Add null checkers to Bluetooth Classic medium ConnectToService

PiperOrigin-RevId: 453542256

internal/platform/implementation/windows/bluetooth_classic_medium.cc

@@ -237,8 +237,13 @@ std::unique_ptr<api::BluetoothSocket> BluetoothClassicMedium::ConnectToService(
       });
 
   try {
-    rfcomm_socket->Connect(requested_service.ConnectionHostName(),
-                           requested_service.ConnectionServiceName());
+    bool success =
+        rfcomm_socket->Connect(requested_service.ConnectionHostName(),
+                               requested_service.ConnectionServiceName());
+    if (!success) {
+      LeaveCriticalSection(&critical_section_);
+      return nullptr;
+    }
   } catch (std::exception exception) {
     // We will log and eat the exception since the caller
     // expects nullptr if it fails

internal/platform/implementation/windows/bluetooth_classic_socket.cc

@@ -83,8 +83,16 @@ api::BluetoothDevice* BluetoothSocket::GetRemoteDevice() {
 // Starts an asynchronous operation on a StreamSocket object to connect to a
 // remote network destination specified by a remote hostname and a remote
 // service name.
-void BluetoothSocket::Connect(HostName connectionHostName,
+bool BluetoothSocket::Connect(HostName connectionHostName,
                               winrt::hstring connectionServiceName) {
+  if (connectionHostName == nullptr || connectionServiceName.empty()) {
+    NEARBY_LOGS(ERROR)
+        << __func__
+        << ": Bluetooth socket connection failed. Attempting to "
+           "connect to empty HostName/MAC address or ServiceName.";
+    return false;
+  }
+
   windows_socket_ = winrt::Windows::Networking::Sockets::StreamSocket();
 
   // https://docs.microsoft.com/en-us/uwp/api/windows.networking.sockets.streamsocket.connectasync?view=winrt-20348
@@ -106,6 +114,7 @@ void BluetoothSocket::Connect(HostName connectionHostName,
   NEARBY_LOGS(INFO) << __func__
                     << ": Bluetooth socket successfully connected to "
                     << bluetooth_device_->GetName();
+  return true;
 }
 
 BluetoothSocket::BluetoothInputStream::BluetoothInputStream(

internal/platform/implementation/windows/bluetooth_classic_socket.h

@@ -93,8 +93,9 @@ class BluetoothSocket : public api::BluetoothSocket {
   api::BluetoothDevice* GetRemoteDevice() override;
 
   // Connect asynchronously to the target remote device
-  void Connect(HostName connectionHostName,
-                            winrt::hstring connectionServiceName);
+  // Returns true if successful, false otherwise
+  bool Connect(HostName connectionHostName,
+               winrt::hstring connectionServiceName);
 
   IAsyncAction CancelIOAsync();