Migrate to AnyInvocable in platform code

PiperOrigin-RevId: 504104740
2026-09-16 15:36:12 -04:00 · 2023-01-23 16:04:21 -08:00
parent 7f34968b78
commit f4d85f9b90
100 changed files with 449 additions and 494 deletions
@@ -47,6 +47,7 @@ cc_library(
    deps = [
        "//internal/platform:base",
        "@com_google_absl//absl/base:core_headers",
+        "@com_google_absl//absl/functional:any_invocable",
        "@com_google_absl//absl/strings",
        "@com_google_absl//absl/time",
    ],
@@ -100,7 +100,7 @@ class BleServerSocket : public api::ble_v2::BleServerSocket {
  Exception Close() override ABSL_LOCKS_EXCLUDED(mutex_);

  bool Connect(std::unique_ptr<BleSocket> socket) ABSL_LOCKS_EXCLUDED(mutex_);
-  void SetCloseNotifier(std::function<void()> notifier) ABSL_LOCKS_EXCLUDED(mutex_);
+  void SetCloseNotifier(absl::AnyInvocable<void()> notifier) ABSL_LOCKS_EXCLUDED(mutex_);

 private:
  Exception DoClose() ABSL_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
@@ -108,7 +108,7 @@ class BleServerSocket : public api::ble_v2::BleServerSocket {
  mutable absl::Mutex mutex_;
  absl::CondVar cond_;
  absl::flat_hash_set<std::unique_ptr<BleSocket>> pending_sockets_ ABSL_GUARDED_BY(mutex_);
-  std::function<void()> close_notifier_ ABSL_GUARDED_BY(mutex_);
+  absl::AnyInvocable<void()> close_notifier_ ABSL_GUARDED_BY(mutex_);
  bool closed_ ABSL_GUARDED_BY(mutex_) = false;
 };

@@ -15,7 +15,7 @@
 #import "internal/platform/implementation/apple/ble.h"

 #include <CoreBluetooth/CoreBluetooth.h>
-#include <functional>
+
 #include <string>
 #include <utility>

@@ -283,7 +283,7 @@ bool BleServerSocket::Connect(std::unique_ptr<BleSocket> socket) {
  return true;
 }

-void BleServerSocket::SetCloseNotifier(std::function<void()> notifier) {
+void BleServerSocket::SetCloseNotifier(absl::AnyInvocable<void()> notifier) {
  absl::MutexLock lock(&mutex_);
  close_notifier_ = std::move(notifier);
 }
@@ -18,7 +18,6 @@

 #import <Foundation/Foundation.h>

-#include <functional>
 #include <memory>

 #include "internal/platform/implementation/scheduled_executor.h"
@@ -16,7 +16,6 @@
 #define PLATFORM_IMPL_APPLE_TIMER_H_
 #ifdef __cplusplus

-#include <functional>
 #include <utility>

 #include "internal/platform/implementation/timer.h"
@@ -29,7 +28,8 @@ class Timer : public api::Timer {
  Timer() = default;
  ~Timer() override = default;

-  bool Create(int delay, int interval, std::function<void()> callback) override;
+  bool Create(int delay, int interval,
+              absl::AnyInvocable<void()> callback) override;

  bool Stop() override;

@@ -14,7 +14,6 @@

 #import "internal/platform/implementation/apple/timer.h"

-#include <functional>
 #include <utility>

 #include "internal/platform/implementation/timer.h"
@@ -22,7 +21,7 @@
 namespace nearby {
 namespace apple {

-bool Timer::Create(int delay, int interval, std::function<void()> callback) { return true; }
+bool Timer::Create(int delay, int interval, absl::AnyInvocable<void()> callback) { return true; }

 bool Timer::Stop() { return true; }

@@ -116,7 +116,7 @@ class WifiLanServerSocket : public api::WifiLanServerSocket {
  Exception Close() override ABSL_LOCKS_EXCLUDED(mutex_);

  bool Connect(std::unique_ptr<WifiLanSocket> socket) ABSL_LOCKS_EXCLUDED(mutex_);
-  void SetCloseNotifier(std::function<void()> notifier) ABSL_LOCKS_EXCLUDED(mutex_);
+  void SetCloseNotifier(absl::AnyInvocable<void()> notifier) ABSL_LOCKS_EXCLUDED(mutex_);

 private:
  Exception DoClose() ABSL_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
@@ -126,7 +126,7 @@ class WifiLanServerSocket : public api::WifiLanServerSocket {
  int port_ ABSL_GUARDED_BY(mutex_);
  absl::CondVar cond_;
  absl::flat_hash_set<std::unique_ptr<WifiLanSocket>> pending_sockets_ ABSL_GUARDED_BY(mutex_);
-  std::function<void()> close_notifier_ ABSL_GUARDED_BY(mutex_);
+  absl::AnyInvocable<void()> close_notifier_ ABSL_GUARDED_BY(mutex_);
  bool closed_ ABSL_GUARDED_BY(mutex_) = false;
 };

@@ -255,7 +255,7 @@ bool WifiLanServerSocket::Connect(std::unique_ptr<WifiLanSocket> socket) {
  return true;
 }

-void WifiLanServerSocket::SetCloseNotifier(std::function<void()> notifier) {
+void WifiLanServerSocket::SetCloseNotifier(absl::AnyInvocable<void()> notifier) {
  absl::MutexLock lock(&mutex_);
  close_notifier_ = std::move(notifier);
 }
@@ -361,6 +361,7 @@ bool WifiLanMedium::StartDiscovery(const std::string& service_type,
      return false;
    }
  }
+  __block DiscoveredServiceCallback client_callback = std::move(callback);
  GNCMBonjourBrowser* browser = [[GNCMBonjourBrowser alloc]
       initWithServiceType:serviceType
      endpointFoundHandler:^GNCMEndpointLostHandler(
@@ -376,9 +377,9 @@ bool WifiLanMedium::StartDiscovery(const std::string& service_type,
          nsd_service_info.SetTxtRecords(txt_records);
        }
        connection_requesters_.insert({CppStringFromObjCString(serviceType), requestConnection});
-        callback.service_discovered_cb(nsd_service_info);
+        client_callback.service_discovered_cb(nsd_service_info);
        return ^{
-          callback.service_lost_cb(nsd_service_info);
+          client_callback.service_lost_cb(nsd_service_info);
        };
      }];
  {
@@ -15,9 +15,9 @@
 #ifndef PLATFORM_API_BLE_H_
 #define PLATFORM_API_BLE_H_

-#include "internal/platform/implementation/bluetooth_classic.h"
 #include "internal/platform/byte_array.h"
 #include "internal/platform/cancellation_flag.h"
+#include "internal/platform/implementation/bluetooth_classic.h"
 #include "internal/platform/input_stream.h"
 #include "internal/platform/output_stream.h"

@@ -77,12 +77,13 @@ class BleMedium {

  // Callback that is invoked when a discovered peripheral is found or lost.
  struct DiscoveredPeripheralCallback {
-    std::function<void(BlePeripheral& peripheral, const std::string& service_id,
-                       bool fast_advertisement)>
+    absl::AnyInvocable<void(BlePeripheral& peripheral,
+                            const std::string& service_id,
+                            bool fast_advertisement)>
        peripheral_discovered_cb =
            DefaultCallback<BlePeripheral&, const std::string&, bool>();
-    std::function<void(BlePeripheral& peripheral,
-                       const std::string& service_id)>
+    absl::AnyInvocable<void(BlePeripheral& peripheral,
+                            const std::string& service_id)>
        peripheral_lost_cb =
            DefaultCallback<BlePeripheral&, const std::string&>();
  };
@@ -99,7 +100,7 @@ class BleMedium {

