_NONNULL_BEGIN
 /** The socket file descriptor for the L2CAP channel. */
 @property(nonatomic, readonly) int socketFD;
 /** The PSM (Protocol/Service Multiplexer) of the L2CAP channel. */
-@property(nonatomic, readonly) CBL2CAPPSM PSM;
+@property(nonatomic, readwrite) CBL2CAPPSM PSM;
 
 @end
 

internal/platform/implementation/apple/Mediums/BLE/Tests/GNCFakePeripheralManager.m

@@ -140,6 +140,7 @@ static const uint16_t kPSM = 192;
     GNCFakeCBL2CAPChannel *fakeChannel = [[GNCFakeCBL2CAPChannel alloc] init];
     fakeChannel.inputStream = fakeStream.inputStream;
     fakeChannel.outputStream = fakeStream.outputStream;
+    fakeChannel.PSM = _PSM;
     [_peripheralDelegate gnc_peripheralManager:self
                            didOpenL2CAPChannel:(CBL2CAPChannel *)fakeChannel
                                          error:_didOpenL2CAPChannelError];

internal/platform/implementation/apple/Mediums/BLE/Tests/GNCMBleUtilsTest.m

@@ -131,7 +131,7 @@ static const NSTimeInterval kWaitForConnectionTimeout = 6.0;  // Allow for the 5
   GNCFakeSocket *fakeSocket = [[GNCFakeSocket alloc] init];
 
   XCTestExpectation *expectation = [self expectationWithDescription:@"Connection success"];
-  GNCMWaitForConnection((GNSSocket *)fakeSocket, ^(BOOL flag) {
+  GNCMWaitForConnection((GNSSocket *)fakeSocket, nil, ^(BOOL flag) {
     XCTAssertTrue(flag);
     [expectation fulfill];
   });
@@ -142,12 +142,31 @@ static const NSTimeInterval kWaitForConnectionTimeout = 6.0;  // Allow for the 5
   [self waitForExpectationsWithTimeout:kTimeout handler:nil];
 }
 
+- (void)testWaitForConnection_CustomQueue {
+  GNCFakeSocket *fakeSocket = [[GNCFakeSocket alloc] init];
+  dispatch_queue_t customQueue = dispatch_queue_create("com.google.nearby.testQueue", DISPATCH_QUEUE_SERIAL);
+
+  XCTestExpectation *expectation = [self expectationWithDescription:@"Connection success on custom queue"];
+  GNCMWaitForConnection((GNSSocket *)fakeSocket, customQueue, ^(BOOL flag) {
+    XCTAssertTrue(flag);
+    // Verify that we are on the custom queue
+    const char *label = dispatch_queue_get_label(DISPATCH_CURRENT_QUEUE_LABEL);
+    XCTAssertEqual(strcmp(label, "com.google.nearby.testQueue"), 0);
+    [expectation fulfill];
+  });
+
+  // Simulate the connection callback
+  [fakeSocket simulateSocketDidConnect];
+
+  [self waitForExpectationsWithTimeout:kTimeout handler:nil];
+}
+
 - (void)testWaitForConnection_Failure_Disconnect {
   GNCFakeSocket *fakeSocket = [[GNCFakeSocket alloc] init];
 
   XCTestExpectation *expectation =
       [self expectationWithDescription:@"Connection failed on disconnect"];
-  GNCMWaitForConnection((GNSSocket *)fakeSocket, ^(BOOL flag) {
+  GNCMWaitForConnection((GNSSocket *)fakeSocket, nil, ^(BOOL flag) {
     XCTAssertFalse(flag);
     [expectation fulfill];
   });
@@ -164,7 +183,7 @@ static const NSTimeInterval kWaitForConnectionTimeout = 6.0;  // Allow for the 5
 
   XCTestExpectation *expectation =
       [self expectationWithDescription:@"Connection failed on timeout"];
-  GNCMWaitForConnection((GNSSocket *)fakeSocket, ^(BOOL flag) {
+  GNCMWaitForConnection((GNSSocket *)fakeSocket, nil, ^(BOOL flag) {
     XCTAssertFalse(flag);
     [expectation fulfill];
   });

internal/platform/implementation/apple/Mediums/BLE/Tests/GNCPeripheralManagerMultiplexerTest.m

@@ -0,0 +1,495 @@
+// Copyright 2026 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#import "internal/platform/implementation/apple/Mediums/BLE/GNCPeripheralManagerMultiplexer.h"
+
+#import <CoreBluetooth/CoreBluetooth.h>
+#import <Foundation/Foundation.h>
+#import <XCTest/XCTest.h>
+
+#import "internal/platform/implementation/apple/Mediums/BLE/GNCPeripheralManager.h"
+#import "internal/platform/implementation/apple/Mediums/BLE/Tests/GNCFakePeripheralManager.h"
+
+@interface GNCPeripheralManagerMultiplexerTest : XCTestCase
+@end
+
+@interface FakePeripheralManagerDelegate : NSObject <GNCPeripheralManagerDelegate>
+@property(nonatomic) XCTestExpectation *expectation;
+@property(nonatomic) BOOL didUpdateStateCalled;
+@property(nonatomic) CBManagerState state;
+
+@property(nonatomic) BOOL didStartAdvertisingCalled;
+@property(nonatomic) NSError *startAdvertisingError;
+
+@property(nonatomic) BOOL didAddServiceCalled;
+@property(nonatomic) CBService *addedService;
+@property(nonatomic) NSError *addServiceError;
+
+@property(nonatomic) BOOL didReceiveReadRequestCalled;
+@property(nonatomic) CBATTRequest *readRequest;
+
+@property(nonatomic) BOOL didPublishL2CAPChannelCalled;
+@property(nonatomic) CBL2CAPPSM publishedPSM;
+@property(nonatomic) NSError *publishL2CAPChannelError;
+
+@property(nonatomic) BOOL didUnpublishL2CAPChannelCalled;
+@property(nonatomic) CBL2CAPPSM unpublishedPSM;
+@property(nonatomic) NSError *unpublishL2CAPChannelError;
+
+@property(nonatomic) BOOL didOpenL2CAPChannelCalled;
+@property(nonatomic) CBL2CAPChannel *openedChannel;
+@property(nonatomic) NSError *openL2CAPChannelError;
+
+@end
+
+@implementation FakePeripheralManagerDelegate
+
+- (void)gnc_peripheralManagerDidUpdateState:(id<GNCPeripheralManager>)peripheral {
+  _didUpdateStateCalled = YES;
+  _state = peripheral.state;
+  if (_expectation) {
+    [_expectation fulfill];
+  }
+}
+
+- (void)gnc_peripheralManagerDidStartAdvertising:(id<GNCPeripheralManager>)peripheral
+                                           error:(nullable NSError *)error {
+  _didStartAdvertisingCalled = YES;
+  _startAdvertisingError = error;
+  if (_expectation) {
+    [_expectation fulfill];
+  }
+}
+
+- (void)gnc_peripheralManager:(id<GNCPeripheralManager>)peripheral
+                didAddService:(CBService *)service
+                        error:(nullable NSError *)error {
+  _didAddServiceCalled = YES;
+  _addedService = service;
+  _addServiceError = error;
+  if (_expectation) {
+    [_expectation fulfill];
+  }
+}
+
+- (void)gnc_peripheralManager:(id<GNCPeripheralManager>)peripheral
+        didReceiveReadRequest:(CBATTRequest *)request {
+  _didReceiveReadRequestCalled = YES;
+  _readRequest = request;
+  if (_expectation) {
+    [_expectation fulfill];
+  }
+}
+
+- (void)gnc_peripheralManager:(id<GNCPeripheralManager>)peripheral
+       didPublishL2CAPChannel:(CBL2CAPPSM)PSM
+                        error:(nullable NSError *)error {
+  _didPublishL2CAPChannelCalled = YES;
+  _publishedPSM = PSM;
+  _publishL2CAPChannelError = error;
+  if (_expectation) {
+    [_expectation fulfill];
+  }
+}
+
+- (void)gnc_peripheralManager:(id<GNCPeripheralManager>)peripheral
+     didUnpublishL2CAPChannel:(CBL2CAPPSM)PSM
+                        error:(NSError *)error {
+  _didUnpublishL2CAPChannelCalled = YES;
+  _unpublishedPSM = PSM;
+  _unpublishL2CAPChannelError = error;
+  if (_expectation) {
+    [_expectation fulfill];
+  }
+}
+
+- (void)gnc_peripheralManager:(id<GNCPeripheralManager>)peripheral
+          didOpenL2CAPChannel:(nullable CBL2CAPChannel *)channel
+                        error:(nullable NSError *)error {
+  _didOpenL2CAPChannelCalled = YES;
+  _openedChannel = channel;
+  _openL2CAPChannelError = error;
+  if (_expectation) {
+    [_expectation fulfill];
+  }
+}
+
+- (void)peripheralManagerDidUpdateState:(nonnull CBPeripheralManager *)peripheral {
+  _didUpdateStateCalled = YES;
+  _state = peripheral.state;
+  if (_expectation) {
+    [_expectation fulfill];
+  }
+}
+
+- (void)peripheralManagerDidStartAdvertising:(CBPeripheralManager *)peripheral
+                                       error:(nullable NSError *)error {
+  _didStartAdvertisingCalled = YES;
+  _startAdvertisingError = error;
+  if (_expectation) {
+    [_expectation fulfill];
+  }
+}
+
+- (void)peripheralManager:(CBPeripheralManager *)peripheral
+            didAddService:(CBService *)service
+                    error:(nullable NSError *)error {
+  _didAddServiceCalled = YES;
+  _addedService = service;
+  _addServiceError = error;
+  if (_expectation) {
+    [_expectation fulfill];
+  }
+}
+
+- (void)peripheralManager:(CBPeripheralManager *)peripheral
+    didReceiveReadRequest:(CBATTRequest *)request {
+  _didReceiveReadRequestCalled = YES;
+  _readRequest = request;
+  if (_expectation) {
+    [_expectation fulfill];
+  }
+}
+
+- (void)peripheralManager:(CBPeripheralManager *)peripheral
+   didPublishL2CAPChannel:(CBL2CAPPSM)PSM
+                    error:(nullable NSError *)error {
+  _didPublishL2CAPChannelCalled = YES;
+  _publishedPSM = PSM;
+  _publishL2CAPChannelError = error;
+  if (_expectation) {
+    [_expectation fulfill];
+  }
+}
+
+- (void)peripheralManager:(CBPeripheralManager *)peripheral
+ didUnpublishL2CAPChannel:(CBL2CAPPSM)PSM
+                    error:(nullable NSError *)error {
+  _didUnpublishL2CAPChannelCalled = YES;
+  _unpublishedPSM = PSM;
+  _unpublishL2CAPChannelError = error;
+  if (_expectation) {
+    [_expectation fulfill];
+  }
+}
+
+- (void)peripheralManager:(CBPeripheralManager *)peripheral
+      didOpenL2CAPChannel:(nullable CBL2CAPChannel *)channel
+                    error:(nullable NSError *)error {
+  _didOpenL2CAPChannelCalled = YES;
+  _openedChannel = channel;
+  _openL2CAPChannelError = error;
+  if (_expectation) {
+    [_expectation fulfill];
+  }
+}
+
+@end
+
+@implementation GNCPeripheralManagerMultiplexerTest
+
+- (void)testMultiplexerForwardsCallbacks {
+  GNCPeripheralManagerMultiplexer *multiplexer =
+      [[GNCPeripheralManagerMultiplexer alloc] initWithCallbackQueue:dispatch_get_main_queue()];
+  FakePeripheralManagerDelegate *delegate1 = [[FakePeripheralManagerDelegate alloc] init];
+  FakePeripheralManagerDelegate *delegate2 = [[FakePeripheralManagerDelegate alloc] init];
+
+  delegate1.expectation = [self expectationWithDescription:@"Delegate 1 called"];
+  delegate2.expectation = [self expectationWithDescription:@"Delegate 2 called"];
+
+  [multiplexer addListener:delegate1];
+  [multiplexer addListener:delegate2];
+
+  GNCFakePeripheralManager *fakeManager = [[GNCFakePeripheralManager alloc] init];
+  fakeManager.state = CBManagerStatePoweredOn;
+
+  [multiplexer gnc_peripheralManagerDidUpdateState:fakeManager];
+
+  [self waitForExpectationsWithTimeout:1 handler:nil];
+
+  XCTAssertTrue(delegate1.didUpdateStateCalled);
+  XCTAssertTrue(delegate2.didUpdateStateCalled);
+  XCTAssertEqual(delegate1.state, CBManagerStatePoweredOn);
+  XCTAssertEqual(delegate2.state, CBManagerStatePoweredOn);
+}
+
+- (void)testMultiplexerRemovesListener {
+  GNCPeripheralManagerMultiplexer *multiplexer =
+      [[GNCPeripheralManagerMultiplexer alloc] initWithCallbackQueue:dispatch_get_main_queue()];
+  FakePeripheralManagerDelegate *delegate1 = [[FakePeripheralManagerDelegate alloc] init];
+
+  delegate1.expectation = [self expectationWithDescription:@"Delegate 1 called"];
+
+  [multiplexer addListener:delegate1];
+
+  GNCFakePeripheralManager *fakeManager = [[GNCFakePeripheralManager alloc] init];
+  fakeManager.state = CBManagerStatePoweredOn;
+
+  [multiplexer removeListener:delegate1];
+  [multiplexer gnc_peripheralManagerDidUpdateState:fakeManager];
+
+  // We expect delegate1 NOT to be called.
+  // Since removals are async, we wait a bit to ensure it had a chance (or didn't).
+  XCTWaiterResult result = [XCTWaiter waitForExpectations:@[ delegate1.expectation ] timeout:0.5];
+  XCTAssertEqual(result, XCTWaiterResultTimedOut);
+  XCTAssertFalse(delegate1.didUpdateStateCalled);
+}
+
+- (void)testMultiplexerForwardsDidStartAdvertising {
+  GNCPeripheralManagerMultiplexer *multiplexer =
+      [[GNCPeripheralManagerMultiplexer alloc] initWithCallbackQueue:dispatch_get_main_queue()];
+  FakePeripheralManagerDelegate *delegate = [[FakePeripheralManagerDelegate alloc] init];
+  delegate.expectation = [self expectationWithDescription:@"Delegate called"];
+  [multiplexer addListener:delegate];
+
+  GNCFakePeripheralManager *fakeManager = [[GNCFakePeripheralManager alloc] init];
+  NSError *error = [NSError errorWithDomain:@"test" code:1 userInfo:nil];
+
+  [multiplexer gnc_peripheralManagerDidStartAdvertising:fakeManager error:error];
+
+  [self waitForExpectationsWithTimeout:1 handler:nil];
+  XCTAssertTrue(delegate.didStartAdvertisingCalled);
+  XCTAssertEqualObjects(delegate.startAdvertisingError, error);
+}
+
+- (void)testMultiplexerForwardsDidAddService {
+  GNCPeripheralManagerMultiplexer *multiplexer =
+      [[GNCPeripheralManagerMultiplexer alloc] initWithCallbackQueue:dispatch_get_main_queue()];
+  FakePeripheralManagerDelegate *delegate = [[FakePeripheralManagerDelegate alloc] init];
+  delegate.expectation = [self expectationWithDescription:@"Delegate called"];
+  [multiplexer addListener:delegate];
+
+  GNCFakePeripheralManager *fakeManager = [[GNCFakePeripheralManager alloc] init];
+  CBMutableService *service =
+      [[CBMutableService alloc] initWithType:[CBUUID UUIDWithString:@"180D"] primary:YES];
+  NSError *error = [NSError errorWithDomain:@"test" code:2 userInfo:nil];
+
+  [multiplexer gnc_peripheralManager:fakeManager didAddService:service error:error];
+
+  [self waitForExpectationsWithTimeout:1 handler:nil];
+  XCTAssertTrue(delegate.didAddServiceCalled);
+  XCTAssertEqualObjects(delegate.addedService, service);
+  XCTAssertEqualObjects(delegate.addServiceError, error);
+}
+
+- (void)testMultiplexerForwardsDidReceiveReadRequest {
+  GNCPeripheralManagerMultiplexer *multiplexer =
+      [[GNCPeripheralManagerMultiplexer alloc] initWithCallbackQueue:dispatch_get_main_queue()];
+  FakePeripheralManagerDelegate *delegate = [[FakePeripheralManagerDelegate alloc] init];
+  delegate.expectation = [self expectationWithDescription:@"Delegate called"];
+  [multiplexer addListener:delegate];
+
+  GNCFakePeripheralManager *fakeManager = [[GNCFakePeripheralManager alloc] init];
+  id request = [NSNull null];  // Use NSNull or any object as placeholder since we can't create
+                               // CBATTRequest
+
+  [multiplexer gnc_peripheralManager:fakeManager didReceiveReadRequest:request];
+
+  [self waitForExpectationsWithTimeout:1 handler:nil];
+  XCTAssertTrue(delegate.didReceiveReadRequestCalled);
+  XCTAssertEqual(delegate.readRequest, request);
+}
+
+- (void)testMultiplexerForwardsDidPublishL2CAPChannel {
+  GNCPeripheralManagerMultiplexer *multiplexer =
+      [[GNCPeripheralManagerMultiplexer alloc] initWithCallbackQueue:dispatch_get_main_queue()];
+  FakePeripheralManagerDelegate *delegate = [[FakePeripheralManagerDelegate alloc] init];
+  delegate.expectation = [self expectationWithDescription:@"Delegate called"];
+  [multiplexer addListener:delegate];
+
+  GNCFakePeripheralManager *fakeManager = [[GNCFakePeripheralManager alloc] init];
+  CBL2CAPPSM psm = 42;
+  NSError *error = [NSError errorWithDomain:@"test" code:3 userInfo:nil];
+
+  [multiplexer gnc_peripheralManager:fakeManager didPublishL2CAPChannel:psm error:error];
+
+  [self waitForExpectationsWithTimeout:1 handler:nil];
+  XCTAssertTrue(delegate.didPublishL2CAPChannelCalled);
+  XCTAssertEqual(delegate.publishedPSM, psm);
+  XCTAssertEqualObjects(delegate.publishL2CAPChannelError, error);
+}
+
+- (void)testMultiplexerForwardsDidUnpublishL2CAPChannel {
+  GNCPeripheralManagerMultiplexer *multiplexer =
+      [[GNCPeripheralManagerMultiplexer alloc] initWithCallbackQueue:dispatch_get_main_queue()];
+  FakePeripheralManagerDelegate *delegate = [[FakePeripheralManagerDelegate alloc] init];
+  delegate.expectation = [self expectationWithDescription:@"Delegate called"];
+  [multiplexer addListener:delegate];
+
+  GNCFakePeripheralManager *fakeManager = [[GNCFakePeripheralManager alloc] init];
+  CBL2CAPPSM psm = 42;
+  NSError *error = [NSError errorWithDomain:@"test" code:4 userInfo:nil];
+
+  [multiplexer gnc_peripheralManager:fakeManager didUnpublishL2CAPChannel:psm error:error];
+
+  [self waitForExpectationsWithTimeout:1 handler:nil];
+  XCTAssertTrue(delegate.didUnpublishL2CAPChannelCalled);
+  XCTAssertEqual(delegate.unpublishedPSM, psm);
+  XCTAssertEqualObjects(delegate.unpublishL2CAPChannelError, error);
+}
+
+- (void)testMultiplexerForwardsDidOpenL2CAPChannel {
+  GNCPeripheralManagerMultiplexer *multiplexer =
+      [[GNCPeripheralManagerMultiplexer alloc] initWithCallbackQueue:dispatch_get_main_queue()];
+  FakePeripheralManagerDelegate *delegate = [[FakePeripheralManagerDelegate alloc] init];
+  delegate.expectation = [self expectationWithDescription:@"Delegate called"];
+  [multiplexer addListener:delegate];
+
+  GNCFakePeripheralManager *fakeManager = [[GNCFakePeripheralManager alloc] init];
+  id channel = [NSNull null];  // Placeholder
+  NSError *error = [NSError errorWithDomain:@"test" code:5 userInfo:nil];
+
+  [multiplexer gnc_peripheralManager:fakeManager didOpenL2CAPChannel:channel error:error];
+
+  [self waitForExpectationsWithTimeout:1 handler:nil];
+  XCTAssertTrue(delegate.didOpenL2CAPChannelCalled);
+  XCTAssertEqual(delegate.openedChannel, channel);
+  XCTAssertEqualObjects(delegate.openL2CAPChannelError, error);
+}
+
+- (void)testCBPeripheralManagerDelegateDidUpdateState {
+  GNCPeripheralManagerMultiplexer *multiplexer =
+      [[GNCPeripheralManagerMultiplexer alloc] initWithCallbackQueue:dispatch_get_main_queue()];
+  FakePeripheralManagerDelegate *delegate = [[FakePeripheralManagerDelegate alloc] init];
+  delegate.expectation = [self expectationWithDescription:@"Delegate called"];
+  [multiplexer addListener:delegate];
+
+  GNCFakePeripheralManager *fakeManager = [[GNCFakePeripheralManager alloc] init];
+  fakeManager.state = CBManagerStatePoweredOn;
+
+  [multiplexer peripheralManagerDidUpdateState:(CBPeripheralManager *)fakeManager];
+
+  [self waitForExpectationsWithTimeout:1 handler:nil];
+  XCTAssertTrue(delegate.didUpdateStateCalled);
+  XCTAssertEqual(delegate.state, CBManagerStatePoweredOn);
+}
+
+- (void)testCBPeripheralManagerDelegateDidStartAdvertising {
+  GNCPeripheralManagerMultiplexer *multiplexer =
+      [[GNCPeripheralManagerMultiplexer alloc] initWithCallbackQueue:dispatch_get_main_queue()];
+  FakePeripheralManagerDelegate *delegate = [[FakePeripheralManagerDelegate alloc] init];
+  delegate.expectation = [self expectationWithDescription:@"Delegate called"];
+  [multiplexer addListener:delegate];
+
+  GNCFakePeripheralManager *fakeManager = [[GNCFakePeripheralManager alloc] init];
+  NSError *error = [NSError errorWithDomain:@"test" code:10 userInfo:nil];
+
+  [multiplexer peripheralManagerDidStartAdvertising:(CBPeripheralManager *)fakeManager error:error];
+
+  [self waitForExpectationsWithTimeout:1 handler:nil];
+  XCTAssertTrue(delegate.didStartAdvertisingCalled);
+  XCTAssertEqualObjects(delegate.startAdvertisingError, error);
+}
+
+- (void)testCBPeripheralManagerDelegateDidAddService {
+  GNCPeripheralManagerMultiplexer *multiplexer =
+      [[GNCPeripheralManagerMultiplexer alloc] initWithCallbackQueue:dispatch_get_main_queue()];
+  FakePeripheralManagerDelegate *delegate = [[FakePeripheralManagerDelegate alloc] init];
+  delegate.expectation = [self expectationWithDescription:@"Delegate called"];
+  [multiplexer addListener:delegate];
+
+  GNCFakePeripheralManager *fakeManager = [[GNCFakePeripheralManager alloc] init];
+  CBMutableService *service =
+      [[CBMutableService alloc] initWithType:[CBUUID UUIDWithString:@"180F"] primary:YES];
+  NSError *error = [NSError errorWithDomain:@"test" code:11 userInfo:nil];
+
+  [multiplexer peripheralManager:(CBPeripheralManager *)fakeManager didAddService:service error:error];
+
+  [self waitForExpectationsWithTimeout:1 handler:nil];
+  XCTAssertTrue(delegate.didAddServiceCalled);
+  XCTAssertEqualObjects(delegate.addedService, service);
+  XCTAssertEqualObjects(delegate.addServiceError, error);
+}
+
+- (void)testCBPeripheralManagerDelegateDidReceiveReadRequest {
+  GNCPeripheralManagerMultiplexer *multiplexer =
+      [[GNCPeripheralManagerMultiplexer alloc] initWithCallbackQueue:dispatch_get_main_queue()];
+  FakePeripheralManagerDelegate *delegate = [[FakePeripheralManagerDelegate alloc] init];
+  delegate.expectation = [self expectationWithDescription:@"Delegate called"];
+  [multiplexer addListener:delegate];
+
+  GNCFakePeripheralManager *fakeManager = [[GNCFakePeripheralManager alloc] init];
+  id request = [NSNull null];
+
+  [multiplexer peripheralManager:(CBPeripheralManager *)fakeManager didReceiveReadRequest:request];
+
+  [self waitForExpectationsWithTimeout:1 handler:nil];
+  XCTAssertTrue(delegate.didReceiveReadRequestCalled);
+  XCTAssertEqual(delegate.readRequest, request);
+}
+
+- (void)testCBPeripheralManagerDelegateDidPublishL2CAPChannel {
+  GNCPeripheralManagerMultiplexer *multiplexer =
+      [[GNCPeripheralManagerMultiplexer alloc] initWithCallbackQueue:dispatch_get_main_queue()];
+  FakePeripheralManagerDelegate *delegate = [[FakePeripheralManagerDelegate alloc] init];
+  delegate.expectation = [self expectationWithDescription:@"Delegate called"];
+  [multiplexer addListener:delegate];
+
+  GNCFakePeripheralManager *fakeManager = [[GNCFakePeripheralManager alloc] init];
+  CBL2CAPPSM psm = 100;
+  NSError *error = [NSError errorWithDomain:@"test" code:13 userInfo:nil];
+
+  [multiplexer peripheralManager:(CBPeripheralManager *)fakeManager
+          didPublishL2CAPChannel:psm
+                           error:error];
+
+  [self waitForExpectationsWithTimeout:1 handler:nil];
+  XCTAssertTrue(delegate.didPublishL2CAPChannelCalled);
+  XCTAssertEqual(delegate.publishedPSM, psm);
+  XCTAssertEqualObjects(delegate.publishL2CAPChannelError, error);
+}
+
+- (void)testCBPeripheralManagerDelegateDidUnpublishL2CAPChannel {
+  GNCPeripheralManagerMultiplexer *multiplexer =
+      [[GNCPeripheralManagerMultiplexer alloc] initWithCallbackQueue:dispatch_get_main_queue()];
+  FakePeripheralManagerDelegate *delegate = [[FakePeripheralManagerDelegate alloc] init];
+  delegate.expectation = [self expectationWithDescription:@"Delegate called"];
+  [multiplexer addListener:delegate];
+
+  GNCFakePeripheralManager *fakeManager = [[GNCFakePeripheralManager alloc] init];
+  CBL2CAPPSM psm = 101;
+  NSError *error = [NSError errorWithDomain:@"test" code:14 userInfo:nil];
+
+  [multiplexer peripheralManager:(CBPeripheralManager *)fakeManager
+       didUnpublishL2CAPChannel:psm
+                          error:error];
+
+  [self waitForExpectationsWithTimeout:1 handler:nil];
+  XCTAssertTrue(delegate.didUnpublishL2CAPChannelCalled);
+  XCTAssertEqual(delegate.unpublishedPSM, psm);
+  XCTAssertEqualObjects(delegate.unpublishL2CAPChannelError, error);
+}
+
+- (void)testCBPeripheralManagerDelegateDidOpenL2CAPChannel {
+  GNCPeripheralManagerMultiplexer *multiplexer =
+      [[GNCPeripheralManagerMultiplexer alloc] initWithCallbackQueue:dispatch_get_main_queue()];
+  FakePeripheralManagerDelegate *delegate = [[FakePeripheralManagerDelegate alloc] init];
+  delegate.expectation = [self expectationWithDescription:@"Delegate called"];
+  [multiplexer addListener:delegate];
+
+  GNCFakePeripheralManager *fakeManager = [[GNCFakePeripheralManager alloc] init];
+  id channel = [NSNull null];
+  NSError *error = [NSError errorWithDomain:@"test" code:15 userInfo:nil];
+
+  [multiplexer peripheralManager:(CBPeripheralManager *)fakeManager
+            didOpenL2CAPChannel:channel
+                          error:error];
+
+  [self waitForExpectationsWithTimeout:1 handler:nil];
+  XCTAssertTrue(delegate.didOpenL2CAPChannelCalled);
+  XCTAssertEqual(delegate.openedChannel, channel);
+  XCTAssertEqualObjects(delegate.openL2CAPChannelError, error);
+}
+
+@end

internal/platform/implementation/apple/Mediums/WiFiCommon/BUILD

@@ -32,7 +32,7 @@ objc_library(
         "GNCNWFramework.m",
         "GNCNWFrameworkError.m",
         "GNCNWFrameworkServerSocket.m",
-        "GNCNWFrameworkSocket.m",
+        "GNCNWFrameworkSocket.mm",
         "GNCNWListenerImpl.m",
         "GNCNWParameters.m",
     ],

internal/platform/implementation/apple/Mediums/WiFiCommon/GNCNWFrameworkError.h

@@ -26,4 +26,5 @@ typedef NS_ERROR_ENUM(GNCNWFrameworkErrorDomain, GNCNWFrameworkError){
     GNCNWFrameworkErrorUnknown,
     GNCNWFrameworkErrorTimedOut,
     GNCNWFrameworkErrorDuplicateDiscovererForServiceType,
+    GNCNWFrameworkErrorNotConnected,
 };

internal/platform/implementation/apple/Mediums/WiFiCommon/GNCNWFrameworkSocket.h

@@ -15,6 +15,12 @@
 #import <Foundation/Foundation.h>
 #import <Network/Network.h>
 
