media/audio/audio_output_stream_sink.cc

// Copyright 2014 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 "media/audio/audio_output_stream_sink.h"

#include "base/bind.h"
#include "base/bind_helpers.h"
#include "base/location.h"
#include "media/audio/audio_manager.h"

namespace media {

AudioOutputStreamSink::AudioOutputStreamSink()
    : render_callback_(NULL),
      audio_task_runner_(AudioManager::Get()->GetTaskRunner()),
      stream_(NULL),
      active_render_callback_(NULL) {
}

AudioOutputStreamSink::~AudioOutputStreamSink() {
}

void AudioOutputStreamSink::Initialize(const AudioParameters& params,
                                       RenderCallback* callback) {
  DCHECK(callback);
  DCHECK(!render_callback_);
  params_ = params;
  render_callback_ = callback;
}

void AudioOutputStreamSink::Start() {
  audio_task_runner_->PostTask(
      FROM_HERE, base::Bind(&AudioOutputStreamSink::DoStart, this));
}

void AudioOutputStreamSink::Stop() {
  ClearCallback();
  audio_task_runner_->PostTask(
      FROM_HERE, base::Bind(&AudioOutputStreamSink::DoStop, this));
}

void AudioOutputStreamSink::Pause() {
  ClearCallback();
  audio_task_runner_->PostTask(
      FROM_HERE, base::Bind(&AudioOutputStreamSink::DoPause, this));
}

void AudioOutputStreamSink::Play() {
  base::AutoLock al(callback_lock_);
  active_render_callback_ = render_callback_;
  audio_task_runner_->PostTask(
      FROM_HERE, base::Bind(&AudioOutputStreamSink::DoPlay, this));
}

bool AudioOutputStreamSink::SetVolume(double volume) {
  audio_task_runner_->PostTask(
      FROM_HERE, base::Bind(&AudioOutputStreamSink::DoSetVolume, this, volume));
  return true;
};

int AudioOutputStreamSink::OnMoreData(AudioBus* dest,
                                      uint32 total_bytes_delay) {
  // Note: Runs on the audio thread created by the OS.
  base::AutoLock al(callback_lock_);
  if (!active_render_callback_)
    return 0;

  return active_render_callback_->Render(
      dest, total_bytes_delay * 1000.0 / params_.GetBytesPerSecond());
}

void AudioOutputStreamSink::OnError(AudioOutputStream* stream) {
  // Note: Runs on the audio thread created by the OS.
  base::AutoLock al(callback_lock_);
  if (active_render_callback_)
    active_render_callback_->OnRenderError();
}

void AudioOutputStreamSink::DoStart() {
  DCHECK(audio_task_runner_->BelongsToCurrentThread());

  // Create an AudioOutputStreamProxy which will handle any and all resampling
  // necessary to generate a low latency output stream.
  stream_ =
      AudioManager::Get()->MakeAudioOutputStreamProxy(params_, std::string());
  if (!stream_ || !stream_->Open()) {
    render_callback_->OnRenderError();
    if (stream_)
      stream_->Close();
    stream_ = NULL;
  }
}

void AudioOutputStreamSink::DoStop() {
  DCHECK(audio_task_runner_->BelongsToCurrentThread());

  if (!stream_)
    return;

  DoPause();
  stream_->Close();
  stream_ = NULL;
}

void AudioOutputStreamSink::DoPause() {
  DCHECK(audio_task_runner_->BelongsToCurrentThread());
  stream_->Stop();
}

void AudioOutputStreamSink::DoPlay() {
  DCHECK(audio_task_runner_->BelongsToCurrentThread());
  stream_->Start(this);
}

void AudioOutputStreamSink::DoSetVolume(double volume) {
  DCHECK(audio_task_runner_->BelongsToCurrentThread());
  stream_->SetVolume(volume);
}

void AudioOutputStreamSink::ClearCallback() {
  base::AutoLock al(callback_lock_);
  active_render_callback_ = NULL;
}

}  // namepace media