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// 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.
#include "base/memory/shared_memory.h"
#include "base/sync_socket.h"
#include "media/audio/audio_parameters.h"
#include "media/base/media_export.h"
namespace media {
// Contains IPC notifications for the state of the server side
// (AudioOutputController) audio state changes and when an AudioOutputController
// has been created. Implemented by AudioOutputDevice.
class MEDIA_EXPORT AudioOutputIPCDelegate {
// Current status of the audio output stream in the browser process. Browser
// sends information about the current playback state and error to the
// renderer process using this type.
enum State {
// Called when state of an audio stream has changed.
virtual void OnStateChanged(State state) = 0;
// Called when an audio stream has been created.
// The shared memory |handle| points to a memory section that's used to
// transfer audio buffers from the AudioOutputIPCDelegate back to the
// AudioRendererHost. The implementation of OnStreamCreated takes ownership.
// The |socket_handle| is used by AudioRendererHost to signal requests for
// audio data to be written into the shared memory. The AudioOutputIPCDelegate
// must read from this socket and provide audio whenever data (search for
// "pending_bytes") is received.
virtual void OnStreamCreated(base::SharedMemoryHandle handle,
base::SyncSocket::Handle socket_handle,
int length) = 0;
// Called when the AudioOutputIPC object is going away and/or when the IPC
// channel has been closed and no more ipc requests can be made.
// Implementations should delete their owned AudioOutputIPC instance
// immediately.
virtual void OnIPCClosed() = 0;
virtual ~AudioOutputIPCDelegate();
// Provides the IPC functionality for an AudioOutputIPCDelegate (e.g., an
// AudioOutputDevice). The implementation should asynchronously deliver the
// messages to an AudioOutputController object (or create one in the case of
// CreateStream()), that may live in a separate process.
class MEDIA_EXPORT AudioOutputIPC {
virtual ~AudioOutputIPC();
// Sends a request to create an AudioOutputController object in the peer
// process and configures it to use the specified audio |params| including
// number of synchronized input channels.|session_id| is used by the browser
// to select the correct input device if the input channel in |params| is
// valid, otherwise it will be ignored. Once the stream has been created,
// the implementation will notify |delegate| by calling OnStreamCreated().
virtual void CreateStream(AudioOutputIPCDelegate* delegate,
const AudioParameters& params,
int session_id) = 0;
// Starts playing the stream. This should generate a call to
// AudioOutputController::Play().
virtual void PlayStream() = 0;
// Pauses an audio stream. This should generate a call to
// AudioOutputController::Pause().
virtual void PauseStream() = 0;
// Closes the audio stream which should shut down the corresponding
// AudioOutputController in the peer process.
virtual void CloseStream() = 0;
// Sets the volume of the audio stream.
virtual void SetVolume(double volume) = 0;
} // namespace media