+#ifdef __cplusplus
+#include <optional>
+#include <string>
+#endif
+
+
 @protocol GNCNWConnection;
 
 @interface GNCNWFrameworkSocket : NSObject
@@ -44,6 +50,21 @@
  */
 - (nullable NSData *)readMaxLength:(NSUInteger)length error:(NSError **_Nullable)error;
 
+/**
+ * Reads the requested amount of bytes from the connection and converts it to a string.
+ *
+ * Blocks execution until the bytes have been read or an error occurs.
+ *
+ * @param length The number of bytes to read.
+ * @param[out] error Error that will be populated on failure. A read may return non-nil data along
+ *                   with an error. This normally happens if the data read is shorter than the
+ *                   requested length.
+ */
+#ifdef __cplusplus
+- (std::optional<std::string>)readStringWithMaxLength:(NSUInteger)length
+                                                error:(NSError **_Nullable)error;
+#endif
+
 /**
  * Writes the given data to the connection.
  *
@@ -54,6 +75,17 @@
  */
 - (BOOL)write:(NSData *)data error:(NSError **_Nullable)error;
 
+/**
+ * Writes raw bytes to the connection.
+ *
+ * @param bytes The buffer to write.
+ * @param length The number of bytes to write.
+ * @param error Error that will be populated on failure.
+ */
+- (BOOL)writeBytes:(const void *)bytes 
+            length:(NSUInteger)length 
+             error:(NSError **_Nullable)error;
+
 /**
  * Gracefully closes the connection to remote endpoint.
  *

internal/platform/implementation/apple/Mediums/WiFiCommon/GNCNWFrameworkSocket.mm

@@ -17,6 +17,9 @@
 #import <Foundation/Foundation.h>
 #import <Network/Network.h>
 
+#include <optional>
+#include <string>
+
 #import "internal/platform/implementation/apple/Log/GNCLogger.h"
 #import "internal/platform/implementation/apple/Mediums/WiFiCommon/GNCNWConnection.h"
 #import "internal/platform/implementation/apple/Mediums/WiFiCommon/GNCNWFrameworkError.h"
@@ -85,6 +88,52 @@ static const NSTimeInterval kConnectionWriteTimeout = 5.0;  // 5 seconds timeout
   return blockResult;
 }
 
+- (std::optional<std::string>)readStringWithMaxLength:(NSUInteger)length error:(NSError **)error {
+  if (!self.connection) {
+    if (error) {
+      *error = [NSError errorWithDomain:GNCNWFrameworkErrorDomain
+                                   code:GNCNWFrameworkErrorNotConnected
+                               userInfo:nil];
+    }
+    return std::nullopt;
+  }
+
+  dispatch_semaphore_t semaphore = dispatch_semaphore_create(0);
+  __block std::string resultString;
+  __block NSError *blockError = nil;
+  __block BOOL contentReceived = NO;
+
+  [self.connection
+      receiveMessageWithMinLength:(uint32_t)length
+                        maxLength:(uint32_t)length
+                completionHandler:^(dispatch_data_t _Nullable content,
+                                    nw_content_context_t _Nullable context, bool isComplete,
+                                    nw_error_t _Nullable receiveError) {
+                  if (receiveError) {
+                    blockError = (__bridge_transfer NSError *)nw_error_copy_cf_error(receiveError);
+                  }
+                  if (content) {
+                    contentReceived = YES;
+                    // OPTIMIZATION: Copy directly from dispatch_data_t into std::string
+                    resultString.reserve(dispatch_data_get_size(content));
+                    dispatch_data_apply(content, ^bool(dispatch_data_t region, size_t offset,
+                                                       const void *buffer, size_t size) {
+                      resultString.append((const char *)buffer, size);
+                      return true;
+                    });
+                  }
+                  dispatch_semaphore_signal(semaphore);
+                }];
+
+  // Block the current thread until the network callback completes.
+  dispatch_semaphore_wait(semaphore, DISPATCH_TIME_FOREVER);
+
+  if (error != nil) {
+    *error = blockError;
+  }
+  return (!contentReceived) ? std::nullopt : std::make_optional(std::move(resultString));
+}
+
 - (BOOL)write:(NSData *)data error:(NSError **)error {
   if (!self.connection) {
     if (error) {
@@ -136,6 +185,50 @@ static const NSTimeInterval kConnectionWriteTimeout = 5.0;  // 5 seconds timeout
   return signaled && blockSuccess;
 }
 
+- (BOOL)writeBytes:(const void *)bytes length:(NSUInteger)length error:(NSError **)error {
+  if (!self.connection) {
+    if (error) {
+      *error = [NSError errorWithDomain:GNCNWFrameworkErrorDomain
+                                   code:GNCNWFrameworkErrorNotConnected
+                               userInfo:nil];
+    }
+    return NO;
+  }
+
+  dispatch_semaphore_t semaphore = dispatch_semaphore_create(0);
+
+  __block NSError *blockError = nil;
+
+  // OPTIMIZATION: Use DISPATCH_DATA_DESTRUCTOR_DEFAULT to perform a
+  // single copy into a GCD-managed buffer. No NSData required.
+  // TODO: edwinwu - Investigate to see if it is worth to make it zero-copy by replacing
+  // DISPATCH_DATA_DESTRUCTOR_DEFAULT with a custom empty destructor:
+  //     dispatch_data_t dispatchData = dispatch_data_create(bytes, length, nil, ^{
+  //         // Zero-copy: ownership remains with the caller.
+  //     });
+  dispatch_data_t dispatchData =
+      dispatch_data_create(bytes, length, nil, DISPATCH_DATA_DESTRUCTOR_DEFAULT);
+
+  [self.connection sendData:dispatchData
+                    context:NW_CONNECTION_DEFAULT_MESSAGE_CONTEXT
+                 isComplete:NO
+          completionHandler:^(nw_error_t _Nullable sendError) {
+            if (sendError) {
+              blockError = (__bridge_transfer NSError *)nw_error_copy_cf_error(sendError);
+            }
+            dispatch_semaphore_signal(semaphore);
+          }];
+
+  // Wait until signaled or the 5-second timeout passes
+  intptr_t waitResult = dispatch_semaphore_wait(
+      semaphore,
+      dispatch_time(DISPATCH_TIME_NOW, (int64_t)(kConnectionWriteTimeout * NSEC_PER_SEC)));
+  if (error != nil) {
+    *error = blockError;
+  }
+  return (waitResult == 0) && (blockError == nil);
+}
+
 - (void)close {
   [_connection cancel];
   _connection = nil;

internal/platform/implementation/apple/Mediums/WiFiCommon/Tests/BUILD

@@ -29,7 +29,7 @@ objc_library(
         "GNCFakeNWConnection.m",
         "GNCFakeNWFramework.m",
         "GNCFakeNWFrameworkServerSocket.m",
-        "GNCFakeNWFrameworkSocket.m",
+        "GNCFakeNWFrameworkSocket.mm",
         "GNCFakeNWListener.m",
     ],
     hdrs = [
@@ -57,7 +57,7 @@ objc_library(
         "GNCNWBrowserImplTest.m",
         "GNCNWConnectionImplTest.m",
         "GNCNWFrameworkServerSocketTest.m",
-        "GNCNWFrameworkSocketTest.m",
+        "GNCNWFrameworkSocketTest.mm",
         "GNCNWFrameworkTest.m",
         "GNCNWListenerImplTest.m",
         "GNCNWParametersTest.m",

internal/platform/implementation/apple/Mediums/WiFiCommon/Tests/GNCFakeNWFrameworkSocket.mm

@@ -44,6 +44,25 @@
   return [NSData data];
 }
 
+- (std::optional<std::string>)readStringWithMaxLength:(NSUInteger)length error:(NSError **)error {
+  if (self.readError) {
+    if (error) *error = self.readError;
+    return std::nullopt;
+  }
+  if (self.dataToRead) {
+    NSData *data = self.dataToRead;
+    self.dataToRead = nil;
+    NSUInteger actualLength = MIN(length, data.length);
+    if (data.length > actualLength) {
+      self.dataToRead =
+          [data subdataWithRange:NSMakeRange(actualLength, data.length - actualLength)];
+    }
+    NSData *returnData = [data subdataWithRange:NSMakeRange(0, actualLength)];
+    return std::string((const char *)returnData.bytes, returnData.length);
+  }
+  return std::string();
+}
+
 - (BOOL)write:(NSData *)data error:(NSError **)error {
   if (self.writeError) {
     if (error) {
@@ -55,6 +74,17 @@
   return YES;
 }
 
+- (BOOL)writeBytes:(const void *)bytes length:(NSUInteger)length error:(NSError **)error {
+  if (self.writeError) {
+    if (error) {
+      *error = self.writeError;
+    }
+    return NO;
+  }
+  [self.writtenData appendBytes:bytes length:length];
+  return YES;
+}
+
 - (void)close {
   self.isClosed = YES;
 }

internal/platform/implementation/apple/Mediums/WiFiCommon/Tests/GNCNWFrameworkSocketTest.mm

@@ -17,6 +17,9 @@
 #import <Network/Network.h>
 #import <XCTest/XCTest.h>
 
+#include <optional>
+#include <string>
+
 #import "internal/platform/implementation/apple/Mediums/WiFiCommon/Tests/GNCFakeNWConnection.h"
 
 NS_ASSUME_NONNULL_BEGIN
@@ -75,6 +78,38 @@ NS_ASSUME_NONNULL_BEGIN
   XCTAssertNil(error);
 }
 
+- (void)testReadStringWithMaxLength_Success {
+  NSError *error = nil;
+  NSString *testString = @"testData";
+  NSData *testData = [testString dataUsingEncoding:NSUTF8StringEncoding];
+  dispatch_data_t dispatchData = dispatch_data_create(testData.bytes, testData.length, dispatch_get_main_queue(), ^{});
+  _fakeConnection.dataToReceive = dispatchData;
+
+  std::optional<std::string> receivedString = [_socket readStringWithMaxLength:testData.length error:&error];
+
+  XCTAssertTrue(receivedString.has_value());
+  XCTAssertEqualObjects(@(receivedString.value().c_str()), testString);
+  XCTAssertNil(error);
+}
+
+- (void)testReadStringWithMaxLength_Error {
+  NSError *error = nil;
+  _fakeConnection.simulateReceiveFailure = YES;
+
+  std::optional<std::string> receivedString = [_socket readStringWithMaxLength:10 error:&error];
+
+  XCTAssertFalse(receivedString.has_value());
+  XCTAssertNil(error);  // Fake doesn't produce an NSError
+}
+
+- (void)testReadStringWithMaxLength_Zero {
+  NSError *error = nil;
+  std::optional<std::string> receivedString = [_socket readStringWithMaxLength:0 error:&error];
+
+  XCTAssertFalse(receivedString.has_value());
+  XCTAssertNil(error);
+}
+
 - (void)testWrite_Success {
   NSError *error = nil;
   NSString *testString = @"testData";
@@ -97,6 +132,28 @@ NS_ASSUME_NONNULL_BEGIN
   XCTAssertFalse(result);
 }
 
+- (void)testWriteBytes_Success {
+  NSError *error = nil;
+  NSString *testString = @"testData";
+  NSData *testData = [testString dataUsingEncoding:NSUTF8StringEncoding];
+
+  BOOL result = [_socket writeBytes:testData.bytes length:testData.length error:&error];
+
+  XCTAssertTrue(result);
+  XCTAssertNil(error);
+}
+
+- (void)testWriteBytes_Error {
+  NSError *error = nil;
+  NSString *testString = @"testData";
+  NSData *testData = [testString dataUsingEncoding:NSUTF8StringEncoding];
+  _fakeConnection.simulateSendFailure = YES;
+
+  BOOL result = [_socket writeBytes:testData.bytes length:testData.length error:&error];
+
+  XCTAssertFalse(result);
+}
+
 - (void)testClose {
   XCTAssertFalse(_fakeConnection.cancelCalled);
   [_socket close];
@@ -105,6 +162,7 @@ NS_ASSUME_NONNULL_BEGIN
   NSError *error = nil;
   XCTAssertNil([_socket readMaxLength:10 error:&error]);
   XCTAssertFalse([_socket write:[NSData data] error:&error]);
+  XCTAssertFalse([_socket writeBytes:"test" length:4 error:&error]);
 }
 
 @end

internal/platform/implementation/apple/Tests/BUILD

@@ -56,8 +56,10 @@ objc_library(
         "//internal/platform/implementation:comm",
         "//internal/platform/implementation:platform",
         "//internal/platform/implementation:types",
+        "//internal/platform/implementation:webrtc_platform",
         "//internal/platform/implementation/apple",  # buildcleaner: keep
         "//internal/platform/implementation/apple:Shared",
+        "//internal/platform/implementation/apple:apple_webrtc",  # buildcleaner: keep
         "//internal/platform/implementation/apple:ble_v2",
         "//internal/platform/implementation/apple:network_utils",
         "//internal/platform/implementation/apple/Flags",

internal/platform/implementation/apple/Tests/GNCAwdlMediumTest.mm

@@ -18,6 +18,9 @@
 
 #include <string>
 
+#include "connections/implementation/flags/nearby_connections_feature_flags.h"
+#include "internal/flags/nearby_flags.h"
+
 #import "internal/platform/implementation/apple/Mediums/WiFiCommon/GNCIPv4Address.h"
 #import "internal/platform/implementation/apple/Mediums/WiFiCommon/GNCNWFramework.h"
 #import "internal/platform/implementation/apple/Mediums/WiFiCommon/Tests/GNCFakeNWConnection.h"
@@ -45,6 +48,7 @@ static const int kTestPort = 1234;
 
 - (void)tearDown {
   _awdlMedium.reset();
+  nearby::NearbyFlags::GetInstance().ResetOverridedValues();
   [super tearDown];
 }
 
@@ -128,6 +132,10 @@ static const int kTestPort = 1234;
 }
 
 - (void)testSocketAndStream {
+  nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+      ::nearby::connections::config_package_nearby::nearby_connections_feature::kEnableSingleCopy,
+      false);
+
   // Create a server socket.
   std::unique_ptr<nearby::api::AwdlServerSocket> serverSocket =
       _awdlMedium->ListenForService(kTestPort);
@@ -167,6 +175,49 @@ static const int kTestPort = 1234;
   XCTAssertTrue(fakeServerSocket.isClosed);
 }
 
+- (void)testSocketAndStream_SingleCopyEnabled {
+  // Enable the flag.
+  nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+      ::nearby::connections::config_package_nearby::nearby_connections_feature::kEnableSingleCopy,
+      true);
+
+  // Create a server socket.
+  std::unique_ptr<nearby::api::AwdlServerSocket> serverSocket =
+      _awdlMedium->ListenForService(kTestPort);
+  XCTAssertTrue(serverSocket != nullptr);
+
+  GNCFakeNWFrameworkServerSocket* fakeServerSocket =
+      (GNCFakeNWFrameworkServerSocket*)_fakeNWFramework.serverSockets[0];
+  GNCFakeNWConnection* connection = [[GNCFakeNWConnection alloc] init];
+  GNCFakeNWFrameworkSocket* fakeSocket =
+      [[GNCFakeNWFrameworkSocket alloc] initWithConnection:connection];
+  fakeServerSocket.socketToReturnOnAccept = fakeSocket;
+
+  // Accept a client socket.
+  std::unique_ptr<nearby::api::AwdlSocket> clientSocket = serverSocket->Accept();
+  XCTAssertTrue(clientSocket != nullptr);
+
+  // Test input stream with optimized single-copy read.
+  nearby::InputStream& inputStream = clientSocket->GetInputStream();
+  fakeSocket.dataToRead = [@"optimized awdl data" dataUsingEncoding:NSUTF8StringEncoding];
+  // "optimized awdl data" is 19 bytes.
+  nearby::ExceptionOr<nearby::ByteArray> readData = inputStream.Read(19);
+
+  XCTAssertTrue(readData.ok());
+  XCTAssertEqual(std::string(readData.result()), "optimized awdl data");
+
+  // Test output stream.
+  nearby::OutputStream& outputStream = clientSocket->GetOutputStream();
+  absl::string_view writeData("write data");
+  XCTAssertTrue(outputStream.Write(writeData).Ok());
+  XCTAssertEqualObjects(fakeSocket.writtenData,
+                        [@"write data" dataUsingEncoding:NSUTF8StringEncoding]);
+
+  // Clean up.
+  XCTAssertTrue(clientSocket->Close().Ok());
+  XCTAssertTrue(serverSocket->Close().Ok());
+}
+
 - (void)testServerSocketGetIPAddress {
   // Create a server socket.
   std::unique_ptr<nearby::api::AwdlServerSocket> serverSocket =
@@ -195,6 +246,39 @@ static const int kTestPort = 1234;
   XCTAssertTrue(serverSocket->Close().Ok());
 }
 
+- (void)testOutputStreamWrite_SingleCopyEnabled {
+  // Enable the flag.
+  nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+      ::nearby::connections::config_package_nearby::nearby_connections_feature::kEnableSingleCopy,
+      true);
+
+  // Create a server socket and accept a client.
+  std::unique_ptr<nearby::api::AwdlServerSocket> serverSocket =
+      _awdlMedium->ListenForService(kTestPort);
+  GNCFakeNWFrameworkServerSocket* fakeServerSocket =
+      (GNCFakeNWFrameworkServerSocket*)_fakeNWFramework.serverSockets[0];
+  GNCFakeNWConnection* connection = [[GNCFakeNWConnection alloc] init];
+  GNCFakeNWFrameworkSocket* fakeSocket =
+      [[GNCFakeNWFrameworkSocket alloc] initWithConnection:connection];
+  fakeServerSocket.socketToReturnOnAccept = fakeSocket;
+  std::unique_ptr<nearby::api::AwdlSocket> clientSocket = serverSocket->Accept();
+  XCTAssertTrue(clientSocket != nullptr);
+
+  // Test output stream.
+  nearby::OutputStream& outputStream = clientSocket->GetOutputStream();
+  absl::string_view writeData("optimized write data");
+  XCTAssertTrue(outputStream.Write(writeData).Ok());
+  XCTAssertEqualObjects(fakeSocket.writtenData,
+                        [@"optimized write data" dataUsingEncoding:NSUTF8StringEncoding]);
+
+  // Clean up.
+  XCTAssertTrue(clientSocket->Close().Ok());
+  XCTAssertTrue(serverSocket->Close().Ok());
+
+  // Reset the flag.
+  nearby::NearbyFlags::GetInstance().ResetOverridedValues();
+}
+
 - (void)testOutputStreamClose {
   // Create a server socket and accept a client.
   std::unique_ptr<nearby::api::AwdlServerSocket> serverSocket =

internal/platform/implementation/apple/Tests/GNCDeviceInfoTest.mm

@@ -49,27 +49,20 @@
 }
 
 - (void)testGetDownloadPath {
-  XCTAssertNotNil(@(_deviceInfo->GetDownloadPath().value().GetPath().c_str()));
+  XCTAssertNotNil(@(_deviceInfo->GetDownloadPath().GetPath().c_str()));
 }
 
 - (void)testGetLocalAppDataPath {
-  XCTAssertNotNil(@(_deviceInfo->GetLocalAppDataPath().value().GetPath().c_str()));
-}
-
-- (void)testGetCommonAppDataPath {
-  XCTAssertNotNil(@(_deviceInfo->GetCommonAppDataPath().value().GetPath().c_str()));
+  XCTAssertNotNil(
+      @(_deviceInfo->GetLocalAppDataPath(nearby::FilePath("sub_path")).GetPath().c_str()));
 }
 
 - (void)testGetTemporaryPath {
-  XCTAssertNotNil(@(_deviceInfo->GetTemporaryPath().value().GetPath().c_str()));
+  XCTAssertNotNil(@(_deviceInfo->GetTemporaryPath().GetPath().c_str()));
 }
 
 - (void)testGetLogPath {
-  XCTAssertNotNil(@(_deviceInfo->GetLogPath().value().GetPath().c_str()));
-}
-
-- (void)testGetCrashDumpPath {
-  XCTAssertNotNil(@(_deviceInfo->GetCrashDumpPath().value().GetPath().c_str()));
+  XCTAssertNotNil(@(_deviceInfo->GetLogPath().GetPath().c_str()));
 }
 
 - (void)testIsScreenLocked {

internal/platform/implementation/apple/Tests/GNCMultiThreadExecutorTest.mm

@@ -93,7 +93,7 @@ using MultiThreadExecutor = ::nearby::api::SubmittableExecutor;
   dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_TARGET_QUEUE_DEFAULT, 0);
   XCTestExpectation *expectation = [self expectationWithDescription:@"finished"];
 
-  const int kRunnableCount = 1000;
+  const int kRunnableCount = 100;
   for (int i = 0; i < kRunnableCount; i++) {
     executor->Execute([self]() { self.counter++; });
   }

internal/platform/implementation/apple/Tests/GNCPlatformTest.mm

@@ -13,6 +13,7 @@
 // limitations under the License.
 
