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 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