webkit/media/webaudiosourceprovider_impl.h

   1 // Copyright (c) 2013 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 WEBKIT_MEDIA_WEBAUDIOSOURCEPROVIDER_IMPL_H_
   6 #define WEBKIT_MEDIA_WEBAUDIOSOURCEPROVIDER_IMPL_H_
   7
   8 #include "base/synchronization/lock.h"
   9 #include "media/base/audio_renderer_sink.h"
  10 #include "third_party/WebKit/Source/Platform/chromium/public/WebVector.h"
  11 #include "third_party/WebKit/Source/WebKit/chromium/public/WebAudioSourceProvider.h"
  12
  13 namespace WebKit {
  14 class WebAudioSourceProviderClient;
  15 }
  16
  17 namespace webkit_media {
  18
  19 // WebAudioSourceProviderImpl provides a bridge between classes:
  20 //     WebKit::WebAudioSourceProvider <---> media::AudioRendererSink
  21 //
  22 // WebAudioSourceProviderImpl wraps an existing audio sink that is used unless
  23 // WebKit has set a client via setClient(). While a client is set WebKit will
  24 // periodically call provideInput() to render a certain number of audio
  25 // sample-frames using the sink's RenderCallback to get the data.
  26 //
  27 // All calls are protected by a lock.
  28 class WebAudioSourceProviderImpl
  29     : public WebKit::WebAudioSourceProvider,
  30       public media::AudioRendererSink {
  31  public:
  32   explicit WebAudioSourceProviderImpl(
  33       const scoped_refptr<media::AudioRendererSink>& sink);
  34
  35   // WebKit::WebAudioSourceProvider implementation.
  36   virtual void setClient(WebKit::WebAudioSourceProviderClient* client);
  37   virtual void provideInput(const WebKit::WebVector<float*>& audio_data,
  38                             size_t number_of_frames);
  39
  40   // media::AudioRendererSink implementation.
  41   virtual void Start() OVERRIDE;
  42   virtual void Stop() OVERRIDE;
  43   virtual void Play() OVERRIDE;
  44   virtual void Pause() OVERRIDE;
  45   virtual bool SetVolume(double volume) OVERRIDE;
  46   virtual void Initialize(const media::AudioParameters& params,
  47                           RenderCallback* renderer) OVERRIDE;
  48
  49  protected:
  50   virtual ~WebAudioSourceProviderImpl();
  51
  52  private:
  53   // Set to true when Initialize() is called.
  54   int channels_;
  55   int sample_rate_;
  56   double volume_;
  57
  58   // Tracks the current playback state.
  59   enum PlaybackState { kStopped, kStarted, kPlaying };
  60   PlaybackState state_;
  61
  62   // Where audio comes from.
  63   media::AudioRendererSink::RenderCallback* renderer_;
  64
  65   // When set via setClient() it overrides |sink_| for consuming audio.
  66   WebKit::WebAudioSourceProviderClient* client_;
  67
  68   // Where audio ends up unless overridden by |client_|.
  69   base::Lock sink_lock_;
  70   scoped_refptr<media::AudioRendererSink> sink_;
  71   scoped_ptr<media::AudioBus> bus_wrapper_;
  72
  73   DISALLOW_IMPLICIT_CONSTRUCTORS(WebAudioSourceProviderImpl);
  74 };
  75
  76 }  // namespace webkit_media
  77
  78 #endif  // WEBKIT_MEDIA_WEBAUDIOSOURCEPROVIDER_IMPL_H_