MediaStream audio: Refactor 3 separate "glue" implementations into one.

content/renderer/media/webrtc/media_stream_remote_audio_track.cc

-// Copyright 2015 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#include "content/renderer/media/webrtc/media_stream_remote_audio_track.h"
-
-#include <stddef.h>
-
-#include <list>
-
-#include "base/logging.h"
-#include "content/public/renderer/media_stream_audio_sink.h"
-#include "third_party/webrtc/api/mediastreaminterface.h"
-
-namespace content {
-
-class MediaStreamRemoteAudioSource::AudioSink
-    : public webrtc::AudioTrackSinkInterface {
- public:
-  AudioSink() {
-  }
-  ~AudioSink() override {
-    DCHECK(sinks_.empty());
-  }
-
-  void Add(MediaStreamAudioSink* sink, MediaStreamAudioTrack* track,
-           bool enabled) {
-    DCHECK(thread_checker_.CalledOnValidThread());
-    SinkInfo info(sink, track, enabled);
-    base::AutoLock lock(lock_);
-    sinks_.push_back(info);
-  }
-
-  void Remove(MediaStreamAudioSink* sink, MediaStreamAudioTrack* track) {
-    DCHECK(thread_checker_.CalledOnValidThread());
-    base::AutoLock lock(lock_);
-    sinks_.remove_if([&sink, &track](const SinkInfo& info) {
-        return info.sink == sink && info.track == track;
-      });
-  }
-
-  void SetEnabled(MediaStreamAudioTrack* track, bool enabled) {
-    DCHECK(thread_checker_.CalledOnValidThread());
-    base::AutoLock lock(lock_);
-    for (SinkInfo& info : sinks_) {
-      if (info.track == track)
-        info.enabled = enabled;
-    }
-  }
-
-  void RemoveAll(MediaStreamAudioTrack* track) {
-    base::AutoLock lock(lock_);
-    sinks_.remove_if([&track](const SinkInfo& info) {
-        return info.track == track;
-      });
-  }
-
-  bool IsNeeded() const {
-    DCHECK(thread_checker_.CalledOnValidThread());
-    return !sinks_.empty();
-  }
-
- private:
-  void OnData(const void* audio_data, int bits_per_sample, int sample_rate,
-              size_t number_of_channels, size_t number_of_frames) override {
-    if (!audio_bus_ ||
-        static_cast<size_t>(audio_bus_->channels()) != number_of_channels ||
-        static_cast<size_t>(audio_bus_->frames()) != number_of_frames) {
-      audio_bus_ = media::AudioBus::Create(number_of_channels,
-                                           number_of_frames);
-    }
-
-    audio_bus_->FromInterleaved(audio_data, number_of_frames,
-                                bits_per_sample / 8);
-
-    bool format_changed = false;
-    if (params_.format() != media::AudioParameters::AUDIO_PCM_LOW_LATENCY ||
-        static_cast<size_t>(params_.channels()) != number_of_channels ||
-        params_.sample_rate() != sample_rate ||
-        static_cast<size_t>(params_.frames_per_buffer()) != number_of_frames) {
-      params_ = media::AudioParameters(
-          media::AudioParameters::AUDIO_PCM_LOW_LATENCY,
-          media::GuessChannelLayout(number_of_channels),
-          sample_rate, 16, number_of_frames);
-      format_changed = true;
-    }
-
-    // TODO(tommi): We should get the timestamp from WebRTC.
-    base::TimeTicks estimated_capture_time(base::TimeTicks::Now());
-
-    base::AutoLock lock(lock_);
-    for (const SinkInfo& info : sinks_) {
-      if (info.enabled) {
-        if (format_changed)
-          info.sink->OnSetFormat(params_);
-        info.sink->OnData(*audio_bus_.get(), estimated_capture_time);
-      }
-    }
-  }
-
-  mutable base::Lock lock_;
-  struct SinkInfo {
-    SinkInfo(MediaStreamAudioSink* sink, MediaStreamAudioTrack* track,
-             bool enabled) : sink(sink), track(track), enabled(enabled) {}
-    MediaStreamAudioSink* sink;
-    MediaStreamAudioTrack* track;
-    bool enabled;
-  };
-  std::list<SinkInfo> sinks_;
-  base::ThreadChecker thread_checker_;
-  media::AudioParameters params_;  // Only used on the callback thread.
-  scoped_ptr<media::AudioBus> audio_bus_;  // Only used on the callback thread.
-};
-
-MediaStreamRemoteAudioTrack::MediaStreamRemoteAudioTrack(
-    const blink::WebMediaStreamSource& source, bool enabled)
-    : MediaStreamAudioTrack(false), source_(source), enabled_(enabled) {
-  DCHECK(source.getExtraData());  // Make sure the source has a native source.
