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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.
// AudioOutputDispatcherImpl is an implementation of AudioOutputDispatcher.
// To avoid opening and closing audio devices more frequently than necessary,
// each dispatcher has a pool of inactive physical streams. A stream is closed
// only if it hasn't been used for a certain period of time (specified via the
// constructor).
#include <list>
#include <map>
#include "base/basictypes.h"
#include "base/memory/ref_counted.h"
#include "base/memory/weak_ptr.h"
#include "base/timer.h"
#include "media/audio/audio_io.h"
#include "media/audio/audio_manager.h"
#include "media/audio/audio_output_dispatcher.h"
#include "media/audio/audio_parameters.h"
class MessageLoop;
namespace media {
class AudioOutputProxy;
class MEDIA_EXPORT AudioOutputDispatcherImpl : public AudioOutputDispatcher {
// |close_delay_ms| specifies delay after the stream is paused until
// the audio device is closed.
AudioOutputDispatcherImpl(AudioManager* audio_manager,
const AudioParameters& params,
const base::TimeDelta& close_delay);
// Opens a new physical stream if there are no pending streams in
// |idle_streams_|. Do not call Close() or Stop() if this method fails.
virtual bool OpenStream() OVERRIDE;
// If there are pending streams in |idle_streams_| then it reuses one of
// them, otherwise creates a new one.
virtual bool StartStream(AudioOutputStream::AudioSourceCallback* callback,
AudioOutputProxy* stream_proxy) OVERRIDE;
// Holds the physical stream temporarily in |pausing_streams_| and then
// |stream| is added to the pool of pending streams (i.e. |idle_streams_|).
virtual void StopStream(AudioOutputProxy* stream_proxy) OVERRIDE;
virtual void StreamVolumeSet(AudioOutputProxy* stream_proxy,
double volume) OVERRIDE;
virtual void CloseStream(AudioOutputProxy* stream_proxy) OVERRIDE;
virtual void Shutdown() OVERRIDE;
typedef std::map<AudioOutputProxy*, AudioOutputStream*> AudioStreamMap;
friend class base::RefCountedThreadSafe<AudioOutputDispatcherImpl>;
virtual ~AudioOutputDispatcherImpl();
friend class AudioOutputProxyTest;
// Creates a new physical output stream, opens it and pushes to
// |idle_streams_|. Returns false if the stream couldn't be created or
// opened.
bool CreateAndOpenStream();
// A task scheduled by StartStream(). Opens a new stream and puts
// it in |idle_streams_|.
void OpenTask();
// Before a stream is reused, it should sit idle for a bit. This task is
// called once that time has elapsed.
void StopStreamTask();
// Called by |close_timer_|. Closes all pending streams.
void ClosePendingStreams();
base::TimeDelta pause_delay_;
size_t paused_proxies_;
typedef std::list<AudioOutputStream*> AudioOutputStreamList;
AudioOutputStreamList idle_streams_;
AudioOutputStreamList pausing_streams_;
// Used to post delayed tasks to ourselves that we cancel inside Shutdown().
base::WeakPtrFactory<AudioOutputDispatcherImpl> weak_this_;
base::DelayTimer<AudioOutputDispatcherImpl> close_timer_;
AudioStreamMap proxy_to_physical_map_;
} // namespace media