Move AudioDevice and AudioInputDevice to media.

content/renderer/media/audio_device.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 audio output stream provided by browser
-// process through IPC.
-//
-// Relationship of classes.
-//
-//  AudioOutputController                AudioDevice
-//           ^                                ^
-//           |                                |
-//           v               IPC              v
-//    AudioRendererHost  <---------> AudioMessageFilter
-//
-// Transportation of audio samples from the render to the browser process
-// is done by using shared memory in combination with a sync socket pair
-// to generate a low latency transport. The AudioDevice user registers an
-// AudioDevice::RenderCallback at construction and will be polled by the
-// AudioDevice for audio to be played out by the underlying audio layers.
-//
-// State sequences.
-//
-//            Task [IO thread]                  IPC [IO thread]
-//
-// Start -> CreateStreamOnIOThread -----> CreateStream ------>
-//       <- OnStreamCreated <- AudioMsg_NotifyStreamCreated <-
-//       ---> PlayOnIOThread -----------> PlayStream -------->
-//
-// Optionally Play() / Pause() sequences may occur:
-// Play -> PlayOnIOThread --------------> PlayStream --------->
-// Pause -> PauseOnIOThread ------------> PauseStream -------->
-// (note that Play() / Pause() sequences before OnStreamCreated are
-//  deferred until OnStreamCreated, with the last valid state being used)
-//
-// AudioDevice::Render => audio transport on audio thread =>
-//                               |
-// Stop --> ShutDownOnIOThread -------->  CloseStream -> Close
-//
-// This class utilizes several threads during its lifetime, namely:
-// 1. Creating thread.
-//    Must be the main render thread.
-// 2. Control thread (may be the main render thread or another thread).
-//    The methods: Start(), Stop(), Play(), Pause(), SetVolume()
-//    must be called on the same thread.
-// 3. IO thread (internal implementation detail - not exposed to public API)
-//    The thread within which this class receives all the IPC messages and
-//    IPC communications can only happen in this thread.
-// 4. Audio transport thread (See AudioDeviceThread).
-//    Responsible for calling the AudioThreadCallback implementation that in
-//    turn calls AudioRendererSink::RenderCallback which feeds audio samples to
-//    the audio layer in the browser process using sync sockets and shared
-//    memory.
-//
-// Implementation notes:
-//
-// - Start() is asynchronous/non-blocking.
-// - Stop() is asynchronous/non-blocking.
-// - Play() is asynchronous/non-blocking.
-// - Pause() is asynchronous/non-blocking.
-// - The user must call Stop() before deleting the class instance.
-
-#ifndef CONTENT_RENDERER_MEDIA_AUDIO_DEVICE_H_
-#define CONTENT_RENDERER_MEDIA_AUDIO_DEVICE_H_
-
-#include "base/basictypes.h"
-#include "base/bind.h"
-#include "base/memory/scoped_ptr.h"
-#include "base/message_loop.h"
-#include "base/shared_memory.h"
-#include "content/common/content_export.h"
-#include "content/renderer/media/audio_device_thread.h"
-#include "content/renderer/media/scoped_loop_observer.h"
-#include "media/audio/audio_output_ipc.h"
-#include "media/audio/audio_parameters.h"
-#include "media/base/audio_renderer_sink.h"
-
-namespace media {
-class AudioParameters;
-}
-
-class CONTENT_EXPORT AudioDevice
-    : NON_EXPORTED_BASE(public media::AudioRendererSink),
-      public media::AudioOutputIPCDelegate,
-      NON_EXPORTED_BASE(public ScopedLoopObserver) {
- public:
-  // Methods called on main render thread -------------------------------------
-
-  // AudioRendererSink implementation.
-  virtual void Initialize(const media::AudioParameters& params,
-                          RenderCallback* callback) OVERRIDE;
-  virtual void Start() OVERRIDE;
-  virtual void Stop() OVERRIDE;
-  virtual void Play() OVERRIDE;
-  virtual void Pause(bool flush) OVERRIDE;
-  virtual bool SetVolume(double volume) OVERRIDE;
-
-  // Methods called on IO thread ----------------------------------------------
-  // AudioOutputIPCDelegate methods.
-  virtual void OnStateChanged(
-      media::AudioOutputIPCDelegate::State state) OVERRIDE;
-  virtual void OnStreamCreated(base::SharedMemoryHandle handle,
-                               base::SyncSocket::Handle socket_handle,
-                               int length) OVERRIDE;
-  virtual void OnIPCClosed() OVERRIDE;
-
-  // Creates an uninitialized AudioDevice. Clients must call Initialize()
-  // before using.
-  // TODO(tommi): When all dependencies on |content| have been removed
-  // from AudioDevice, move this class over to media/audio.
-  AudioDevice(media::AudioOutputIPC* ipc,
-              const scoped_refptr<base::MessageLoopProxy>& io_loop);
-
- protected:
-  // Magic required by ref_counted.h to avoid any code deleting the object
-  // accidentally while there are references to it.
-  friend class base::RefCountedThreadSafe<AudioDevice>;
-  virtual ~AudioDevice();
-
- private:
-  // Methods called on IO thread ----------------------------------------------
-  // The following methods are tasks posted on the IO thread that needs to
-  // be executed on that thread. They interact with AudioMessageFilter and
-  // sends IPC messages on that thread.
-  void CreateStreamOnIOThread(const media::AudioParameters& params);
-  void PlayOnIOThread();
-  void PauseOnIOThread(bool flush);
-  void ShutDownOnIOThread();
-  void SetVolumeOnIOThread(double volume);
-
-  // MessageLoop::DestructionObserver implementation for the IO loop.
-  // If the IO loop dies before we do, we shut down the audio thread from here.
-  virtual void WillDestroyCurrentMessageLoop() OVERRIDE;
-
-  media::AudioParameters audio_parameters_;
-
-  RenderCallback* callback_;
-
-  // A pointer to the IPC layer that takes care of sending requests over to
-  // the AudioRendererHost.
-  media::AudioOutputIPC* ipc_;
-
-  // Our stream ID on the message filter. Only accessed on the IO thread.
-  // Must only be modified on the IO thread.
-  int stream_id_;
-
-  // State of Play() / Pause() calls before OnStreamCreated() is called.
-  bool play_on_start_;
-
-  // Set to |true| when OnStreamCreated() is called.
-  // Set to |false| when ShutDownOnIOThread() is called.
-  // This is for use with play_on_start_ to track Play() / Pause() state.
-  // Must only be touched from the IO thread.
-  bool is_started_;
-
-  // Our audio thread callback class.  See source file for details.
-  class AudioThreadCallback;
-
-  // In order to avoid a race between OnStreamCreated and Stop(), we use this
-  // guard to control stopping and starting the audio thread.
-  base::Lock audio_thread_lock_;
-  AudioDeviceThread audio_thread_;
-  scoped_ptr<AudioDevice::AudioThreadCallback> audio_callback_;
-
-
-  DISALLOW_COPY_AND_ASSIGN(AudioDevice);
-};
-
-#endif  // CONTENT_RENDERER_MEDIA_AUDIO_DEVICE_H_