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