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/origin.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   // Called when state of an audio stream has changed.
  35   virtual void OnStateChanged(AudioOutputIPCDelegateState state) = 0;
  36
  37   // Called when an authorization request for an output device has been
  38   // completed
  39   virtual void OnDeviceAuthorized(
  40       bool success,
  41       const media::AudioParameters& output_params) = 0;
  42
  43   // Called when an audio stream has been created.
  44   // The shared memory |handle| points to a memory section that's used to
  45   // transfer audio buffers from the AudioOutputIPCDelegate back to the
  46   // AudioRendererHost.  The implementation of OnStreamCreated takes ownership.
  47   // The |socket_handle| is used by AudioRendererHost to signal requests for
  48   // audio data to be written into the shared memory. The AudioOutputIPCDelegate
  49   // must read from this socket and provide audio whenever data (search for
  50   // "pending_bytes") is received.
  51   virtual void OnStreamCreated(base::SharedMemoryHandle handle,
  52                                base::SyncSocket::Handle socket_handle,
  53                                int length) = 0;
  54
  55   // Called when an attempt to switch the output device has been completed
  56   virtual void OnOutputDeviceSwitched(SwitchOutputDeviceResult result) = 0;
  57
  58   // Called when the AudioOutputIPC object is going away and/or when the IPC
  59   // channel has been closed and no more ipc requests can be made.
  60   // Implementations should delete their owned AudioOutputIPC instance
  61   // immediately.
  62   virtual void OnIPCClosed() = 0;
  63
  64  protected:
  65   virtual ~AudioOutputIPCDelegate();
  66 };
  67
  68 // Provides the IPC functionality for an AudioOutputIPCDelegate (e.g., an
  69 // AudioOutputDevice).  The implementation should asynchronously deliver the
  70 // messages to an AudioOutputController object (or create one in the case of
  71 // CreateStream()), that may live in a separate process.
  72 class MEDIA_EXPORT AudioOutputIPC {
  73  public:
  74   virtual ~AudioOutputIPC();
  75
  76   // Sends a request to authorize the use of a specific audio output device
  77   // in the peer process.
  78   // If |session_id| is nonzero, the browser selects the output device
  79   // associated with an opened input device indicated by |session_id|. If no
  80   // such device is found, the browser attempts to select the device indicated
  81   // by |device_id|. If |device_id| is the empty string, the default
  82   // audio output device will be selected.
  83   // Once the authorization process is complete, the implementation will
  84   // notify |delegate| by calling OnDeviceAuthorized().
  85   virtual void RequestDeviceAuthorization(
  86       AudioOutputIPCDelegate* delegate,
  87       int session_id,
  88       const std::string& device_id,
  89       const url::Origin& security_origin) = 0;
  90
  91   // Sends a request to create an AudioOutputController object in the peer
  92   // process and configures it to use the specified audio |params| including
  93   // number of synchronized input channels.
  94   // Once the stream has been created, the implementation will notify
  95   // |delegate| by calling OnStreamCreated().
  96   virtual void CreateStream(AudioOutputIPCDelegate* delegate,
  97                             const AudioParameters& params) = 0;
  98
  99   // Starts playing the stream.  This should generate a call to
 100   // AudioOutputController::Play().
 101   virtual void PlayStream() = 0;
 102
 103   // Pauses an audio stream.  This should generate a call to
 104   // AudioOutputController::Pause().
 105   virtual void PauseStream() = 0;
 106
 107   // Closes the audio stream which should shut down the corresponding
 108   // AudioOutputController in the peer process.
 109   virtual void CloseStream() = 0;
 110
 111   // Sets the volume of the audio stream.
 112   virtual void SetVolume(double volume) = 0;
 113
 114   // Switches the output device of the audio stream.
 115   virtual void SwitchOutputDevice(const std::string& device_id,
 116                                   const url::Origin& security_origin) = 0;
 117 };
 118
 119 }  // namespace media
 120
 121 #endif  // MEDIA_AUDIO_AUDIO_OUTPUT_IPC_H_