// Copyright (c) 2011 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.
//
// AudioRendererHost serves audio related requests from AudioRenderer which
// lives inside the render process and provide access to audio hardware.
//
// This class is owned by BrowserRenderProcessHost, and instantiated on UI
// thread, but all other operations and method calls happen on IO thread, so we
// need to be extra careful about the lifetime of this object. AudioManager is a
// singleton and created in IO thread, audio output streams are also created in
// the IO thread, so we need to destroy them also in IO thread. After this class
// is created, a task of OnInitialized() is posted on IO thread in which
// singleton of AudioManager is created and.
//
// Here's an example of a typical IPC dialog for audio:
//
// Renderer AudioRendererHost
// | |
// | CreateStream > |
// | < Created |
// | |
// | Play > |
// | < Playing | time
// | |
// | < RequestAudioPacket |
// | AudioPacketReady > |
// | ... |
// | < RequestAudioPacket |
// | AudioPacketReady > |
// | |
// | ... |
// | < RequestAudioPacket |
// | AudioPacketReady > |
// | ... |
// | Pause > |
// | < Paused |
// | ... |
// | Start > |
// | < Started |
// | ... |
// | Close > |
// v v
// The above mode of operation uses relatively big buffers and has latencies
// of 50 ms or more. There is a second mode of operation which is low latency.
// For low latency audio, the picture above is modified by not having the
// RequestAudioPacket and the AudioPacketReady messages, instead a SyncSocket
// pair is used to signal buffer readiness without having to route messages
// using the IO thread.
#ifndef CONTENT_BROWSER_RENDERER_HOST_AUDIO_RENDERER_HOST_H_
#define CONTENT_BROWSER_RENDERER_HOST_AUDIO_RENDERER_HOST_H_
#pragma once
#include <map>
#include "base/gtest_prod_util.h"
#include "base/memory/ref_counted.h"
#include "base/memory/scoped_ptr.h"
#include "base/process.h"
#include "base/shared_memory.h"
#include "content/browser/browser_message_filter.h"
#include "content/browser/browser_thread.h"
#include "media/audio/audio_io.h"
#include "media/audio/audio_output_controller.h"
#include "media/audio/simple_sources.h"
class AudioManager;
struct AudioParameters;
class AudioRendererHost : public BrowserMessageFilter,
public media::AudioOutputController::EventHandler {
public:
typedef std::pair<int32, int> AudioEntryId;
struct AudioEntry {
AudioEntry();
~AudioEntry();
// The AudioOutputController that manages the audio stream.
scoped_refptr<media::AudioOutputController> controller;
// Render view ID that requested the audio stream.
int32 render_view_id;
// The audio stream ID in the render view.
int stream_id;
// Shared memory for transmission of the audio data.
base::SharedMemory shared_memory;
// The synchronous reader to be used by the controller. We have the
// ownership of the reader.
scoped_ptr<media::AudioOutputController::SyncReader> reader;
bool pending_buffer_request;
// Set to true after we called Close() for the controller.
bool pending_close;
};
typedef std::map<AudioEntryId, AudioEntry*> AudioEntryMap;
// Called from UI thread from the owner of this object.
AudioRendererHost();
// BrowserMessageFilter implementation.
virtual void OnChannelClosing();
virtual void OnDestruct() const;
virtual bool OnMessageReceived(const IPC::Message& message,
bool* message_was_ok);
/////////////////////////////////////////////////////////////////////////////
// AudioOutputController::EventHandler implementations.
virtual void OnCreated(media::AudioOutputController* controller);
virtual void OnPlaying(media::AudioOutputController* controller);
virtual void OnPaused(media::AudioOutputController* controller);
virtual void OnError(media::AudioOutputController* controller,
int error_code);
virtual void OnMoreData(media::AudioOutputController* controller,
AudioBuffersState buffers_state);
private:
friend class AudioRendererHostTest;
friend class BrowserThread;
friend class DeleteTask<AudioRendererHost>;
friend class MockAudioRendererHost;
FRIEND_TEST_ALL_PREFIXES(AudioRendererHostTest, CreateMockStream);
FRIEND_TEST_ALL_PREFIXES(AudioRendererHostTest, MockStreamDataConversation);
virtual ~AudioRendererHost();
////////////////////////////////////////////////////////////////////////////
// Methods called on IO thread.
// Returns true if the message is an audio related message and should be
// handled by this class.
bool IsAudioRendererHostMessage(const IPC::Message& message);
// Audio related IPC message handlers.
// Creates an audio output stream with the specified format. If this call is
// successful this object would keep an internal entry of the stream for the
// required properties.
void OnCreateStream(const IPC::Message& msg, int stream_id,
const AudioParameters& params,
bool low_latency);
// Play the audio stream referenced by |stream_id|.
void OnPlayStream(const IPC::Message& msg, int stream_id);
// Pause the audio stream referenced by |stream_id|.
void OnPauseStream(const IPC::Message& msg, int stream_id);
// Discard all audio data in stream referenced by |stream_id|.
void OnFlushStream(const IPC::Message& msg, int stream_id);
// Close the audio stream referenced by |stream_id|.
void OnCloseStream(const IPC::Message& msg, int stream_id);
// Set the volume of the audio stream referenced by |stream_id|.
void OnSetVolume(const IPC::Message& msg, int stream_id, double volume);
// Get the volume of the audio stream referenced by |stream_id|.
void OnGetVolume(const IPC::Message& msg, int stream_id);
// Notify packet has been prepared for the audio stream.
void OnNotifyPacketReady(const IPC::Message& msg, int stream_id,
uint32 packet_size);
// Complete the process of creating an audio stream. This will set up the
// shared memory or shared socket in low latency mode.
void DoCompleteCreation(media::AudioOutputController* controller);
// Send a state change message to the renderer.
void DoSendPlayingMessage(media::AudioOutputController* controller);
void DoSendPausedMessage(media::AudioOutputController* controller);
// Request more data from the renderer. This method is used only in normal
// latency mode.
void DoRequestMoreData(media::AudioOutputController* controller,
AudioBuffersState buffers_state);
// Handle error coming from audio stream.
void DoHandleError(media::AudioOutputController* controller, int error_code);
// Send an error message to the renderer.
void SendErrorMessage(int32 render_view_id, int32 stream_id);
// Delete all audio entry and all audio streams
void DeleteEntries();
// Closes the stream. The stream is then deleted in DeleteEntry() after it
// is closed.
void CloseAndDeleteStream(AudioEntry* entry);
// Called on the audio thread after the audio stream is closed.
void OnStreamClosed(AudioEntry* entry);
// Delete an audio entry and close the related audio stream.
void DeleteEntry(AudioEntry* entry);
// Delete audio entry and close the related audio stream due to an error,
// and error message is send to the renderer.
void DeleteEntryOnError(AudioEntry* entry);
// A helper method to look up a AudioEntry with a tuple of render view
// id and stream id. Returns NULL if not found.
AudioEntry* LookupById(int render_view_id, int stream_id);
// Search for a AudioEntry having the reference to |controller|.
// This method is used to look up an AudioEntry after a controller
// event is received.
AudioEntry* LookupByController(media::AudioOutputController* controller);
// A map of id to audio sources.
AudioEntryMap audio_entries_;
DISALLOW_COPY_AND_ASSIGN(AudioRendererHost);
};
#endif // CONTENT_BROWSER_RENDERER_HOST_AUDIO_RENDERER_HOST_H_