 #include "internal/platform/implementation/platform.h"
+#include "internal/platform/implementation/webrtc_platform.h"
 
 #import <Foundation/Foundation.h>
 #import <XCTest/XCTest.h>
@@ -320,7 +321,7 @@ void GNCEnsureFileAtPath(std::string path) {
 }
 
 - (void)testCreateWebRtcMedium {
-  auto webrtc_medium = nearby::api::ImplementationPlatform::CreateWebRtcMedium();
+  auto webrtc_medium = nearby::api::WebRtcImplementationPlatform::CreateWebRtcMedium();
   XCTAssertNotEqual(webrtc_medium.get(), nullptr);
 }
 

internal/platform/implementation/apple/Tests/GNCSingleThreadExecutorTest.mm

@@ -76,20 +76,14 @@ using SingleThreadExecutor = ::nearby::api::SubmittableExecutor;
 // Tests that shutting down an existing task allows to complete.
 - (void)testShutdownToAllowExistingTaskComplete {
   std::unique_ptr<SingleThreadExecutor> executor([self executor]);
-
-  dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_TARGET_QUEUE_DEFAULT, 0);
   XCTestExpectation *expectation = [self expectationWithDescription:@"finished"];
-
-  executor->Execute([self]() { self.counter++; });
-
-  executor->Shutdown();
-
-  dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0.2 * NSEC_PER_SEC)), queue, ^{
-    XCTAssertEqual(self.counter, 1);
+  executor->Execute([self, expectation]() {
+    self.counter++;
     [expectation fulfill];
   });
-
-  [self waitForExpectationsWithTimeout:0.5 handler:nil];
+  executor->Shutdown();
+  [self waitForExpectationsWithTimeout:1.0 handler:nil];
+  XCTAssertEqual(self.counter, 1);
 }
 
 @end

internal/platform/implementation/apple/Tests/GNCTimerTest.mm

@@ -65,7 +65,7 @@
   auto timer = std::make_unique<nearby::apple::Timer>();
 
   std::atomic<int> fireCount = 0;
-  XCTAssertTrue(timer->Create(10, 10, [&]() {
+  XCTAssertTrue(timer->Create(100, 100, [&]() {
     if (fireCount.fetch_add(1) == 1) {
       dispatch_async(dispatch_get_main_queue(), ^{
         [expectation fulfill];
@@ -73,9 +73,9 @@
     }
   }));
 
-  [self waitForExpectationsWithTimeout:1.0 handler:nil];
+  [self waitForExpectationsWithTimeout:2.0 handler:nil];
   XCTAssertTrue(timer->Stop());
-  XCTAssertEqual(fireCount.load(), 2);
+  XCTAssertGreaterThanOrEqual(fireCount.load(), 2);
 }
 
 - (void)testRestart {

internal/platform/implementation/apple/Tests/GNCWifiHotspotMediumTest.mm

@@ -19,8 +19,11 @@
 
 #include <string>
 
+#include "connections/implementation/flags/nearby_connections_feature_flags.h"
+#include "internal/flags/nearby_flags.h"
 #include "internal/platform/byte_array.h"
 #include "internal/platform/exception.h"
+
 #import "internal/platform/implementation/apple/Mediums/CoreLocation/CLLocationManager/Fake/CLLocationManagerFake.h"
 #import "internal/platform/implementation/apple/Mediums/Hotspot/GNCHotspotMedium.h"
 #import "internal/platform/implementation/apple/Mediums/WiFiCommon/GNCIPv4Address.h"
@@ -59,8 +62,8 @@ const char kIPAddress[] = "192.168.1.2";
   _medium.locationManager = _fakeLocationManager;
   _hotspotMedium = std::make_unique<nearby::apple::WifiHotspotMedium>(_medium);
   _service_address = {
-    .address = {static_cast<char>(192), static_cast<char>(168), 1, 2},
-    .port = 1234,
+      .address = {static_cast<char>(192), static_cast<char>(168), 1, 2},
+      .port = 1234,
   };
 }
 
@@ -98,6 +101,10 @@ const char kIPAddress[] = "192.168.1.2";
 }
 
 - (void)testInputStreamRead {
+  nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+      ::nearby::connections::config_package_nearby::nearby_connections_feature::kEnableSingleCopy,
+      false);
+
   nearby::CancellationFlag cancellationFlag;
   std::unique_ptr<nearby::api::WifiHotspotSocket> socket =
       _hotspotMedium->ConnectToService(_service_address, &cancellationFlag);
@@ -110,6 +117,28 @@ const char kIPAddress[] = "192.168.1.2";
   XCTAssertTrue(readData.ok());
   XCTAssertEqual(readData.result().size(), 4);
   XCTAssertEqual(strncmp(readData.result().data(), "Test", 4), 0);
+
+  nearby::NearbyFlags::GetInstance().ResetOverridedValues();
+}
+
+- (void)testInputStreamRead_SingleCopyEnabled {
+  // Enable the flag
+  nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+      ::nearby::connections::config_package_nearby::nearby_connections_feature::kEnableSingleCopy,
+      true);
+
+  nearby::CancellationFlag cancellationFlag;
+  std::unique_ptr<nearby::api::WifiHotspotSocket> socket =
+      _hotspotMedium->ConnectToService(_service_address, &cancellationFlag);
+  GNCFakeNWFrameworkSocket *fakeSocket = _fakeNWFramework.sockets.firstObject;
+  fakeSocket.dataToRead = [@"HotspotOpt" dataUsingEncoding:NSUTF8StringEncoding];
+
+  nearby::ExceptionOr<nearby::ByteArray> readData = socket->GetInputStream().Read(10);
+
+  XCTAssertTrue(readData.ok());
+  XCTAssertEqual(std::string(readData.result()), "HotspotOpt");
+
+  nearby::NearbyFlags::GetInstance().ResetOverridedValues();
 }
 
 - (void)testInputStreamClose {
@@ -125,6 +154,10 @@ const char kIPAddress[] = "192.168.1.2";
 }
 
 - (void)testOutputStreamWrite {
+  nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+      ::nearby::connections::config_package_nearby::nearby_connections_feature::kEnableSingleCopy,
+      false);
+
   nearby::CancellationFlag cancellationFlag;
   std::unique_ptr<nearby::api::WifiHotspotSocket> socket =
       _hotspotMedium->ConnectToService(_service_address, &cancellationFlag);
@@ -136,6 +169,29 @@ const char kIPAddress[] = "192.168.1.2";
 
   XCTAssertTrue(writeResult.Ok());
   XCTAssertEqualObjects(fakeSocket.writtenData, data);
+
+  nearby::NearbyFlags::GetInstance().ResetOverridedValues();
+}
+
+- (void)testOutputStreamWrite_SingleCopyEnabled {
+  // Enable the flag
+  nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+      ::nearby::connections::config_package_nearby::nearby_connections_feature::kEnableSingleCopy,
+      true);
+
+  nearby::CancellationFlag cancellationFlag;
+  std::unique_ptr<nearby::api::WifiHotspotSocket> socket =
+      _hotspotMedium->ConnectToService(_service_address, &cancellationFlag);
+  GNCFakeNWFrameworkSocket *fakeSocket = _fakeNWFramework.sockets.firstObject;
+  NSData *data = [@"TestDataOpt" dataUsingEncoding:NSUTF8StringEncoding];
+  absl::string_view data_str(reinterpret_cast<const char *>(data.bytes), data.length);
+
+  nearby::Exception writeResult = socket->GetOutputStream().Write(data_str);
+
+  XCTAssertTrue(writeResult.Ok());
+  XCTAssertEqualObjects(fakeSocket.writtenData, data);
+
+  nearby::NearbyFlags::GetInstance().ResetOverridedValues();
 }
 
 - (void)testSocketClose {

internal/platform/implementation/apple/Tests/GNCWifiLanMediumTest.mm

@@ -18,6 +18,9 @@
 
 #include <string>
 
+#include "connections/implementation/flags/nearby_connections_feature_flags.h"
+#include "internal/flags/nearby_flags.h"
+
 #import "internal/platform/implementation/apple/Mediums/WiFiCommon/GNCIPv4Address.h"
 #import "internal/platform/implementation/apple/Mediums/WiFiCommon/GNCNWFramework.h"
 #import "internal/platform/implementation/apple/Mediums/WiFiCommon/Tests/GNCFakeNWConnection.h"
@@ -118,6 +121,10 @@
 }
 
 - (void)testSocketAndStream {
+  nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+      ::nearby::connections::config_package_nearby::nearby_connections_feature::kEnableSingleCopy,
+      false);
+
   // Create a server socket.
   std::unique_ptr<nearby::api::WifiLanServerSocket> serverSocket =
       _wifiLanMedium->ListenForService(1234);
@@ -155,6 +162,38 @@
   // Test closing the server socket.
   XCTAssertTrue(serverSocket->Close().Ok());
   XCTAssertTrue(fakeServerSocket.isClosed);
+  // Reset the flag.
+  nearby::NearbyFlags::GetInstance().ResetOverridedValues();
+}
+
+- (void)testSocketAndStream_SingleCopyEnabled {
+  // Enable the flag
+  nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+      ::nearby::connections::config_package_nearby::nearby_connections_feature::kEnableSingleCopy,
+      true);
+
+  // Create a server socket and accept a client.
+  std::unique_ptr<nearby::api::WifiLanServerSocket> serverSocket =
+      _wifiLanMedium->ListenForService(1234);
+  GNCFakeNWFrameworkServerSocket* fakeServerSocket =
+      (GNCFakeNWFrameworkServerSocket*)_fakeNWFramework.serverSockets[0];
+  GNCFakeNWConnection* connection = [[GNCFakeNWConnection alloc] init];
+  GNCFakeNWFrameworkSocket* fakeSocket =
+      [[GNCFakeNWFrameworkSocket alloc] initWithConnection:connection];
+  fakeServerSocket.socketToReturnOnAccept = fakeSocket;
+
+  std::unique_ptr<nearby::api::WifiLanSocket> clientSocket = serverSocket->Accept();
+  nearby::InputStream& inputStream = clientSocket->GetInputStream();
+
+  // Test optimized single-copy read.
+  fakeSocket.dataToRead = [@"optimized data" dataUsingEncoding:NSUTF8StringEncoding];
+  nearby::ExceptionOr<nearby::ByteArray> readData = inputStream.Read(14);
+
+  XCTAssertTrue(readData.ok());
+  XCTAssertEqual(std::string(readData.result()), "optimized data");
+
+  // Reset the flag.
+  nearby::NearbyFlags::GetInstance().ResetOverridedValues();
 }
 
 - (void)testServerSocketGetIPAddress {
@@ -185,6 +224,39 @@
   XCTAssertTrue(serverSocket->Close().Ok());
 }
 
+- (void)testOutputStreamWrite_SingleCopyEnabled {
+  // Enable the flag
+  nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
+      ::nearby::connections::config_package_nearby::nearby_connections_feature::kEnableSingleCopy,
+      true);
+
+  // Create a server socket and accept a client.
+  std::unique_ptr<nearby::api::WifiLanServerSocket> serverSocket =
+      _wifiLanMedium->ListenForService(1234);
+  GNCFakeNWFrameworkServerSocket* fakeServerSocket =
+      (GNCFakeNWFrameworkServerSocket*)_fakeNWFramework.serverSockets[0];
+  GNCFakeNWConnection* connection = [[GNCFakeNWConnection alloc] init];
+  GNCFakeNWFrameworkSocket* fakeSocket =
+      [[GNCFakeNWFrameworkSocket alloc] initWithConnection:connection];
+  fakeServerSocket.socketToReturnOnAccept = fakeSocket;
+
+  std::unique_ptr<nearby::api::WifiLanSocket> clientSocket = serverSocket->Accept();
+  nearby::OutputStream& outputStream = clientSocket->GetOutputStream();
+
+  // Test optimized single-copy write.
+  absl::string_view writeData("optimized data");
+  XCTAssertTrue(outputStream.Write(writeData).Ok());
+  XCTAssertEqualObjects(fakeSocket.writtenData,
+                        [@"optimized data" dataUsingEncoding:NSUTF8StringEncoding]);
+
+  // Clean up.
+  XCTAssertTrue(clientSocket->Close().Ok());
+  XCTAssertTrue(serverSocket->Close().Ok());
+
+  // Reset the flag.
+  nearby::NearbyFlags::GetInstance().ResetOverridedValues();
+}
+
 - (void)testOutputStreamClose {
   // Create a server socket and accept a client.
   std::unique_ptr<nearby::api::WifiLanServerSocket> serverSocket =

internal/platform/implementation/apple/Tests/UtilsTest.mm

@@ -56,8 +56,9 @@ using ::nearby::ObjCStringFromCppString;
 - (void)testUUIDStringFromNSUUID {
   NSString *uuidString = @"E621E1F8-C36C-495A-93FC-0C247A3E6E5F";
   NSUUID *uuid = [[NSUUID alloc] initWithUUIDString:uuidString];
-  std::string expectedCppString = [uuidString UTF8String];
-  XCTAssertEqual(nearby::UUIDStringFromNSUUID(uuid), expectedCppString);
+  XCTAssert(nearby::UUIDStringFromNSUUID(uuid) ==
+            std::string([uuidString UTF8String],
+                        [uuidString lengthOfBytesUsingEncoding:NSUTF8StringEncoding]));
 }
 
 - (void)testBluetoothUUIDConversions {

internal/platform/implementation/apple/Tests/ble_gatt_client_test.mm

@@ -210,19 +210,6 @@
   XCTAssertFalse(result);
 }
 
-- (void)testSetCharacteristicSubscriptionReturnsFalse {
-  GNCBLEGATTCharacteristic *characteristic =
-      [[GNCBLEGATTCharacteristic alloc] initWithUUID:[CBUUID UUIDWithString:@"B2B4"]
-                                         serviceUUID:[CBUUID UUIDWithString:@"FEF3"]
-                                         permissions:CBAttributePermissionsReadable
-                                          properties:CBCharacteristicPropertyNotify];
-  nearby::api::ble::GattCharacteristic cppCharacteristic =
-      nearby::apple::CPPGATTCharacteristicFromObjC(characteristic);
-  BOOL result = _gattClient->SetCharacteristicSubscription(cppCharacteristic, true,
-                                                           [](absl::string_view value) {});
-  XCTAssertFalse(result);
-}
-
 - (void)testDisconnectWhenFlagEnabled {
   nearby::NearbyFlags::GetInstance().OverrideBoolFlagValue(
       nearby::connections::config_package_nearby::nearby_connections_feature::

internal/platform/implementation/apple/Tests/ble_l2cap_server_socket_test.mm

@@ -50,8 +50,9 @@
 
 - (void)testBleL2capServerSocketAccept {
   XCTestExpectation *expectation = [self expectationWithDescription:@"accept"];
+  nearby::apple::BleL2capServerSocket *serverSocket = _serverSocket.get();
   dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
-    std::unique_ptr<nearby::api::ble::BleL2capSocket> clientSocket = _serverSocket->Accept();
+    std::unique_ptr<nearby::api::ble::BleL2capSocket> clientSocket = serverSocket->Accept();
     XCTAssertNotEqual(clientSocket.get(), nullptr);
     [expectation fulfill];
   });
@@ -76,8 +77,9 @@
 
 - (void)testBleL2capServerSocketClose {
   XCTestExpectation *expectation = [self expectationWithDescription:@"close"];
+  nearby::apple::BleL2capServerSocket *serverSocket = _serverSocket.get();
   dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
-    std::unique_ptr<nearby::api::ble::BleL2capSocket> clientSocket = _serverSocket->Accept();
+    std::unique_ptr<nearby::api::ble::BleL2capSocket> clientSocket = serverSocket->Accept();
     XCTAssertEqual(clientSocket.get(), nullptr);
     [expectation fulfill];
   });

internal/platform/implementation/apple/Tests/ble_medium_test.mm

@@ -23,9 +23,7 @@
 #include <utility>
 #include <vector>
 
-#import "internal/platform/implementation/apple/Mediums/BLE/GNCBLEGATTClient.h"
-#import "internal/platform/implementation/apple/Mediums/BLE/GNCBLEGATTServer.h"
-#import "internal/platform/implementation/apple/Mediums/BLE/GNCBLEL2CAPClient.h"
+#import "internal/platform/implementation/apple/Flags/GNCFeatureFlags.h"
 #import "internal/platform/implementation/apple/Mediums/BLE/GNCBLEMedium.h"
 #import "internal/platform/implementation/apple/Mediums/BLE/GNCPeripheral.h"
 #import "internal/platform/implementation/apple/Mediums/BLE/Sockets/Source/Central/GNSCentralManager.h"
@@ -33,9 +31,13 @@
 #import "internal/platform/implementation/apple/Mediums/BLE/Sockets/Source/Peripheral/GNSPeripheralManager.h"
 #import "internal/platform/implementation/apple/Mediums/BLE/Sockets/Source/Peripheral/GNSPeripheralServiceManager.h"
 #import "internal/platform/implementation/apple/Mediums/BLE/Sockets/Source/Shared/GNSSocket.h"
+#import "internal/platform/implementation/apple/Mediums/BLE/Tests/GNCBLEMedium+Testing.h"
 #import "internal/platform/implementation/apple/Mediums/BLE/Tests/GNCFakeBLEGATTServer.h"
 #import "internal/platform/implementation/apple/Mediums/BLE/Tests/GNCFakeBLEMedium.h"
+#import "internal/platform/implementation/apple/Mediums/BLE/Tests/GNCFakeCentralManager.h"
 #import "internal/platform/implementation/apple/Mediums/BLE/Tests/GNCFakePeripheral.h"
+#import "internal/platform/implementation/apple/Mediums/BLE/Tests/GNCFakePeripheralManager.h"
+#import "internal/platform/implementation/apple/Mediums/BLE/Tests/GNCFakeSocket.h"
 #include "internal/platform/implementation/apple/ble_utils.h"
 #include "internal/platform/implementation/ble.h"
 #import "third_party/objective_c/ocmock/v3/Source/OCMock/OCMock.h"
@@ -45,11 +47,16 @@ namespace apple {
 
 class BleMediumPeer {
  public:
-  static void SetSocketCentralManager(BleMedium *ble_medium, GNSCentralManager *manager) {
-    ble_medium->socketCentralManager_ = manager;
+  static void SetPeripheralManagerFactory(BleMedium *ble_medium,
+                                          BleMedium::PeripheralManagerFactory factory) {
+    ble_medium->peripheral_manager_factory_ = std::move(factory);
   }
-  static void SetSocketPeripheralManager(BleMedium *ble_medium, GNSPeripheralManager *manager) {
-    ble_medium->socketPeripheralManager_ = manager;
+  static void SetCentralManagerFactory(BleMedium *ble_medium,
+                                       BleMedium::CentralManagerFactory factory) {
+    ble_medium->central_manager_factory_ = std::move(factory);
+  }
+  static GNSPeripheralServiceManager *GetSocketPeripheralServiceManager(BleMedium *ble_medium) {
+    return ble_medium->socketPeripheralServiceManager_;
   }
 };
 
@@ -71,7 +78,11 @@ static const char *const kTestServiceID = "TestServiceID";
 
 - (void)setUp {
   [super setUp];
-  _fakeGNCBLEMedium = [[GNCFakeBLEMedium alloc] init];
+  GNCFakeCentralManager *fakeCentralManager = [[GNCFakeCentralManager alloc] init];
+  GNCFakePeripheralManager *fakePeripheralManager = [[GNCFakePeripheralManager alloc] init];
+  _fakeGNCBLEMedium = [[GNCFakeBLEMedium alloc] initWithCentralManager:fakeCentralManager
+                                                     peripheralManager:fakePeripheralManager
+                                                                 queue:dispatch_get_main_queue()];
   _medium = std::make_unique<nearby::apple::BleMedium>((GNCBLEMedium *)_fakeGNCBLEMedium);
 }
 
@@ -79,6 +90,28 @@ static const char *const kTestServiceID = "TestServiceID";
   [super tearDown];
 }
 
+- (void)testOpenServerSocket_UsesFactoryForInitialization {
+  __block BOOL factoryWasCalled = NO;
+  id mockPeripheralManager = OCMClassMock([GNSPeripheralManager class]);
+  OCMStub([mockPeripheralManager addPeripheralServiceManager:[OCMArg any]
+                                   bleServiceAddedCompletion:[OCMArg any]])
+      .andDo(^(GNSPeripheralManager *localSelf, GNSPeripheralServiceManager *manager,
+               void (^completion)(NSError *error)) {
+        completion(nil);
+      });
+
+  nearby::apple::BleMediumPeer::SetPeripheralManagerFactory(_medium.get(), ^() {
+    factoryWasCalled = YES;
+    return mockPeripheralManager;
+  });
+
+  // This call should trigger the factory inside BleMedium.
+  auto server_socket = _medium->OpenServerSocket(kTestServiceID);
+
+  XCTAssertTrue(factoryWasCalled, @"BleMedium should have requested the manager from the factory.");
+  XCTAssertNotEqual(server_socket.get(), nullptr);
+}
+
 #pragma mark - Advertising Tests
 
 - (void)testStartAdvertising_Success {
@@ -225,8 +258,8 @@ static const char *const kTestServiceID = "TestServiceID";
 #pragma mark - GATT Server Tests
 
 - (void)testStartGattServer_Success {
-  _fakeGNCBLEMedium.fakeGATTServer = [[GNCFakeBLEGATTServer alloc] init];
-
+  _fakeGNCBLEMedium.fakeGATTServer = [[GNCFakeBLEGATTServer alloc] initWithPeripheralManager:nil
+                                                                                       queue:nil];
   auto gatt_server = _medium->StartGattServer({});
 
   XCTAssertNotEqual(gatt_server.get(), nullptr);
@@ -422,7 +455,9 @@ static const char *const kTestServiceID = "TestServiceID";
   id mockCentralManager = OCMClassMock([GNSCentralManager class]);
   OCMStub([mockCentralManager retrieveCentralPeerWithIdentifier:fakePeripheral.identifier])
       .andReturn(nil);
-  nearby::apple::BleMediumPeer::SetSocketCentralManager(_medium.get(), mockCentralManager);
+  nearby::apple::BleMediumPeer::SetCentralManagerFactory(_medium.get(), ^(CBUUID *uuid) {
+    return mockCentralManager;
+  });
 
   auto socket = _medium->Connect(kTestServiceID, nearby::api::ble::TxPowerLevel::kUltraLow,
                                  fakePeripheral.identifier.hash, nullptr);
@@ -460,7 +495,9 @@ static const char *const kTestServiceID = "TestServiceID";
   id mockCentralManager = OCMClassMock([GNSCentralManager class]);
   OCMStub([mockCentralManager retrieveCentralPeerWithIdentifier:fakePeripheral.identifier])
       .andReturn(mockCentralPeerManager);
-  nearby::apple::BleMediumPeer::SetSocketCentralManager(_medium.get(), mockCentralManager);
+  nearby::apple::BleMediumPeer::SetCentralManagerFactory(_medium.get(), ^(CBUUID *uuid) {
+    return mockCentralManager;
+  });
 
   auto socket = _medium->Connect(kTestServiceID, nearby::api::ble::TxPowerLevel::kUltraLow,
                                  fakePeripheral.identifier.hash, nullptr);
@@ -470,7 +507,10 @@ static const char *const kTestServiceID = "TestServiceID";
 
 #pragma mark - Server Socket Tests
 
-- (void)testOpenServerSocket_Success {
+- (void)testOpenServerSocket_Success_LegacyPath {
+  id mockFeatureFlags = OCMClassMock([GNCFeatureFlags class]);
+  OCMStub([mockFeatureFlags fixBleServerSocketDeadlockEnabled]).andReturn(NO);
+
   id mockPeripheralManager = OCMClassMock([GNSPeripheralManager class]);
   OCMStub([mockPeripheralManager addPeripheralServiceManager:[OCMArg any]
                                    bleServiceAddedCompletion:[OCMArg any]])
@@ -478,11 +518,97 @@ static const char *const kTestServiceID = "TestServiceID";
                void (^completion)(NSError *error)) {
         completion(nil);
       });
-  nearby::apple::BleMediumPeer::SetSocketPeripheralManager(_medium.get(), mockPeripheralManager);
+  nearby::apple::BleMediumPeer::SetPeripheralManagerFactory(_medium.get(), ^() {
+    return mockPeripheralManager;
+  });
 
   auto server_socket = _medium->OpenServerSocket(kTestServiceID);
 
   XCTAssertNotEqual(server_socket.get(), nullptr);
+
+  GNSPeripheralServiceManager *serviceManager =
+      nearby::apple::BleMediumPeer::GetSocketPeripheralServiceManager(_medium.get());
+  XCTAssertNotNil(serviceManager);
+}
+
+- (void)testOpenServerSocket_Success_OptimizedPath {
+  id mockFeatureFlags = OCMClassMock([GNCFeatureFlags class]);
+  OCMStub([mockFeatureFlags fixBleServerSocketDeadlockEnabled]).andReturn(YES);
+
+  id mockPeripheralManager = OCMClassMock([GNSPeripheralManager class]);
+  OCMStub([mockPeripheralManager addPeripheralServiceManager:[OCMArg any]
+                                   bleServiceAddedCompletion:[OCMArg any]])
+      .andDo(^(GNSPeripheralManager *localSelf, GNSPeripheralServiceManager *manager,
+               void (^completion)(NSError *error)) {
+        completion(nil);
+      });
+  nearby::apple::BleMediumPeer::SetPeripheralManagerFactory(_medium.get(), ^() {
+    return mockPeripheralManager;
+  });
+
+  auto server_socket = _medium->OpenServerSocket(kTestServiceID);
+
+  XCTAssertNotEqual(server_socket.get(), nullptr);
+
+  GNSPeripheralServiceManager *serviceManager =
+      nearby::apple::BleMediumPeer::GetSocketPeripheralServiceManager(_medium.get());
+  XCTAssertNotNil(serviceManager);
+}
+
+- (void)testOpenServerSocket_OptimizedPath_AcceptSocketAfterClose {
+  id mockFeatureFlags = OCMClassMock([GNCFeatureFlags class]);
+  OCMStub([mockFeatureFlags fixBleServerSocketDeadlockEnabled]).andReturn(YES);
+
+  id mockPeripheralManager = OCMClassMock([GNSPeripheralManager class]);
+  OCMStub([mockPeripheralManager addPeripheralServiceManager:[OCMArg any]
+                                   bleServiceAddedCompletion:[OCMArg any]])
+      .andDo(^(GNSPeripheralManager *localSelf, GNSPeripheralServiceManager *manager,
+               void (^completion)(NSError *error)) {
+        completion(nil);
+      });
+  nearby::apple::BleMediumPeer::SetPeripheralManagerFactory(_medium.get(), ^() {
+    return mockPeripheralManager;
+  });
+
+  auto server_socket = _medium->OpenServerSocket(kTestServiceID);
+  XCTAssertNotEqual(server_socket.get(), nullptr);
+  __block BOOL (^capturedHandler)(GNSSocket *) = nil;
+  id mockServiceManagerClass = OCMClassMock([GNSPeripheralServiceManager class]);
+  OCMStub([mockServiceManagerClass alloc]).andReturn(mockServiceManagerClass);
+  OCMStub([mockServiceManagerClass initWithBleServiceUUID:[OCMArg any]
+                                 addPairingCharacteristic:NO
+                                shouldAcceptSocketHandler:[OCMArg any]])
+      .andDo(^(NSInvocation *invocation) {
+        BOOL (^handler)(GNSSocket *);
+        [invocation getArgument:&handler atIndex:4];
+        capturedHandler = handler;
+      })
+      .andReturn(mockServiceManagerClass);
+
+  auto server_socket_for_handler_capture = _medium->OpenServerSocket(kTestServiceID);
+  XCTAssertNotEqual(server_socket_for_handler_capture.get(), nullptr);
+  XCTAssertNotNil(capturedHandler);
+
+  // Invoke the shouldAcceptSocketHandler with a fake socket.
+  GNCFakeSocket *fakeSocket = [[GNCFakeSocket alloc] init];
+  BOOL result = capturedHandler((GNSSocket *)fakeSocket);
+  XCTAssertTrue(result);
+
+  // Close the server_socket. This triggers the close notifier, setting server_socket_ptr_ to null.
+  server_socket_for_handler_capture->Close();
+
+  // Now simulate the connection completing. It should safely ignore the connection because
+  // server_socket_ptr_ is null, preventing use-after-free or deadlocks.
+  [fakeSocket simulateSocketDidConnect];
+
+  // Since we use dispatch_async internally for connection callback, give it a small amount of time
+  // to process so we know it didn't crash.
+  XCTestExpectation *expectation2 = [self expectationWithDescription:@"Wait for async execution"];
+  dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0.1 * NSEC_PER_SEC)),
+                 dispatch_get_main_queue(), ^{
+                   [expectation2 fulfill];
+                 });
+  [self waitForExpectations:@[ expectation2 ] timeout:1.0];
 }
 
 - (void)testOpenServerSocket_Failure {
@@ -493,7 +619,9 @@ static const char *const kTestServiceID = "TestServiceID";
                void (^completion)(NSError *error)) {
         completion([NSError errorWithDomain:@"test" code:0 userInfo:nil]);
       });
-  nearby::apple::BleMediumPeer::SetSocketPeripheralManager(_medium.get(), mockPeripheralManager);
+  nearby::apple::BleMediumPeer::SetPeripheralManagerFactory(_medium.get(), ^() {
+    return mockPeripheralManager;
+  });
 
   auto server_socket = _medium->OpenServerSocket(kTestServiceID);
 
@@ -508,7 +636,9 @@ static const char *const kTestServiceID = "TestServiceID";
                void (^completion)(NSError *error)){
           // Do not call completion to simulate timeout.
       });
-  nearby::apple::BleMediumPeer::SetSocketPeripheralManager(_medium.get(), mockPeripheralManager);
+  nearby::apple::BleMediumPeer::SetPeripheralManagerFactory(_medium.get(), ^() {
+    return mockPeripheralManager;
+  });
 
   auto server_socket = _medium->OpenServerSocket(kTestServiceID);
 
@@ -646,18 +776,20 @@ static const char *const kTestServiceID = "TestServiceID";
   NSDictionary<CBUUID *, NSData *> *serviceData =
       @{[CBUUID UUIDWithString:kTestServiceUUIDString] : [NSData dataWithBytes:"test" length:4]};
 
-  __block XCTestExpectation *expectation1 = [self expectationWithDescription:@"Callback 1"];
+  XCTestExpectation *expectation1 = [self expectationWithDescription:@"Callback 1"];
   XCTestExpectation *expectation2 = [self expectationWithDescription:@"Callback 2"];
   expectation2.inverted = YES;  // Should NOT be called.
 