  // Callback that is invoked when a new connection is accepted.
  struct AcceptedConnectionCallback {
-    std::function<void(BleSocket& socket, const std::string& service_id)>
+    absl::AnyInvocable<void(BleSocket& socket, const std::string& service_id)>
        accepted_cb = DefaultCallback<BleSocket&, const std::string&>();
  };

@@ -17,7 +17,6 @@

 #include <algorithm>
 #include <cstdint>
-#include <functional>
 #include <limits>
 #include <map>
 #include <memory>
@@ -103,11 +103,11 @@ class BluetoothClassicMedium {
    // and at any time afterwards, until device_lost_cb() is called.
    // It is not safe to use BluetoothDevice after returning from
    // device_lost_cb() callback.
-    std::function<void(BluetoothDevice& device)> device_discovered_cb =
+    absl::AnyInvocable<void(BluetoothDevice& device)> device_discovered_cb =
        DefaultCallback<BluetoothDevice&>();
-    std::function<void(BluetoothDevice& device)> device_name_changed_cb =
+    absl::AnyInvocable<void(BluetoothDevice& device)> device_name_changed_cb =
        DefaultCallback<BluetoothDevice&>();
-    std::function<void(BluetoothDevice& device)> device_lost_cb =
+    absl::AnyInvocable<void(BluetoothDevice& device)> device_lost_cb =
        DefaultCallback<BluetoothDevice&>();
  };

@@ -15,7 +15,6 @@
 #ifndef THIRD_PARTY_NEARBY_INTERNAL_PLATFORM_IMPLEMENTATION_CREDENTIAL_CALLBACKS_H_
 #define THIRD_PARTY_NEARBY_INTERNAL_PLATFORM_IMPLEMENTATION_CREDENTIAL_CALLBACKS_H_

-#include <functional>
 #include <ostream>
 #include <string>
 #include <vector>
@@ -15,7 +15,6 @@
 #ifndef THIRD_PARTY_NEARBY_INTERNAL_PLATFORM_IMPLEMENTATION_CREDENTIAL_STORAGE_H_
 #define THIRD_PARTY_NEARBY_INTERNAL_PLATFORM_IMPLEMENTATION_CREDENTIAL_STORAGE_H_

-#include <functional>
 #include <string>
 #include <vector>

@@ -19,11 +19,11 @@
 #include <string>

 #include "absl/synchronization/mutex.h"
-#include "internal/platform/implementation/ble.h"
 #include "internal/platform/cancellation_flag_listener.h"
+#include "internal/platform/implementation/ble.h"
+#include "internal/platform/implementation/shared/count_down_latch.h"
 #include "internal/platform/logging.h"
 #include "internal/platform/medium_environment.h"
-#include "internal/platform/implementation/shared/count_down_latch.h"

 namespace nearby {
 namespace g3 {
@@ -135,7 +135,7 @@ bool BleServerSocket::Connect(BleSocket& socket) {
  return true;
 }

-void BleServerSocket::SetCloseNotifier(std::function<void()> notifier) {
+void BleServerSocket::SetCloseNotifier(absl::AnyInvocable<void()> notifier) {
  absl::MutexLock lock(&mutex_);
  close_notifier_ = std::move(notifier);
 }
@@ -303,7 +303,8 @@ bool BleMedium::StartAcceptingConnections(const std::string& service_id,
  NEARBY_LOGS(INFO) << "G3 Ble StartAcceptingConnections: service_id="
                    << service_id;
  auto& env = MediumEnvironment::Instance();
-  env.UpdateBleMediumForAcceptedConnection(*this, service_id, callback);
+  env.UpdateBleMediumForAcceptedConnection(*this, service_id,
+                                           std::move(callback));
  return true;
 }

@@ -22,14 +22,14 @@
 #include "absl/container/flat_hash_set.h"
 #include "absl/strings/escaping.h"
 #include "absl/synchronization/mutex.h"
-#include "internal/platform/implementation/ble.h"
 #include "internal/platform/byte_array.h"
-#include "internal/platform/input_stream.h"
-#include "internal/platform/output_stream.h"
+#include "internal/platform/implementation/ble.h"
 #include "internal/platform/implementation/g3/bluetooth_adapter.h"
 #include "internal/platform/implementation/g3/bluetooth_classic.h"
 #include "internal/platform/implementation/g3/multi_thread_executor.h"
 #include "internal/platform/implementation/g3/pipe.h"
+#include "internal/platform/input_stream.h"
+#include "internal/platform/output_stream.h"

 namespace nearby {
 namespace g3 {
@@ -125,7 +125,7 @@ class BleServerSocket {
  // Called by the server side of a connection before passing ownership of
  // BleServerSocker to user, to track validity of a pointer to this
  // server socket,
-  void SetCloseNotifier(std::function<void()> notifier)
+  void SetCloseNotifier(absl::AnyInvocable<void()> notifier)
      ABSL_LOCKS_EXCLUDED(mutex_);

  // Returns Exception::kIo on error, Exception::kSuccess otherwise.
@@ -138,7 +138,7 @@ class BleServerSocket {
  absl::Mutex mutex_;
  absl::CondVar cond_;
  absl::flat_hash_set<BleSocket*> pending_sockets_ ABSL_GUARDED_BY(mutex_);
-  std::function<void()> close_notifier_ ABSL_GUARDED_BY(mutex_);
+  absl::AnyInvocable<void()> close_notifier_ ABSL_GUARDED_BY(mutex_);
  bool closed_ ABSL_GUARDED_BY(mutex_) = false;
 };

@@ -15,7 +15,6 @@
 #include "internal/platform/implementation/g3/ble_v2.h"

 #include <cstdint>
-#include <functional>
 #include <iostream>
 #include <memory>
 #include <optional>
@@ -166,7 +165,7 @@ bool BleV2ServerSocket::Connect(BleV2Socket& socket) {
  return true;
 }

-void BleV2ServerSocket::SetCloseNotifier(std::function<void()> notifier) {
+void BleV2ServerSocket::SetCloseNotifier(absl::AnyInvocable<void()> notifier) {
  absl::MutexLock lock(&mutex_);
  close_notifier_ = std::move(notifier);
 }
@@ -16,7 +16,6 @@
 #define PLATFORM_IMPL_G3_BLE_V2_H_

 #include <cstdint>
-#include <functional>
 #include <memory>
 #include <optional>
 #include <string>
@@ -133,7 +132,7 @@ class BleV2ServerSocket : public api::ble_v2::BleServerSocket {
  // Called by the server side of a connection before passing ownership of
  // BleServerSocker to user, to track validity of a pointer to this
  // server socket.
-  void SetCloseNotifier(std::function<void()> notifier)
+  void SetCloseNotifier(absl::AnyInvocable<void()> notifier)
      ABSL_LOCKS_EXCLUDED(mutex_);

  // Returns Exception::kIo on error, Exception::kSuccess otherwise.
@@ -147,7 +146,7 @@ class BleV2ServerSocket : public api::ble_v2::BleServerSocket {
  absl::CondVar cond_;
  BluetoothAdapter* adapter_ = nullptr;  // Our Adapter. Read only.
  absl::flat_hash_set<BleV2Socket*> pending_sockets_ ABSL_GUARDED_BY(mutex_);
-  std::function<void()> close_notifier_ ABSL_GUARDED_BY(mutex_);
+  absl::AnyInvocable<void()> close_notifier_ ABSL_GUARDED_BY(mutex_);
  bool closed_ ABSL_GUARDED_BY(mutex_) = false;
 };

