Merge AudioRendererImpl and AudioRendererBase; add NullAudioSink

content/renderer/media/audio_renderer_impl.h

-// Copyright (c) 2012 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.
-//
-// Audio rendering unit utilizing AudioDevice.
-//
-// This class lives inside three threads during it's lifetime, namely:
-// 1. Render thread.
-//    This object is created on the render thread.
-// 2. Pipeline thread
-//    OnInitialize() is called here with the audio format.
-//    Play/Pause/Seek also happens here.
-// 3. Audio thread created by the AudioDevice.
-//    Render() is called here where audio data is decoded into raw PCM data.
-
-#ifndef CONTENT_RENDERER_MEDIA_AUDIO_RENDERER_IMPL_H_
-#define CONTENT_RENDERER_MEDIA_AUDIO_RENDERER_IMPL_H_
-#pragma once
-
-#include <vector>
-
-#include "base/gtest_prod_util.h"
-#include "base/memory/scoped_ptr.h"
-#include "base/synchronization/lock.h"
-#include "content/renderer/media/audio_device.h"
-#include "media/audio/audio_io.h"
-#include "media/audio/audio_parameters.h"
-#include "media/base/audio_renderer_sink.h"
-#include "media/filters/audio_renderer_base.h"
-
-class AudioMessageFilter;
-
-class CONTENT_EXPORT AudioRendererImpl
-    : public media::AudioRendererBase,
-      NON_EXPORTED_BASE(public media::AudioRendererSink::RenderCallback) {
- public:
-  // Methods called on Render thread ------------------------------------------
-  // An AudioRendererSink is used as the destination for the rendered audio.
-  explicit AudioRendererImpl(media::AudioRendererSink* sink);
-  virtual ~AudioRendererImpl();
-
-  // Methods called on pipeline thread ----------------------------------------
-  // media::Filter implementation.
-  virtual void SetPlaybackRate(float rate) OVERRIDE;
-  virtual void Pause(const base::Closure& callback) OVERRIDE;
-  virtual void Seek(base::TimeDelta time,
-                    const media::PipelineStatusCB& cb) OVERRIDE;
-  virtual void Play(const base::Closure& callback) OVERRIDE;
-
-  // media::AudioRenderer implementation.
-  virtual void SetVolume(float volume) OVERRIDE;
-
- protected:
-  // Methods called on pipeline thread ----------------------------------------
-  // These methods are called from AudioRendererBase.
-  virtual bool OnInitialize(int bits_per_channel,
-                            ChannelLayout channel_layout,
-                            int sample_rate) OVERRIDE;
-  virtual void OnStop() OVERRIDE;
-  virtual void OnRenderEndOfStream() OVERRIDE;
-
- private:
-  // For access to constructor and IO thread methods.
-  friend class AudioRendererImplTest;
-  friend class DelegateCaller;
-  FRIEND_TEST_ALL_PREFIXES(AudioRendererImplTest, Stop);
-  FRIEND_TEST_ALL_PREFIXES(AudioRendererImplTest,
-                           DestroyedMessageLoop_ConsumeAudioSamples);
-  FRIEND_TEST_ALL_PREFIXES(AudioRendererImplTest, UpdateEarliestEndTime);
-  // Helper methods.
-  // Convert number of bytes to duration of time using information about the
-  // number of channels, sample rate and sample bits.
-  base::TimeDelta ConvertToDuration(int bytes);
-
-  // Methods called on pipeline thread ----------------------------------------
-  void DoPlay();
-  void DoPause();
-  void DoSeek();
-
-  // media::AudioRendererSink::RenderCallback implementation.
-  virtual size_t Render(const std::vector<float*>& audio_data,
-                        size_t number_of_frames,
-                        size_t audio_delay_milliseconds) OVERRIDE;
-  virtual void OnRenderError() OVERRIDE;
-
-  // Accessors used by tests.
-  base::Time earliest_end_time() const {
-    return earliest_end_time_;
-  }
-
-  void set_earliest_end_time(const base::Time& earliest_end_time) {
-    earliest_end_time_ = earliest_end_time;
-  }
-
-  uint32 bytes_per_second() const {
-    return bytes_per_second_;
-  }
-
-  // Estimate earliest time when current buffer can stop playing.
-  void UpdateEarliestEndTime(int bytes_filled,
-                             base::TimeDelta request_delay,
-                             base::Time time_now);
-
-  // Used to calculate audio delay given bytes.
-  uint32 bytes_per_second_;
-
-  // A flag that indicates this filter is called to stop.
-  bool stopped_;
-
-  // The sink (destination) for rendered audio.
-  scoped_refptr<media::AudioRendererSink> sink_;
-
-  // Set to true when OnInitialize() is called.
-  bool is_initialized_;
-
-  // We're supposed to know amount of audio data OS or hardware buffered, but
-  // that is not always so -- on my Linux box
-  // AudioBuffersState::hardware_delay_bytes never reaches 0.
-  //
-  // As a result we cannot use it to find when stream ends. If we just ignore
-  // buffered data we will notify host that stream ended before it is actually
-  // did so, I've seen it done ~140ms too early when playing ~150ms file.
-  //
-  // Instead of trying to invent OS-specific solution for each and every OS we
-  // are supporting, use simple workaround: every time we fill the buffer we
-  // remember when it should stop playing, and do not assume that buffer is
-  // empty till that time. Workaround is not bulletproof, as we don't exactly
-  // know when that particular data would start playing, but it is much better
-  // than nothing.
-  base::Time earliest_end_time_;
-
-  media::AudioParameters audio_parameters_;
-
-  DISALLOW_COPY_AND_ASSIGN(AudioRendererImpl);
-};
-
-#endif  // CONTENT_RENDERER_MEDIA_AUDIO_RENDERER_IMPL_H_