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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.
#ifndef MEDIA_AUDIO_AUDIO_OUTPUT_PROXY_H_
#define MEDIA_AUDIO_AUDIO_OUTPUT_PROXY_H_
#include "base/basictypes.h"
#include "base/compiler_specific.h"
#include "base/memory/ref_counted.h"
#include "base/threading/non_thread_safe.h"
#include "media/audio/audio_io.h"
#include "media/audio/audio_parameters.h"
namespace media {
class AudioOutputDispatcher;
// AudioOutputProxy is an audio otput stream that uses resources more
// efficiently than a regular audio output stream: it opens audio
// device only when sound is playing, i.e. between Start() and Stop()
// (there is still one physical stream per each audio output proxy in
// playing state).
//
// AudioOutputProxy uses AudioOutputDispatcher to open and close
// physical output streams.
class MEDIA_EXPORT AudioOutputProxy
: public AudioOutputStream,
public NON_EXPORTED_BASE(base::NonThreadSafe) {
public:
// Caller keeps ownership of |dispatcher|.
explicit AudioOutputProxy(AudioOutputDispatcher* dispatcher);
// AudioOutputStream interface.
virtual bool Open() OVERRIDE;
virtual void Start(AudioSourceCallback* callback) OVERRIDE;
virtual void Stop() OVERRIDE;
virtual void SetVolume(double volume) OVERRIDE;
virtual void GetVolume(double* volume) OVERRIDE;
virtual void Close() OVERRIDE;
private:
enum State {
kCreated,
kOpened,
kPlaying,
kClosed,
kOpenError,
kStartError,
};
virtual ~AudioOutputProxy();
scoped_refptr<AudioOutputDispatcher> dispatcher_;
State state_;
// Need to save volume here, so that we can restore it in case the stream
// is stopped, and then started again.
double volume_;
DISALLOW_COPY_AND_ASSIGN(AudioOutputProxy);
};
} // namespace media
#endif // MEDIA_AUDIO_AUDIO_OUTPUT_PROXY_H_
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