+  auto callback1_fulfilled = std::make_shared<std::atomic<bool>>(false);
+
   nearby::api::ble::BleMedium::ScanCallback callback = {
       .advertisement_found_cb = std::function<void(nearby::api::ble::BlePeripheral::UniqueId,
                                                    nearby::api::ble::BleAdvertisementData)>(
-          ^(nearby::api::ble::BlePeripheral::UniqueId peripheral_id,
-            const nearby::api::ble::BleAdvertisementData &advertisement) {
-            if ([expectation1.description isEqualToString:@"Callback 1"]) {
+          [callback1_fulfilled, expectation1, expectation2](
+              nearby::api::ble::BlePeripheral::UniqueId peripheral_id,
+              const nearby::api::ble::BleAdvertisementData &advertisement) {
+            if (!callback1_fulfilled->exchange(true)) {
               [expectation1 fulfill];
-              expectation1 = nil;  // Prevent double fulfillment
             } else {
               [expectation2 fulfill];
             }

internal/platform/implementation/apple/Tests/ble_server_socket_test.mm

@@ -42,8 +42,9 @@
 
 - (void)testBleServerSocketAccept {
   XCTestExpectation *expectation = [self expectationWithDescription:@"accept"];
+  nearby::apple::BleServerSocket *serverSocket = _serverSocket.get();
   dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
-    std::unique_ptr<nearby::api::ble::BleSocket> clientSocket = _serverSocket->Accept();
+    std::unique_ptr<nearby::api::ble::BleSocket> clientSocket = serverSocket->Accept();
     XCTAssertNotEqual(clientSocket.get(), nullptr);
     [expectation fulfill];
   });
@@ -57,8 +58,9 @@
 
 - (void)testBleServerSocketClose {
   XCTestExpectation *expectation = [self expectationWithDescription:@"close"];
+  nearby::apple::BleServerSocket *serverSocket = _serverSocket.get();
   dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
-    std::unique_ptr<nearby::api::ble::BleSocket> clientSocket = _serverSocket->Accept();
+    std::unique_ptr<nearby::api::ble::BleSocket> clientSocket = serverSocket->Accept();
     XCTAssertEqual(clientSocket.get(), nullptr);
     [expectation fulfill];
   });

internal/platform/implementation/apple/atomic_boolean_test.cc

@@ -15,7 +15,7 @@
 #include "internal/platform/implementation/apple/atomic_boolean.h"
 
 #include "gtest/gtest.h"
-#include "thread/fiber/fiber.h"
+#include "third_party/gloop/thread/fiber/fiber.h"
 
 namespace nearby {
 namespace apple {

internal/platform/implementation/apple/atomic_uint32_test.cc

@@ -15,7 +15,7 @@
 #include "internal/platform/implementation/apple/atomic_uint32.h"
 
 #include "gtest/gtest.h"
-#include "thread/fiber/fiber.h"
+#include "third_party/gloop/thread/fiber/fiber.h"
 
 namespace nearby {
 namespace apple {

internal/platform/implementation/apple/awdl.mm

@@ -19,6 +19,7 @@
 #include <string>
 #include <utility>
 
+#import "internal/platform/implementation/apple/Flags/GNCFeatureFlags.h"
 #import "internal/platform/implementation/apple/Log/GNCLogger.h"
 #import "internal/platform/implementation/apple/Mediums/WiFiCommon/GNCIPv4Address.h"
 #import "internal/platform/implementation/apple/Mediums/WiFiCommon/GNCNWFramework.h"
@@ -35,12 +36,22 @@ AwdlInputStream::AwdlInputStream(GNCNWFrameworkSocket* socket) : socket_(socket)
 
 ExceptionOr<ByteArray> AwdlInputStream::Read(std::int64_t size) {
   NSError* error = nil;
-  NSData* data = [socket_ readMaxLength:size error:&error];
-  if (data == nil) {
-    GNCLoggerError(@"Error reading socket: %@", error);
-    return {Exception::kIo};
+  if (GNCFeatureFlags.singleCopyEnabled) {
+    auto result = [socket_ readStringWithMaxLength:size error:&error];
+    if (!result.has_value()) {
+      GNCLoggerError(@"Error reading socket: %@", error);
+      return {Exception::kIo};
+    }
+    // OPTIMIZATION: Zero-copy transfer from std::string to ByteArray
+    return ExceptionOr<ByteArray>{ByteArray(std::move(result.value()))};
+  } else {
+    NSData* data = [socket_ readMaxLength:size error:&error];
+    if (data == nil) {
+      GNCLoggerError(@"Error reading socket: %@", error);
+      return {Exception::kIo};
+    }
+    return ExceptionOr<ByteArray>{ByteArray((const char*)data.bytes, data.length)};
   }
-  return ExceptionOr<ByteArray>{ByteArray((const char*)data.bytes, data.length)};
 }
 
 Exception AwdlInputStream::Close() {
@@ -55,7 +66,15 @@ AwdlOutputStream::AwdlOutputStream(GNCNWFrameworkSocket* socket) : socket_(socke
 
 Exception AwdlOutputStream::Write(absl::string_view data) {
   NSError* error = nil;
-  BOOL result = [socket_ write:[NSData dataWithBytes:data.data() length:data.size()] error:&error];
+  BOOL result = NO;
+
+  if (GNCFeatureFlags.singleCopyEnabled) {
+    // OPTIMIZATION: Write raw bytes directly, avoiding NSData creation.
+    result = [socket_ writeBytes:data.data() length:data.size() error:&error];
+  } else {
+    result = [socket_ write:[NSData dataWithBytes:data.data() length:data.size()] error:&error];
+  }
+
   if (!result) {
     GNCLoggerError(@"Error writing socket: %@", error);
     return {Exception::kIo};

internal/platform/implementation/apple/ble_gatt_client.h

@@ -66,16 +66,6 @@ class GattClient : public api::ble::GattClient {
   bool WriteCharacteristic(const api::ble::GattCharacteristic &characteristic,
                            absl::string_view value, api::ble::GattClient::WriteType type) override;
 
-  // Enable or disable notifications/indications for a given characteristic.
-  //
-  // Once notifications are enabled for a characteristic, on_characteristic_changed_cb will be
-  // triggered if the remote device indicates that the given characteristic has changed.
-  //
-  // Returns whether or not the subscription was successful.
-  bool SetCharacteristicSubscription(
-      const api::ble::GattCharacteristic &characteristic, bool enable,
-      absl::AnyInvocable<void(absl::string_view value)> on_characteristic_changed_cb) override;
-
   // Disconnects an established connection, or cancels a connection attempt currently in progress.
   void Disconnect() override;
 

internal/platform/implementation/apple/ble_gatt_client.mm

@@ -121,13 +121,6 @@ bool GattClient::WriteCharacteristic(const api::ble::GattCharacteristic &charact
   return false;
 }
 
-// TODO(b/290385712): Implement.
-bool GattClient::SetCharacteristicSubscription(
-    const api::ble::GattCharacteristic &characteristic, bool enable,
-    absl::AnyInvocable<void(absl::string_view value)> on_characteristic_changed_cb) {
-  return false;
-}
-
 void GattClient::Disconnect() {
   // There seems to be an issue between some iOS<>Android device pairs where the Android device will
   // not connect to the iOS device if the iOS device disconnects and then attempts to reconnect.

internal/platform/implementation/apple/ble_l2cap_socket.mm

@@ -14,9 +14,11 @@
 
 #import "internal/platform/implementation/apple/ble_l2cap_socket.h"
 
+#import "internal/platform/implementation/apple/Flags/GNCFeatureFlags.h"
 #import "internal/platform/implementation/apple/Log/GNCLogger.h"
 #import "internal/platform/implementation/apple/Mediums/BLE/GNCBLEL2CAPConnection.h"
 #import "internal/platform/implementation/apple/utils.h"
+
 #include "internal/platform/implementation/ble.h"
 
 namespace nearby {
@@ -52,40 +54,81 @@ BleL2capInputStream::~BleL2capInputStream() {
 }
 
 ExceptionOr<ByteArray> BleL2capInputStream::Read(std::int64_t size) {
-  // Block until either (a) the connection has been closed, (b) we have enough data to return.
-  NSData *dataToReturn;
-  [condition_ lock];
-  while (true) {
-    // Check if the stream has been closed or severed.
-    if (!newDataPackets_) break;
+  if (GNCFeatureFlags.singleCopyEnabled) {
+    std::string dataToReturn;
+    bool success = false;
 
-    if (newDataPackets_.count > 0) {
-      // Add the packet data to the accumulated data.
-      for (NSData *data in newDataPackets_) {
-        if (data.length > 0) {
-          [accumulatedData_ appendData:data];
+    [condition_ lock];
+    while (true) {
+      // Check if the stream has been closed or severed.
+      if (!newDataPackets_) break;
+
+      if (newDataPackets_.count > 0) {
+        // Add the packet data to the accumulated data.
+        for (NSData *data in newDataPackets_) {
+          if (data.length > 0) {
+            [accumulatedData_ appendData:data];
+          }
         }
+        [newDataPackets_ removeAllObjects];
       }
-      [newDataPackets_ removeAllObjects];
+
+      if (accumulatedData_.length > 0) {
+        std::int64_t sizeToReturn =
+            (accumulatedData_.length < size) ? accumulatedData_.length : size;
+        NSRange range = NSMakeRange(0, (NSUInteger)sizeToReturn);
+
+        // Copy bytes directly into std::string, avoiding [NSData subdataWithRange:]
+        dataToReturn.assign((const char *)accumulatedData_.bytes, sizeToReturn);
+        [accumulatedData_ replaceBytesInRange:range withBytes:nil length:0];
+
+        success = true;
+        break;
+      }
+      [condition_ wait];
     }
+    [condition_ unlock];
 
-    if (accumulatedData_.length > 0) {
-      // Return up to |size| bytes of the data.
-      std::int64_t sizeToReturn = (accumulatedData_.length < size) ? accumulatedData_.length : size;
-      NSRange range = NSMakeRange(0, (NSUInteger)sizeToReturn);
-      dataToReturn = [accumulatedData_ subdataWithRange:range];
-      [accumulatedData_ replaceBytesInRange:range withBytes:nil length:0];
-      break;
+    if (success) {
+      // OPTIMIZATION: Zero-copy transfer from std::string to ByteArray
+      return ExceptionOr<ByteArray>{ByteArray(std::move(dataToReturn))};
+    } else {
+      return ExceptionOr<ByteArray>{Exception::kIo};
     }
-
-    [condition_ wait];
-  }
-  [condition_ unlock];
-
-  if (dataToReturn) {
-    return ExceptionOr<ByteArray>{ByteArray((const char *)dataToReturn.bytes, dataToReturn.length)};
   } else {
-    return ExceptionOr<ByteArray>{Exception::kIo};
+    // Legacy Path
+    NSData *dataToReturn;
+    [condition_ lock];
+    while (true) {
+      if (!newDataPackets_) break;
+
+      if (newDataPackets_.count > 0) {
+        for (NSData *data in newDataPackets_) {
+          if (data.length > 0) {
+            [accumulatedData_ appendData:data];
+          }
+        }
+        [newDataPackets_ removeAllObjects];
+      }
+
+      if (accumulatedData_.length > 0) {
+        std::int64_t sizeToReturn =
+            (accumulatedData_.length < size) ? accumulatedData_.length : size;
+        NSRange range = NSMakeRange(0, (NSUInteger)sizeToReturn);
+        dataToReturn = [accumulatedData_ subdataWithRange:range];
+        [accumulatedData_ replaceBytesInRange:range withBytes:nil length:0];
+        break;
+      }
+      [condition_ wait];
+    }
+    [condition_ unlock];
+
+    if (dataToReturn) {
+      return ExceptionOr<ByteArray>{
+          ByteArray((const char *)dataToReturn.bytes, dataToReturn.length)};
+    } else {
+      return ExceptionOr<ByteArray>{Exception::kIo};
+    }
   }
 }
 
@@ -111,7 +154,17 @@ Exception BleL2capOutputStream::Write(absl::string_view data) {
     return {Exception::kIo};
   }
 
-  NSMutableData *packet = [NSMutableData dataWithBytes:data.data() length:data.size()];
+  NSData *packet;
+  if (GNCFeatureFlags.singleCopyEnabled) {
+    // OPTIMIZATION: Use DISPATCH_DATA_DESTRUCTOR_DEFAULT to perform a
+    // single copy into a GCD-managed buffer. No NSData required.
+    dispatch_data_t dispatchData =
+        dispatch_data_create(data.data(), data.size(), nil, DISPATCH_DATA_DESTRUCTOR_DEFAULT);
+    // dispatch_data_t is toll-free bridged to NSData
+    packet = (NSData *)dispatchData;
+  } else {
+    packet = [NSMutableData dataWithBytes:data.data() length:data.size()];
+  }
 
   // Send the data, blocking until the completion handler is called.
   __block BOOL isComplete = NO;

internal/platform/implementation/apple/ble_medium.h

@@ -21,6 +21,7 @@
 
 #import <Foundation/Foundation.h>
 
+#include <functional>
 #include <memory>
 #include <string>
 #include <vector>
@@ -50,6 +51,10 @@ class BleMedium : public api::ble::BleMedium {
   friend class BleMediumPeer;
 
  public:
+  // Define factory types for managers.
+  using PeripheralManagerFactory = std::function<GNSPeripheralManager *()>;
+  using CentralManagerFactory = std::function<GNSCentralManager *(CBUUID *)>;
+
   BleMedium();
   // For testing only.
   explicit BleMedium(GNCBLEMedium *medium);
@@ -207,9 +212,20 @@ class BleMedium : public api::ble::BleMedium {
                                   NSDictionary<CBUUID *, NSData *> *service_data);
   NSDate *GetLastTimestampToCleanExpiredAdvertisementPackets();
 
+  // Opens a BLE server socket based on service ID with deadlock safety.
+  std::unique_ptr<api::ble::BleServerSocket> OpenServerSocketWithDeadlockSafety(
+      const std::string &service_id);
+
+  // Opens a BLE server socket based on service ID using the legacy implementation.
+  std::unique_ptr<api::ble::BleServerSocket> OpenServerSocketLegacy(const std::string &service_id);
+
   // The executor for handling callbacks.
   apple::SingleThreadExecutor callback_executor_;
 
+  // Factories for lazy initialization
+  PeripheralManagerFactory peripheral_manager_factory_ = nullptr;
+  CentralManagerFactory central_manager_factory_ = nullptr;
+
   GNCBLEMedium *medium_;
 
   PeripheralsMap peripherals_;
@@ -229,14 +245,22 @@ class BleMedium : public api::ble::BleMedium {
 
   GNSPeripheralServiceManager *socketPeripheralServiceManager_;
   GNSPeripheralManager *socketPeripheralManager_;
-  GNSCentralManager *socketCentralManager_;
+
+  absl::Mutex scanning_mutex_;
+  GNSCentralManager *socketCentralManager_ ABSL_GUARDED_BY(scanning_mutex_);
 
   // Used for the blocking version of StartAdvertising and only has an advertisement found callback.
-  api::ble::BleMedium::ScanCallback scan_cb_;
+  std::shared_ptr<api::ble::BleMedium::ScanCallback> scan_cb_ ABSL_GUARDED_BY(scanning_mutex_);
   // Used for the async version of StartAdvertising and has both an advertisement found and result
   // callback.
-  api::ble::BleMedium::ScanningCallback scanning_cb_;
+  std::shared_ptr<api::ble::BleMedium::ScanningCallback> scanning_cb_
+      ABSL_GUARDED_BY(scanning_mutex_);
 
+  // Used for the BleServerSocket.
+  absl::Mutex server_socket_mutex_;
+  BleServerSocket *server_socket_ptr_ ABSL_GUARDED_BY(server_socket_mutex_) = nullptr;
+
+  // Used for the L2CAP server socket.
   absl::Mutex l2cap_server_socket_mutex_;
   BleL2capServerSocket *l2cap_server_socket_ptr_ = nullptr;
 

internal/platform/implementation/apple/ble_medium.mm

@@ -173,11 +173,19 @@ void BleMedium::HandleAdvertisementFound(id<GNCPeripheral> peripheral,
   }
 #endif
 
-  if (scanning_cb_.advertisement_found_cb) {
-    scanning_cb_.advertisement_found_cb(unique_id, data);
+  std::shared_ptr<api::ble::BleMedium::ScanningCallback> scanning_cb;
+  std::shared_ptr<api::ble::BleMedium::ScanCallback> scan_cb;
+  {
+    absl::MutexLock lock(&scanning_mutex_);
+    scanning_cb = scanning_cb_;
+    scan_cb = scan_cb_;
   }
-  if (scan_cb_.advertisement_found_cb) {
-    scan_cb_.advertisement_found_cb(unique_id, data);
+
+  if (scanning_cb && scanning_cb->advertisement_found_cb) {
+    scanning_cb->advertisement_found_cb(unique_id, data);
+  }
+  if (scan_cb && scan_cb->advertisement_found_cb) {
+    scan_cb->advertisement_found_cb(unique_id, data);
   }
 }
 
@@ -185,7 +193,17 @@ std::unique_ptr<api::ble::BleMedium::ScanningSession> BleMedium::StartScanning(
     const Uuid &service_uuid, api::ble::TxPowerLevel tx_power_level,
     api::ble::BleMedium::ScanningCallback callback) {
   CBUUID *serviceUUID = CBUUID128FromCPP(service_uuid);
-  scanning_cb_ = std::move(callback);
+
+  {
+    absl::MutexLock lock(&scanning_mutex_);
+    scanning_cb_ = std::make_shared<api::ble::BleMedium::ScanningCallback>(std::move(callback));
+
+    if (central_manager_factory_) {
+      socketCentralManager_ = central_manager_factory_(serviceUUID);
+    } else {
+      socketCentralManager_ = [[GNSCentralManager alloc] initWithSocketServiceUUID:serviceUUID];
+    }
+  }
 
   // Clear the map of discovered peripherals only when we are starting a new scan. If we cleared the
   // map every time we stopped a scan, we would not be able to connect to peripherals that we
@@ -193,8 +211,10 @@ std::unique_ptr<api::ble::BleMedium::ScanningSession> BleMedium::StartScanning(
   peripherals_.Clear();
   ClearAdvertisementPacketsMap();
 
-  socketCentralManager_ = [[GNSCentralManager alloc] initWithSocketServiceUUID:serviceUUID];
-  [socketCentralManager_ startNoScanModeWithAdvertisedServiceUUIDs:@[ serviceUUID ]];
+  {
+    absl::MutexLock lock(&scanning_mutex_);
+    [socketCentralManager_ startNoScanModeWithAdvertisedServiceUUIDs:@[ serviceUUID ]];
+  }
 
   dispatch_semaphore_t semaphore = dispatch_semaphore_create(0);
   __block NSError *blockError = nil;
@@ -207,8 +227,13 @@ std::unique_ptr<api::ble::BleMedium::ScanningSession> BleMedium::StartScanning(
       }
       completionHandler:^(NSError *error) {
         blockError = error;
-        if (scanning_cb_.start_scanning_result) {
-          scanning_cb_.start_scanning_result(
+        std::shared_ptr<api::ble::BleMedium::ScanningCallback> scanning_cb;
+        {
+          absl::MutexLock lock(&scanning_mutex_);
+          scanning_cb = scanning_cb_;
+        }
+        if (scanning_cb && scanning_cb->start_scanning_result) {
+          scanning_cb->start_scanning_result(
               error == nil ? absl::OkStatus()
                            : absl::InternalError(error.localizedDescription.UTF8String));
         }
@@ -218,8 +243,13 @@ std::unique_ptr<api::ble::BleMedium::ScanningSession> BleMedium::StartScanning(
   dispatch_time_t timeout = dispatch_time(DISPATCH_TIME_NOW, kApiTimeoutInSeconds * NSEC_PER_SEC);
   if (dispatch_semaphore_wait(semaphore, timeout) != 0) {
     GNCLoggerError(@"Start scanning operation timed out.");
-    if (scanning_cb_.start_scanning_result) {
-      scanning_cb_.start_scanning_result(absl::DeadlineExceededError("Start scanning timed out"));
+    std::shared_ptr<api::ble::BleMedium::ScanningCallback> scanning_cb;
+    {
+      absl::MutexLock lock(&scanning_mutex_);
+      scanning_cb = scanning_cb_;
+    }
+    if (scanning_cb && scanning_cb->start_scanning_result) {
+      scanning_cb->start_scanning_result(absl::DeadlineExceededError("Start scanning timed out"));
     }
     return nullptr;
   }
@@ -239,7 +269,17 @@ std::unique_ptr<api::ble::BleMedium::ScanningSession> BleMedium::StartScanning(
 bool BleMedium::StartScanning(const Uuid &service_uuid, api::ble::TxPowerLevel tx_power_level,
                               api::ble::BleMedium::ScanCallback callback) {
   CBUUID *serviceUUID = CBUUID128FromCPP(service_uuid);
-  scan_cb_ = std::move(callback);
+
+  {
+    absl::MutexLock lock(&scanning_mutex_);
+    scan_cb_ = std::make_shared<api::ble::BleMedium::ScanCallback>(std::move(callback));
+
+    if (central_manager_factory_) {
+      socketCentralManager_ = central_manager_factory_(serviceUUID);
+    } else {
+      socketCentralManager_ = [[GNSCentralManager alloc] initWithSocketServiceUUID:serviceUUID];
+    }
+  }
 
   // Clear the map of discovered peripherals only when we are starting a new scan. If we cleared the
   // map every time we stopped a scan, we would not be able to connect to peripherals that we
@@ -247,8 +287,10 @@ bool BleMedium::StartScanning(const Uuid &service_uuid, api::ble::TxPowerLevel t
   peripherals_.Clear();
   ClearAdvertisementPacketsMap();
 
-  socketCentralManager_ = [[GNSCentralManager alloc] initWithSocketServiceUUID:serviceUUID];
-  [socketCentralManager_ startNoScanModeWithAdvertisedServiceUUIDs:@[ serviceUUID ]];
+  {
+    absl::MutexLock lock(&scanning_mutex_);
+    [socketCentralManager_ startNoScanModeWithAdvertisedServiceUUIDs:@[ serviceUUID ]];
+  }
 
   dispatch_semaphore_t semaphore = dispatch_semaphore_create(0);
   __block NSError *blockError = nil;
@@ -286,7 +328,16 @@ bool BleMedium::StartMultipleServicesScanning(const std::vector<Uuid> &service_u
     [serviceUUIDs addObject:CBUUID128FromCPP(service_uuid)];
   }
 
-  scan_cb_ = std::move(callback);
+  {
+    absl::MutexLock lock(&scanning_mutex_);
+    scan_cb_ = std::make_shared<api::ble::BleMedium::ScanCallback>(std::move(callback));
+
+    if (central_manager_factory_) {
+      socketCentralManager_ = central_manager_factory_(serviceUUIDs[0]);
+    } else {
+      socketCentralManager_ = [[GNSCentralManager alloc] initWithSocketServiceUUID:serviceUUIDs[0]];
+    }
+  }
 
   // Clear the map of discovered peripherals only when we are starting a new scan. If we cleared the
   // map every time we stopped a scan, we would not be able to connect to peripherals that we
@@ -294,8 +345,10 @@ bool BleMedium::StartMultipleServicesScanning(const std::vector<Uuid> &service_u
   peripherals_.Clear();
   ClearAdvertisementPacketsMap();
 
-  socketCentralManager_ = [[GNSCentralManager alloc] initWithSocketServiceUUID:serviceUUIDs[0]];
-  [socketCentralManager_ startNoScanModeWithAdvertisedServiceUUIDs:@[ serviceUUIDs[0] ]];
+  {
+    absl::MutexLock lock(&scanning_mutex_);
+    [socketCentralManager_ startNoScanModeWithAdvertisedServiceUUIDs:@[ serviceUUIDs[0] ]];
+  }
 
   dispatch_semaphore_t semaphore = dispatch_semaphore_create(0);
   __block NSError *blockError = nil;
@@ -321,7 +374,12 @@ bool BleMedium::StartMultipleServicesScanning(const std::vector<Uuid> &service_u
 }
 
 bool BleMedium::StopScanning() {
-  [socketCentralManager_ stopNoScanMode];
+  {
+    absl::MutexLock lock(&scanning_mutex_);
+    [socketCentralManager_ stopNoScanMode];
+    scan_cb_ = nullptr;
+    scanning_cb_ = nullptr;
+  }
 
   dispatch_semaphore_t semaphore = dispatch_semaphore_create(0);
   __block NSError *blockError = nil;
@@ -448,24 +506,118 @@ std::unique_ptr<api::ble::GattClient> BleMedium::ConnectToGattServer(
 // TODO(b/293336684): Old Weave code that need to be deleted once shared Weave is complete.
 std::unique_ptr<api::ble::BleServerSocket> BleMedium::OpenServerSocket(
     const std::string &service_id) {
+  if (GNCFeatureFlags.fixBleServerSocketDeadlockEnabled) {
+    return OpenServerSocketWithDeadlockSafety(service_id);
+  } else {
+    return OpenServerSocketLegacy(service_id);
+  }
+}
+
+std::unique_ptr<api::ble::BleServerSocket> BleMedium::OpenServerSocketWithDeadlockSafety(
+    const std::string &service_id) {
   auto server_socket = std::make_unique<BleServerSocket>();
-  __block auto server_socket_ptr = server_socket.get();
 
   if (socketPeripheralManager_ == nil) {
-    socketPeripheralManager_ = [[GNSPeripheralManager alloc] initWithAdvertisedName:nil
-                                                                  restoreIdentifier:nil];
+    if (peripheral_manager_factory_) {
+      socketPeripheralManager_ = peripheral_manager_factory_();
+    } else {
+      socketPeripheralManager_ = [[GNSPeripheralManager alloc] initWithAdvertisedName:nil
+                                                                    restoreIdentifier:nil];
+    }
   }
 
