media/audio/audio_output_dispatcher_impl.h

   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
  28 namespace media {
  29
  30 class AudioOutputProxy;
  31
  32 class 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   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   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   void StopStream(AudioOutputProxy* stream_proxy) override;
  53
  54   void StreamVolumeSet(AudioOutputProxy* stream_proxy, double volume) override;
  55
  56   // Closes |idle_streams_| until the number of |idle_streams_| is equal to the
  57   // |idle_proxies_| count.  If there are no |idle_proxies_| a single stream is
  58   // kept alive until |close_timer_| fires.
  59   void CloseStream(AudioOutputProxy* stream_proxy) override;
  60
  61   void Shutdown() override;
  62
  63  private:
  64   friend class base::RefCountedThreadSafe<AudioOutputDispatcherImpl>;
  65   ~AudioOutputDispatcherImpl() override;
  66
  67   // Creates a new physical output stream, opens it and pushes to
  68   // |idle_streams_|.  Returns false if the stream couldn't be created or
  69   // opened.
  70   bool CreateAndOpenStream();
  71
  72   // Closes all |idle_streams_|.
  73   void CloseAllIdleStreams();
  74   // Similar to CloseAllIdleStreams(), but keeps |keep_alive| streams alive.
  75   void CloseIdleStreams(size_t keep_alive);
  76
  77   size_t idle_proxies_;
  78   std::vector<AudioOutputStream*> idle_streams_;
  79
  80   // When streams are stopped they're added to |idle_streams_|, if no stream is
  81   // reused before |close_delay_| elapses |close_timer_| will run
  82   // CloseIdleStreams().
  83   base::DelayTimer<AudioOutputDispatcherImpl> close_timer_;
  84
  85   typedef std::map<AudioOutputProxy*, AudioOutputStream*> AudioStreamMap;
  86   AudioStreamMap proxy_to_physical_map_;
  87
  88   scoped_ptr<AudioLog> audio_log_;
  89   typedef std::map<AudioOutputStream*, int> AudioStreamIDMap;
  90   AudioStreamIDMap audio_stream_ids_;
  91   int audio_stream_id_;
  92
  93   DISALLOW_COPY_AND_ASSIGN(AudioOutputDispatcherImpl);
  94 };
  95
  96 }  // namespace media
  97
  98 #endif  // MEDIA_AUDIO_AUDIO_OUTPUT_DISPATCHER_IMPL_H_