feat: add GNCBLEL2CAPClient

PiperOrigin-RevId: 749085219

internal/platform/implementation/apple/Mediums/BLEv2/GNCBLEGATTClient.m

@@ -285,7 +285,9 @@ static NSError *AlreadyReadingCharacteristicError() {
 
 - (void)peripheral:(CBPeripheral *)peripheral didDiscoverServices:(nullable NSError *)error {
   dispatch_async(_queue, ^{
-    [self gnc_peripheral:peripheral didDiscoverServices:error];
+    if ([self respondsToSelector:@selector(gnc_peripheral:didDiscoverServices:)]) {
+      [self gnc_peripheral:peripheral didDiscoverServices:error];
+    }
   });
 }
 
@@ -293,7 +295,10 @@ static NSError *AlreadyReadingCharacteristicError() {
     didDiscoverCharacteristicsForService:(CBService *)service
                                    error:(nullable NSError *)error {
   dispatch_async(_queue, ^{
-    [self gnc_peripheral:peripheral didDiscoverCharacteristicsForService:service error:error];
+    if ([self respondsToSelector:@selector(gnc_peripheral:
+                                     didDiscoverCharacteristicsForService:error:)]) {
+      [self gnc_peripheral:peripheral didDiscoverCharacteristicsForService:service error:error];
+    }
   });
 }
 
@@ -301,7 +306,10 @@ static NSError *AlreadyReadingCharacteristicError() {
     didUpdateValueForCharacteristic:(CBCharacteristic *)characteristic
                               error:(nullable NSError *)error {
   dispatch_async(_queue, ^{
-    [self gnc_peripheral:peripheral didUpdateValueForCharacteristic:characteristic error:error];
+    if ([self respondsToSelector:@selector(gnc_peripheral:
+                                     didUpdateValueForCharacteristic:error:)]) {
+      [self gnc_peripheral:peripheral didUpdateValueForCharacteristic:characteristic error:error];
+    }
   });
 }
 

internal/platform/implementation/apple/Mediums/BLEv2/GNCBLEL2CAPClient.h

@@ -0,0 +1,53 @@
+// 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 <Foundation/Foundation.h>
+
+@protocol GNCPeripheral;
+
+NS_ASSUME_NONNULL_BEGIN
+
+/**
+ * A block to be invoked after a call to @c disconnect, requesting that the local connection to the
+ * remote peripheral be cancelled.
+ *
+ * @param peripheral The remote peripheral to disconnect from.
+ */
+typedef void (^GNCRequestDisconnectionHandler)(id<GNCPeripheral> peripheral);
+
+/**
+ * An object that can be used to connect BLE over L2CAP on a remote peripheral.
+ *
+ * @note The public APIs of this class are thread safe.
+ */
+@interface GNCBLEL2CAPClient : NSObject
+
+- (instancetype)init NS_UNAVAILABLE;
+
+/**
+ * Initializes the L2CAP client with a specified peripheral.
+ *
+ * @param peripheral The peripheral instance.
+ * @param requestDisconnectionHandler Called on a private queue with @c peripheral when the
+ *                                    connection to the peripheral should be cancelled.
+ */
+- (instancetype)initWithPeripheral:(id<GNCPeripheral>)peripheral
+       requestDisconnectionHandler:(GNCRequestDisconnectionHandler)requestDisconnectionHandler;
+
+/** Cancels an active or pending local connection to a peripheral. */
+- (void)disconnect;
+
+@end
+
+NS_ASSUME_NONNULL_END

internal/platform/implementation/apple/Mediums/BLEv2/GNCBLEL2CAPClient.m

@@ -0,0 +1,91 @@
+// 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/BLEv2/GNCBLEL2CAPClient.h"
+
+#import <CoreBluetooth/CoreBluetooth.h>
+#import <Foundation/Foundation.h>
+
+#import "internal/platform/implementation/apple/Mediums/BLEv2/GNCBLEError.h"
+#import "internal/platform/implementation/apple/Mediums/BLEv2/GNCPeripheral.h"
+#import "GoogleToolboxForMac/GTMLogger.h"
+
+static char *const kGNCBLEL2CAPClientQueueLabel = "com.googlenearby.GNCBLEL2CAPClient";
+
+@interface GNCBLEL2CAPClient () <GNCPeripheralDelegate>
+@end
+
+@implementation GNCBLEL2CAPClient {
+  dispatch_queue_t _queue;
+  id<GNCPeripheral> _peripheral;
+  GNCRequestDisconnectionHandler _requestDisconnectionHandler;
+
+  // The L2CAP channel that is used to send and receive data.
+  CBL2CAPChannel *_channel;
+}
+
+- (instancetype)initWithPeripheral:(id<GNCPeripheral>)peripheral
+       requestDisconnectionHandler:(GNCRequestDisconnectionHandler)requestDisconnectionHandler {
+  return [self initWithPeripheral:peripheral
+                            queue:dispatch_queue_create(kGNCBLEL2CAPClientQueueLabel,
+                                                        DISPATCH_QUEUE_SERIAL)
+      requestDisconnectionHandler:requestDisconnectionHandler];
+};
+
+// This is private and should only be used for tests. The provided peripheral must call
+// delegate methods on the main queue.
+- (instancetype)initWithPeripheral:(id<GNCPeripheral>)peripheral
+                             queue:(nullable dispatch_queue_t)queue
+       requestDisconnectionHandler:(GNCRequestDisconnectionHandler)requestDisconnectionHandler {
+  self = [super init];
+  if (self) {
+    _queue = queue ?: dispatch_get_main_queue();
+    _peripheral = peripheral;
+    _peripheral.peripheralDelegate = self;
+    _requestDisconnectionHandler = requestDisconnectionHandler;
+  }
+  return self;
+};
+
+- (void)disconnect {
+  dispatch_async(_queue, ^{
+    _requestDisconnectionHandler(_peripheral);
+  });
+}
+
+#pragma mark - GNCPeripheralDelegate
+
+- (void)gnc_peripheral:(id<GNCPeripheral>)peripheral didOpenL2CAPChannel:(CBL2CAPChannel *)channel
+                                                                  error:(NSError *)error {
+  dispatch_assert_queue(_queue);
+  if (error) {
+    GTMLoggerError(@"[NEARBY] Failed to open L2CAP channel: %@", error);
+    return;
+  }
+  GTMLoggerInfo(@"[NEARBY] Opened L2CAP channel: %@", channel);
+  _channel = channel;
+  // TODO: b/399815436 - Implement to wrap up l2cap channel.
+}
+
+#pragma mark - CBPeripheralDelegate
+
+- (void)peripheral:(CBPeripheral *)peripheral
+    didOpenL2CAPChannel:(CBL2CAPChannel *)channel
+                  error:(NSError *)error {
+  if ([self respondsToSelector:@selector(gnc_peripheral:didOpenL2CAPChannel:error:)]) {
+    [self gnc_peripheral:peripheral didOpenL2CAPChannel:channel error:error];
+  }
+}
+
+@end