-}
-
-MediaStreamRemoteAudioTrack::~MediaStreamRemoteAudioTrack() {
-  DCHECK(main_render_thread_checker_.CalledOnValidThread());
-  // Ensure the track is stopped.
-  MediaStreamAudioTrack::Stop();
-}
-
-void MediaStreamRemoteAudioTrack::SetEnabled(bool enabled) {
-  DCHECK(main_render_thread_checker_.CalledOnValidThread());
-
-  // This affects the shared state of the source for whether or not it's a part
-  // of the mixed audio that's rendered for remote tracks from WebRTC.
-  // All tracks from the same source will share this state and thus can step
-  // on each other's toes.
-  // This is also why we can't check the |enabled_| state for equality with
-  // |enabled| before setting the mixing enabled state. |enabled_| and the
-  // shared state might not be the same.
-  source()->SetEnabledForMixing(enabled);
-
-  enabled_ = enabled;
-  source()->SetSinksEnabled(this, enabled);
-}
-
-void MediaStreamRemoteAudioTrack::OnStop() {
-  DCHECK(main_render_thread_checker_.CalledOnValidThread());
-  DVLOG(1) << "MediaStreamRemoteAudioTrack::OnStop()";
-
-  source()->RemoveAll(this);
-
-  // Stop means that a track should be stopped permanently. But
-  // since there is no proper way of doing that on a remote track, we can
-  // at least disable the track. Blink will not call down to the content layer
-  // after a track has been stopped.
-  SetEnabled(false);
-}
-
-void MediaStreamRemoteAudioTrack::AddSink(MediaStreamAudioSink* sink) {
-  DCHECK(main_render_thread_checker_.CalledOnValidThread());
-  return source()->AddSink(sink, this, enabled_);
-}
-
-void MediaStreamRemoteAudioTrack::RemoveSink(MediaStreamAudioSink* sink) {
-  DCHECK(main_render_thread_checker_.CalledOnValidThread());
-  return source()->RemoveSink(sink, this);
-}
-
-media::AudioParameters MediaStreamRemoteAudioTrack::GetOutputFormat() const {
-  DCHECK(main_render_thread_checker_.CalledOnValidThread());
-  // This method is not implemented on purpose and should be removed.
-  // TODO(tommi): See comment for GetOutputFormat in MediaStreamAudioTrack.
-  NOTIMPLEMENTED();
-  return media::AudioParameters();
-}
-
-webrtc::AudioTrackInterface* MediaStreamRemoteAudioTrack::GetAudioAdapter() {
-  DCHECK(main_render_thread_checker_.CalledOnValidThread());
-  return source()->GetAudioAdapter();
-}
-
-MediaStreamRemoteAudioSource* MediaStreamRemoteAudioTrack::source() const {
-  return static_cast<MediaStreamRemoteAudioSource*>(source_.getExtraData());
-}
-
-MediaStreamRemoteAudioSource::MediaStreamRemoteAudioSource(
-    const scoped_refptr<webrtc::AudioTrackInterface>& track) : track_(track) {}
-
-MediaStreamRemoteAudioSource::~MediaStreamRemoteAudioSource() {
-  DCHECK(thread_checker_.CalledOnValidThread());
-}
-
-void MediaStreamRemoteAudioSource::SetEnabledForMixing(bool enabled) {
-  DCHECK(thread_checker_.CalledOnValidThread());
-  track_->set_enabled(enabled);
-}
-
-void MediaStreamRemoteAudioSource::AddSink(MediaStreamAudioSink* sink,
-                                           MediaStreamAudioTrack* track,
-                                           bool enabled) {
-  DCHECK(thread_checker_.CalledOnValidThread());
-  if (!sink_) {
-    sink_.reset(new AudioSink());
-    track_->AddSink(sink_.get());
-  }
-
-  sink_->Add(sink, track, enabled);
-}
-
-void MediaStreamRemoteAudioSource::RemoveSink(MediaStreamAudioSink* sink,
-                                              MediaStreamAudioTrack* track) {
-  DCHECK(thread_checker_.CalledOnValidThread());
-  DCHECK(sink_);
-
-  sink_->Remove(sink, track);
-
-  if (!sink_->IsNeeded()) {
-    track_->RemoveSink(sink_.get());
-    sink_.reset();
-  }
-}
-
-void MediaStreamRemoteAudioSource::SetSinksEnabled(MediaStreamAudioTrack* track,
-                                                   bool enabled) {
-  if (sink_)
-    sink_->SetEnabled(track, enabled);
-}
-
-void MediaStreamRemoteAudioSource::RemoveAll(MediaStreamAudioTrack* track) {
-  if (sink_)
-    sink_->RemoveAll(track);
-}
-
-webrtc::AudioTrackInterface* MediaStreamRemoteAudioSource::GetAudioAdapter() {
-  DCHECK(thread_checker_.CalledOnValidThread());
-  return track_.get();
-}
-
-}  // namespace content