@@ -18,11 +18,11 @@
 #include <string>

 #include "absl/synchronization/mutex.h"
-#include "internal/platform/implementation/bluetooth_classic.h"
 #include "internal/platform/cancellation_flag_listener.h"
+#include "internal/platform/implementation/bluetooth_classic.h"
+#include "internal/platform/implementation/g3/bluetooth_adapter.h"
 #include "internal/platform/logging.h"
 #include "internal/platform/medium_environment.h"
-#include "internal/platform/implementation/g3/bluetooth_adapter.h"

 namespace nearby {
 namespace g3 {
@@ -139,7 +139,8 @@ bool BluetoothServerSocket::Connect(BluetoothSocket& socket) {
  return true;
 }

-void BluetoothServerSocket::SetCloseNotifier(std::function<void()> notifier) {
+void BluetoothServerSocket::SetCloseNotifier(
+    absl::AnyInvocable<void()> notifier) {
  absl::MutexLock lock(&mutex_);
  close_notifier_ = std::move(notifier);
 }
@@ -21,14 +21,14 @@
 #include "absl/container/flat_hash_map.h"
 #include "absl/container/flat_hash_set.h"
 #include "absl/synchronization/mutex.h"
-#include "internal/platform/implementation/bluetooth_classic.h"
 #include "internal/platform/byte_array.h"
 #include "internal/platform/exception.h"
+#include "internal/platform/implementation/bluetooth_classic.h"
+#include "internal/platform/implementation/g3/bluetooth_adapter.h"
+#include "internal/platform/implementation/g3/pipe.h"
 #include "internal/platform/input_stream.h"
 #include "internal/platform/listeners.h"
 #include "internal/platform/output_stream.h"
-#include "internal/platform/implementation/g3/bluetooth_adapter.h"
-#include "internal/platform/implementation/g3/pipe.h"

 namespace nearby {
 namespace g3 {
@@ -137,7 +137,7 @@ class BluetoothServerSocket : public api::BluetoothServerSocket {
  // Called by the server side of a connection before passing ownership of
  // BluetoothServerSocker to user, to track validity of a pointer to this
  // server socket,
-  void SetCloseNotifier(std::function<void()> notifier)
+  void SetCloseNotifier(absl::AnyInvocable<void()> notifier)
      ABSL_LOCKS_EXCLUDED(mutex_);

  // Returns Exception::kIo on error, Exception::kSuccess otherwise.
@@ -152,7 +152,7 @@ class BluetoothServerSocket : public api::BluetoothServerSocket {
  BluetoothAdapter* adapter_ = nullptr;  // Our Adapter. Read only.
  absl::flat_hash_set<BluetoothSocket*> pending_sockets_
      ABSL_GUARDED_BY(mutex_);
-  std::function<void()> close_notifier_ ABSL_GUARDED_BY(mutex_);
+  absl::AnyInvocable<void()> close_notifier_ ABSL_GUARDED_BY(mutex_);
  bool closed_ ABSL_GUARDED_BY(mutex_) = false;
 };

@@ -15,7 +15,6 @@
 #ifndef PLATFORM_IMPL_G3_TIMER_H_
 #define PLATFORM_IMPL_G3_TIMER_H_

-#include <functional>
 #include <utility>

 #include "internal/platform/implementation/timer.h"
@@ -29,7 +28,7 @@ class Timer : public api::Timer {
  ~Timer() override = default;

  bool Create(int delay, int interval,
-              std::function<void()> callback) override {
+              absl::AnyInvocable<void()> callback) override {
    if (delay < 0 || interval < 0) {
      return false;
    }
@@ -61,7 +60,7 @@ class Timer : public api::Timer {
  }

 private:
-  std::function<void()> callback_;
+  absl::AnyInvocable<void()> callback_;
  bool is_stopped_ = false;
 };

@@ -15,6 +15,7 @@
 #include "internal/platform/implementation/g3/webrtc.h"

 #include <memory>
+#include <utility>

 #include "internal/platform/medium_environment.h"
 #include "webrtc/api/task_queue/default_task_queue_factory.h"
@@ -39,8 +40,8 @@ bool WebRtcSignalingMessenger::StartReceivingMessages(
    OnSignalingMessageCallback on_message_callback,
    OnSignalingCompleteCallback on_complete_callback) {
  auto& env = MediumEnvironment::Instance();
-  env.RegisterWebRtcSignalingMessenger(self_id_, on_message_callback,
-                                       on_complete_callback);
+  env.RegisterWebRtcSignalingMessenger(self_id_, std::move(on_message_callback),
+                                       std::move(on_complete_callback));
  return true;
 }

@@ -83,7 +84,7 @@ void WebRtcMedium::CreatePeerConnection(

  single_thread_executor_.Execute(
      [&env, callback = std::move(callback),
-       peer_connection = peer_connection_or_error.MoveValue()]() {
+       peer_connection = peer_connection_or_error.MoveValue()]() mutable {
        absl::SleepFor(env.GetPeerConnectionLatency());
        callback(peer_connection);
      });
@@ -14,7 +14,6 @@

 #include "internal/platform/implementation/g3/wifi_direct.h"

-#include <functional>
 #include <iostream>
 #include <memory>
 #include <optional>
@@ -30,7 +29,6 @@
 namespace nearby {
 namespace g3 {

-
 // Code for WifiDirectSocket
 WifiDirectSocket::~WifiDirectSocket() {
  absl::MutexLock lock(&mutex_);
@@ -94,7 +92,7 @@ OutputStream& WifiDirectSocket::GetLocalOutputStream() {

 // Code for WifiDirectServerSocket
 std::string WifiDirectServerSocket::GetName(absl::string_view ip_address,
-                                         int port) {
+                                            int port) {
  return absl::StrCat(ip_address, ":", port);
 }

@@ -134,7 +132,8 @@ bool WifiDirectServerSocket::Connect(WifiDirectSocket& socket) {
  return true;
 }

-void WifiDirectServerSocket::SetCloseNotifier(std::function<void()> notifier) {
+void WifiDirectServerSocket::SetCloseNotifier(
+    absl::AnyInvocable<void()> notifier) {
  absl::MutexLock lock(&mutex_);
  close_notifier_ = std::move(notifier);
 }
@@ -291,8 +290,8 @@ std::unique_ptr<api::WifiDirectSocket> WifiDirectMedium::ConnectToService(
  return socket;
 }

-std::unique_ptr<api::WifiDirectServerSocket>
-WifiDirectMedium::ListenForService(int port) {
+std::unique_ptr<api::WifiDirectServerSocket> WifiDirectMedium::ListenForService(
+    int port) {
  auto& env = MediumEnvironment::Instance();
  auto server_socket = std::make_unique<WifiDirectServerSocket>();

@@ -15,7 +15,6 @@
 #ifndef PLATFORM_IMPL_G3_WIFI_DIRECT_H_
 #define PLATFORM_IMPL_G3_WIFI_DIRECT_H_

-#include <functional>
 #include <memory>
 #include <optional>
 #include <string>
@@ -144,7 +143,7 @@ class WifiDirectServerSocket : public api::WifiDirectServerSocket {
  // Called by the server side of a connection before passing ownership of
  // WifiDirectServerSocker to user, to track validity of a pointer to this
  // server socket.
-  void SetCloseNotifier(std::function<void()> notifier)
+  void SetCloseNotifier(absl::AnyInvocable<void()> notifier)
      ABSL_LOCKS_EXCLUDED(mutex_);

  // Returns Exception::kIo on error, Exception::kSuccess otherwise.
@@ -164,7 +163,7 @@ class WifiDirectServerSocket : public api::WifiDirectServerSocket {
  absl::CondVar cond_;
  absl::flat_hash_set<WifiDirectSocket*> pending_sockets_
      ABSL_GUARDED_BY(mutex_);
-  std::function<void()> close_notifier_ ABSL_GUARDED_BY(mutex_);
+  absl::AnyInvocable<void()> close_notifier_ ABSL_GUARDED_BY(mutex_);
  bool closed_ ABSL_GUARDED_BY(mutex_) = false;
 };

