1// Copyright (c) 2012 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5// AudioOutputDispatcherImpl is an implementation of AudioOutputDispatcher.
6//
7// To avoid opening and closing audio devices more frequently than necessary,
8// each dispatcher has a pool of inactive physical streams. A stream is closed
9// only if it hasn't been used for a certain period of time (specified via the
10// constructor).
11//
12
13#ifndef MEDIA_AUDIO_AUDIO_OUTPUT_DISPATCHER_IMPL_H_
14#define MEDIA_AUDIO_AUDIO_OUTPUT_DISPATCHER_IMPL_H_
15
16#include <map>
17#include <vector>
18
19#include "base/basictypes.h"
20#include "base/memory/ref_counted.h"
21#include "base/timer/timer.h"
22#include "media/audio/audio_io.h"
23#include "media/audio/audio_logging.h"
24#include "media/audio/audio_manager.h"
25#include "media/audio/audio_output_dispatcher.h"
26#include "media/audio/audio_parameters.h"
27
28namespace media {
29
30class AudioOutputProxy;
31
32class MEDIA_EXPORT AudioOutputDispatcherImpl : public AudioOutputDispatcher {
33 public:
34  // |close_delay| specifies delay after the stream is idle until the audio
35  // device is closed.
36  AudioOutputDispatcherImpl(AudioManager* audio_manager,
37                            const AudioParameters& params,
38                            const std::string& output_device_id,
39                            const base::TimeDelta& close_delay);
40
41  // Opens a new physical stream if there are no pending streams in
42  // |idle_streams_|.  Do not call Close() or Stop() if this method fails.
43  virtual bool OpenStream() OVERRIDE;
44
45  // If there are pending streams in |idle_streams_| then it reuses one of
46  // them, otherwise creates a new one.
47  virtual bool StartStream(AudioOutputStream::AudioSourceCallback* callback,
48                           AudioOutputProxy* stream_proxy) OVERRIDE;
49
50  // Stops the stream assigned to the specified proxy and moves it into
51  // |idle_streams_| for reuse by other proxies.
52  virtual void StopStream(AudioOutputProxy* stream_proxy) OVERRIDE;
53
54  virtual void StreamVolumeSet(AudioOutputProxy* stream_proxy,
55                               double volume) OVERRIDE;
56
57  // Closes |idle_streams_| until the number of |idle_streams_| is equal to the
58  // |idle_proxies_| count.  If there are no |idle_proxies_| a single stream is
59  // kept alive until |close_timer_| fires.
60  virtual void CloseStream(AudioOutputProxy* stream_proxy) OVERRIDE;
61
62  virtual void Shutdown() OVERRIDE;
63
64 private:
65  friend class base::RefCountedThreadSafe<AudioOutputDispatcherImpl>;
66  virtual ~AudioOutputDispatcherImpl();
67
68  // Creates a new physical output stream, opens it and pushes to
69  // |idle_streams_|.  Returns false if the stream couldn't be created or
70  // opened.
71  bool CreateAndOpenStream();
72
73  // Closes all |idle_streams_|.
74  void CloseAllIdleStreams();
75  // Similar to CloseAllIdleStreams(), but keeps |keep_alive| streams alive.
76  void CloseIdleStreams(size_t keep_alive);
77
78  size_t idle_proxies_;
79  std::vector<AudioOutputStream*> idle_streams_;
80
81  // When streams are stopped they're added to |idle_streams_|, if no stream is
82  // reused before |close_delay_| elapses |close_timer_| will run
83  // CloseIdleStreams().
84  base::DelayTimer<AudioOutputDispatcherImpl> close_timer_;
85
86  typedef std::map<AudioOutputProxy*, AudioOutputStream*> AudioStreamMap;
87  AudioStreamMap proxy_to_physical_map_;
88
89  scoped_ptr<AudioLog> audio_log_;
90  typedef std::map<AudioOutputStream*, int> AudioStreamIDMap;
91  AudioStreamIDMap audio_stream_ids_;
92  int audio_stream_id_;
93
94  DISALLOW_COPY_AND_ASSIGN(AudioOutputDispatcherImpl);
95};
96
97}  // namespace media
98
99#endif  // MEDIA_AUDIO_AUDIO_OUTPUT_DISPATCHER_IMPL_H_
100