media/audio/audio_output_ipc.h

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef MEDIA_AUDIO_AUDIO_OUTPUT_IPC_H_
   6 #define MEDIA_AUDIO_AUDIO_OUTPUT_IPC_H_
   7
   8 #include <string>
   9
  10 #include "base/memory/shared_memory.h"
  11 #include "base/sync_socket.h"
  12 #include "media/audio/audio_parameters.h"
  13 #include "media/base/media_export.h"
  14 #include "url/gurl.h"
  15
  16 namespace media {
  17
  18 // Result of an audio output device switch operation
  19 enum SwitchOutputDeviceResult {
  20   SWITCH_OUTPUT_DEVICE_RESULT_SUCCESS = 0,
  21   SWITCH_OUTPUT_DEVICE_RESULT_ERROR_NOT_FOUND,
  22   SWITCH_OUTPUT_DEVICE_RESULT_ERROR_NOT_AUTHORIZED,
  23   SWITCH_OUTPUT_DEVICE_RESULT_ERROR_OBSOLETE,
  24   SWITCH_OUTPUT_DEVICE_RESULT_ERROR_NOT_SUPPORTED,
  25   SWITCH_OUTPUT_DEVICE_RESULT_LAST =
  26       SWITCH_OUTPUT_DEVICE_RESULT_ERROR_NOT_SUPPORTED,
  27 };
  28
  29 // Current status of the audio output stream in the browser process. Browser
  30 // sends information about the current playback state and error to the
  31 // renderer process using this type.
  32 enum AudioOutputIPCDelegateState {
  33   AUDIO_OUTPUT_IPC_DELEGATE_STATE_PLAYING,
  34   AUDIO_OUTPUT_IPC_DELEGATE_STATE_PAUSED,
  35   AUDIO_OUTPUT_IPC_DELEGATE_STATE_ERROR,
  36   AUDIO_OUTPUT_IPC_DELEGATE_STATE_LAST = AUDIO_OUTPUT_IPC_DELEGATE_STATE_ERROR
  37 };
  38
  39 // Contains IPC notifications for the state of the server side
  40 // (AudioOutputController) audio state changes and when an AudioOutputController
  41 // has been created.  Implemented by AudioOutputDevice.
  42 class MEDIA_EXPORT AudioOutputIPCDelegate {
  43  public:
  44
  45   // Called when state of an audio stream has changed.
  46   virtual void OnStateChanged(AudioOutputIPCDelegateState state) = 0;
  47
  48   // Called when an audio stream has been created.
  49   // The shared memory |handle| points to a memory section that's used to
  50   // transfer audio buffers from the AudioOutputIPCDelegate back to the
  51   // AudioRendererHost.  The implementation of OnStreamCreated takes ownership.
  52   // The |socket_handle| is used by AudioRendererHost to signal requests for
  53   // audio data to be written into the shared memory. The AudioOutputIPCDelegate
  54   // must read from this socket and provide audio whenever data (search for
  55   // "pending_bytes") is received.
  56   virtual void OnStreamCreated(base::SharedMemoryHandle handle,
  57                                base::SyncSocket::Handle socket_handle,
  58                                int length) = 0;
  59
  60   // Called when the AudioOutputIPC object is going away and/or when the IPC
  61   // channel has been closed and no more ipc requests can be made.
  62   // Implementations should delete their owned AudioOutputIPC instance
  63   // immediately.
  64   virtual void OnIPCClosed() = 0;
  65
  66  protected:
  67   virtual ~AudioOutputIPCDelegate();
  68 };
  69
  70 // Provides the IPC functionality for an AudioOutputIPCDelegate (e.g., an
  71 // AudioOutputDevice).  The implementation should asynchronously deliver the
  72 // messages to an AudioOutputController object (or create one in the case of
  73 // CreateStream()), that may live in a separate process.
  74 class MEDIA_EXPORT AudioOutputIPC {
  75  public:
  76   virtual ~AudioOutputIPC();
  77
  78   // Sends a request to create an AudioOutputController object in the peer
  79   // process and configures it to use the specified audio |params| including
  80   // number of synchronized input channels.|session_id| is used by the browser
  81   // to select the correct input device if the input channel in |params| is
  82   // valid, otherwise it will be ignored.  Once the stream has been created,
  83   // the implementation will notify |delegate| by calling OnStreamCreated().
  84   virtual void CreateStream(AudioOutputIPCDelegate* delegate,
  85                             const AudioParameters& params,
  86                             int session_id) = 0;
  87
  88   // Starts playing the stream.  This should generate a call to
  89   // AudioOutputController::Play().
  90   virtual void PlayStream() = 0;
  91
  92   // Pauses an audio stream.  This should generate a call to
  93   // AudioOutputController::Pause().
  94   virtual void PauseStream() = 0;
  95
  96   // Closes the audio stream which should shut down the corresponding
  97   // AudioOutputController in the peer process.
  98   virtual void CloseStream() = 0;
  99
 100   // Sets the volume of the audio stream.
 101   virtual void SetVolume(double volume) = 0;
 102 };
 103
 104 }  // namespace media
 105
 106 #endif  // MEDIA_AUDIO_AUDIO_OUTPUT_IPC_H_