@@ -14,7 +14,6 @@

 #include "internal/platform/implementation/g3/wifi_hotspot.h"

-#include <functional>
 #include <iostream>
 #include <memory>
 #include <optional>
@@ -23,8 +22,8 @@

 #include "absl/strings/str_format.h"
 #include "absl/synchronization/mutex.h"
-#include "internal/platform/implementation/wifi_hotspot.h"
 #include "internal/platform/cancellation_flag_listener.h"
+#include "internal/platform/implementation/wifi_hotspot.h"
 #include "internal/platform/logging.h"
 #include "internal/platform/medium_environment.h"

@@ -99,7 +98,7 @@ OutputStream& WifiHotspotSocket::GetLocalOutputStream() {

 // Code for WifiHotspotServerSocket
 std::string WifiHotspotServerSocket::GetName(absl::string_view ip_address,
-                                         int port) {
+                                             int port) {
  return absl::StrCat(ip_address, ":", port);
 }

@@ -139,7 +138,8 @@ bool WifiHotspotServerSocket::Connect(WifiHotspotSocket& socket) {
  return true;
 }

-void WifiHotspotServerSocket::SetCloseNotifier(std::function<void()> notifier) {
+void WifiHotspotServerSocket::SetCloseNotifier(
+    absl::AnyInvocable<void()> notifier) {
  absl::MutexLock lock(&mutex_);
  close_notifier_ = std::move(notifier);
 }
@@ -186,8 +186,7 @@ bool WifiHotspotMedium::StartWifiHotspot(
    HotspotCredentials* hotspot_credentials) {
  absl::MutexLock lock(&mutex_);

-  if (!IsInterfaceValid())
-    return false;
+  if (!IsInterfaceValid()) return false;

  std::string ssid = absl::StrCat("DIRECT-", Prng().NextUint32());
  hotspot_credentials->SetSSID(ssid);
@@ -199,7 +198,8 @@ bool WifiHotspotMedium::StartWifiHotspot(

  auto& env = MediumEnvironment::Instance();
  env.UpdateWifiHotspotMediumForStartOrConnect(*this, hotspot_credentials,
-                                       /*is_ap=*/true, /*enabled=*/true);
+                                               /*is_ap=*/true,
+                                               /*enabled=*/true);

  return true;
 }
@@ -208,13 +208,12 @@ bool WifiHotspotMedium::StopWifiHotspot() {
  absl::MutexLock lock(&mutex_);
  NEARBY_LOGS(INFO) << "G3 StopWifiHotspot";

-  if (!IsInterfaceValid())
-    return false;
+  if (!IsInterfaceValid()) return false;

  auto& env = MediumEnvironment::Instance();
-  env.UpdateWifiHotspotMediumForStartOrConnect(*this, /*credentials*/nullptr,
-                                                 /*is_ap=*/true,
-                                                 /*enabled=*/false);
+  env.UpdateWifiHotspotMediumForStartOrConnect(*this, /*credentials*/ nullptr,
+                                               /*is_ap=*/true,
+                                               /*enabled=*/false);
  return true;
 }

@@ -230,13 +229,15 @@ bool WifiHotspotMedium::ConnectWifiHotspot(
  auto* remote_medium = static_cast<WifiHotspotMedium*>(
      env.GetWifiHotspotMedium(hotspot_credentials->GetSSID(), {}));
  if (!remote_medium) {
-     env.UpdateWifiHotspotMediumForStartOrConnect(*this, hotspot_credentials,
-                                        /*is_ap=*/false, /*enabled=*/false);
+    env.UpdateWifiHotspotMediumForStartOrConnect(*this, hotspot_credentials,
+                                                 /*is_ap=*/false,
+                                                 /*enabled=*/false);
    return false;
  }

  env.UpdateWifiHotspotMediumForStartOrConnect(*this, hotspot_credentials,
-                                        /*is_ap=*/false, /*enabled=*/true);
+                                               /*is_ap=*/false,
+                                               /*enabled=*/true);
  return true;
 }

@@ -246,8 +247,9 @@ bool WifiHotspotMedium::DisconnectWifiHotspot() {
  NEARBY_LOGS(INFO) << "G3 DisconnectWifiHotspot";

  auto& env = MediumEnvironment::Instance();
-  env.UpdateWifiHotspotMediumForStartOrConnect(*this, /*credentials*/nullptr,
-                                      /*is_ap=*/false, /*enabled=*/false);
+  env.UpdateWifiHotspotMediumForStartOrConnect(*this, /*credentials*/ nullptr,
+                                               /*is_ap=*/false,
+                                               /*enabled=*/false);
  return true;
 }

@@ -259,8 +261,8 @@ std::unique_ptr<api::WifiHotspotSocket> WifiHotspotMedium::ConnectToService(
                    << ", ip address + port=" << socket_name;
  // First, find an instance of remote medium, that exposed this service.
  auto& env = MediumEnvironment::Instance();
-  auto* remote_medium = static_cast<WifiHotspotMedium*>(
-      env.GetWifiHotspotMedium({}, ip_address));
+  auto* remote_medium =
+      static_cast<WifiHotspotMedium*>(env.GetWifiHotspotMedium({}, ip_address));
  if (remote_medium == nullptr) {
    return {};
  }
@@ -318,8 +320,7 @@ WifiHotspotMedium::ListenForService(int port) {

  std::string dot_decimal_ip;
  std::string ip_address = env.GetFakeIPAddress();
-  if (ip_address.empty())
-    return nullptr;
+  if (ip_address.empty()) return nullptr;

  for (auto byte : ip_address) {
    absl::StrAppend(&dot_decimal_ip, absl::StrFormat("%d", byte), ".");
@@ -15,19 +15,18 @@
 #ifndef PLATFORM_IMPL_G3_WIFI_HOTSPOT_H_
 #define PLATFORM_IMPL_G3_WIFI_HOTSPOT_H_

-#include <functional>
 #include <memory>
 #include <optional>
 #include <string>
 #include <utility>

 #include "absl/synchronization/mutex.h"
-#include "internal/platform/implementation/wifi_hotspot.h"
 #include "internal/platform/byte_array.h"
-#include "internal/platform/input_stream.h"
-#include "internal/platform/output_stream.h"
 #include "internal/platform/implementation/g3/multi_thread_executor.h"
 #include "internal/platform/implementation/g3/pipe.h"
+#include "internal/platform/implementation/wifi_hotspot.h"
+#include "internal/platform/input_stream.h"
+#include "internal/platform/output_stream.h"

 namespace nearby {
 namespace g3 {
@@ -64,7 +63,7 @@ class WifiHotspotSocket : public api::WifiHotspotSocket {
  // Returns address of a remote WifiHotspotSocket or nullptr.
  WifiHotspotSocket* GetRemoteSocket() ABSL_LOCKS_EXCLUDED(mutex_);

-    // Returns true if connection exists to the (possibly closed) remote socket.
+  // Returns true if connection exists to the (possibly closed) remote socket.
  bool IsConnected() const ABSL_LOCKS_EXCLUDED(mutex_);

  // Returns true if socket is closed.
@@ -148,7 +147,7 @@ class WifiHotspotServerSocket : public api::WifiHotspotServerSocket {
  // Called by the server side of a connection before passing ownership of
  // WifiHotspotServerSocker to user, to track validity of a pointer to this
  // server socket.
-  void SetCloseNotifier(std::function<void()> notifier)
+  void SetCloseNotifier(absl::AnyInvocable<void()> notifier)
      ABSL_LOCKS_EXCLUDED(mutex_);