-  if (socketPeripheralManager_ == nil) {
-    GNCLoggerError(@"Failed to create peripheral manager.");
-    return nullptr;
+  // Fix for b/494335036 (Registry + Background Queue)
+  {
+    absl::MutexLock lock(server_socket_mutex_);
+    server_socket_ptr_ = server_socket.get();
   }
+  server_socket->SetCloseNotifier([this]() {
+    absl::MutexLock lock(server_socket_mutex_);
+    server_socket_ptr_ = nullptr;
+  });
 
   socketPeripheralServiceManager_ = [[GNSPeripheralServiceManager alloc]
          initWithBleServiceUUID:[CBUUID UUIDWithString:kWeaveServiceUUID]
        addPairingCharacteristic:NO
       shouldAcceptSocketHandler:^BOOL(GNSSocket *socket) {
-        GNCMWaitForConnection(socket, ^(BOOL didConnect) {
+        // Optimized Path: Use background queue and registry validation.
+        GNCMWaitForConnection(socket, connection_callback_queue_, ^(BOOL didConnect) {
+          GNCMBleConnection *connection =
+              [GNCMBleConnection connectionWithSocket:socket
+                                            serviceID:nil
+                                  expectedIntroPacket:YES
+                                        callbackQueue:connection_callback_queue_];
+
+          auto socket_wrapper = std::make_unique<BleSocket>(connection);
+          socket_wrapper->SetCloseNotifier(
+              [socketPeripheralManager = socketPeripheralManager_,
+               serviceUUID = socketPeripheralServiceManager_.serviceUUID]() {
+                [socketPeripheralManager
+                    removePeripheralServiceManagerForServiceUUID:serviceUUID
+                                     bleServiceRemovedCompletion:^(NSError *_Nullable error) {
+                                       GNCLoggerInfo(@"BleSocket is removed peripheral manager.");
+                                     }];
+              });
+
+          connection.connectionHandlers = socket_wrapper->GetInputStream().GetConnectionHandlers();
+
+          // Fix: Verify the BleServerSocket still exists before calling Connect().
+          // This prevents the use-after-free/deadlock reported in b/494335036.
+          absl::MutexLock lock(server_socket_mutex_);
+          if (server_socket_ptr_) {
+            server_socket_ptr_->Connect(std::move(socket_wrapper));
+            GNCLoggerInfo(@"BleServerSocket is created with connection");
+          } else {
+            GNCLoggerWarning(@"BleServerSocket was destroyed; ignoring connection.");
+          }
+        });
+        return YES;
+      }];
+
+  dispatch_semaphore_t semaphore = dispatch_semaphore_create(0);
+  __block NSError *blockError = nil;
+  [socketPeripheralManager_ addPeripheralServiceManager:socketPeripheralServiceManager_
+                              bleServiceAddedCompletion:^(NSError *error) {
+                                if (error != nil) {
+                                  GNCLoggerError(@"Failed to add Weave service: %@", error);
+                                  blockError = error;
+                                }
+                                dispatch_semaphore_signal(semaphore);
+                              }];
+  [socketPeripheralManager_ start];
+  dispatch_time_t timeout = dispatch_time(DISPATCH_TIME_NOW, kApiTimeoutInSeconds * NSEC_PER_SEC);
+  if (dispatch_semaphore_wait(semaphore, timeout) != 0) {
+    GNCLoggerError(@"OpenServerSocket operation timed out.");
+    return nullptr;
+  }
+  if (blockError != nil) {
+    return nullptr;
+  }
+  return std::move(server_socket);
+}
+
+std::unique_ptr<api::ble::BleServerSocket> BleMedium::OpenServerSocketLegacy(
+    const std::string &service_id) {
+  auto server_socket = std::make_unique<BleServerSocket>();
+
+  if (socketPeripheralManager_ == nil) {
+    if (peripheral_manager_factory_) {
+      socketPeripheralManager_ = peripheral_manager_factory_();
+    } else {
+      socketPeripheralManager_ = [[GNSPeripheralManager alloc] initWithAdvertisedName:nil
+                                                                    restoreIdentifier:nil];
+    }
+  }
+
+  // Raw pointer for closure capture in the legacy path (risks use-after-free).
+  BleServerSocket *server_socket_ptr = server_socket.get();
+
+  socketPeripheralServiceManager_ = [[GNSPeripheralServiceManager alloc]
+         initWithBleServiceUUID:[CBUUID UUIDWithString:kWeaveServiceUUID]
+       addPairingCharacteristic:NO
+      shouldAcceptSocketHandler:^BOOL(GNSSocket *socket) {
+        // Legacy Path: Verbatim copy of original code (blocks Main Thread).
+        GNCMWaitForConnection(socket, nil, ^(BOOL didConnect) {
           GNCMBleConnection *connection =
               [GNCMBleConnection connectionWithSocket:socket
                                             // This must be nil as the advertiser even though we
@@ -588,8 +740,12 @@ std::unique_ptr<api::ble::BleSocket> BleMedium::Connect(
     return nullptr;
   }
 
-  GNSCentralPeerManager *updatedCentralPeerManager =
-      [socketCentralManager_ retrieveCentralPeerWithIdentifier:peripheral.identifier];
+  GNSCentralPeerManager *updatedCentralPeerManager;
+  {
+    absl::MutexLock lock(&scanning_mutex_);
+    updatedCentralPeerManager =
+        [socketCentralManager_ retrieveCentralPeerWithIdentifier:peripheral.identifier];
+  }
   if (!updatedCentralPeerManager) {
     return nullptr;
   }
@@ -603,7 +759,14 @@ std::unique_ptr<api::ble::BleSocket> BleMedium::Connect(
                                dispatch_semaphore_signal(semaphore);
                                return;
                              }
-                             GNCMWaitForConnection(nssocket, ^(BOOL didConnect) {
+
+                             // Suggestion: Use the connection callback queue instead of nil
+                             dispatch_queue_t targetQueue =
+                                 GNCFeatureFlags.fixBleServerSocketDeadlockEnabled
+                                     ? connection_callback_queue_
+                                     : nil;
+
+                             GNCMWaitForConnection(nssocket, targetQueue, ^(BOOL didConnect) {
                                if (!didConnect) {
                                  dispatch_semaphore_signal(semaphore);
                                  return;

internal/platform/implementation/apple/ble_socket.mm

@@ -14,13 +14,13 @@
 
 #import "internal/platform/implementation/apple/ble_socket.h"
 
-#include "internal/platform/implementation/ble.h"
-
+#import "internal/platform/implementation/apple/Flags/GNCFeatureFlags.h"
 #import "internal/platform/implementation/apple/Mediums/BLE/GNCMBleConnection.h"
 #import "internal/platform/implementation/apple/ble_peripheral.h"
 #import "internal/platform/implementation/apple/ble_utils.h"
 #import "internal/platform/implementation/apple/utils.h"
 
+#include "internal/platform/implementation/ble.h"
 // TODO(b/293336684): Remove this file when shared Weave is complete.
 
 namespace nearby {
@@ -55,45 +55,94 @@ BleInputStream::~BleInputStream() {
 }
 
 ExceptionOr<ByteArray> BleInputStream::Read(std::int64_t size) {
-  // Block until either (a) the connection has been closed, (b) we have enough data to return.
-  NSData *dataToReturn;
-  [condition_ lock];
-  while (true) {
-    // Check if the stream has been closed or severed.
-    if (!newDataPackets_) break;
+  if (GNCFeatureFlags.singleCopyEnabled) {
+    std::string dataToReturn;
+    bool success = false;
 
-    if (newDataPackets_.count > 0) {
-      // Add the packet data to the accumulated data.
-      for (NSData *data in newDataPackets_) {
-        if (data.length > 0) {
-          [accumulatedData_ appendData:data];
+    [condition_ lock];
+    while (true) {
+      // Check if the stream has been closed or severed.
+      if (!newDataPackets_) break;
+
+      if (newDataPackets_.count > 0) {
+        // Add the packet data to the accumulated data.
+        for (NSData *data in newDataPackets_) {
+          if (data.length > 0) {
+            [accumulatedData_ appendData:data];
+          }
         }
+        [newDataPackets_ removeAllObjects];
       }
-      [newDataPackets_ removeAllObjects];
+
+      if ((size == -1) && (accumulatedData_.length > 0)) {
+        // Return all of the data.
+        dataToReturn.assign((const char *)accumulatedData_.bytes, accumulatedData_.length);
+        accumulatedData_ = [NSMutableData data];
+        success = true;
+        break;
+      } else if (accumulatedData_.length > 0) {
+        // Return up to |size| bytes of the data.
+        std::int64_t sizeToReturn =
+            (accumulatedData_.length < size) ? accumulatedData_.length : size;
+        NSRange range = NSMakeRange(0, (NSUInteger)sizeToReturn);
+        // Copy bytes directly into std::string, avoiding [NSData subdataWithRange:]
+        dataToReturn.assign((const char *)accumulatedData_.bytes, sizeToReturn);
+        [accumulatedData_ replaceBytesInRange:range withBytes:nil length:0];
+        success = true;
+        break;
+      }
+
+      [condition_ wait];
     }
+    [condition_ unlock];
 
-    if ((size == -1) && (accumulatedData_.length > 0)) {
-      // Return all of the data.
-      dataToReturn = accumulatedData_;
-      accumulatedData_ = [NSMutableData data];
-      break;
-    } else if (accumulatedData_.length > 0) {
-      // Return up to |size| bytes of the data.
-      std::int64_t sizeToReturn = (accumulatedData_.length < size) ? accumulatedData_.length : size;
-      NSRange range = NSMakeRange(0, (NSUInteger)sizeToReturn);
-      dataToReturn = [accumulatedData_ subdataWithRange:range];
-      [accumulatedData_ replaceBytesInRange:range withBytes:nil length:0];
-      break;
+    if (success) {
+      // OPTIMIZATION: Zero-copy transfer from std::string to ByteArray
+      return ExceptionOr<ByteArray>{ByteArray(std::move(dataToReturn))};
+    } else {
+      return ExceptionOr<ByteArray>{Exception::kIo};
     }
-
-    [condition_ wait];
-  }
-  [condition_ unlock];
-
-  if (dataToReturn) {
-    return ExceptionOr<ByteArray>(ByteArrayFromNSData(dataToReturn));
   } else {
-    return ExceptionOr<ByteArray>{Exception::kIo};
+    // Legacy path
+    NSData *dataToReturn;
+    [condition_ lock];
+    while (true) {
+      // Check if the stream has been closed or severed.
+      if (!newDataPackets_) break;
+
+      if (newDataPackets_.count > 0) {
+        for (NSData *data in newDataPackets_) {
+          if (data.length > 0) {
+            [accumulatedData_ appendData:data];
+          }
+        }
+        [newDataPackets_ removeAllObjects];
+      }
+
+      if ((size == -1) && (accumulatedData_.length > 0)) {
+        // Return all of the data.
+        dataToReturn = accumulatedData_;
+        accumulatedData_ = [NSMutableData data];
+        break;
+      } else if (accumulatedData_.length > 0) {
+        // Return up to |size| bytes of the data.
+        std::int64_t sizeToReturn =
+            (accumulatedData_.length < size) ? accumulatedData_.length : size;
+        NSRange range = NSMakeRange(0, (NSUInteger)sizeToReturn);
+        dataToReturn = [accumulatedData_ subdataWithRange:range];
+        [accumulatedData_ replaceBytesInRange:range withBytes:nil length:0];
+        break;
+      }
+
+      [condition_ wait];
+    }
+    [condition_ unlock];
+
+    if (dataToReturn) {
+      return ExceptionOr<ByteArray>(ByteArrayFromNSData(dataToReturn));
+    } else {
+      return ExceptionOr<ByteArray>{Exception::kIo};
+    }
   }
 }
 
@@ -119,7 +168,17 @@ Exception BleOutputStream::Write(absl::string_view data) {
     return {Exception::kIo};
   }
 
-  NSMutableData *packet = [NSMutableData dataWithBytes:data.data() length:data.size()];
+  NSData *packet;
+  if (GNCFeatureFlags.singleCopyEnabled) {
+    // OPTIMIZATION: Use DISPATCH_DATA_DESTRUCTOR_DEFAULT to perform a
+    // single copy into a GCD-managed buffer. No NSData required.
+    dispatch_data_t dispatchData =
+        dispatch_data_create(data.data(), data.size(), nil, DISPATCH_DATA_DESTRUCTOR_DEFAULT);
+    // dispatch_data_t is toll-free bridged to NSData
+    packet = (NSData *)dispatchData;
+  } else {
+    packet = [NSMutableData dataWithBytes:data.data() length:data.size()];
+  }
 
   // Send the data, blocking until the completion handler is called.
   __block bool isComplete = NO;

internal/platform/implementation/apple/condition_variable_test.cc

@@ -16,8 +16,8 @@
 
 #include "gtest/gtest.h"
 #include "absl/time/clock.h"
+#include "third_party/gloop/thread/fiber/fiber.h"
 #include "internal/platform/implementation/apple/mutex.h"
-#include "thread/fiber/fiber.h"
 
 namespace nearby {
 namespace apple {

internal/platform/implementation/apple/count_down_latch_test.cc

@@ -18,7 +18,7 @@
 
 #include "gtest/gtest.h"
 #include "absl/time/time.h"
-#include "thread/fiber/fiber.h"
+#include "third_party/gloop/thread/fiber/fiber.h"
 
 namespace nearby {
 namespace apple {

internal/platform/implementation/apple/device_info.h

@@ -34,17 +34,13 @@ class DeviceInfo : public api::DeviceInfo {
 
   api::DeviceInfo::OsType GetOsType() const override;
 
-  std::optional<FilePath> GetDownloadPath() const override;
+  FilePath GetDownloadPath() const override;
 
-  std::optional<FilePath> GetLocalAppDataPath() const override;
+  FilePath GetLocalAppDataPath(FilePath sub_path) const override;
 
-  std::optional<FilePath> GetCommonAppDataPath() const override;
+  FilePath GetTemporaryPath() const override;
 
-  std::optional<FilePath> GetTemporaryPath() const override;
-
-  std::optional<FilePath> GetLogPath() const override;
-
-  std::optional<FilePath> GetCrashDumpPath() const override;
+  FilePath GetLogPath() const override;
 
   bool IsScreenLocked() const override;
 

internal/platform/implementation/apple/device_info.mm

@@ -79,7 +79,7 @@ api::DeviceInfo::OsType DeviceInfo::GetOsType() const {
 #endif
 }
 
-std::optional<FilePath> DeviceInfo::GetDownloadPath() const {
+FilePath DeviceInfo::GetDownloadPath() const {
   NSFileManager *manager = [NSFileManager defaultManager];
 
   NSError *error = nil;
@@ -90,30 +90,24 @@ std::optional<FilePath> DeviceInfo::GetDownloadPath() const {
                                            error:&error];
   if (!downloadsURL) {
     GNCLoggerError(@"Failed to get download path: %@", error);
-    return std::nullopt;
+    return GetTemporaryPath();
   }
 
   return FilePath(absl::string_view([downloadsURL.path cString]));
 }
 
-std::optional<FilePath> DeviceInfo::GetLocalAppDataPath() const {
-  return FilePath(absl::string_view([GNCLocalAppDataPath().path cString]));
+FilePath DeviceInfo::GetLocalAppDataPath(FilePath sub_path) const {
+  return FilePath(absl::string_view([GNCLocalAppDataPath().path cString])).append(sub_path);
 }
 
-std::optional<FilePath> DeviceInfo::GetCommonAppDataPath() const { return GetLocalAppDataPath(); }
-
-std::optional<FilePath> DeviceInfo::GetTemporaryPath() const {
+FilePath DeviceInfo::GetTemporaryPath() const {
   return FilePath(absl::string_view([NSTemporaryDirectory() cString]));
 }
 
-std::optional<FilePath> DeviceInfo::GetLogPath() const {
+FilePath DeviceInfo::GetLogPath() const {
   return FilePath(absl::string_view([GNCLogPath().path cString]));
 }
 
-std::optional<FilePath> DeviceInfo::GetCrashDumpPath() const {
-  return FilePath(absl::string_view([GNCCrashDumpPath().path cString]));
-}
-
 bool DeviceInfo::IsScreenLocked() const { return false; }
 
 void DeviceInfo::RegisterScreenLockedListener(

internal/platform/implementation/apple/mutex_test.cc

@@ -18,7 +18,7 @@
 #include "absl/base/thread_annotations.h"
 #include "absl/synchronization/notification.h"
 #include "absl/time/time.h"
-#include "thread/fiber/fiber.h"
+#include "third_party/gloop/thread/fiber/fiber.h"
 
 namespace nearby {
 namespace apple {

internal/platform/implementation/apple/platform.mm

@@ -45,10 +45,6 @@
 #include "internal/platform/implementation/shared/file.h"
 #include "internal/platform/payload_id.h"
 
-#ifndef NO_WEBRTC
-#import "internal/platform/implementation/apple/webrtc.h"
-#endif
-
 namespace nearby {
 namespace api {
 
@@ -205,12 +201,6 @@ std::unique_ptr<WifiDirectMedium> ImplementationPlatform::CreateWifiDirectMedium
   return nullptr;
 }
 
-#ifndef NO_WEBRTC
-std::unique_ptr<WebRtcMedium> ImplementationPlatform::CreateWebRtcMedium() {
-  return std::make_unique<apple::WebRtcMedium>();
-}
-#endif
-
 std::unique_ptr<AppLifecycleMonitor> ImplementationPlatform::CreateAppLifecycleMonitor(
     std::function<void(AppLifecycleMonitor::AppLifecycleState)> state_updated_callback) {
 #if TARGET_OS_IPHONE

internal/platform/implementation/apple/utils.mm

@@ -27,11 +27,15 @@ bool CppBoolFromObjCBool(BOOL b) { return b ? true : false; }
 char CharFromNSNumber(NSNumber* n) { return n.charValue; }
 
 NSString* ObjCStringFromCppString(absl::string_view s) {
-  return [NSString stringWithUTF8String:s.data()];
+  return [[NSString alloc] initWithBytes:s.data() length:s.size() encoding:NSUTF8StringEncoding];
 }
 
 std::string CppStringFromObjCString(NSString* s) {
-  return std::string([s UTF8String], [s lengthOfBytesUsingEncoding:NSUTF8StringEncoding]);
+  if (!s) return std::string();
+  const char* cstr = [s UTF8String];
+  if (!cstr) return std::string();
+  NSUInteger len = [s lengthOfBytesUsingEncoding:NSUTF8StringEncoding];
+  return std::string(cstr, len);
 }
 
 NSData* NSDataFromByteArray(ByteArray byteArray) {

internal/platform/implementation/apple/webrtc.h

@@ -1,62 +0,0 @@
-// Copyright 2025 Google LLC
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     https://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-#ifndef PLATFORM_IMPL_APPLE_WEBRTC_H_
-#define PLATFORM_IMPL_APPLE_WEBRTC_H_
-
-#ifndef NO_WEBRTC
-
-#include <memory>
-#include <optional>
-#include <string>
-
-#include "absl/strings/string_view.h"
-#include "internal/platform/implementation/webrtc.h"
-#include "webrtc/api/peer_connection_interface.h"
-
-namespace nearby::apple {
-
-class WebRtcMedium : public api::WebRtcMedium {
- public:
-  ~WebRtcMedium() override = default;
-
-  // Gets the default two-letter country code associated with current locale.
-  // For example, en_US locale resolves to "US".
-  // This follows the ISO 3166-1 Alpha-2 standard.
-  std::string GetDefaultCountryCode() override;
-
-  // Creates and returns a new webrtc::PeerConnectionInterface object via
-  // |callback|.
-  void CreatePeerConnection(webrtc::PeerConnectionObserver* observer,
-                            PeerConnectionCallback callback) override;
-
-  // Creates and returns a new webrtc::PeerConnectionInterface object via
-  // |callback| with |PeerConnectionFactoryInterface::Options|.
-  void CreatePeerConnection(
-      std::optional<webrtc::PeerConnectionFactoryInterface::Options> options,
-      webrtc::PeerConnectionObserver* observer,
-      PeerConnectionCallback callback) override;
-
-  // Returns a signaling messenger for sending WebRTC signaling messages.
-  std::unique_ptr<api::WebRtcSignalingMessenger> GetSignalingMessenger(
-      absl::string_view self_id,
-      const location::nearby::connections::LocationHint& location_hint)
-      override;
-};
-
-}  // namespace nearby::apple
-
-#endif  // #ifndef NO_WEBRTC
-
-#endif  // PLATFORM_IMPL_APPLE_WEBRTC_H_

internal/platform/implementation/apple/webrtc.mm

@@ -1,99 +0,0 @@
-// Copyright 2025 Google LLC
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     https://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-#ifndef NO_WEBRTC
-
-#include "internal/platform/implementation/apple/webrtc.h"
-
-#import <Foundation/Foundation.h>
-
-#include <memory>
-#include <optional>
-#include <string>
-#include <utility>
-
-#include "absl/status/status.h"
-#include "absl/strings/string_view.h"
-#include "internal/platform/count_down_latch.h"
-#include "internal/platform/crypto.h"
-#include "internal/platform/logging.h"
-#include "internal/platform/tachyon_express_signaling_messenger.h"
-#include "internal/proto/tachyon.pb.h"
-#include "internal/proto/tachyon_enums.proto.h"
-#include "webrtc/api/create_modular_peer_connection_factory.h"
-#include "webrtc/api/task_queue/default_task_queue_factory.h"
-
-namespace nearby::apple {
-
-std::string WebRtcMedium::GetDefaultCountryCode() {
-  NSString* countryCode = [NSLocale.currentLocale objectForKey:NSLocaleCountryCode];
-  if (countryCode) {
-    return std::string([countryCode UTF8String]);
-  }
-  return "US";
-}
-
-void WebRtcMedium::CreatePeerConnection(webrtc::PeerConnectionObserver* observer,
-                                        PeerConnectionCallback callback) {
-  CreatePeerConnection(std::nullopt, observer, std::move(callback));
-}
-
-void WebRtcMedium::CreatePeerConnection(
-    std::optional<webrtc::PeerConnectionFactoryInterface::Options> options,
-    webrtc::PeerConnectionObserver* observer, PeerConnectionCallback callback) {
-  webrtc::PeerConnectionInterface::RTCConfiguration rtc_config;
-  rtc_config.sdp_semantics = webrtc::SdpSemantics::kUnifiedPlan;
-  // TODO: b/261663238 - Add the TURN servers and go beyond the default servers.
-  webrtc::PeerConnectionInterface::IceServer ice_server;
-  ice_server.urls.emplace_back("stun:stun.l.google.com:19302");
-  ice_server.urls.emplace_back("stun:stun1.l.google.com:19302");
-  ice_server.urls.emplace_back("stun:stun2.l.google.com:19302");
-  ice_server.urls.emplace_back("stun:stun3.l.google.com:19302");
-  ice_server.urls.emplace_back("stun:stun4.l.google.com:19302");
-  rtc_config.servers.push_back(ice_server);
-
-  std::unique_ptr<webrtc::Thread> signaling_thread = webrtc::Thread::Create();
-  signaling_thread->SetName("signaling_thread", nullptr);
-  if (!signaling_thread->Start()) {
-    callback(/*peer_connection=*/nullptr);
-    return;
-  }
-
-  webrtc::PeerConnectionDependencies dependencies(observer);
-  webrtc::PeerConnectionFactoryDependencies factory_dependencies;
-  factory_dependencies.signaling_thread = signaling_thread.release();
-
-  webrtc::scoped_refptr<webrtc::PeerConnectionFactoryInterface> peer_connection_factory =
-      webrtc::CreateModularPeerConnectionFactory(std::move(factory_dependencies));
-  if (options.has_value()) {
-    peer_connection_factory->SetOptions(options.value());
-  }
-  webrtc::RTCErrorOr<webrtc::scoped_refptr<webrtc::PeerConnectionInterface>>
-      peer_connection_or_error =
-          peer_connection_factory->CreatePeerConnectionOrError(rtc_config, std::move(dependencies));
-  if (peer_connection_or_error.ok()) {
-    callback(peer_connection_or_error.MoveValue());
-  } else {
-    callback(/*peer_connection=*/nullptr);
-  }
-}
-
-std::unique_ptr<api::WebRtcSignalingMessenger> WebRtcMedium::GetSignalingMessenger(
-    absl::string_view self_id, const location::nearby::connections::LocationHint& location_hint) {
-  return std::make_unique<TachyonExpressSignalingMessenger>(self_id, location_hint);
-}
-
-}  // namespace nearby::apple
-
-#endif  // #ifndef NO_WEBRTC

internal/platform/implementation/apple/webrtc_platform.mm

@@ -0,0 +1,39 @@
+// Copyright 2026 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "internal/platform/implementation/webrtc_platform.h"
+
+#import <Foundation/Foundation.h>
+
+#include <memory>
+
+#include "connections/implementation/mediums/webrtc/webrtc_medium_impl.h"
+
+namespace nearby {
+namespace api {
+
+std::unique_ptr<WebRtcMedium> WebRtcImplementationPlatform::CreateWebRtcMedium() {
+  return std::make_unique<nearby::connections::mediums::WebRtcMediumImpl>();
+}
+
+std::string WebRtcImplementationPlatform::GetDefaultCountryCode() {
+  NSString* countryCode = [NSLocale.currentLocale objectForKey:NSLocaleCountryCode];
+  if (countryCode) {
+    return std::string([countryCode UTF8String]);
+  }
+  return "US";
+}
+
+}  // namespace api
+}  // namespace nearby

internal/platform/implementation/apple/wifi_hotspot.mm

@@ -23,6 +23,8 @@
 #include <arpa/inet.h>
 #include "internal/base/masker.h"
 #include "internal/platform/cancellation_flag_listener.h"
+
+#import "internal/platform/implementation/apple/Flags/GNCFeatureFlags.h"
 #import "internal/platform/implementation/apple/Log/GNCLogger.h"
 #import "internal/platform/implementation/apple/Mediums/Hotspot/GNCHotspotMedium.h"
 #import "internal/platform/implementation/apple/Mediums/WiFiCommon/GNCIPv4Address.h"
@@ -43,12 +45,22 @@ WifiHotspotInputStream::WifiHotspotInputStream(GNCNWFrameworkSocket* socket) : s
 
