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      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 std::string& input_device_id,
     40                             const base::TimeDelta& close_delay);
     41 
     42   // Opens a new physical stream if there are no pending streams in
     43   // |idle_streams_|.  Do not call Close() or Stop() if this method fails.
     44   virtual bool OpenStream() OVERRIDE;
     45 
     46   // If there are pending streams in |idle_streams_| then it reuses one of
     47   // them, otherwise creates a new one.
     48   virtual bool StartStream(AudioOutputStream::AudioSourceCallback* callback,
     49                            AudioOutputProxy* stream_proxy) OVERRIDE;
     50 
     51   // Stops the stream assigned to the specified proxy and moves it into
     52   // |idle_streams_| for reuse by other proxies.
     53   virtual void StopStream(AudioOutputProxy* stream_proxy) OVERRIDE;
     54 
     55   virtual void StreamVolumeSet(AudioOutputProxy* stream_proxy,
     56                                double volume) OVERRIDE;
     57 
     58   // Closes |idle_streams_| until the number of |idle_streams_| is equal to the
     59   // |idle_proxies_| count.  If there are no |idle_proxies_| a single stream is
     60   // kept alive until |close_timer_| fires.
     61   virtual void CloseStream(AudioOutputProxy* stream_proxy) OVERRIDE;
     62 
     63   virtual void Shutdown() OVERRIDE;
     64 
     65   virtual void CloseStreamsForWedgeFix() OVERRIDE;
     66   virtual void RestartStreamsForWedgeFix() OVERRIDE;
     67 
     68  private:
     69   friend class base::RefCountedThreadSafe<AudioOutputDispatcherImpl>;
     70   virtual ~AudioOutputDispatcherImpl();
     71 
     72   // Creates a new physical output stream, opens it and pushes to
     73   // |idle_streams_|.  Returns false if the stream couldn't be created or
     74   // opened.
     75   bool CreateAndOpenStream();
     76 
     77   // Closes all |idle_streams_|.
     78   void CloseAllIdleStreams();
     79   // Similar to CloseAllIdleStreams(), but keeps |keep_alive| streams alive.
     80   void CloseIdleStreams(size_t keep_alive);
     81 
     82   size_t idle_proxies_;
     83   std::vector<AudioOutputStream*> idle_streams_;
     84 
     85   // When streams are stopped they're added to |idle_streams_|, if no stream is
     86   // reused before |close_delay_| elapses |close_timer_| will run
     87   // CloseIdleStreams().
     88   base::DelayTimer<AudioOutputDispatcherImpl> close_timer_;
     89 
     90   typedef std::map<AudioOutputProxy*, AudioOutputStream*> AudioStreamMap;
     91   AudioStreamMap proxy_to_physical_map_;
     92 
     93   scoped_ptr<AudioLog> audio_log_;
     94   typedef std::map<AudioOutputStream*, int> AudioStreamIDMap;
     95   AudioStreamIDMap audio_stream_ids_;
     96   int audio_stream_id_;
     97 
     98   DISALLOW_COPY_AND_ASSIGN(AudioOutputDispatcherImpl);
     99 };
    100 
    101 }  // namespace media
    102 
    103 #endif  // MEDIA_AUDIO_AUDIO_OUTPUT_DISPATCHER_IMPL_H_
    104