internal/platform/implementation/apple/Mediums/BLEv2/GNCPeripheral.h

@@ -131,6 +131,7 @@ NS_ASSUME_NONNULL_BEGIN
  * @param peripheral The peripheral to which the services belong.
  * @param error The reason the call failed, or @c nil if no error occurred.
  */
+@optional
 - (void)gnc_peripheral:(id<GNCPeripheral>)peripheral didDiscoverServices:(nullable NSError *)error;
 
 /**
@@ -164,6 +165,19 @@ NS_ASSUME_NONNULL_BEGIN
     didUpdateValueForCharacteristic:(CBCharacteristic *)characteristic
                               error:(nullable NSError *)error;
 
+/**
+ * Tells the delegate that the peripheral opened an L2CAP channel.
+ *
+ * Called when your app calls the @c openL2CAPChannel: method. If successful, the @c error parameter
+ * is @c nil. If unsuccessful, the @c error parameter returns the cause of the failure.
+ *
+ * @param peripheral The peripheral providing this information.
+ * @param channel The L2CAP channel that was opened.
+ * @param error The reason the call failed, or @c nil if no error occurred.
+ */
+- (void)gnc_peripheral:(id<GNCPeripheral>)peripheral
+    didOpenL2CAPChannel:(CBL2CAPChannel *)characteristic
+                  error:(nullable NSError *)error;
 @end
 
 /**

internal/platform/implementation/apple/Mediums/BUILD

@@ -25,6 +25,7 @@ objc_library(
         "BLEv2/GNCBLEGATTCharacteristic.m",
         "BLEv2/GNCBLEGATTClient.m",
         "BLEv2/GNCBLEGATTServer.m",
+        "BLEv2/GNCBLEL2CAPClient.m",
         "BLEv2/GNCBLEL2CAPServer.m",
         "BLEv2/GNCBLEL2CAPStream.m",
         "BLEv2/GNCBLEMedium.m",
@@ -52,6 +53,7 @@ objc_library(
         "BLEv2/GNCBLEGATTCharacteristic.h",
         "BLEv2/GNCBLEGATTClient.h",
         "BLEv2/GNCBLEGATTServer.h",
+        "BLEv2/GNCBLEL2CAPClient.h",
         "BLEv2/GNCBLEL2CAPServer.h",
         "BLEv2/GNCBLEL2CAPStream.h",
         "BLEv2/GNCBLEMedium.h",

internal/platform/implementation/apple/Tests/BUILD

@@ -28,6 +28,7 @@ objc_library(
         "GNCBLEGATTClientTest.m",
         "GNCBLEGATTServer+Testing.h",
         "GNCBLEGATTServerTest.m",
+        "GNCBLEL2CAPClientTest.m",
         "GNCBLEL2CAPFakeInputOutputStream.h",
         "GNCBLEL2CAPFakeInputOutputStream.m",
         "GNCBLEL2CAPServerTest.m",

internal/platform/implementation/apple/Tests/GNCBLEL2CAPClientTest.m

@@ -0,0 +1,48 @@
+// 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/BLEv2/GNCBLEL2CAPClient.h"
+
+#import <CoreBluetooth/CoreBluetooth.h>
+#import <Foundation/Foundation.h>
+#import <XCTest/XCTest.h>
+
+#import "internal/platform/implementation/apple/Mediums/BLEv2/GNCPeripheral.h"
+#import "internal/platform/implementation/apple/Tests/GNCFakePeripheral.h"
+
+@interface GNCBLEL2CAPClientTest : XCTestCase
+@end
+
+@implementation GNCBLEL2CAPClientTest
+
+#pragma mark - Tests
+
+- (void)testDisconnect {
+  GNCFakePeripheral *fakePeripheral = [[GNCFakePeripheral alloc] init];
+  XCTestExpectation *expectation = [[XCTestExpectation alloc] initWithDescription:@"Disconnect."];
+
+  GNCBLEL2CAPClient *l2capClient =
+      [[GNCBLEL2CAPClient alloc] initWithPeripheral:fakePeripheral
+                        requestDisconnectionHandler:^(id<GNCPeripheral> _Nonnull peripheral) {
+                          XCTAssertNotNil(peripheral);
+                          [expectation fulfill];
+                        }];
+
+  [l2capClient disconnect];
+
+  [self waitForExpectations:@[ expectation ] timeout:3];
+}
+
+@end
+