Move AudioDevice and AudioInputDevice to media.

content/renderer/media/audio_input_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.
-
-// Low-latency audio capturing class utilizing audio input stream provided
-// by a server (browser) process by use of an IPC interface.
-//
-// Relationship of classes:
-//
-//  AudioInputController                 AudioInputDevice
-//           ^                                  ^
-//           |                                  |
-//           v                  IPC             v
-// AudioInputRendererHost  <---------> media::AudioInputIPCDelegate
-//           ^                       (impl in AudioInputMessageFilter)
-//           |
-//           v
-// AudioInputDeviceManager
-//
-// Transportation of audio samples from the browser to the render process
-// is done by using shared memory in combination with a SyncSocket.
-// The AudioInputDevice user registers an AudioInputDevice::CaptureCallback by
-// calling Initialize().  The callback will be called with recorded audio from
-// the underlying audio layers.
-// The session ID is used by the AudioInputRendererHost to start the device
-// referenced by this ID.
-//
-// State sequences:
-//
-// Sequence where session_id has not been set using SetDevice():
-// ('<-' signifies callbacks, -> signifies calls made by AudioInputDevice)
-// Start -> InitializeOnIOThread -> CreateStream ->
-//       <- OnStreamCreated <-
-//       -> StartOnIOThread -> PlayStream ->
-//
-// Sequence where session_id has been set using SetDevice():
-// Start -> InitializeOnIOThread -> StartDevice ->
-//       <- OnDeviceReady <-
-//       -> CreateStream ->
-//       <- OnStreamCreated <-
-//       -> StartOnIOThread -> PlayStream ->
-//
-// AudioInputDevice::Capture => low latency audio transport on audio thread =>
-//                               |
-// Stop --> ShutDownOnIOThread ------>  CloseStream -> Close
-//
-// This class depends on two threads to function:
-//
-// 1. An IO thread.
-//    This thread is used to asynchronously process Start/Stop etc operations
-//    that are available via the public interface.  The public methods are
-//    asynchronous and simply post a task to the IO thread to actually perform
-//    the work.
-// 2. Audio transport thread.
-//    Responsible for calling the CaptureCallback and feed audio samples from
-//    the server side audio layer using a socket and shared memory.
-//
-// Implementation notes:
-// - The user must call Stop() before deleting the class instance.
-
-#ifndef CONTENT_RENDERER_MEDIA_AUDIO_INPUT_DEVICE_H_
-#define CONTENT_RENDERER_MEDIA_AUDIO_INPUT_DEVICE_H_
-
-#include <string>
-#include <vector>
-
-#include "base/basictypes.h"
-#include "base/compiler_specific.h"
-#include "base/memory/scoped_ptr.h"
-#include "base/shared_memory.h"
-#include "content/common/content_export.h"
-#include "content/renderer/media/audio_device_thread.h"
-#include "content/renderer/media/audio_input_message_filter.h"
-#include "content/renderer/media/scoped_loop_observer.h"
-#include "media/audio/audio_parameters.h"
-
-// TODO(henrika): This class is based on the AudioDevice class and it has
-// many components in common. Investigate potential for re-factoring.
-// TODO(henrika): Add support for event handling (e.g. OnStateChanged,
-// OnCaptureStopped etc.) and ensure that we can deliver these notifications
-// to any clients using this class.
-class CONTENT_EXPORT AudioInputDevice
-    : NON_EXPORTED_BASE(public media::AudioInputIPCDelegate),
-      NON_EXPORTED_BASE(public ScopedLoopObserver),
-      public base::RefCountedThreadSafe<AudioInputDevice> {
- public:
-  class CONTENT_EXPORT CaptureCallback {
-   public:
-    virtual void Capture(const std::vector<float*>& audio_data,
-                         int number_of_frames,
-                         int audio_delay_milliseconds,
-                         double volume) = 0;
-    virtual void OnCaptureError() = 0;
-   protected:
-    virtual ~CaptureCallback() {}
-  };
-
-  class CONTENT_EXPORT CaptureEventHandler {
-   public:
-    // Notification to the client that the device with the specific |device_id|
-    // has been started.
-    // This callback is triggered as a result of StartDevice().
-    virtual void OnDeviceStarted(const std::string& device_id) = 0;
-
-    // Notification to the client that the device has been stopped.
-    virtual void OnDeviceStopped() = 0;
-
-   protected:
-    virtual ~CaptureEventHandler() {}
-  };
-
-  AudioInputDevice(media::AudioInputIPC* ipc,
-                   const scoped_refptr<base::MessageLoopProxy>& io_loop);
-
-  // Initializes the AudioInputDevice.  This method must be called before
-  // any other methods can be used.
-  void Initialize(const media::AudioParameters& params,
-                  CaptureCallback* callback,
-                  CaptureEventHandler* event_handler);
-
-  // Specify the |session_id| to query which device to use.
-  // Start() will use the second sequence if this method is called before.
-  void SetDevice(int session_id);
-
-  // Starts audio capturing.
-  // TODO(henrika): add support for notification when recording has started.
-  void Start();
-
-  // Stops audio capturing.
-  // TODO(henrika): add support for notification when recording has stopped.
-  void Stop();
-
-  // Sets the capture volume scaling, with range [0.0, 1.0] inclusive.
-  // Returns |true| on success.
-  void SetVolume(double volume);
-
-  // Sets the Automatic Gain Control state to on or off.
-  // This method must be called before Start(). It will not have any effect
-  // if it is called while capturing has already started.
-  void SetAutomaticGainControl(bool enabled);
-
- protected:
-  // Methods called on IO thread ----------------------------------------------
-  // media::AudioInputIPCDelegate implementation.
-  virtual void OnStreamCreated(base::SharedMemoryHandle handle,
-                               base::SyncSocket::Handle socket_handle,
-                               int length) OVERRIDE;
-  virtual void OnVolume(double volume) OVERRIDE;
-  virtual void OnStateChanged(
-      media::AudioInputIPCDelegate::State state) OVERRIDE;
-  virtual void OnDeviceReady(const std::string& device_id) OVERRIDE;
-  virtual void OnIPCClosed() OVERRIDE;
-
-  friend class base::RefCountedThreadSafe<AudioInputDevice>;
-  virtual ~AudioInputDevice();
-
- 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 AudioInputMessageFilter and
-  // sends IPC messages on that thread.
-  void InitializeOnIOThread();
-  void SetSessionIdOnIOThread(int session_id);
-  void StartOnIOThread();
-  void ShutDownOnIOThread();
-  void SetVolumeOnIOThread(double volume);
-  void SetAutomaticGainControlOnIOThread(bool enabled);
-
-  // 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_;
-
-  CaptureCallback* callback_;
-  CaptureEventHandler* event_handler_;
-
-  media::AudioInputIPC* ipc_;
-
-  // Our stream ID on the message filter. Only modified on the IO thread.
-  int stream_id_;
-
-  // The media session ID used to identify which input device to be started.
-  // Only modified on the IO thread.
-  int session_id_;
-
-  // State variable used to indicate it is waiting for a OnDeviceReady()
-  // callback. Only modified on the IO thread.
-  bool pending_device_ready_;
-
-  // Stores the Automatic Gain Control state. Default is false.
-  // Only modified on the IO thread.
-  bool agc_is_enabled_;
-
-  // 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<AudioInputDevice::AudioThreadCallback> audio_callback_;
-
-  DISALLOW_IMPLICIT_CONSTRUCTORS(AudioInputDevice);
-};
-
-#endif  // CONTENT_RENDERER_MEDIA_AUDIO_INPUT_DEVICE_H_