| /* | 
 |  *  Copyright 2015 The WebRTC project authors. All Rights Reserved. | 
 |  * | 
 |  *  Use of this source code is governed by a BSD-style license | 
 |  *  that can be found in the LICENSE file in the root of the source | 
 |  *  tree. An additional intellectual property rights grant can be found | 
 |  *  in the file PATENTS.  All contributing project authors may | 
 |  *  be found in the AUTHORS file in the root of the source tree. | 
 |  */ | 
 |  | 
 | #ifndef PC_MEDIASTREAMOBSERVER_H_ | 
 | #define PC_MEDIASTREAMOBSERVER_H_ | 
 |  | 
 | #include "api/mediastreaminterface.h" | 
 | #include "rtc_base/scoped_ref_ptr.h" | 
 | #include "rtc_base/sigslot.h" | 
 |  | 
 | namespace webrtc { | 
 |  | 
 | // Helper class which will listen for changes to a stream and emit the | 
 | // corresponding signals. | 
 | class MediaStreamObserver : public ObserverInterface { | 
 |  public: | 
 |   explicit MediaStreamObserver(MediaStreamInterface* stream); | 
 |   ~MediaStreamObserver(); | 
 |  | 
 |   const MediaStreamInterface* stream() const { return stream_; } | 
 |  | 
 |   void OnChanged() override; | 
 |  | 
 |   sigslot::signal2<AudioTrackInterface*, MediaStreamInterface*> | 
 |       SignalAudioTrackAdded; | 
 |   sigslot::signal2<AudioTrackInterface*, MediaStreamInterface*> | 
 |       SignalAudioTrackRemoved; | 
 |   sigslot::signal2<VideoTrackInterface*, MediaStreamInterface*> | 
 |       SignalVideoTrackAdded; | 
 |   sigslot::signal2<VideoTrackInterface*, MediaStreamInterface*> | 
 |       SignalVideoTrackRemoved; | 
 |  | 
 |  private: | 
 |   rtc::scoped_refptr<MediaStreamInterface> stream_; | 
 |   AudioTrackVector cached_audio_tracks_; | 
 |   VideoTrackVector cached_video_tracks_; | 
 | }; | 
 |  | 
 | }  // namespace webrtc | 
 |  | 
 | #endif  // PC_MEDIASTREAMOBSERVER_H_ |