 ExceptionOr<ByteArray> WifiHotspotInputStream::Read(std::int64_t size) {
   NSError* error = nil;
-  NSData* data = [socket_ readMaxLength:size error:&error];
-  if (data == nil) {
-    GNCLoggerError(@"Error reading socket: %@", error);
-    return {Exception::kIo};
+  if (GNCFeatureFlags.singleCopyEnabled) {
+    auto result = [socket_ readStringWithMaxLength:size error:&error];
+    if (!result.has_value()) {
+      GNCLoggerError(@"Error reading socket: %@", error);
+      return {Exception::kIo};
+    }
+    // OPTIMIZATION: Zero-copy transfer from std::string to ByteArray
+    return ExceptionOr<ByteArray>{ByteArray(std::move(result.value()))};
+  } else {
+    NSData* data = [socket_ readMaxLength:size error:&error];
+    if (data == nil) {
+      GNCLoggerError(@"Error reading socket: %@", error);
+      return {Exception::kIo};
+    }
+    return ExceptionOr<ByteArray>{ByteArray((const char*)data.bytes, data.length)};
   }
-  return ExceptionOr<ByteArray>{ByteArray((const char*)data.bytes, data.length)};
 }
 
 Exception WifiHotspotInputStream::Close() {
@@ -63,7 +75,15 @@ WifiHotspotOutputStream::WifiHotspotOutputStream(GNCNWFrameworkSocket* socket) :
 
 Exception WifiHotspotOutputStream::Write(absl::string_view data) {
   NSError* error = nil;
-  BOOL result = [socket_ write:[NSData dataWithBytes:data.data() length:data.size()] error:&error];
+  BOOL result = NO;
+
+  if (GNCFeatureFlags.singleCopyEnabled) {
+    // OPTIMIZATION: Write raw bytes directly, avoiding NSData creation.
+    result = [socket_ writeBytes:data.data() length:data.size() error:&error];
+  } else {
+    result = [socket_ write:[NSData dataWithBytes:data.data() length:data.size()] error:&error];
+  }
+
   if (!result) {
     GNCLoggerError(@"Error writing socket: %@", error);
     return {Exception::kIo};
@@ -150,7 +170,7 @@ std::unique_ptr<api::WifiHotspotSocket> WifiHotspotMedium::ConnectToService(
   }
   // 4 bytes IP address format.
   NSData* host_ip_address = [NSData dataWithBytes:service_address.address.data()
-                                            length:service_address.address.size()];
+                                           length:service_address.address.size()];
   host = [GNCIPv4Address addressFromData:host_ip_address];
   GNCLoggerInfo(@"Connect to Hotspot host server: %@", [host dottedRepresentation]);
 

internal/platform/implementation/apple/wifi_lan.mm

@@ -19,6 +19,7 @@
 #include <string>
 #include <utility>
 
+#import "internal/platform/implementation/apple/Flags/GNCFeatureFlags.h"
 #import "internal/platform/implementation/apple/Log/GNCLogger.h"
 #import "internal/platform/implementation/apple/Mediums/WiFiCommon/GNCIPv4Address.h"
 #import "internal/platform/implementation/apple/Mediums/WiFiCommon/GNCNWFramework.h"
@@ -35,12 +36,22 @@ WifiLanInputStream::WifiLanInputStream(GNCNWFrameworkSocket* socket) : socket_(s
 
 ExceptionOr<ByteArray> WifiLanInputStream::Read(std::int64_t size) {
   NSError* error = nil;
-  NSData* data = [socket_ readMaxLength:size error:&error];
-  if (data == nil) {
-    GNCLoggerError(@"Error reading socket: %@", error);
-    return {Exception::kIo};
+  if (GNCFeatureFlags.singleCopyEnabled) {
+    auto result = [socket_ readStringWithMaxLength:size error:&error];
+    if (!result.has_value()) {
+      GNCLoggerError(@"Error reading socket: %@", error);
+      return {Exception::kIo};
+    }
+    // OPTIMIZATION: Zero-copy transfer from std::string to ByteArray
+    return ExceptionOr<ByteArray>{ByteArray(std::move(result.value()))};
+  } else {
+    NSData* data = [socket_ readMaxLength:size error:&error];
+    if (data == nil) {
+      GNCLoggerError(@"Error reading socket: %@", error);
+      return {Exception::kIo};
+    }
+    return ExceptionOr<ByteArray>{ByteArray((const char*)data.bytes, data.length)};
   }
-  return ExceptionOr<ByteArray>{ByteArray((const char*)data.bytes, data.length)};
 }
 
 Exception WifiLanInputStream::Close() {
@@ -55,7 +66,15 @@ WifiLanOutputStream::WifiLanOutputStream(GNCNWFrameworkSocket* socket) : socket_
 
 Exception WifiLanOutputStream::Write(absl::string_view data) {
   NSError* error = nil;
-  BOOL result = [socket_ write:[NSData dataWithBytes:data.data() length:data.size()] error:&error];
+  BOOL result = NO;
+
+  if (GNCFeatureFlags.singleCopyEnabled) {
+    // OPTIMIZATION: Write raw bytes directly, avoiding NSData creation.
+    result = [socket_ writeBytes:data.data() length:data.size() error:&error];
+  } else {
+    result = [socket_ write:[NSData dataWithBytes:data.data() length:data.size()] error:&error];
+  }
+
   if (!result) {
     GNCLoggerError(@"Error writing socket: %@", error);
     return {Exception::kIo};

internal/platform/implementation/auth_status.h

@@ -1,88 +0,0 @@
-// Copyright 2024 Google LLC
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     https://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-#ifndef THIRD_PARTY_NEARBY_INTERNAL_PLATFORM_IMPLEMENTATION_AUTH_STATUS_H_
-#define THIRD_PARTY_NEARBY_INTERNAL_PLATFORM_IMPLEMENTATION_AUTH_STATUS_H_
-
-namespace nearby {
-
-enum AuthStatus {
-  AUTH_STATUS_UNSPECIFIED = 0,
-  // Request completed successfully, the results should be in the correct order
-  // up to the given count.
-  SUCCESS = 1,
-
-  // Request encountered a generic error.
-  GENERIC_ERROR = 2,
-
-  // Request as specified is not supported.
-  UNSUPPORTED = 3,
-
-  // Request failed and should be retried soon.
-  TEMPORARILY_UNAVAILABLE = 4,
-
-  // Request failed due to an unavailable resource.
-  UNAVAILABLE_RESOURCE = 5,
-
-  // The request failed due to an invalid argument.
-  INVALID_ARGUMENT = 6,
-
-  // In case the status could not be retrieved.
-  UNKNOWN_STATUS = 7,
-
-  // Currently used as a way to signal an ETag mismatch.
-  PRECONDITION_FAILED = 8,
-
-  // Exclusively used to report when user did not consent to required scopes.
-  // Do NOT use this for another other scenarios.
-  PERMISSION_DENIED = 9,
-
-  // The resource exists, but the requested attribute of it does not.
-  MISSING_ATTRIBUTE = 10,
-
-  // The method was interrupted and the caller should exit the current unit of
-  // work immediately.
-  INTERRUPTED = 11,
-
-  // User signed in with an unexpected account.
-  SIGNED_IN_WITH_WRONG_ACCOUNT = 12,
-
-  // Used when data cannot be parsed properly.
-  PARSE_ERROR = 13,
-
-  // Used to report that the local HTTP server for receiving the authorization
-  // code cannot be created.
-  CANT_CREATE_AUTH_SERVER = 14,
-
-  // Used to report that the system browser for authenticating the user cannot
-  // be open.
-  CANT_OPEN_BROWSER_FOR_AUTH = 15,
-
-  // Used to report that the authorization code cannot be received.
-  CANT_RECEIVE_AUTH_CODE = 16,
-
-  // Used to report that the account is blocked (e.g. CAA).
-  ACCOUNT_BLOCKED = 17,
-
-  // Receiving the authorization code failed because it took longer than the
-  // timeout.
-  AUTH_CODE_TIMEOUT_EXCEEDED = 18,
-
-  // Used to report when user presses the cancel button during login process.
-  USER_CANCELED = 19,
-};
-
-}  // namespace nearby
-
-#endif  // THIRD_PARTY_NEARBY_INTERNAL_PLATFORM_IMPLEMENTATION_AUTH_STATUS_H_

internal/platform/implementation/ble.h

@@ -29,7 +29,6 @@
 #include "absl/status/statusor.h"
 #include "absl/strings/str_format.h"
 #include "absl/strings/string_view.h"
-#include "absl/types/optional.h"
 #include "internal/platform/byte_array.h"
 #include "internal/platform/cancellation_flag.h"
 #include "internal/platform/exception.h"
@@ -155,26 +154,26 @@ struct GattCharacteristic {
   Property property;
 
   // overloading operator for enum class Permission and Property
-  friend inline Permission operator|(Permission a, Permission b) {
+  friend Permission operator|(Permission a, Permission b) {
     return static_cast<Permission>(static_cast<int>(a) | static_cast<int>(b));
   }
 
-  friend inline Permission operator&(Permission a, Permission b) {
+  friend Permission operator&(Permission a, Permission b) {
     return static_cast<Permission>(static_cast<int>(a) & static_cast<int>(b));
   }
-  friend inline Permission& operator|=(Permission& a, Permission b) {
+  friend Permission& operator|=(Permission& a, Permission b) {
     a = a | b;
     return a;
   }
 
-  friend inline Property operator|(Property a, Property b) {
+  friend Property operator|(Property a, Property b) {
     return static_cast<Property>(static_cast<int>(a) | static_cast<int>(b));
   }
 
-  friend inline Property operator&(Property a, Property b) {
+  friend Property operator&(Property a, Property b) {
     return static_cast<Property>(static_cast<int>(a) & static_cast<int>(b));
   }
-  friend inline Property& operator|=(Property& a, Property b) {
+  friend Property& operator|=(Property& a, Property b) {
     a = a | b;
     return a;
   }
@@ -231,13 +230,13 @@ class GattClient {
   // It is okay for duplicate services to exist, as long as the specified
   // characteristic UUID is unique among all services of the same UUID.
   // NOLINTNEXTLINE(google3-legacy-absl-backports)
-  virtual absl::optional<GattCharacteristic> GetCharacteristic(
+  virtual std::optional<GattCharacteristic> GetCharacteristic(
       const Uuid& service_uuid, const Uuid& characteristic_uuid) = 0;
 
   // https://developer.android.com/reference/android/bluetooth/BluetoothGatt.html#readCharacteristic(android.bluetooth.BluetoothGattCharacteristic)
   // https://developer.android.com/reference/android/bluetooth/BluetoothGattCharacteristic.html#getValue()
   // NOLINTNEXTLINE(google3-legacy-absl-backports)
-  virtual absl::optional<std::string> ReadCharacteristic(
+  virtual std::optional<std::string> ReadCharacteristic(
       const GattCharacteristic& characteristic) = 0;
 
   // https://developer.android.com/reference/android/bluetooth/BluetoothGattCharacteristic.html#setValue(byte[])
@@ -248,14 +247,6 @@ class GattClient {
   virtual bool WriteCharacteristic(const GattCharacteristic& characteristic,
                                    absl::string_view value, WriteType type) = 0;
 
-  // https://developer.android.com/reference/android/bluetooth/BluetoothGatt.html#setCharacteristicNotification(android.bluetooth.BluetoothGattCharacteristic,%20boolean)
-  //
-  // Enable or disable notifications/indications for a given characteristic.
-  virtual bool SetCharacteristicSubscription(
-      const GattCharacteristic& characteristic, bool enable,
-      absl::AnyInvocable<void(absl::string_view value)>
-          on_characteristic_changed_cb) = 0;
-
   // https://developer.android.com/reference/android/bluetooth/BluetoothGatt.html#disconnect()
   virtual void Disconnect() = 0;
 };
@@ -281,7 +272,7 @@ class GattServer {
   // more information about this descriptor, please go to:
   // https://www.bluetooth.com/specifications/Gatt/viewer?attributeXmlFile=org.bluetooth.descriptor.Gatt.client_characteristic_configuration.xml
   // NOLINTNEXTLINE(google3-legacy-absl-backports)
-  virtual absl::optional<GattCharacteristic> CreateCharacteristic(
+  virtual std::optional<GattCharacteristic> CreateCharacteristic(
       const Uuid& service_uuid, const Uuid& characteristic_uuid,
       GattCharacteristic::Permission permission,
       GattCharacteristic::Property property) = 0;

internal/platform/implementation/device_info.h

@@ -15,12 +15,14 @@
 #ifndef PLATFORM_API_DEVICE_INFO_H_
 #define PLATFORM_API_DEVICE_INFO_H_
 
+#include <cstddef>
 #include <functional>
 #include <optional>
 #include <string>
 
 #include "absl/strings/string_view.h"
 #include "internal/base/file_path.h"
+#include "internal/base/files.h"
 
 namespace nearby {
 namespace api {
@@ -46,12 +48,15 @@ class DeviceInfo {
   virtual OsType GetOsType() const = 0;
 
   // Gets known paths of current user.
-  virtual std::optional<FilePath> GetDownloadPath() const = 0;
-  virtual std::optional<FilePath> GetLocalAppDataPath() const = 0;
-  virtual std::optional<FilePath> GetCommonAppDataPath() const = 0;
-  virtual std::optional<FilePath> GetTemporaryPath() const = 0;
-  virtual std::optional<FilePath> GetLogPath() const = 0;
-  virtual std::optional<FilePath> GetCrashDumpPath() const = 0;
+  virtual FilePath GetDownloadPath() const = 0;
+  virtual FilePath GetLocalAppDataPath(FilePath sub_path) const = 0;
+  virtual FilePath GetTemporaryPath() const = 0;
+  virtual FilePath GetLogPath() const = 0;
+
+  virtual std::optional<size_t> GetAvailableDiskSpaceInBytes(
+      const FilePath& path) const {
+        return Files::GetAvailableDiskSpaceInBytes(path);
+  };
 
   // Monitor screen status
   virtual bool IsScreenLocked() const = 0;
@@ -66,6 +71,24 @@ class DeviceInfo {
   virtual bool AllowSleep() = 0;
 };
 
+template <typename Sink>
+void AbslStringify(Sink& sink, DeviceInfo::DeviceType device_type) {
+  switch (device_type) {
+    case DeviceInfo::DeviceType::kUnknown:
+      sink.Append("Unknown");
+      return;
+    case DeviceInfo::DeviceType::kPhone:
+      sink.Append("Phone");
+      return;
+    case DeviceInfo::DeviceType::kTablet:
+      sink.Append("Tablet");
+      return;
+    case DeviceInfo::DeviceType::kLaptop:
+      sink.Append("PC");
+      return;
+  }
+}
+
 }  // namespace api
 }  // namespace nearby
 

internal/platform/implementation/device_info_test.cc

@@ -0,0 +1,29 @@
+// Copyright 2026 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "internal/platform/implementation/device_info.h"
+
+#include "gtest/gtest.h"
+#include "absl/strings/str_cat.h"
+
+namespace nearby::api {
+namespace {
+
+TEST(DeviceInfoTest, DeviceTypeToStringTest) {
+  DeviceInfo::DeviceType type = DeviceInfo::DeviceType::kPhone;
+  EXPECT_EQ(absl::StrCat(type), "Phone");
+}
+
+}  // namespace
+}  // namespace nearby::api

internal/platform/implementation/g3/BUILD

@@ -85,6 +85,7 @@ cc_library(
         "bluetooth_adapter.cc",
         "bluetooth_classic.cc",
         "credential_storage_impl.cc",
+        "webrtc.cc",
         "wifi_direct.cc",
         "wifi_hotspot.cc",
         "wifi_lan.cc",
@@ -96,6 +97,7 @@ cc_library(
         "bluetooth_classic.h",
         "credential_storage_impl.h",
         "socket_base.h",
+        "webrtc.h",
         "wifi.h",
         "wifi_direct.h",
         "wifi_hotspot.h",
@@ -112,11 +114,14 @@ cc_library(
         "//internal/platform:types",
         "//internal/platform:uuid",
         "//internal/platform/implementation:comm",
+        "//internal/platform/implementation:webrtc_platform",
         "//internal/platform/implementation:wifi_utils",
         "//internal/proto:credential_cc_proto",
         "//third_party/webrtc/files/stable/webrtc/api:create_modular_peer_connection_factory",
-        "//third_party/webrtc/files/stable/webrtc/api:libjingle_peerconnection_api",
+        "//third_party/webrtc/files/stable/webrtc/api:peer_connection_interface",
         "//third_party/webrtc/files/stable/webrtc/api:scoped_refptr",
+        "//third_party/webrtc/files/stable/webrtc/rtc_base:checks",
+        "//third_party/webrtc/files/stable/webrtc/rtc_base:threading",
         "@com_google_absl//absl/base:core_headers",
         "@com_google_absl//absl/container:flat_hash_map",
         "@com_google_absl//absl/container:flat_hash_set",
@@ -177,8 +182,8 @@ cc_library(
     testonly = True,
     srcs = [
         "platform.cc",
+        "webrtc_platform.cc",
     ],
-    defines = ["NO_WEBRTC"],
     visibility = [
         "//connections:__subpackages__",
         "//connections:partners",
@@ -191,10 +196,9 @@ cc_library(
         "//internal/preferences:__subpackages__",
         "//internal/proto/analytics:__subpackages__",
         "//internal/weave:__subpackages__",
-        "//location/nearby/cpp:__subpackages__",
         "//location/nearby/sharing/sdk:__subpackages__",
-        "//presence:__subpackages__",
         "//sharing:__subpackages__",
+        "//third_party/nearby/presence:__subpackages__",
     ],
     deps = [
         ":comm",
@@ -208,14 +212,16 @@ cc_library(
         "//internal/platform/implementation:comm",
         "//internal/platform/implementation:platform",
         "//internal/platform/implementation:types",
+        "//internal/platform/implementation:webrtc_platform",
         "//internal/platform/implementation/shared:count_down_latch",
         "//internal/platform/implementation/shared:file",
+        "//third_party/gloop/thread",
         "@com_google_absl//absl/base:core_headers",
         "@com_google_absl//absl/status",
         "@com_google_absl//absl/status:statusor",
         "@com_google_absl//absl/strings",
-        "@com_google_nisaba//nisaba/port:thread_pool",
     ],
+    alwayslink = 1,
 )
 
 cc_library(

internal/platform/implementation/g3/ble.cc

@@ -679,33 +679,6 @@ bool BleMedium::GattClient::WriteCharacteristic(
   return status.ok();
 }
 
-bool BleMedium::GattClient::SetCharacteristicSubscription(
-    const api::ble::GattCharacteristic& characteristic, bool enable,
-    absl::AnyInvocable<void(absl::string_view value)>
-        on_characteristic_changed_cb) {
-  absl::MutexLock lock(mutex_);
-  if (!is_connection_alive_) {
-    return false;
-  }
-  Borrowed<api::ble::GattServer*> borrowed = gatt_server_.Borrow();
-  if (!borrowed) {
-    return false;
-  }
-  BleMedium::GattServer* gatt_server =
-      static_cast<BleMedium::GattServer*>(*borrowed);
-  LOG(INFO) << "G3 Ble SetCharacteristicSubscription, characteristic=("
-            << characteristic.service_uuid.Get16BitAsString() << ","
-            << std::string(characteristic.uuid) << "), enable = " << enable;
-  if (enable) {
-    return gatt_server->AddCharacteristicSubscription(
-        peripheral_id_, characteristic,
-        std::move(on_characteristic_changed_cb));
-  } else {
-    return gatt_server->RemoveCharacteristicSubscription(peripheral_id_,
-                                                         characteristic);
-  }
-}
-
 void BleMedium::GattClient::Disconnect() {
   bool was_alive = is_connection_alive_.exchange(false);
   if (!was_alive) return;

internal/platform/implementation/g3/ble.h

@@ -282,11 +282,6 @@ class BleMedium : public api::ble::BleMedium {
         absl::string_view value,
         api::ble::GattClient::WriteType write_type) override;
 
-    bool SetCharacteristicSubscription(
-        const api::ble::GattCharacteristic& characteristic, bool enable,
-        absl::AnyInvocable<void(absl::string_view value)>
-            on_characteristic_changed_cb) override;
-
     void Disconnect() override;
 
     void OnServerDisconnected();

internal/platform/implementation/g3/device_info.h

@@ -45,33 +45,24 @@ class DeviceInfo : public api::DeviceInfo {
     return api::DeviceInfo::OsType::kChromeOs;
   }
 
-  std::optional<FilePath> GetDownloadPath() const override {
+  FilePath GetDownloadPath() const override {
     return Files::GetTemporaryDirectory();
   }
 
-  std::optional<FilePath> GetLocalAppDataPath() const override {
+  FilePath GetLocalAppDataPath(FilePath sub_path) const override {
     if (MediumEnvironment::Instance()
             .GetEnvironmentConfig()
             .use_temporary_directory_for_app_path) {
-      return Files::GetTemporaryDirectory();
+      return Files::GetTemporaryDirectory().append(sub_path);
     }
-
-    return GetAppDataPath();
+    return GetAppDataPath().append(sub_path);
   }
 
-  std::optional<FilePath> GetCommonAppDataPath() const override {
+  FilePath GetTemporaryPath() const override {
     return Files::GetTemporaryDirectory();
   }
 
-  std::optional<FilePath> GetTemporaryPath() const override {
-    return Files::GetTemporaryDirectory();
-  }
-
-  std::optional<FilePath> GetLogPath() const override {
-    return Files::GetTemporaryDirectory();
-  }
-
-  std::optional<FilePath> GetCrashDumpPath() const override {
+  FilePath GetLogPath() const override {
     return Files::GetTemporaryDirectory();
   }
 

internal/platform/implementation/g3/platform.cc

@@ -14,7 +14,6 @@
 
 #include "internal/platform/implementation/platform.h"
 
-#include <cstddef>
 #include <cstdint>
 #include <functional>
 #include <memory>
@@ -25,6 +24,7 @@
 #include "absl/status/statusor.h"
 #include "absl/strings/str_cat.h"
 #include "absl/strings/string_view.h"
+#include "third_party/gloop/thread/thread.h"
 #include "internal/base/file_path.h"
 #include "internal/base/files.h"
 #include "internal/platform/implementation/app_lifecycle_monitor.h"
@@ -55,11 +55,6 @@
 #include "internal/platform/logging.h"
 #include "internal/platform/os_name.h"
 #include "internal/platform/payload_id.h"
-#include "thread/thread.h"
-#ifndef NO_WEBRTC
-#include "internal/platform/implementation/g3/webrtc.h"
-#include "internal/platform/implementation/webrtc.h"
-#endif
 #include "internal/platform/implementation/g3/atomic_boolean.h"
 #include "internal/platform/implementation/g3/atomic_reference.h"
 #include "internal/platform/implementation/g3/ble.h"
@@ -80,7 +75,6 @@
 #include "internal/platform/implementation/g3/wifi_lan.h"
 #include "internal/platform/implementation/shared/file.h"
 #include "internal/platform/implementation/wifi.h"
-#include "internal/platform/medium_environment.h"
 
 namespace nearby {
 namespace api {
@@ -219,16 +213,6 @@ ImplementationPlatform::CreateWifiDirectMedium() {
   return std::make_unique<g3::WifiDirectMedium>();
 }
 
-#ifndef NO_WEBRTC
-std::unique_ptr<WebRtcMedium> ImplementationPlatform::CreateWebRtcMedium() {
-  if (MediumEnvironment::Instance().GetEnvironmentConfig().webrtc_enabled) {
-    return std::make_unique<g3::WebRtcMedium>();
-  } else {
-    return nullptr;
-  }
-}
-#endif
-
 std::unique_ptr<AppLifecycleMonitor>
 ImplementationPlatform::CreateAppLifecycleMonitor(
     std::function<void(AppLifecycleMonitor::AppLifecycleState)>

internal/platform/implementation/g3/scheduled_executor.cc

@@ -16,16 +16,15 @@
 
 #include <atomic>
 #include <memory>
-#include <optional>
 #include <utility>
 
 #include "absl/strings/str_format.h"
 #include "absl/synchronization/mutex.h"
 #include "absl/time/time.h"
 #include "internal/platform/implementation/cancelable.h"
+#include "internal/platform/logging.h"
 #include "internal/platform/medium_environment.h"
 #include "internal/platform/runnable.h"
-#include "internal/test/fake_clock.h"
 
 namespace nearby {
 namespace g3 {
@@ -66,20 +65,13 @@ class ScheduledCancelable : public api::Cancelable {
 }  // namespace
 
 ScheduledExecutor::ScheduledExecutor() {
-  std::optional<FakeClock*> fake_clock =
-      MediumEnvironment::Instance().GetSimulatedClock();
-  if (fake_clock.has_value()) {
-    name_ = absl::StrFormat("G3 scheduled executor %p", this);
-    (*fake_clock)->AddObserver(name_, [this]() { RunReadyTasks(); });
-  }
+  name_ = absl::StrFormat("G3 scheduled executor %p", this);
+  MediumEnvironment::Instance().AddSimulatedClockObserver(
+      name_, [this]() { RunReadyTasks(); });
 }
 
 ScheduledExecutor::~ScheduledExecutor() {
-  std::optional<FakeClock*> fake_clock =
-      MediumEnvironment::Instance().GetSimulatedClock();
-  if (fake_clock.has_value()) {
-    (*fake_clock)->RemoveObserver(name_);
-  }
+  MediumEnvironment::Instance().RemoveSimulatedClockObserver(name_);
   executor_.Shutdown();
 }
 