  // Returns Exception::kIo on error, Exception::kSuccess otherwise.
@@ -168,7 +167,7 @@ class WifiHotspotServerSocket : public api::WifiHotspotServerSocket {
  absl::CondVar cond_;
  absl::flat_hash_set<WifiHotspotSocket*> pending_sockets_
      ABSL_GUARDED_BY(mutex_);
-  std::function<void()> close_notifier_ ABSL_GUARDED_BY(mutex_);
+  absl::AnyInvocable<void()> close_notifier_ ABSL_GUARDED_BY(mutex_);
  bool closed_ ABSL_GUARDED_BY(mutex_) = false;
 };

@@ -184,7 +183,7 @@ class WifiHotspotMedium : public api::WifiHotspotMedium {
  WifiHotspotMedium& operator=(WifiHotspotMedium&&) = delete;

  // If the WiFi Adaptor supports to start a Hotspot interface.
-  bool IsInterfaceValid() const override { return true;}
+  bool IsInterfaceValid() const override { return true; }

  // Discoverer connects to server socket
  std::unique_ptr<api::WifiHotspotSocket> ConnectToService(
@@ -211,7 +210,7 @@ class WifiHotspotMedium : public api::WifiHotspotMedium {

 private:
  // Gets error message from exception pointer
-//  std::string GetErrorMessage(std::exception_ptr eptr);
+  //  std::string GetErrorMessage(std::exception_ptr eptr);

  // Protects to access some members
  absl::Mutex mutex_;
@@ -220,7 +219,6 @@ class WifiHotspotMedium : public api::WifiHotspotMedium {
      ABSL_GUARDED_BY(mutex_);
 };

-
 }  // namespace g3
 }  // namespace nearby

@@ -22,8 +22,8 @@
 #include "absl/strings/escaping.h"
 #include "absl/strings/str_format.h"
 #include "absl/synchronization/mutex.h"
-#include "internal/platform/implementation/wifi_lan.h"
 #include "internal/platform/cancellation_flag_listener.h"
+#include "internal/platform/implementation/wifi_lan.h"
 #include "internal/platform/logging.h"
 #include "internal/platform/medium_environment.h"
 #include "internal/platform/nsd_service_info.h"
@@ -146,7 +146,8 @@ bool WifiLanServerSocket::Connect(WifiLanSocket& socket) {
  return true;
 }

-void WifiLanServerSocket::SetCloseNotifier(std::function<void()> notifier) {
+void WifiLanServerSocket::SetCloseNotifier(
+    absl::AnyInvocable<void()> notifier) {
  absl::MutexLock lock(&mutex_);
  close_notifier_ = std::move(notifier);
 }
@@ -22,13 +22,13 @@
 #include "absl/container/flat_hash_map.h"
 #include "absl/container/flat_hash_set.h"
 #include "absl/synchronization/mutex.h"
-#include "internal/platform/implementation/wifi_lan.h"
 #include "internal/platform/byte_array.h"
+#include "internal/platform/implementation/g3/multi_thread_executor.h"
+#include "internal/platform/implementation/g3/pipe.h"
+#include "internal/platform/implementation/wifi_lan.h"
 #include "internal/platform/input_stream.h"
 #include "internal/platform/nsd_service_info.h"
 #include "internal/platform/output_stream.h"
-#include "internal/platform/implementation/g3/multi_thread_executor.h"
-#include "internal/platform/implementation/g3/pipe.h"

 namespace nearby {
 namespace g3 {
@@ -144,7 +144,7 @@ class WifiLanServerSocket : public api::WifiLanServerSocket {
  // Called by the server side of a connection before passing ownership of
  // WifiLanServerSocker to user, to track validity of a pointer to this
  // server socket.
-  void SetCloseNotifier(std::function<void()> notifier)
+  void SetCloseNotifier(absl::AnyInvocable<void()> notifier)
      ABSL_LOCKS_EXCLUDED(mutex_);

  // Returns Exception::kIo on error, Exception::kSuccess otherwise.
@@ -159,7 +159,7 @@ class WifiLanServerSocket : public api::WifiLanServerSocket {
  int port_ ABSL_GUARDED_BY(mutex_);
  absl::CondVar cond_;
  absl::flat_hash_set<WifiLanSocket*> pending_sockets_ ABSL_GUARDED_BY(mutex_);
-  std::function<void()> close_notifier_ ABSL_GUARDED_BY(mutex_);
+  absl::AnyInvocable<void()> close_notifier_ ABSL_GUARDED_BY(mutex_);
  bool closed_ ABSL_GUARDED_BY(mutex_) = false;
 };

@@ -15,12 +15,11 @@
 #ifndef PLATFORM_API_LISTENABLE_FUTURE_H_
 #define PLATFORM_API_LISTENABLE_FUTURE_H_

-#include <functional>
 #include <memory>

+#include "internal/platform/exception.h"
 #include "internal/platform/implementation/executor.h"
 #include "internal/platform/implementation/future.h"
-#include "internal/platform/exception.h"
 #include "internal/platform/runnable.h"

 namespace nearby {
@@ -16,7 +16,6 @@
 #define PLATFORM_API_SCHEDULED_EXECUTOR_H_

 #include <cstdint>
-#include <functional>
 #include <memory>

 #include "absl/time/time.h"
@@ -15,7 +15,6 @@
 #ifndef PLATFORM_API_SUBMITTABLE_EXECUTOR_H_
 #define PLATFORM_API_SUBMITTABLE_EXECUTOR_H_

-#include <functional>
 #include <memory>

 #include "internal/platform/implementation/executor.h"
@@ -28,7 +27,7 @@ namespace api {
 // Main interface to be used by platform as a base class for
 // - MultiThreadExecutorWrapper
 // - SingleThreadExecutorWrapper
-// Platform must override bool submit(std::function<void()>) method.
+// Platform must override bool submit(absl::AnyInvocable<void()>) method.
 class SubmittableExecutor : public Executor {
 public:
  ~SubmittableExecutor() override = default;
@@ -15,7 +15,7 @@
 #ifndef PLATFORM_API_TIMER_H_
 #define PLATFORM_API_TIMER_H_

-#include <functional>
+#include "absl/functional/any_invocable.h"

 namespace nearby {
 namespace api {
@@ -35,7 +35,7 @@ class Timer {
  //
  // @return   return true if success, otherwise false
  virtual bool Create(int delay, int interval,
-                      std::function<void()> callback) = 0;
+                      absl::AnyInvocable<void()> callback) = 0;

  // Stops timer. No timer signal is sent after the call.
  virtual bool Stop() = 0;
@@ -15,7 +15,6 @@
 #ifndef PLATFORM_API_WEBRTC_H_
 #define PLATFORM_API_WEBRTC_H_

-#include <functional>
 #include <memory>
 #include <string>

@@ -29,8 +28,8 @@ namespace api {

 class WebRtcSignalingMessenger {
 public:
-  using OnSignalingMessageCallback = std::function<void(const ByteArray&)>;
-  using OnSignalingCompleteCallback = std::function<void(bool)>;
+  using OnSignalingMessageCallback = absl::AnyInvocable<void(const ByteArray&)>;
+  using OnSignalingCompleteCallback = absl::AnyInvocable<void(bool)>;

  virtual ~WebRtcSignalingMessenger() = default;

@@ -45,8 +44,8 @@ class WebRtcSignalingMessenger {

 class WebRtcMedium {
 public:
-  using PeerConnectionCallback =
-      std::function<void(rtc::scoped_refptr<webrtc::PeerConnectionInterface>)>;
+  using PeerConnectionCallback = absl::AnyInvocable<void(
+      rtc::scoped_refptr<webrtc::PeerConnectionInterface>)>;

  virtual ~WebRtcMedium() = default;

