1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
|
// Copyright 2012 The Chromium Authors
// 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/compiler_specific.h"
#include "base/memory/weak_ptr.h"
#include "base/sequence_checker.h"
#include "media/audio/audio_io.h"
#include "media/base/audio_parameters.h"
namespace media {
class AudioOutputDispatcher;
// AudioOutputProxy is an audio output 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:
// Caller keeps ownership of |dispatcher|.
explicit AudioOutputProxy(base::WeakPtr<AudioOutputDispatcher> dispatcher);
AudioOutputProxy(const AudioOutputProxy&) = delete;
AudioOutputProxy& operator=(const AudioOutputProxy&) = delete;
// AudioOutputStream interface.
bool Open() override;
void Start(AudioSourceCallback* callback) override;
void Stop() override;
void SetVolume(double volume) override;
void GetVolume(double* volume) override;
void Close() override;
void Flush() override;
AudioOutputDispatcher* get_dispatcher_for_testing() const {
return dispatcher_.get();
}
private:
enum State {
kCreated,
kOpened,
kPlaying,
kClosed,
kOpenError,
kStartError,
};
~AudioOutputProxy() override;
base::WeakPtr<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_;
SEQUENCE_CHECKER(sequence_checker_);
};
} // namespace media
#endif // MEDIA_AUDIO_AUDIO_OUTPUT_PROXY_H_
|