@@ -96,10 +88,10 @@ std::shared_ptr<api::Cancelable> ScheduledExecutor::Schedule(
       runnable();
     }
   };
-  std::optional<FakeClock*> fake_clock =
-      MediumEnvironment::Instance().GetSimulatedClock();
-  if (fake_clock.has_value()) {
-    absl::Time trigger_time = (*fake_clock)->Now() + delay;
+  if (MediumEnvironment::Instance()
+          .GetEnvironmentConfig()
+          .use_simulated_clock) {
+    absl::Time trigger_time = MediumEnvironment::Instance().Now() + delay;
     absl::MutexLock lock(mutex_);
     tasks_.insert(std::pair<absl::Time, std::unique_ptr<Runnable>>(
         trigger_time, std::make_unique<Runnable>(std::move(task))));
@@ -110,15 +102,12 @@ std::shared_ptr<api::Cancelable> ScheduledExecutor::Schedule(
 }
 
 void ScheduledExecutor::RunReadyTasks() {
-  std::optional<FakeClock*> fake_clock =
-      MediumEnvironment::Instance().GetSimulatedClock();
   if (executor_.InShutdown()) {
     return;
   }
-  if (!fake_clock.has_value()) {
-    return;
-  }
-  absl::Time current_time = (*fake_clock)->Now();
+  CHECK(
+      MediumEnvironment::Instance().GetEnvironmentConfig().use_simulated_clock);
+  absl::Time current_time = MediumEnvironment::Instance().Now();
   absl::MutexLock lock(mutex_);
   for (auto it = tasks_.begin(); it != tasks_.end();) {
     if (it->first <= current_time) {

internal/platform/implementation/g3/system_clock.cc

@@ -15,26 +15,21 @@
 #include "internal/platform/implementation/system_clock.h"
 
 #include "absl/time/clock.h"
+#include "absl/time/time.h"
 #include "internal/platform/exception.h"
 #include "internal/platform/medium_environment.h"
-#include "internal/test/fake_clock.h"
 
 namespace nearby {
 
 absl::Time SystemClock::ElapsedRealtime() {
-  absl::optional<FakeClock*> fake_clock =
-      MediumEnvironment::Instance().GetSimulatedClock();
-  if (fake_clock.has_value()) {
-    return (*fake_clock)->Now();
-  }
-  return absl::Now();
+  return MediumEnvironment::Instance().Now();
 }
 
 Exception SystemClock::Sleep(absl::Duration duration) {
-  absl::optional<FakeClock*> fake_clock =
-      MediumEnvironment::Instance().GetSimulatedClock();
-  if (fake_clock.has_value()) {
-    (*fake_clock)->FastForward(duration);
+  if (MediumEnvironment::Instance()
+          .GetEnvironmentConfig()
+          .use_simulated_clock) {
+    MediumEnvironment::Instance().FastForward(duration);
   } else {
     absl::SleepFor(duration);
   }

internal/platform/implementation/g3/webrtc.cc

@@ -24,10 +24,11 @@
 #include "internal/platform/byte_array.h"
 #include "internal/platform/implementation/webrtc.h"
 #include "internal/platform/medium_environment.h"
-#include "webrtc/api/create_modular_peer_connection_factory.h"
-#include "webrtc/api/peer_connection_interface.h"
-#include "webrtc/api/scoped_refptr.h"
-#include "webrtc/rtc_base/checks.h"
+#include "third_party/webrtc/files/stable/webrtc/api/create_modular_peer_connection_factory.h"
+#include "third_party/webrtc/files/stable/webrtc/api/peer_connection_interface.h"
+#include "third_party/webrtc/files/stable/webrtc/api/scoped_refptr.h"
+#include "third_party/webrtc/files/stable/webrtc/rtc_base/checks.h"
+#include "third_party/webrtc/files/stable/webrtc/rtc_base/thread.h"
 
 namespace nearby {
 namespace g3 {
@@ -60,8 +61,6 @@ void WebRtcSignalingMessenger::StopReceivingMessages() {
 
 WebRtcMedium::~WebRtcMedium() { single_thread_executor_.Shutdown(); }
 
-std::string WebRtcMedium::GetDefaultCountryCode() { return "US"; }
-
 void WebRtcMedium::CreatePeerConnection(
     webrtc::PeerConnectionObserver* observer, PeerConnectionCallback callback) {
   CreatePeerConnection(std::nullopt, observer, std::move(callback));

internal/platform/implementation/g3/webrtc.h

@@ -23,7 +23,7 @@
 #include "internal/platform/byte_array.h"
 #include "internal/platform/implementation/webrtc.h"
 #include "internal/platform/implementation/g3/single_thread_executor.h"
-#include "webrtc/api/peer_connection_interface.h"
+#include "third_party/webrtc/files/stable/webrtc/api/peer_connection_interface.h"
 
 namespace nearby {
 namespace g3 {
@@ -59,8 +59,6 @@ class WebRtcMedium : public api::WebRtcMedium {
   WebRtcMedium() = default;
   ~WebRtcMedium() override;
 
-  std::string GetDefaultCountryCode() override;
-
   // Creates and returns a new webrtc::PeerConnectionInterface object via
   // |callback|.
   void CreatePeerConnection(webrtc::PeerConnectionObserver* observer,

internal/platform/implementation/g3/webrtc_platform.cc

@@ -0,0 +1,39 @@
+// Copyright 2026 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "internal/platform/implementation/webrtc_platform.h"
+
+#include <memory>
+#include <string>
+
+#include "internal/platform/implementation/g3/webrtc.h"
+#include "internal/platform/implementation/webrtc.h"
+#include "internal/platform/medium_environment.h"
+
+namespace nearby::api {
+
+std::unique_ptr<WebRtcMedium>
+WebRtcImplementationPlatform::CreateWebRtcMedium() {
+  if (MediumEnvironment::Instance().GetEnvironmentConfig().webrtc_enabled) {
+    return std::make_unique<g3::WebRtcMedium>();
+  } else {
+    return nullptr;
+  }
+}
+
+std::string WebRtcImplementationPlatform::GetDefaultCountryCode() {
+  return "US";
+}
+
+}  // namespace nearby::api

internal/platform/implementation/g3/wifi.h

@@ -17,6 +17,9 @@
 
 #include <string>
 
+#include "absl/base/thread_annotations.h"
+#include "absl/strings/str_cat.h"
+#include "absl/strings/str_format.h"
 #include "absl/synchronization/mutex.h"
 #include "internal/platform/implementation/wifi.h"
 #include "internal/platform/medium_environment.h"

internal/platform/implementation/platform.h

@@ -39,15 +39,10 @@
 #include "internal/platform/implementation/log_message.h"
 #include "internal/platform/implementation/mutex.h"
 #include "internal/platform/implementation/output_file.h"
+#include "internal/platform/implementation/preferences_manager.h"
 #include "internal/platform/implementation/scheduled_executor.h"
 #include "internal/platform/implementation/submittable_executor.h"
 #include "internal/platform/implementation/timer.h"
-#ifndef NO_WEBRTC
-#include "internal/platform/implementation/webrtc.h"
-#endif
-#ifndef NEARBY_CHROMIUM
-#include "internal/platform/implementation/preferences_manager.h"
-#endif
 #include "internal/platform/implementation/wifi.h"
 #include "internal/platform/implementation/wifi_direct.h"
 #include "internal/platform/implementation/wifi_hotspot.h"
@@ -136,10 +131,6 @@ class ImplementationPlatform {
   static std::unique_ptr<WifiHotspotMedium> CreateWifiHotspotMedium();
   static std::unique_ptr<WifiDirectMedium> CreateWifiDirectMedium();
   static std::unique_ptr<Timer> CreateTimer();
-  static std::unique_ptr<DeviceInfo> CreateDeviceInfo();
-#ifndef NO_WEBRTC
-  static std::unique_ptr<WebRtcMedium> CreateWebRtcMedium();
-#endif
 
 #if defined(NEARBY_CHROMIUM)
   static std::unique_ptr<AppLifecycleMonitor> CreateAppLifecycleMonitor(
@@ -147,11 +138,17 @@ class ImplementationPlatform {
           state_updated_callback) {
     return nullptr;
   }
+  static std::unique_ptr<nearby::api::PreferencesManager>
+  CreatePreferencesManager(absl::string_view path) {
+    return nullptr;
+  }
 #else
   static std::unique_ptr<AppLifecycleMonitor> CreateAppLifecycleMonitor(
       std::function<void(AppLifecycleMonitor::AppLifecycleState)>
           state_updated_callback);
-#endif
+  static std::unique_ptr<nearby::api::PreferencesManager>
+  CreatePreferencesManager(absl::string_view path);
+  static std::unique_ptr<DeviceInfo> CreateDeviceInfo();
 
   // Gets HTTP response from remote server.
   //
@@ -161,15 +158,6 @@ class ImplementationPlatform {
   //         return WebResponse if HTTP status code between 200 and 300.
   //         other cases will return absl Status in error.
   static absl::StatusOr<WebResponse> SendRequest(const WebRequest& request);
-
-#if defined(NEARBY_CHROMIUM)
-  static std::unique_ptr<nearby::api::PreferencesManager>
-  CreatePreferencesManager(absl::string_view path) {
-    return nullptr;
-  }
-#else
-  static std::unique_ptr<nearby::api::PreferencesManager>
-  CreatePreferencesManager(absl::string_view path);
 #endif
 };
 

internal/platform/implementation/presence_advertiser_demo.cc

@@ -0,0 +1,236 @@
+// Copyright 2026 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <signal.h>
+
+#include <cstdlib>
+#include <iostream>
+#include <string>
+#include <vector>
+
+#include "absl/status/status.h"
+#include "absl/synchronization/notification.h"
+#include "internal/platform/system_clock.h"
+#include "internal/platform/single_thread_executor.h"
+#include "presence/broadcast_request.h"
+#include "presence/data_element.h"
+#include "presence/implementation/broadcast_manager.h"
+#include "presence/implementation/credential_manager.h"
+#include "presence/implementation/mediums/mediums.h"
+#include "presence/power_mode.h"
+
+namespace {
+
+absl::Notification g_shutdown;
+
+void QuitHandler(int, siginfo_t*, void*) {
+  if (!g_shutdown.HasBeenNotified()) g_shutdown.Notify();
+}
+
+void PrintUsage(const char* program) {
+  std::cerr
+      << "Usage: " << program << " [--name <device_name>] [--tx_power <int>]\n"
+      << "Example:\n"
+      << "  " << program << " --name \"Linux Presence Demo\" --tx_power 20\n";
+}
+
+// For a public-identity broadcast demo, credentials are never requested.
+class DemoCredentialManager : public nearby::presence::CredentialManager {
+ public:
+  void GenerateCredentials(
+      const nearby::internal::DeviceIdentityMetaData&,
+      absl::string_view,
+      const std::vector<nearby::internal::IdentityType>&,
+      int,
+      int,
+      nearby::presence::GenerateCredentialsResultCallback callback) override {
+    callback.credentials_generated_cb(
+        absl::UnimplementedError("Not used in public broadcast demo"));
+  }
+
+  void UpdateRemotePublicCredentials(
+      absl::string_view,
+      absl::string_view,
+      const std::vector<nearby::internal::SharedCredential>&,
+      nearby::presence::UpdateRemotePublicCredentialsCallback callback)
+      override {
+    callback.credentials_updated_cb(
+        absl::UnimplementedError("Not used in public broadcast demo"));
+  }
+
+  void UpdateLocalCredential(
+      const nearby::presence::CredentialSelector&,
+      nearby::internal::LocalCredential,
+      nearby::presence::SaveCredentialsResultCallback callback) override {
+    callback.credentials_saved_cb(
+        absl::UnimplementedError("Not used in public broadcast demo"));
+  }
+
+  void GetLocalCredentials(
+      const nearby::presence::CredentialSelector&,
+      nearby::presence::GetLocalCredentialsResultCallback callback) override {
+    callback.credentials_fetched_cb(
+        absl::NotFoundError("No local credentials in demo manager"));
+  }
+
+  void GetPublicCredentials(
+      const nearby::presence::CredentialSelector&,
+      nearby::presence::PublicCredentialType,
+      nearby::presence::GetPublicCredentialsResultCallback callback) override {
+    callback.credentials_fetched_cb(
+        absl::NotFoundError("No public credentials in demo manager"));
+  }
+
+  nearby::presence::SubscriberId SubscribeForPublicCredentials(
+      const nearby::presence::CredentialSelector&,
+      nearby::presence::PublicCredentialType,
+      nearby::presence::GetPublicCredentialsResultCallback callback) override {
+    callback.credentials_fetched_cb(
+        absl::NotFoundError("No subscriptions in demo manager"));
+    return 0;
+  }
+
+  void UnsubscribeFromPublicCredentials(nearby::presence::SubscriberId) override {
+  }
+
+  std::string DecryptDeviceIdentityMetaData(
+      absl::string_view,
+      absl::string_view,
+      absl::string_view) override {
+    return "";
+  }
+
+  void SetDeviceIdentityMetaData(
+      const nearby::internal::DeviceIdentityMetaData& device_identity_metadata,
+      bool,
+      absl::string_view,
+      const std::vector<nearby::internal::IdentityType>&,
+      int,
+      int,
+      nearby::presence::GenerateCredentialsResultCallback) override {
+    metadata_ = device_identity_metadata;
+  }
+
+  nearby::internal::DeviceIdentityMetaData GetDeviceIdentityMetaData()
+      override {
+    return metadata_;
+  }
+
+ private:
+  nearby::internal::DeviceIdentityMetaData metadata_;
+};
+
+}  // namespace
+
+int main(int argc, char** argv) {
+  // Force-link the platform SystemClock implementation from static archives.
+  (void)nearby::SystemClock::ElapsedRealtime();
+
+  std::string device_name = "Nearby Presence Demo";
+  int tx_power = 20;
+
+  for (int i = 1; i < argc; ++i) {
+    std::string arg = argv[i];
+    if ((arg == "-h") || (arg == "--help")) {
+      PrintUsage(argv[0]);
+      return 0;
+    }
+    if (arg == "--name") {
+      if (i + 1 >= argc) {
+        std::cerr << "Missing value for --name\n";
+        return 2;
+      }
+      device_name = argv[++i];
+      continue;
+    }
+    if (arg == "--tx_power") {
+      if (i + 1 >= argc) {
+        std::cerr << "Missing value for --tx_power\n";
+        return 2;
+      }
+      tx_power = std::atoi(argv[++i]);
+      continue;
+    }
+    std::cerr << "Unknown argument: " << arg << "\n";
+    PrintUsage(argv[0]);
+    return 2;
+  }
+
+  struct sigaction action {};
+  action.sa_sigaction = QuitHandler;
+  action.sa_flags = SA_SIGINFO;
+  sigaction(SIGINT, &action, nullptr);
+  sigaction(SIGTERM, &action, nullptr);
+
+  nearby::SingleThreadExecutor executor;
+  nearby::presence::Mediums mediums;
+  DemoCredentialManager credential_manager;
+  nearby::presence::BroadcastManager manager(mediums, credential_manager,
+                                             executor);
+
+  nearby::presence::PresenceBroadcast::BroadcastSection section = {
+      .identity = nearby::internal::IdentityType::IDENTITY_TYPE_PUBLIC,
+      .extended_properties = {
+          nearby::presence::DataElement(
+              nearby::presence::ActionBit::kNearbyShareAction),
+        nearby::presence::DataElement(
+            nearby::presence::ActionBit::kPresenceManagerAction),
+    },
+      .account_name = "",
+      .manager_app_id = "",
+  };
+  nearby::presence::PresenceBroadcast presence_broadcast = {
+      .sections = {section},
+  };
+  nearby::presence::BroadcastRequest request = {
+      .tx_power = tx_power,
+      .power_mode = nearby::presence::PowerMode::kLowLatency,
+      .variant = presence_broadcast,
+  };
+
+  absl::Status broadcast_status;
+  absl::Notification started;
+  auto session = manager.StartBroadcast(
+      request,
+      nearby::presence::BroadcastCallback{
+          .start_broadcast_cb =
+              [&broadcast_status, &started](absl::Status status) {
+                broadcast_status = status;
+                started.Notify();
+              },
+      });
+  if (!session.ok()) {
+    std::cerr << "Failed to initiate broadcast: " << session.status() << "\n";
+    return 1;
+  }
+
+  started.WaitForNotification();
+  if (!broadcast_status.ok()) {
+    std::cerr << "Broadcast start failed: " << broadcast_status << "\n";
+    manager.StopBroadcast(*session);
+    executor.Shutdown();
+    return 1;
+  }
+
+  std::cout << "Nearby Presence advertising started.\n"
+            << "  device_name: " << device_name << "\n"
+            << "  session_id: " << *session << "\n"
+            << "Press Ctrl+C to stop.\n";
+
+  g_shutdown.WaitForNotification();
+  manager.StopBroadcast(*session);
+  executor.Shutdown();
+  std::cout << "Stopped Presence advertising.\n";
+  return 0;
+}

internal/platform/implementation/presence_scanner_demo.cc

@@ -0,0 +1,444 @@
+// Copyright 2026 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <signal.h>
+
+#include <cstdint>
+#include <cstdlib>
+#include <cmath>
+#include <iomanip>
+#include <iostream>
+#include <limits>
+#include <memory>
+#include <optional>
+#include <sstream>
+#include <string>
+#include <vector>
+
+#include "absl/synchronization/notification.h"
+#include "internal/platform/bluetooth_adapter.h"
+#include "internal/platform/system_clock.h"
+#include "internal/proto/credential.pb.h"
+#include "presence/power_mode.h"
+#include "presence/presence_device.h"
+#include "presence/presence_service_impl.h"
+#include "presence/scan_request.h"
+
+#if defined(__linux__)
+#include "internal/platform/implementation/linux/bluetooth_adapter.h"
+#include "internal/platform/implementation/linux/bluetooth_devices.h"
+#endif
+
+namespace {
+
+absl::Notification g_shutdown;
+
+void QuitHandler(int, siginfo_t*, void*) {
+  if (!g_shutdown.HasBeenNotified()) g_shutdown.Notify();
+}
+
+std::string RangeTypeToString(
+    const std::string& range) {
+  return range;
+}
+
+std::string EstimateZone(double distance_meters) {
+  constexpr double kTapDistanceThresholdMeters = 0.08;
+  constexpr double kReachDistanceThresholdMeters = 0.56;
+  constexpr double kShortRangeDistanceThresholdMeters = 1.26;
+  constexpr double kLongRangeDistanceThresholdMeters = 3.06;
+
+  if (distance_meters <= kTapDistanceThresholdMeters) return "tap";
+  if (distance_meters <= kReachDistanceThresholdMeters) return "reach";
+  if (distance_meters <= kShortRangeDistanceThresholdMeters) return "short";
+  if (distance_meters <= kLongRangeDistanceThresholdMeters) return "long";
+  return "far";
+}
+
+double EstimateDistanceMeters(int adjusted_rssi) {
+  // Mirrors presence/fpp/fpp/src/fspl_converter.rs.
+  constexpr int kTxPowerAtZeroMetersDb = -20;
+  constexpr int kFsplAtOneMeterDb = 40;
+  const int fspl = kTxPowerAtZeroMetersDb - adjusted_rssi;
+  return std::pow(10.0, static_cast<double>(fspl - kFsplAtOneMeterDb) / 20.0);
+}
+
+std::string FormatProximity(int rssi, std::optional<int8_t> tx_power) {
+  const int adjusted_rssi = rssi + tx_power.value_or(0);
+  const double distance_meters = EstimateDistanceMeters(adjusted_rssi);
+  const std::string zone = EstimateZone(distance_meters);
+  std::ostringstream stream;
+  stream << std::fixed << std::setprecision(2) << "distance_m="
+         << distance_meters << " zone=" << RangeTypeToString(zone)
+         << " rssi=" << rssi;
+  if (tx_power.has_value()) {
+    stream << " tx_power=" << static_cast<int>(*tx_power);
+  }
+  return stream.str();
+}
+
+std::string FormatProximityUnavailable() { return "proximity=unavailable"; }
+
+std::string IdentityTypeToString(nearby::internal::IdentityType identity_type) {
+  switch (identity_type) {
+    case nearby::internal::IDENTITY_TYPE_PUBLIC:
+      return "public";
+    case nearby::internal::IDENTITY_TYPE_PRIVATE_GROUP:
+      return "private_group";
+    case nearby::internal::IDENTITY_TYPE_CONTACTS_GROUP:
+      return "contacts_group";
+    default:
+      return "unspecified";
+  }
+}
+
+std::optional<uint64_t> ParseHexId(const std::string& hex_id) {
+  if (hex_id.empty()) return std::nullopt;
+  try {
+    size_t parsed_size = 0;
+    uint64_t id = std::stoull(hex_id, &parsed_size, 16);
+    if (parsed_size != hex_id.size()) return std::nullopt;
+    return id;
+  } catch (...) {
+    return std::nullopt;
+  }
+}
+
+class SignalProvider {
+ public:
+  SignalProvider() {
+#if defined(__linux__)
+    nearby::BluetoothAdapter adapter;
+    auto* linux_adapter =
+        dynamic_cast<nearby::linux::BluetoothAdapter*>(&adapter.GetImpl());
+    if (linux_adapter == nullptr) {
+      return;
+    }
+    shared_devices_ = nearby::linux::GetSharedBluetoothDevices(
+        linux_adapter->GetConnection(), linux_adapter->GetObjectPath());
+#endif
+  }
+
+  std::optional<int> GetRssi(uint64_t device_id) const {
+#if defined(__linux__)
+    if (!shared_devices_) return std::nullopt;
+    auto device = shared_devices_->devices->get_device_by_unique_id(device_id);
+    if (!device) return std::nullopt;
+    auto rssi = device->GetRssi();
+    if (!rssi.has_value()) return std::nullopt;
+    return static_cast<int>(*rssi);
+#else
+    (void)device_id;
+    return std::nullopt;
+#endif
+  }
+
+  std::optional<int8_t> GetTxPower(uint64_t device_id) const {
+#if defined(__linux__)
+    if (!shared_devices_) return std::nullopt;
+    auto device = shared_devices_->devices->get_device_by_unique_id(device_id);
+    if (!device) return std::nullopt;
+    auto tx_power = device->GetTxPower();
+    if (!tx_power.has_value()) return std::nullopt;
+    if (*tx_power < std::numeric_limits<int8_t>::min() ||
+        *tx_power > std::numeric_limits<int8_t>::max()) {
+      return std::nullopt;
+    }
+    return static_cast<int8_t>(*tx_power);
+#else
+    (void)device_id;
+    return std::nullopt;
+#endif
+  }
+
+ private:
+#if defined(__linux__)
+  std::shared_ptr<nearby::linux::SharedBluetoothDevices> shared_devices_;
+#endif
+};
+
+void PrintUsage(const char* program) {
+  std::cerr << "Usage: " << program
+            << " [--power low|balanced|low-latency] [--screen-on-only]"
+            << " [--identities all|public|private|contacts|csv]"
+            << " [--manager-app-id <id>] [--account-name <name>]\n";
+}
+
+nearby::presence::PowerMode ParsePowerMode(const std::string& arg) {
+  if (arg == "low") return nearby::presence::PowerMode::kLowPower;
+  if (arg == "low-latency") return nearby::presence::PowerMode::kLowLatency;
+  return nearby::presence::PowerMode::kBalanced;
+}
+
+bool AddIdentityTypeFromToken(
+    const std::string& token,
+    std::vector<nearby::internal::IdentityType>& identity_types) {
+  using IdentityType = nearby::internal::IdentityType;
+  IdentityType identity = IdentityType::IDENTITY_TYPE_UNSPECIFIED;
+  if (token == "public") {
+    identity = IdentityType::IDENTITY_TYPE_PUBLIC;
+  } else if (token == "private") {
+    identity = IdentityType::IDENTITY_TYPE_PRIVATE_GROUP;
+  } else if (token == "contacts") {
+    identity = IdentityType::IDENTITY_TYPE_CONTACTS_GROUP;
+  } else {
+    return false;
+  }
+
+  for (auto existing : identity_types) {
+    if (existing == identity) return true;
+  }
+  identity_types.push_back(identity);
+  return true;
+}
+
+bool ParseIdentityTypes(
+    const std::string& arg,
+    std::vector<nearby::internal::IdentityType>& identity_types) {
+  identity_types.clear();
+  if (arg == "all") {
+    return true;
+  }
+  size_t start = 0;
+  while (start < arg.size()) {
+    size_t comma = arg.find(',', start);
+    std::string token = arg.substr(
+        start, comma == std::string::npos ? std::string::npos : comma - start);
+    if (!AddIdentityTypeFromToken(token, identity_types)) return false;
+    if (comma == std::string::npos) break;
+    start = comma + 1;
+  }
+  return !identity_types.empty();
+}
+
+bool ContainsIdentityType(const std::vector<nearby::internal::IdentityType>& ids,
+                          nearby::internal::IdentityType identity_type) {
+  for (auto id : ids) {
+    if (id == identity_type) return true;
+  }
+  return false;
+}
+
+std::string IdentitySelectionToString(
+    const std::vector<nearby::internal::IdentityType>& identity_types) {
+  if (identity_types.empty()) {
+    return "all";
+  }
+  std::string result;
+  for (size_t i = 0; i < identity_types.size(); ++i) {
+    if (i > 0) result += ",";
+    result += IdentityTypeToString(identity_types[i]);
+  }
+  return result;
+}
+
+}  // namespace
+
+int main(int argc, char** argv) {
+  (void)nearby::SystemClock::ElapsedRealtime();
+
+  nearby::presence::PowerMode power_mode = nearby::presence::PowerMode::kBalanced;
+  bool screen_on_only = false;
+  std::string identities_arg = "all";
+  std::string manager_app_id;
+  std::string account_name;
+  for (int i = 1; i < argc; ++i) {
+    std::string arg = argv[i];
+    if ((arg == "-h") || (arg == "--help")) {
+      PrintUsage(argv[0]);
+      return 0;
+    }
+    if (arg == "--power") {
+      if (i + 1 >= argc) {
+        std::cerr << "Missing value for --power\n";
+        return 2;
+      }
+      power_mode = ParsePowerMode(argv[++i]);
+      continue;
+    }
+    if (arg == "--screen-on-only") {
+      screen_on_only = true;
+      continue;
+    }
+    if (arg == "--identities") {
+      if (i + 1 >= argc) {
+        std::cerr << "Missing value for --identities\n";
+        return 2;
+      }
+      identities_arg = argv[++i];
+      continue;
+    }
+    if (arg == "--manager-app-id") {
+      if (i + 1 >= argc) {
+        std::cerr << "Missing value for --manager-app-id\n";
+        return 2;
+      }
+      manager_app_id = argv[++i];
+      continue;
+    }
+    if (arg == "--account-name") {
+      if (i + 1 >= argc) {
+        std::cerr << "Missing value for --account-name\n";
+        return 2;
+      }
+      account_name = argv[++i];
+      continue;
+    }
+    std::cerr << "Unknown argument: " << arg << "\n";
+    PrintUsage(argv[0]);
+    return 2;
+  }
+
+  std::vector<nearby::internal::IdentityType> identity_types;
+  if (!ParseIdentityTypes(identities_arg, identity_types)) {
+    std::cerr << "Invalid --identities value: " << identities_arg << "\n";
+    PrintUsage(argv[0]);
+    return 2;
+  }
+
+  struct sigaction action {};
+  action.sa_sigaction = QuitHandler;
+  action.sa_flags = SA_SIGINFO;
+  sigaction(SIGINT, &action, nullptr);
+  sigaction(SIGTERM, &action, nullptr);
+
+  SignalProvider signal_provider;
+  nearby::presence::PresenceServiceImpl service;
+  auto client = service.CreatePresenceClient();
+
+  nearby::presence::ScanRequest request;
+  request.use_ble = true;
+  request.scan_type = nearby::presence::ScanType::kPresenceScan;
+  request.power_mode = power_mode;
+  request.scan_only_when_screen_on = screen_on_only;
+  request.manager_app_id = manager_app_id;
+  request.account_name = account_name;
+  request.identity_types = identity_types;
+
+  const bool scans_non_public =
+      request.identity_types.empty() ||
+      ContainsIdentityType(request.identity_types,
+                           nearby::internal::IdentityType::
+                               IDENTITY_TYPE_PRIVATE_GROUP) ||
+      ContainsIdentityType(request.identity_types,
+                           nearby::internal::IdentityType::
+                               IDENTITY_TYPE_CONTACTS_GROUP);
+  if (scans_non_public && request.manager_app_id.empty()) {
+    std::cerr << "Warning: scanning private/contact identities without "
+                 "--manager-app-id usually results in empty remote credentials.\n";
+  }
+
+  absl::Status start_status;
+  absl::Notification started;
+  auto scan_session = client->StartScan(
+      request,
+      nearby::presence::ScanCallback{
+          .start_scan_cb =
+              [&start_status, &started](absl::Status status) {
+                start_status = status;
+                started.Notify();
+              },
+          .on_discovered_cb =
+              [&signal_provider](nearby::presence::PresenceDevice device) {
+                std::string remote_hex =
+                    device.GetDeviceIdentityMetadata().bluetooth_mac_address();
+                std::optional<uint64_t> device_id = ParseHexId(remote_hex);
+                if (!device_id.has_value()) {
+                  std::cout << "[DISCOVERED] endpoint=" << device.GetEndpointId()
+                            << " identity="
+                            << IdentityTypeToString(device.GetIdentityType())
+                            << " remote_hex=" << remote_hex
+                            << " " << FormatProximityUnavailable() << "\n";
+                  return;
+                }
+                std::optional<int> rssi = signal_provider.GetRssi(*device_id);
+                std::optional<int8_t> tx_power =
+                    signal_provider.GetTxPower(*device_id);
+                std::string proximity_desc = FormatProximityUnavailable();
+                if (rssi.has_value()) {
+                  proximity_desc = FormatProximity(*rssi, tx_power);
+                }
+                std::cout << "[DISCOVERED] endpoint=" << device.GetEndpointId()
+                          << " identity="
+                          << IdentityTypeToString(device.GetIdentityType())
+                          << " remote_hex=" << remote_hex << " "
+                          << proximity_desc << "\n";
+              },
+          .on_updated_cb =
+              [&signal_provider](nearby::presence::PresenceDevice device) {
+                std::string remote_hex =
+                    device.GetDeviceIdentityMetadata().bluetooth_mac_address();
+                std::optional<uint64_t> device_id = ParseHexId(remote_hex);
+                if (!device_id.has_value()) {
+                  std::cout << "[UPDATED] endpoint=" << device.GetEndpointId()
+                            << " identity="
+                            << IdentityTypeToString(device.GetIdentityType())
+                            << " remote_hex=" << remote_hex
+                            << " " << FormatProximityUnavailable() << "\n";
+                  return;
+                }
+                std::optional<int> rssi = signal_provider.GetRssi(*device_id);
+                std::optional<int8_t> tx_power =
+                    signal_provider.GetTxPower(*device_id);
+                std::string proximity_desc = FormatProximityUnavailable();
+                if (rssi.has_value()) {
+                  proximity_desc = FormatProximity(*rssi, tx_power);
+                }
+                std::cout << "[UPDATED] endpoint=" << device.GetEndpointId()
+                          << " identity="
+                          << IdentityTypeToString(device.GetIdentityType())
+                          << " remote_hex=" << remote_hex << " "
+                          << proximity_desc << "\n";
+              },
+          .on_lost_cb =
+              [](nearby::presence::PresenceDevice device) {
+                std::cout << "[LOST] endpoint=" << device.GetEndpointId()
+                          << " remote_hex="
+                          << device.GetDeviceIdentityMetadata()
+                                 .bluetooth_mac_address()
+                          << "\n";
+              }});
+
+  if (!scan_session.ok()) {
+    std::cerr << "Failed to initiate scan: " << scan_session.status() << "\n";
+    return 1;
+  }
+
+  started.WaitForNotification();
+  if (!start_status.ok()) {
+    std::cerr << "Scan start failed: " << start_status << "\n";
+    client->StopScan(*scan_session);
+    return 1;
+  }
+
+  std::cout << "Presence scan started.\n"
+            << "  session_id: " << *scan_session << "\n"
+            << "  identities: "
+            << IdentitySelectionToString(request.identity_types) << "\n"
+            << "  manager_app_id: "
+            << (request.manager_app_id.empty() ? "<empty>"
+                                               : request.manager_app_id)
+            << "\n"
+            << "  account_name: "
+            << (request.account_name.empty() ? "<empty>" : request.account_name)
+            << "\n"
+            << "  mode: printing discovered/updated/lost events with proximity "
+               "estimates when RSSI is available\n"
+            << "Press Ctrl+C to stop.\n";
+
+  g_shutdown.WaitForNotification();
+  client->StopScan(*scan_session);
+  std::cout << "Stopped Presence scan.\n";
+  return 0;
+}