@@ -99,9 +99,9 @@ class WifiLanMedium {

  // Callback that is invoked when a discovered service is found or lost.
  struct DiscoveredServiceCallback {
-    std::function<void(NsdServiceInfo service_info)> service_discovered_cb =
-        DefaultCallback<NsdServiceInfo>();
-    std::function<void(NsdServiceInfo service_info)> service_lost_cb =
+    absl::AnyInvocable<void(NsdServiceInfo service_info)>
+        service_discovered_cb = DefaultCallback<NsdServiceInfo>();
+    absl::AnyInvocable<void(NsdServiceInfo service_info)> service_lost_cb =
        DefaultCallback<NsdServiceInfo>();
  };

@@ -17,7 +17,6 @@

 #include <guiddef.h>

-#include <functional>
 #include <future>  //  NOLINT
 #include <memory>
 #include <string>
@@ -121,4 +120,3 @@ class BleMedium : public api::BleMedium {
 }  // namespace nearby

 #endif  // THIRD_PARTY_NEARBY_INTERNAL_PLATFORM_IMPLEMENTATION_WINDOWS_BLE_MEDIUM_H_
-
@@ -229,8 +229,7 @@ TEST(BleMedium, DISABLED_StartAdvertising_ExtendedAdvertising) {

  ByteArray advertising_data(advertising_data_byte_array);

-  EXPECT_TRUE(
-      ble_medium.StartAdvertising("NearbyShare", advertising_data, ""));
+  EXPECT_TRUE(ble_medium.StartAdvertising("NearbyShare", advertising_data, ""));
 }

 TEST(BleMedium, DISABLED_StopAdvertising) {
@@ -254,35 +253,30 @@ TEST(BleMedium, DISABLED_StartScanning) {
  BluetoothAdapter bluetoothAdapter;
  BleMedium ble_medium(bluetoothAdapter);

-  BleMedium::DiscoveredPeripheralCallback discovered_peripheral_callback = {
-      .peripheral_discovered_cb = [this](api::BlePeripheral& peripheral,
-                                         const std::string& service_id,
-                                         bool fast_advertisement) {},
-      .peripheral_lost_cb = [this](api::BlePeripheral& peripheral,
-                                   const std::string& service_id) {}};
-
-  EXPECT_TRUE(ble_medium.StartScanning("NearbyShare", "\xfe\xf3",
-                                       discovered_peripheral_callback));
+  EXPECT_TRUE(ble_medium.StartScanning(
+      "NearbyShare", "\xfe\xf3",
+      {.peripheral_discovered_cb = [](api::BlePeripheral& peripheral,
+                                      const std::string& service_id,
+                                      bool fast_advertisement) {},
+       .peripheral_lost_cb = [](api::BlePeripheral& peripheral,
+                                const std::string& service_id) {}}));
 }

 TEST(BleMedium, DISABLED_ReceiveAdvertisement) {
  absl::Notification advertisement_received_notification;
-
  BluetoothAdapter bluetoothAdapter;
  BleMedium ble_medium(bluetoothAdapter);

-  BleMedium::DiscoveredPeripheralCallback discovered_peripheral_callback = {
-      .peripheral_discovered_cb =
-          [this, &advertisement_received_notification](
-              api::BlePeripheral& peripheral, const std::string& service_id,
-              bool fast_advertisement) {
-            advertisement_received_notification.Notify();
-          },
-      .peripheral_lost_cb = [this](api::BlePeripheral& peripheral,
-                                   const std::string& service_id) {}};
+  EXPECT_TRUE(ble_medium.StartScanning(
+      "NearbyShare", "\xfe\xf3",
+      {.peripheral_discovered_cb =
+           [&](api::BlePeripheral& peripheral, const std::string& service_id,
+               bool fast_advertisement) {
+             advertisement_received_notification.Notify();
+           },
+       .peripheral_lost_cb = [](api::BlePeripheral& peripheral,
+                                const std::string& service_id) {}}));

-  EXPECT_TRUE(ble_medium.StartScanning("NearbyShare", "\xfe\xf3",
-                                       discovered_peripheral_callback));
  EXPECT_TRUE(
      advertisement_received_notification.WaitForNotificationWithTimeout(
          absl::Seconds(5)));
@@ -292,15 +286,14 @@ TEST(BleMedium, DISABLED_StopScanning) {
  BluetoothAdapter bluetoothAdapter;
  BleMedium ble_medium(bluetoothAdapter);

-  BleMedium::DiscoveredPeripheralCallback discovered_peripheral_callback = {
-      .peripheral_discovered_cb =
-          [this](api::BlePeripheral& peripheral, const std::string& service_id,
-                 bool fast_advertisement) { EXPECT_TRUE(fast_advertisement); },
-      .peripheral_lost_cb = [this](api::BlePeripheral& peripheral,
-                                   const std::string& service_id) {}};
+  EXPECT_TRUE(ble_medium.StartScanning(
+      "NearbyShare", "\xfe\xf3",
+      {.peripheral_discovered_cb =
+           [](api::BlePeripheral& peripheral, const std::string& service_id,
+              bool fast_advertisement) { EXPECT_TRUE(fast_advertisement); },
+       .peripheral_lost_cb = [](api::BlePeripheral& peripheral,
+                                const std::string& service_id) {}}));

-  EXPECT_TRUE(ble_medium.StartScanning("NearbyShare", "\xfe\xf3",
-                                       discovered_peripheral_callback));
  EXPECT_TRUE(ble_medium.StopScanning("NearbyShare"));
 }

@@ -15,7 +15,6 @@
 #ifndef THIRD_PARTY_NEARBY_INTERNAL_PLATFORM_IMPLEMENTATION_WINDOWS_BLE_V2_H_
 #define THIRD_PARTY_NEARBY_INTERNAL_PLATFORM_IMPLEMENTATION_WINDOWS_BLE_V2_H_

-#include <functional>
 #include <memory>
 #include <string>

@@ -107,18 +106,20 @@ class BleV2Medium : public api::ble_v2::BleMedium {
          BluetoothLEAdvertisementPublisher publisher,
      winrt::Windows::Devices::Bluetooth::Advertisement::
          BluetoothLEAdvertisementPublisherStatusChangedEventArgs args);
-  std::function<void()> publisher_started_callback_ ABSL_GUARDED_BY(mutex_);
-  std::function<void()> publisher_stopped_callback_ ABSL_GUARDED_BY(mutex_);
-  std::function<void()> publisher_error_callback_ ABSL_GUARDED_BY(mutex_);
+  absl::AnyInvocable<void()> publisher_started_callback_
+      ABSL_GUARDED_BY(mutex_);
+  absl::AnyInvocable<void()> publisher_stopped_callback_
+      ABSL_GUARDED_BY(mutex_);
+  absl::AnyInvocable<void()> publisher_error_callback_ ABSL_GUARDED_BY(mutex_);

  winrt::event_token watcher_token_;
  void WatcherHandler(winrt::Windows::Devices::Bluetooth::Advertisement::
                          BluetoothLEAdvertisementWatcher watcher,
                      winrt::Windows::Devices::Bluetooth::Advertisement::
                          BluetoothLEAdvertisementWatcherStoppedEventArgs args);
-  std::function<void()> watcher_started_callback_ ABSL_GUARDED_BY(mutex_);
-  std::function<void()> watcher_stopped_callback_ ABSL_GUARDED_BY(mutex_);
-  std::function<void()> watcher_error_callback_ ABSL_GUARDED_BY(mutex_);
+  absl::AnyInvocable<void()> watcher_started_callback_ ABSL_GUARDED_BY(mutex_);
+  absl::AnyInvocable<void()> watcher_stopped_callback_ ABSL_GUARDED_BY(mutex_);
+  absl::AnyInvocable<void()> watcher_error_callback_ ABSL_GUARDED_BY(mutex_);

  winrt::event_token advertisement_received_token_;
  void AdvertisementReceivedHandler(
@@ -20,10 +20,11 @@
 #include <guiddef.h>
 // clang-format on

-#include <functional>
 #include <optional>
 #include <string>
+#include <utility>

+#include "absl/functional/any_invocable.h"
 #include "internal/platform/implementation/bluetooth_adapter.h"
 #include "internal/platform/implementation/windows/generated/winrt/Windows.Devices.Bluetooth.h"
 #include "internal/platform/implementation/windows/generated/winrt/Windows.Devices.Radios.h"
@@ -52,7 +53,8 @@ class BluetoothAdapter : public api::BluetoothAdapter {

  ~BluetoothAdapter() override = default;

-  typedef std::function<void(api::BluetoothAdapter::ScanMode)> ScanModeCallback;
+  typedef absl::AnyInvocable<void(api::BluetoothAdapter::ScanMode)>
+      ScanModeCallback;

  // Synchronously sets the status of the BluetoothAdapter to 'status', and
  // returns true if the operation was a success.
@@ -88,8 +90,8 @@ class BluetoothAdapter : public api::BluetoothAdapter {
  std::string GetNameFromComputerName() const;

  void SetOnScanModeChanged(ScanModeCallback callback) {
-    if (scan_mode_changed_ == nullptr) {
-      scan_mode_changed_ = callback;
+    if (scan_mode_changed_) {
+      scan_mode_changed_ = std::move(callback);
    }
  }

@@ -111,7 +113,7 @@ class BluetoothAdapter : public api::BluetoothAdapter {
  void find_and_replace(char *source, const char *strFind,
                        const char *strReplace) const;
  ScanMode scan_mode_ = ScanMode::kNone;
-  ScanModeCallback scan_mode_changed_ = nullptr;
+  ScanModeCallback scan_mode_changed_;

  // Used to fake the device name when the device name is longer than android
  // limitation.
@@ -163,16 +163,14 @@ TEST(BluetoothAdapter, DISABLED_SetOnScanModeChanged) {
  api::BluetoothAdapter::ScanMode mode =
      api::BluetoothAdapter::ScanMode::kUnknown;
  absl::Notification scan_mode_changed_notification;
-  BluetoothAdapter::ScanModeCallback callback =
-      [&mode, &scan_mode_changed_notification](
-          api::BluetoothAdapter::ScanMode scan_mode) {
-        mode = scan_mode;
-        scan_mode_changed_notification.Notify();
-      };
  BluetoothAdapter bluetooth_adapter;
  bluetooth_adapter.SetScanMode(mode);

-  bluetooth_adapter.SetOnScanModeChanged(callback);
+  bluetooth_adapter.SetOnScanModeChanged(
+      [&](api::BluetoothAdapter::ScanMode scan_mode) {
+        mode = scan_mode;
+        scan_mode_changed_notification.Notify();
+      });
  bluetooth_adapter.SetScanMode(
      api::BluetoothAdapter::ScanMode::kConnectableDiscoverable);
  EXPECT_TRUE(scan_mode_changed_notification.WaitForNotificationWithTimeout(
@@ -154,7 +154,7 @@ bool BluetoothClassicMedium::StartDiscovery(
  NEARBY_LOGS(INFO) << "StartDiscovery is called.";

  bool result = false;
-  discovery_callback_ = discovery_callback;
+  discovery_callback_ = std::move(discovery_callback);

  if (!IsWatcherStarted()) {
    result = StartScanning();
@@ -16,7 +16,6 @@

 #include <codecvt>
 #include <exception>
-#include <functional>
 #include <locale>
 #include <memory>
 #include <string>
@@ -55,7 +54,8 @@ std::unique_ptr<api::BluetoothSocket> BluetoothServerSocket::Accept() {
  return std::make_unique<BluetoothSocket>(bluetooth_socket);
 }

-void BluetoothServerSocket::SetCloseNotifier(std::function<void()> notifier) {
+void BluetoothServerSocket::SetCloseNotifier(
+    absl::AnyInvocable<void()> notifier) {
  close_notifier_ = std::move(notifier);
 }

@@ -17,7 +17,6 @@

 #include <Windows.h>

-#include <functional>
 #include <memory>
 #include <queue>
 #include <string>
@@ -74,7 +73,7 @@ class BluetoothServerSocket : public api::BluetoothServerSocket {
  // Called by the server side of a connection before passing ownership of
  // WifiLanServerSocker to user, to track validity of a pointer to this
  // server socket.
-  void SetCloseNotifier(std::function<void()> notifier);
+  void SetCloseNotifier(absl::AnyInvocable<void()> notifier);

  bool listen();

@@ -98,7 +97,7 @@ class BluetoothServerSocket : public api::BluetoothServerSocket {
  winrt::event_token listener_event_token_{};

  // Close notifier
-  std::function<void()> close_notifier_ = nullptr;
+  absl::AnyInvocable<void()> close_notifier_ = nullptr;

  // IP addresses of the computer. mDNS uses them to advertise.
  std::vector<std::string> ip_addresses_{};
@@ -24,7 +24,7 @@ namespace windows {
 // Main interface to be used by platform as a base class for
 // - MultiThreadExecutorWrapper
 // - SingleThreadExecutorWrapper
-// Platform must override bool submit(std::function<void()>) method.
+// Platform must override bool submit(absl::AnyInvocable<void()>) method.
 class SubmittableExecutor : public api::SubmittableExecutor {
 public:
  SubmittableExecutor();
@@ -14,7 +14,6 @@

 #include "internal/platform/implementation/windows/thread_pool.h"

-#include <functional>
 #include <vector>

 #include "gtest/gtest.h"
@@ -14,7 +14,6 @@

 #include "internal/platform/implementation/windows/timer.h"

-#include <functional>
 #include <memory>

 #include "internal/platform/logging.h"
@@ -24,7 +23,8 @@ namespace windows {

 Timer::~Timer() { Stop(); }

-bool Timer::Create(int delay, int interval, std::function<void()> callback) {
+bool Timer::Create(int delay, int interval,
+                   absl::AnyInvocable<void()> callback) {
  if ((delay < 0) || (interval < 0)) {
    NEARBY_LOGS(WARNING) << "Delay and interval shouldn\'t be negative value.";
    return false;
@@ -90,8 +90,8 @@ bool Timer::FireNow() {
 }

 void CALLBACK Timer::TimerRoutine(PVOID lpParam, BOOLEAN TimerOrWaitFired) {
-  std::function<void()>* callback =
-      reinterpret_cast<std::function<void()>*>(lpParam);
+  absl::AnyInvocable<void()>* callback =
+      reinterpret_cast<absl::AnyInvocable<void()>*>(lpParam);
  if (*callback != NULL) {
    (*callback)();
  }
@@ -17,8 +17,6 @@

 #include <windows.h>

-#include <functional>
-
 #include "internal/platform/implementation/timer.h"

 namespace nearby {
@@ -29,7 +27,8 @@ class Timer : public api::Timer {
  Timer() = default;
  ~Timer() override;

-  bool Create(int delay, int interval, std::function<void()> callback) override;
+  bool Create(int delay, int interval,
+              absl::AnyInvocable<void()> callback) override;
  bool Stop() override;
  bool FireNow() override;

@@ -38,7 +37,7 @@ class Timer : public api::Timer {

  int delay_;
  int interval_;
-  std::function<void()> callback_;
+  absl::AnyInvocable<void()> callback_;
  HANDLE handle_ = NULL;
  HANDLE timer_queue_handle_ = NULL;
 };
@@ -14,8 +14,8 @@

 #include "internal/platform/implementation/timer.h"

-#include <chrono>      // NOLINT
-#include <functional>  // NOLINT
+#include <chrono>  // NOLINT
+// NOLINT
 #include <memory>
 #include <thread>  // NOLINT

@@ -28,26 +28,24 @@ namespace {

 TEST(Timer, TestCreateTimer) {
  int count = 0;
-  std::function<void()> callback = [&count]() { ++count; };

  std::unique_ptr<nearby::api::Timer> timer =
      nearby::api::ImplementationPlatform::CreateTimer();

  ASSERT_TRUE(timer != nullptr);
-  EXPECT_FALSE(timer->Create(-100, 0, callback));
+  EXPECT_FALSE(timer->Create(-100, 0, [&]() { ++count; }));
  EXPECT_TRUE(timer->Stop());
 }

 // This test case cannot run on Google3
 TEST(Timer, DISABLED_TestRepeatTimer) {
  int count = 0;
-  std::function<void()> callback = [&count]() { count++; };

  std::unique_ptr<nearby::api::Timer> timer =
      nearby::api::ImplementationPlatform::CreateTimer();

  ASSERT_TRUE(timer != nullptr);
-  EXPECT_TRUE(timer->Create(300, 300, callback));
+  EXPECT_TRUE(timer->Create(300, 300, [&]() { ++count; }));
  std::this_thread::sleep_for(std::chrono::seconds(1));
  EXPECT_TRUE(timer->Stop());
  EXPECT_EQ(count, 3);
@@ -55,10 +53,11 @@ TEST(Timer, DISABLED_TestRepeatTimer) {

 TEST(Timer, DISABLED_TestFireNow) {
  int count = 0;
-  std::function<void()> callback = [&count]() { ++count; };
+
  auto timer = nearby::api::ImplementationPlatform::CreateTimer();
+
  EXPECT_TRUE(timer != nullptr);
-  EXPECT_TRUE(timer->Create(3000, 3000, callback));
+  EXPECT_TRUE(timer->Create(3000, 3000, [&]() { ++count; }));
  EXPECT_TRUE(timer->FireNow());
  EXPECT_TRUE(timer->Stop());
  EXPECT_EQ(count, 1);
@@ -22,7 +22,6 @@
 // Standard C/C++ headers
 #include <deque>
 #include <exception>
-#include <functional>
 #include <memory>
 #include <optional>
 #include <string>
@@ -191,7 +190,7 @@ class WifiDirectServerSocket : public api::WifiDirectServerSocket {
  // Called by the server side of a connection before passing ownership of
  // WifiDirectServerSocker to user, to track validity of a pointer to this
  // server socket.
-  void SetCloseNotifier(std::function<void()> notifier);
+  void SetCloseNotifier(absl::AnyInvocable<void()> notifier);

  // Returns Exception::kIo on error, Exception::kSuccess otherwise.
  Exception Close() override;
@@ -217,7 +216,7 @@ class WifiDirectServerSocket : public api::WifiDirectServerSocket {
  winrt::event_token listener_event_token_{};

  // Close notifier
-  std::function<void()> close_notifier_ = nullptr;
+  absl::AnyInvocable<void()> close_notifier_ = nullptr;

  // IP addresses of the computer. mDNS uses them to advertise.
  std::vector<std::string> ip_addresses_{};
@@ -15,7 +15,6 @@
 #include <windows.h>

 #include <exception>
-#include <functional>
 #include <memory>
 #include <string>
 #include <vector>
@@ -82,7 +81,8 @@ std::unique_ptr<api::WifiDirectSocket> WifiDirectServerSocket::Accept() {
  return std::make_unique<WifiDirectSocket>(wifi_direct_socket);
 }

-void WifiDirectServerSocket::SetCloseNotifier(std::function<void()> notifier) {
+void WifiDirectServerSocket::SetCloseNotifier(
+    absl::AnyInvocable<void()> notifier) {
  close_notifier_ = std::move(notifier);
 }

@@ -20,7 +20,7 @@
 #include <wlanapi.h>

 // Standard C/C++ headers
-#include <functional>
+
 #include <memory>
 #include <optional>
 #include <string>
@@ -185,7 +185,7 @@ class WifiHotspotServerSocket : public api::WifiHotspotServerSocket {
  // Called by the server side of a connection before passing ownership of
  // WifiHotspotServerSocker to user, to track validity of a pointer to this
  // server socket.
-  void SetCloseNotifier(std::function<void()> notifier);
+  void SetCloseNotifier(absl::AnyInvocable<void()> notifier);

  // Returns Exception::kIo on error, Exception::kSuccess otherwise.
  Exception Close() override;
@@ -211,7 +211,7 @@ class WifiHotspotServerSocket : public api::WifiHotspotServerSocket {
  winrt::event_token listener_event_token_{};

  // Close notifier
-  std::function<void()> close_notifier_ = nullptr;
+  absl::AnyInvocable<void()> close_notifier_ = nullptr;

  // IP addresses of the computer. mDNS uses them to advertise.
  std::vector<std::string> ip_addresses_{};
@@ -15,7 +15,6 @@
 #include <windows.h>

 #include <exception>
-#include <functional>
 #include <memory>
 #include <string>
 #include <vector>
@@ -82,7 +81,8 @@ std::unique_ptr<api::WifiHotspotSocket> WifiHotspotServerSocket::Accept() {
  return std::make_unique<WifiHotspotSocket>(wifi_hotspot_socket);
 }

-void WifiHotspotServerSocket::SetCloseNotifier(std::function<void()> notifier) {
+void WifiHotspotServerSocket::SetCloseNotifier(
+    absl::AnyInvocable<void()> notifier) {
  close_notifier_ = std::move(notifier);
 }

@@ -23,7 +23,6 @@

 // Standard C/C++ headers
 #include <exception>
-#include <functional>
 #include <memory>
 #include <optional>
 #include <string>
@@ -35,8 +34,8 @@
 #include "absl/synchronization/mutex.h"
 #include "absl/time/time.h"
 #include "absl/types/optional.h"
-#include "internal/platform/count_down_latch.h"
 #include "internal/platform/cancellation_flag_listener.h"
+#include "internal/platform/count_down_latch.h"
 #include "internal/platform/exception.h"
 #include "internal/platform/implementation/wifi_lan.h"
 #include "internal/platform/implementation/windows/scheduled_executor.h"
@@ -187,7 +186,7 @@ class WifiLanServerSocket : public api::WifiLanServerSocket {
  // Called by the server side of a connection before passing ownership of
  // WifiLanServerSocker to user, to track validity of a pointer to this
  // server socket.
-  void SetCloseNotifier(std::function<void()> notifier);
+  void SetCloseNotifier(absl::AnyInvocable<void()> notifier);

  // Returns Exception::kIo on error, Exception::kSuccess otherwise.
  Exception Close() override;
@@ -208,7 +207,7 @@ class WifiLanServerSocket : public api::WifiLanServerSocket {
  winrt::event_token listener_event_token_{};

  // Close notifier
-  std::function<void()> close_notifier_ = nullptr;
+  absl::AnyInvocable<void()> close_notifier_ = nullptr;

  // IP addresses of the computer. mDNS uses them to advertise.
  std::vector<std::string> ip_addresses_{};
@@ -15,7 +15,6 @@
 #include <windows.h>

 #include <exception>
-#include <functional>
 #include <memory>
 #include <string>
 #include <vector>
@@ -84,7 +83,8 @@ std::unique_ptr<api::WifiLanSocket> WifiLanServerSocket::Accept() {
  return std::make_unique<WifiLanSocket>(wifi_lan_socket);
 }

-void WifiLanServerSocket::SetCloseNotifier(std::function<void()> notifier) {
+void WifiLanServerSocket::SetCloseNotifier(
+    absl::AnyInvocable<void()> notifier) {
  close_notifier_ = std::move(notifier);
 }