Initial commit of the CancellationFlag implementation

PiperOrigin-RevId: 389276621

cpp/platform/impl/windows/bluetooth_classic_medium.cc

@@ -14,15 +14,18 @@
 
 #include "platform/impl/windows/bluetooth_classic_medium.h"
 
-#include "platform/base/exception.h"
-#include "platform/impl/windows/bluetooth_classic_device.h"
-#include "platform/impl/windows/bluetooth_classic_socket.h"
 #include "platform/impl/windows/generated/winrt/Windows.Devices.Bluetooth.Rfcomm.h"
 #include "platform/impl/windows/generated/winrt/Windows.Devices.Bluetooth.h"
 #include "platform/impl/windows/generated/winrt/Windows.Devices.Enumeration.h"
 #include "platform/impl/windows/generated/winrt/Windows.Foundation.Collections.h"
 #include "platform/impl/windows/generated/winrt/base.h"
+
+#include "platform/base/exception.h"
+#include "platform/impl/windows/bluetooth_classic_device.h"
+#include "platform/impl/windows/bluetooth_classic_socket.h"
 #include "platform/public/logging.h"
+#include "platform/base/cancellation_flag.h"
+#include "platform/base/cancellation_flag_listener.h"
 
 namespace location {
 namespace nearby {
@@ -136,6 +139,11 @@ std::unique_ptr<api::BluetoothSocket> BluetoothClassicMedium::ConnectToService(
   std::unique_ptr<BluetoothSocket> rfcommSocket =
       std::make_unique<BluetoothSocket>();
 
+  location::nearby::CancellationFlagListener cancellationFlagListener(
+      cancellation_flag,
+      [&rfcommSocket]() { rfcommSocket.get()->CancelIOAsync().get();
+    });
+
   try {
     rfcommSocket
         ->ConnectAsync(requestedService.ConnectionHostName(),

cpp/platform/impl/windows/bluetooth_classic_socket.cc

@@ -82,6 +82,12 @@ ExceptionOr<ByteArray> BluetoothSocket::BluetoothInputStream::Read(
   return ExceptionOr(data);
 }
 
+IAsyncAction BluetoothSocket::CancelIOAsync() {
+  // Cancels pending reads and writes over a StreamSocket object.
+  // https://docs.microsoft.com/en-us/uwp/api/windows.networking.sockets.streamsocket.cancelioasync?view=winrt-20348
+  return windows_socket_.as<StreamSocket>().CancelIOAsync();
+}
+
 Exception BluetoothSocket::BluetoothInputStream::Close() {
   try {
     winrt_stream_.Close();

cpp/platform/impl/windows/bluetooth_classic_socket.h

@@ -56,6 +56,10 @@ using winrt::Windows::Storage::Streams::InputStreamOptions;
 // https://docs.microsoft.com/en-us/uwp/api/windows.storage.streams.datareader?view=winrt-20348
 using winrt::Windows::Storage::Streams::DataReader;
 
+// Represents an asynchronous action.
+// https://docs.microsoft.com/en-us/uwp/api/windows.foundation.iasyncaction?view=winrt-20348
+using winrt::Windows::Foundation::IAsyncAction;
+
 // https://developer.android.com/reference/android/bluetooth/BluetoothSocket.html.
 class BluetoothSocket : public api::BluetoothSocket {
  public:
@@ -88,8 +92,10 @@ class BluetoothSocket : public api::BluetoothSocket {
   api::BluetoothDevice* GetRemoteDevice() override;
 
   // Connect asynchronously to the target remote device
-  winrt::Windows::Foundation::IAsyncAction ConnectAsync(
-      HostName connectionHostName, winrt::hstring connectionServiceName);
+  IAsyncAction ConnectAsync(HostName connectionHostName,
+                            winrt::hstring connectionServiceName);
+
+  IAsyncAction CancelIOAsync();
 
  private:
   class BluetoothInputStream : public InputStream {