internal/platform/implementation/shared/file.h

@@ -15,7 +15,6 @@
 #ifndef PLATFORM_IMPL_SHARED_FILE_H_
 #define PLATFORM_IMPL_SHARED_FILE_H_
 
-#include <cstddef>
 #include <cstdint>
 #include <fstream>
 #include <memory>
@@ -23,6 +22,7 @@
 
 #include "absl/strings/string_view.h"
 #include "absl/time/time.h"
+#include "internal/platform/byte_array.h"
 #include "internal/platform/exception.h"
 #include "internal/platform/implementation/input_file.h"
 #include "internal/platform/implementation/output_file.h"
@@ -49,7 +49,7 @@ class IOFile final : public api::InputFile, public api::OutputFile {
   void SetLastModifiedTime(absl::Time last_modified_time) override;
 
  private:
-  explicit IOFile(absl::string_view file_path) : path_(file_path) {};
+  explicit IOFile(absl::string_view file_path) : path_(file_path) {}
   void OpenForRead();
   void OpenForWrite();
 

internal/platform/implementation/signin_attempt.h

@@ -1,48 +0,0 @@
-// Copyright 2024 Google LLC
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     https://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-#ifndef THIRD_PARTY_NEARBY_INTERNAL_PLATFORM_IMPLEMENTATION_SIGNIN_ATTEMPT_H_
-#define THIRD_PARTY_NEARBY_INTERNAL_PLATFORM_IMPLEMENTATION_SIGNIN_ATTEMPT_H_
-
-#include <string>
-
-#include "absl/functional/any_invocable.h"
-#include "absl/strings/string_view.h"
-#include "internal/platform/implementation/account_info.h"
-#include "internal/platform/implementation/auth_status.h"
-
-namespace nearby {
-
-class SigninAttempt {
- public:
-  SigninAttempt() = default;
-  virtual ~SigninAttempt() = default;
-
-  // Starts a new sign-in attempt.
-  // `callback` is called with the status of the request, client_id,
-  // client_secret, and account_info if the request is successful. Returns the
-  // auth url if the request is successful.
-  virtual std::string Start(
-      absl::AnyInvocable<void(AuthStatus, absl::string_view, absl::string_view,
-                              const AccountInfo&)>
-          callback) = 0;
-
-  // Tears down the machinery set up to request auth tokens, including the HTTP
-  // server.
-  virtual void Close() = 0;
-};
-
-}  // namespace nearby
-
-#endif  // THIRD_PARTY_NEARBY_INTERNAL_PLATFORM_IMPLEMENTATION_SIGNIN_ATTEMPT_H_

internal/platform/implementation/webrtc.h

@@ -15,17 +15,15 @@
 #ifndef PLATFORM_API_WEBRTC_H_
 #define PLATFORM_API_WEBRTC_H_
 
-#ifndef NO_WEBRTC
-
 #include <memory>
 #include <optional>
-#include <string>
 
 #include "absl/functional/any_invocable.h"
 #include "absl/strings/string_view.h"
 #include "connections/implementation/proto/offline_wire_formats.pb.h"
 #include "internal/platform/byte_array.h"
-#include "webrtc/api/peer_connection_interface.h"
+#include "third_party/webrtc/files/stable/webrtc/api/peer_connection_interface.h"
+#include "third_party/webrtc/files/stable/webrtc/api/scoped_refptr.h"
 
 namespace nearby {
 namespace api {
@@ -53,10 +51,6 @@ class WebRtcMedium {
 
   virtual ~WebRtcMedium() = default;
 
-  // Gets the default two-letter country code associated with current locale.
-  // For example, en_US locale resolves to "US".
-  virtual std::string GetDefaultCountryCode() = 0;
-
   // Creates and returns a new webrtc::PeerConnectionInterface object via
   // |callback|.
   virtual void CreatePeerConnection(webrtc::PeerConnectionObserver* observer,
@@ -78,6 +72,4 @@ class WebRtcMedium {
 }  // namespace api
 }  // namespace nearby
 
-#endif
-
 #endif  // PLATFORM_API_WEBRTC_H_

internal/platform/implementation/webrtc_platform.h

@@ -0,0 +1,37 @@
+// Copyright 2026 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef PLATFORM_API_WEBRTC_PLATFORM_H_
+#define PLATFORM_API_WEBRTC_PLATFORM_H_
+
+#include <memory>
+#include <string>
+
+#include "internal/platform/implementation/webrtc.h"
+
+namespace nearby::api {
+
+class WebRtcImplementationPlatform {
+ public:
+  static std::unique_ptr<WebRtcMedium> CreateWebRtcMedium();
+
+  // Gets the default two-letter country code associated with current locale.
+  // For example, en_US locale resolves to "US".
+  // This follows the ISO 3166-1 Alpha-2 standard.
+  static std::string GetDefaultCountryCode();
+};
+
+}  // namespace nearby::api
+
+#endif  // PLATFORM_API_WEBRTC_PLATFORM_H_

internal/platform/implementation/wifi_direct.h

@@ -17,12 +17,12 @@
 
 #include <cstdint>
 #include <memory>
+#include <optional>
 #include <string>
 #include <utility>
 #include <vector>
 
 #include "absl/strings/string_view.h"
-#include "absl/types/optional.h"
 #include "internal/platform/cancellation_flag.h"
 #include "internal/platform/exception.h"
 #include "internal/platform/input_stream.h"
@@ -121,7 +121,7 @@ class WifiDirectMedium {
   virtual bool DisconnectWifiDirect() = 0;
 
   // Returns the port range as a pair of min and max port.
-  virtual absl::optional<std::pair<std::int32_t, std::int32_t>>
+  virtual std::optional<std::pair<std::int32_t, std::int32_t>>
   GetDynamicPortRange() = 0;
 
   // Returns the supported WifiDirect auth types.

internal/platform/implementation/windows/BUILD

@@ -74,9 +74,7 @@ cc_library(
     ],
     defines = ["_SILENCE_CLANG_COROUTINE_MESSAGE"],
     tags = ["windows"],
-    visibility = [
-        "//sharing/internal/impl/windows:__pkg__",
-    ],
+    visibility = ["//visibility:private"],
     deps = [
         ":device_paths",
         ":string_utils",
@@ -151,10 +149,7 @@ cc_library(
         "WINVER=_WIN32_WINNT_WIN10",
     ],
     tags = ["windows"],
-    visibility = [
-        "//:__subpackages__",
-        "//location/nearby:__subpackages__",
-    ],
+    visibility = ["//:__subpackages__"],
     deps = [
         ":socket_address",
         ":string_utils",
@@ -175,10 +170,7 @@ cc_library(
     ],
     compatible_with = ["//buildenv/target:non_prod"],
     tags = ["windows"],
-    visibility = [
-        "//:__subpackages__",
-        "//location/nearby:__subpackages__",
-    ],
+    visibility = ["//location/nearby:__subpackages__"],
 )
 
 cc_library(
@@ -191,10 +183,7 @@ cc_library(
     ],
     compatible_with = ["//buildenv/target:non_prod"],
     tags = ["windows"],
-    visibility = [
-        "//:__subpackages__",
-        "//location/nearby:__subpackages__",
-    ],
+    visibility = ["//location/nearby:__subpackages__"],
     deps = [
         ":scoped_wlan_memory",
         "//internal/platform:logging",
@@ -243,6 +232,18 @@ cc_library(
     ],
 )
 
+cc_library(
+    name = "webrtc_platform",
+    srcs = ["webrtc_platform.cc"],
+    tags = ["windows"],
+    deps = [
+        "//connections/implementation/mediums/webrtc:webrtc_medium_impl",
+        "//internal/platform:logging",
+        "//internal/platform/implementation:webrtc_platform",
+    ],
+    alwayslink = True,
+)
+
 cc_library(
     name = "windows",
     srcs = [
@@ -268,7 +269,6 @@ cc_library(
         "preferences_manager.cc",
         "preferences_repository.cc",
         "system_clock.cc",
-        "webrtc.cc",
         "wifi_direct_medium.cc",
         "wifi_direct_server_socket.cc",
         "wifi_direct_socket.cc",
@@ -301,7 +301,6 @@ cc_library(
         "nearby_server_socket.h",
         "preferences_manager.h",
         "preferences_repository.h",
-        "webrtc.h",
         "wifi.h",
         "wifi_direct.h",
         "wifi_hotspot.h",
@@ -316,6 +315,9 @@ cc_library(
         "-DNO_INTEL_PIE",
         "-D_WIN32_WINNT=_WIN32_WINNT_WIN10 -DWINVER=_WIN32_WINNT_WIN10",
     ],
+    linkopts = [
+        "iphlpapi.lib",
+    ],
     tags = ["windows"],
     visibility = [
         "//chrome/chromeos/assistant/data_migration/lib:__pkg__",
@@ -323,8 +325,8 @@ cc_library(
         "//connections:partners",
         "//internal/platform:__subpackages__",
         "//location/nearby:__subpackages__",
-        "//presence:__subpackages__",
         "//sharing:__subpackages__",
+        "//third_party/nearby/presence:__subpackages__",
     ],
     deps = [
         ":crypto",  # build_cleaner: keep
@@ -358,11 +360,6 @@ cc_library(
         "//internal/platform/implementation/shared:count_down_latch",
         "//internal/platform/implementation/windows/generated:types",
         "//third_party/intel/pie",
-        "//third_party/webrtc/files/stable/webrtc/api:create_modular_peer_connection_factory",
-        "//third_party/webrtc/files/stable/webrtc/api:libjingle_peerconnection_api",
-        "//third_party/webrtc/files/stable/webrtc/api:rtc_error",
-        "//third_party/webrtc/files/stable/webrtc/api:scoped_refptr",
-        "//third_party/webrtc/files/stable/webrtc/rtc_base:threading",
         "@com_google_absl//absl/base:core_headers",
         "@com_google_absl//absl/base:nullability",
         "@com_google_absl//absl/container:flat_hash_map",
@@ -374,7 +371,6 @@ cc_library(
         "@com_google_absl//absl/strings:str_format",
         "@com_google_absl//absl/synchronization",
         "@com_google_absl//absl/time",
-        "@com_google_absl//absl/types:optional",
         "@com_google_absl//absl/types:span",
         "@com_google_protobuf//:protobuf",
         "@com_google_protobuf//json",
@@ -396,9 +392,7 @@ cc_library(
         "WINVER=_WIN32_WINNT_WIN10",
     ],
     tags = ["windows"],
-    visibility = [
-        "//:__subpackages__",
-    ],
+    visibility = ["//visibility:private"],
     deps = [
         "//internal/platform:base",
         "//internal/platform:logging",
@@ -460,7 +454,6 @@ cc_test(
         "thread_pool_test.cc",
         "timer_test.cc",
         "utils_test.cc",
-        "webrtc_test.cc",
         "wifi_direct_test.cc",
         "wifi_hotspot_test.cc",
         "wifi_medium_test.cc",

internal/platform/implementation/windows/ble_gatt_client.cc

@@ -17,7 +17,6 @@
 #include <windows.h>
 
 #include <algorithm>
-#include <cctype>
 #include <cstring>
 #include <exception>
 #include <memory>
@@ -30,7 +29,6 @@
 #include "absl/strings/str_join.h"
 #include "absl/strings/string_view.h"
 #include "absl/synchronization/mutex.h"
-#include "absl/types/optional.h"
 #include "internal/platform/implementation/ble.h"
 #include "internal/platform/implementation/windows/bluetooth_adapter.h"
 #include "internal/platform/implementation/windows/utils.h"
@@ -261,7 +259,7 @@ bool BleGattClient::DiscoverServiceAndCharacteristics(
   return false;
 }
 
-absl::optional<api::ble::GattCharacteristic> BleGattClient::GetCharacteristic(
+std::optional<api::ble::GattCharacteristic> BleGattClient::GetCharacteristic(
     const Uuid& service_uuid, const Uuid& characteristic_uuid) {
   absl::MutexLock lock(mutex_);
   VLOG(1) << __func__ << ": Stared to get characteristic UUID="
@@ -273,7 +271,7 @@ absl::optional<api::ble::GattCharacteristic> BleGattClient::GetCharacteristic(
 
     if (!gatt_characteristic.has_value()) {
       LOG(ERROR) << __func__ << ": Failed to get native GATT characteristic.";
-      return absl::nullopt;
+      return std::nullopt;
     }
 
     api::ble::GattCharacteristic result;
@@ -323,10 +321,10 @@ absl::optional<api::ble::GattCharacteristic> BleGattClient::GetCharacteristic(
                << error.code() << ": " << winrt::to_string(error.message());
   }
 
-  return absl::nullopt;
+  return std::nullopt;
 }
 
-absl::optional<std::string> BleGattClient::ReadCharacteristic(
+std::optional<std::string> BleGattClient::ReadCharacteristic(
     const api::ble::GattCharacteristic& characteristic) {
   absl::MutexLock lock(mutex_);
   VLOG(1) << __func__
@@ -338,7 +336,7 @@ absl::optional<std::string> BleGattClient::ReadCharacteristic(
 
     if (!gatt_characteristic.has_value()) {
       LOG(ERROR) << __func__ << ": Failed to get native GATT characteristic.";
-      return absl::nullopt;
+      return std::nullopt;
     }
 
     GattReadResult result =
@@ -347,7 +345,7 @@ absl::optional<std::string> BleGattClient::ReadCharacteristic(
       LOG(ERROR) << __func__
                  << ": Failed to read GATT characteristic with error: "
                  << GattCommunicationStatusToString(result.Status());
-      return absl::nullopt;
+      return std::nullopt;
     }
 
     IBuffer buffer = result.Value();
@@ -377,7 +375,7 @@ absl::optional<std::string> BleGattClient::ReadCharacteristic(
                << error.code() << ": " << winrt::to_string(error.message());
   }
 
-  return absl::nullopt;
+  return std::nullopt;
 }
 
 bool BleGattClient::WriteCharacteristic(
@@ -431,80 +429,6 @@ bool BleGattClient::WriteCharacteristic(
   return false;
 }
 
-bool BleGattClient::SetCharacteristicSubscription(
-    const api::ble::GattCharacteristic& characteristic, bool enable,
-    absl::AnyInvocable<void(absl::string_view value)>
-        on_characteristic_changed_cb) {
-  absl::MutexLock lock(mutex_);
-  VLOG(1) << __func__ << ": Started to set Characteristic Subscription.";
-  GattClientCharacteristicConfigurationDescriptorValue gcccd_value =
-      GattClientCharacteristicConfigurationDescriptorValue::None;
-  if ((characteristic.property & Property::kNotify) != Property::kNone) {
-    gcccd_value = GattClientCharacteristicConfigurationDescriptorValue::Notify;
-  } else if ((characteristic.property & Property::kIndicate) !=
-             Property::kNone) {
-    gcccd_value =
-        GattClientCharacteristicConfigurationDescriptorValue::Indicate;
-  } else {
-    LOG(WARNING) << "Characeristic: " << std::string(characteristic.uuid)
-                 << " supports neither notifications nor indications.";
-    return false;
-  }
-
-  std::optional<GattCharacteristic> gatt_characteristic;
-
-  gatt_characteristic =
-      native_characteristic_map_[characteristic].native_characteristic;
-
-  if (!gatt_characteristic.has_value()) {
-    LOG(ERROR) << __func__ << ": Failed to get native GATT characteristic.";
-    return false;
-  }
-
-  // Write characteristic configuration descriptor
-  if (!WriteCharacteristicConfigurationDescriptor(
-          gatt_characteristic.value(),
-          enable
-              ? gcccd_value
-              : GattClientCharacteristicConfigurationDescriptorValue::None)) {
-    return false;
-  }
-
-  // Set value changed handler
-  try {
-    if (enable) {
-      native_characteristic_map_[characteristic].on_characteristic_changed_cb =
-          std::move(on_characteristic_changed_cb);
-      native_characteristic_map_[characteristic].notification_token =
-          gatt_characteristic->ValueChanged(
-              [&](GattCharacteristic const& native_characteristic,
-                  GattValueChangedEventArgs args) {
-                BleGattClient::OnCharacteristicValueChanged(characteristic,
-                                                            args);
-              });
-
-      if (!native_characteristic_map_[characteristic].notification_token) {
-        LOG(ERROR) << __func__ << ": Failed to add value change handler.";
-        return false;
-      }
-    } else if (native_characteristic_map_[characteristic].notification_token) {
-      gatt_characteristic->ValueChanged(std::exchange(
-          native_characteristic_map_[characteristic].notification_token, {}));
-    }
-    LOG(ERROR) << __func__ << ": Successfully set Characteristic Subscription.";
-    return true;
-  } catch (std::exception exception) {
-    LOG(ERROR) << __func__ << ": Failed to set Characteristic Subscription."
-               << exception.what();
-  } catch (const winrt::hresult_error& error) {
-    LOG(ERROR) << __func__
-               << ": Failed to set Characteristic Subscription."
-                  " WinRT exception: "
-               << error.code() << ": " << winrt::to_string(error.message());
-  }
-  return false;
-}
-
 void BleGattClient::Disconnect() {
   absl::MutexLock lock(mutex_);
   try {
@@ -533,12 +457,12 @@ std::optional<GattCharacteristic> BleGattClient::GetNativeCharacteristic(
   try {
     if (ble_device_ == nullptr) {
       LOG(ERROR) << __func__ << ": BLE device is disconnected.";
-      return absl::nullopt;
+      return std::nullopt;
     }
 
     if (gatt_devices_services_result_ == nullptr) {
       LOG(ERROR) << __func__ << ": No available GATT services.";
-      return absl::nullopt;
+      return std::nullopt;
     }
 
     for (const auto& service : gatt_devices_services_result_.Services()) {
@@ -579,7 +503,7 @@ std::optional<GattCharacteristic> BleGattClient::GetNativeCharacteristic(
         << error.code() << ": " << winrt::to_string(error.message());
   }
 
-  return absl::nullopt;
+  return std::nullopt;
 }
 
 bool BleGattClient::WriteCharacteristicConfigurationDescriptor(

internal/platform/implementation/windows/ble_gatt_client.h

@@ -17,8 +17,6 @@
 
 #include <windows.h>
 
-#include <cstddef>
-#include <memory>
 #include <optional>
 #include <string>
 #include <vector>
@@ -28,8 +26,6 @@
 #include "absl/functional/any_invocable.h"
 #include "absl/strings/string_view.h"
 #include "absl/synchronization/mutex.h"
-#include "absl/types/optional.h"
-#include "internal/platform/byte_array.h"
 #include "internal/platform/implementation/ble.h"
 #include "internal/platform/uuid.h"
 #include "winrt/Windows.Devices.Bluetooth.GenericAttributeProfile.h"
@@ -50,11 +46,11 @@ class BleGattClient : public api::ble::GattClient {
       const std::vector<Uuid>& characteristic_uuids) override
       ABSL_LOCKS_EXCLUDED(mutex_);
 
-  absl::optional<api::ble::GattCharacteristic> GetCharacteristic(
+  std::optional<api::ble::GattCharacteristic> GetCharacteristic(
       const Uuid& service_uuid, const Uuid& characteristic_uuid) override
       ABSL_LOCKS_EXCLUDED(mutex_);
 
-  absl::optional<std::string> ReadCharacteristic(
+  std::optional<std::string> ReadCharacteristic(
       const api::ble::GattCharacteristic& characteristic) override
       ABSL_LOCKS_EXCLUDED(mutex_);
 
@@ -63,11 +59,6 @@ class BleGattClient : public api::ble::GattClient {
                            api::ble::GattClient::WriteType write_type) override
       ABSL_LOCKS_EXCLUDED(mutex_);
 
-  bool SetCharacteristicSubscription(
-      const api::ble::GattCharacteristic& characteristic, bool enable,
-      absl::AnyInvocable<void(absl::string_view value)>
-          on_characteristic_changed_cb) override ABSL_LOCKS_EXCLUDED(mutex_);
-
   void Disconnect() override ABSL_LOCKS_EXCLUDED(mutex_);
 
  private: