| /* | 
 |  *  Copyright 2011 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. | 
 |  */ | 
 |  | 
 | #include "pc/audio_track.h" | 
 |  | 
 | #include <string> | 
 |  | 
 | #include "absl/strings/string_view.h" | 
 | #include "api/make_ref_counted.h" | 
 | #include "api/media_stream_interface.h" | 
 | #include "api/media_stream_track.h" | 
 | #include "api/scoped_refptr.h" | 
 | #include "api/sequence_checker.h" | 
 |  | 
 | namespace webrtc { | 
 |  | 
 | // static | 
 | scoped_refptr<AudioTrack> AudioTrack::Create( | 
 |     absl::string_view id, | 
 |     const scoped_refptr<AudioSourceInterface>& source) { | 
 |   return make_ref_counted<AudioTrack>(id, source); | 
 | } | 
 |  | 
 | AudioTrack::AudioTrack(absl::string_view label, | 
 |                        const scoped_refptr<AudioSourceInterface>& source) | 
 |     : MediaStreamTrack<AudioTrackInterface>(label), audio_source_(source) { | 
 |   if (audio_source_) { | 
 |     audio_source_->RegisterObserver(this); | 
 |     OnChanged(); | 
 |   } | 
 | } | 
 |  | 
 | AudioTrack::~AudioTrack() { | 
 |   RTC_DCHECK_RUN_ON(&signaling_thread_checker_); | 
 |   set_state(MediaStreamTrackInterface::kEnded); | 
 |   if (audio_source_) | 
 |     audio_source_->UnregisterObserver(this); | 
 | } | 
 |  | 
 | std::string AudioTrack::kind() const { | 
 |   return kAudioKind; | 
 | } | 
 |  | 
 | AudioSourceInterface* AudioTrack::GetSource() const { | 
 |   // Callable from any thread. | 
 |   return audio_source_.get(); | 
 | } | 
 |  | 
 | void AudioTrack::AddSink(AudioTrackSinkInterface* sink) { | 
 |   RTC_DCHECK_RUN_ON(&signaling_thread_checker_); | 
 |   if (audio_source_) | 
 |     audio_source_->AddSink(sink); | 
 | } | 
 |  | 
 | void AudioTrack::RemoveSink(AudioTrackSinkInterface* sink) { | 
 |   RTC_DCHECK_RUN_ON(&signaling_thread_checker_); | 
 |   if (audio_source_) | 
 |     audio_source_->RemoveSink(sink); | 
 | } | 
 |  | 
 | void AudioTrack::OnChanged() { | 
 |   RTC_DCHECK_RUN_ON(&signaling_thread_checker_); | 
 |   if (audio_source_->state() == MediaSourceInterface::kEnded) { | 
 |     set_state(kEnded); | 
 |   } else { | 
 |     set_state(kLive); | 
 |   } | 
 | } | 
 |  | 
 | }  // namespace webrtc |