media/audio/audio_output_stream_sink.h

   1 // Copyright 2014 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 #ifndef MEDIA_AUDIO_AUDIO_OUTPUT_STREAM_SINK_H_
   6 #define MEDIA_AUDIO_AUDIO_OUTPUT_STREAM_SINK_H_
   7
   8 #include <string>
   9
  10 #include "base/compiler_specific.h"
  11 #include "base/single_thread_task_runner.h"
  12 #include "base/synchronization/lock.h"
  13 #include "media/audio/audio_io.h"
  14 #include "media/base/audio_renderer_sink.h"
  15 #include "media/base/media_export.h"
  16
  17 namespace media {
  18
  19 // Wrapper which exposes the browser side audio interface (AudioOutputStream) as
  20 // if it were a renderer side audio interface (AudioRendererSink). Note: This
  21 // will not work for sandboxed renderers.
  22 //
  23 // TODO(dalecurtis): Delete this class once we have a proper mojo audio service;
  24 // tracked by http://crbug.com/425368
  25 class MEDIA_EXPORT AudioOutputStreamSink
  26     : NON_EXPORTED_BASE(public AudioRendererSink),
  27       public AudioOutputStream::AudioSourceCallback {
  28  public:
  29   AudioOutputStreamSink();
  30
  31   // AudioRendererSink implementation.
  32   void Initialize(const AudioParameters& params,
  33                   RenderCallback* callback) override;
  34   void Start() override;
  35   void Stop() override;
  36   void Pause() override;
  37   void Play() override;
  38   bool SetVolume(double volume) override;
  39   OutputDevice* GetOutputDevice() override;
  40
  41   // AudioSourceCallback implementation.
  42   int OnMoreData(AudioBus* dest, uint32 total_bytes_delay) override;
  43   void OnError(AudioOutputStream* stream) override;
  44
  45  private:
  46   ~AudioOutputStreamSink() override;
  47
  48   // Helper methods for running AudioManager methods on the audio thread.
  49   void DoStart();
  50   void DoStop();
  51   void DoPause();
  52   void DoPlay();
  53   void DoSetVolume(double volume);
  54
  55   // Clears |active_render_callback_| under lock, synchronously stopping render
  56   // callbacks from any thread.  Must be called before Pause() and Stop()
  57   // trampoline to their helper methods on the audio thread.
  58   void ClearCallback();
  59
  60   // Parameters provided by Initialize(), cached for use on other threads.
  61   AudioParameters params_;
  62
  63   // Since Initialize() is only called once for AudioRenderSinks, save the
  64   // callback both here and under |active_render_callback_| which will be
  65   // cleared during Pause() and Stop() to achieve "synchronous" stoppage.
  66   RenderCallback* render_callback_;
  67
  68   // The task runner for the audio thread.
  69   const scoped_refptr<base::SingleThreadTaskRunner> audio_task_runner_;
  70
  71   // The actual AudioOutputStream, must only be accessed on the audio thread.
  72   AudioOutputStream* stream_;
  73
  74   // Lock and callback for forwarding OnMoreData() calls into Render() calls.
  75   base::Lock callback_lock_;
  76   RenderCallback* active_render_callback_;
  77
  78   DISALLOW_COPY_AND_ASSIGN(AudioOutputStreamSink);
  79 };
  80
  81 }  // namepace media
  82
  83 #endif  // MEDIA_AUDIO_AUDIO_OUTPUT_STREAM_SINK_H_