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