text: /*
   *  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.
   */
  
  #ifndef PC_AUDIOTRACK_H_
  #define PC_AUDIOTRACK_H_
  
  #include <string>
  
  #include "api/mediastreaminterface.h"
  #include "api/notifier.h"
  #include "pc/mediastreamtrack.h"
  #include "rtc_base/constructormagic.h"
  #include "rtc_base/scoped_ref_ptr.h"
  #include "rtc_base/thread_checker.h"
  
  namespace webrtc {
  
  class AudioTrack : public MediaStreamTrack<AudioTrackInterface>,
                     public ObserverInterface {
   protected:
    // Protected ctor to force use of factory method.
    AudioTrack(const std::string& label,
               const rtc::scoped_refptr<AudioSourceInterface>& source);
    ~AudioTrack() override;
  
   public:
    static rtc::scoped_refptr<AudioTrack> Create(
        const std::string& id,
        const rtc::scoped_refptr<AudioSourceInterface>& source);
  
   private:
    // MediaStreamTrack implementation.
    std::string kind() const override;
  
    // AudioTrackInterface implementation.
    AudioSourceInterface* GetSource() const override;
  
    void AddSink(AudioTrackSinkInterface* sink) override;
    void RemoveSink(AudioTrackSinkInterface* sink) override;
  
    // ObserverInterface implementation.
    void OnChanged() override;
  
   private:
    const rtc::scoped_refptr<AudioSourceInterface> audio_source_;
    rtc::ThreadChecker thread_checker_;
    RTC_DISALLOW_IMPLICIT_CONSTRUCTORS(AudioTrack);
  };
  
  }  // namespace webrtc
  
  #endif  // PC_AUDIOTRACK_H_
  