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      1 // Copyright 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 CONTENT_RENDERER_MEDIA_WEBAUDIOSOURCEPROVIDER_IMPL_H_
      6 #define CONTENT_RENDERER_MEDIA_WEBAUDIOSOURCEPROVIDER_IMPL_H_
      7 
      8 #include "base/callback.h"
      9 #include "base/memory/weak_ptr.h"
     10 #include "base/synchronization/lock.h"
     11 #include "content/common/content_export.h"
     12 #include "media/base/audio_renderer_sink.h"
     13 #include "third_party/WebKit/public/platform/WebAudioSourceProvider.h"
     14 #include "third_party/WebKit/public/platform/WebVector.h"
     15 
     16 namespace blink {
     17 class WebAudioSourceProviderClient;
     18 }
     19 
     20 namespace content {
     21 
     22 // WebAudioSourceProviderImpl provides a bridge between classes:
     23 //     blink::WebAudioSourceProvider <---> media::AudioRendererSink
     24 //
     25 // WebAudioSourceProviderImpl wraps an existing audio sink that is used unless
     26 // WebKit has set a client via setClient(). While a client is set WebKit will
     27 // periodically call provideInput() to render a certain number of audio
     28 // sample-frames using the sink's RenderCallback to get the data.
     29 //
     30 // All calls are protected by a lock.
     31 class CONTENT_EXPORT WebAudioSourceProviderImpl
     32     : NON_EXPORTED_BASE(public blink::WebAudioSourceProvider),
     33       NON_EXPORTED_BASE(public media::AudioRendererSink) {
     34  public:
     35   explicit WebAudioSourceProviderImpl(
     36       const scoped_refptr<media::AudioRendererSink>& sink);
     37 
     38   // blink::WebAudioSourceProvider implementation.
     39   virtual void setClient(blink::WebAudioSourceProviderClient* client);
     40   virtual void provideInput(const blink::WebVector<float*>& audio_data,
     41                             size_t number_of_frames);
     42 
     43   // media::AudioRendererSink implementation.
     44   virtual void Start() OVERRIDE;
     45   virtual void Stop() OVERRIDE;
     46   virtual void Play() OVERRIDE;
     47   virtual void Pause() OVERRIDE;
     48   virtual bool SetVolume(double volume) OVERRIDE;
     49   virtual void Initialize(const media::AudioParameters& params,
     50                           RenderCallback* renderer) OVERRIDE;
     51 
     52  protected:
     53   virtual ~WebAudioSourceProviderImpl();
     54 
     55  private:
     56   // Calls setFormat() on |client_| from the Blink renderer thread.
     57   void OnSetFormat();
     58 
     59   base::WeakPtrFactory<WebAudioSourceProviderImpl> weak_this_;
     60 
     61   // Closure that posts a task to call OnSetFormat() on the renderer thread.
     62   base::Closure set_format_cb_;
     63 
     64   // Set to true when Initialize() is called.
     65   int channels_;
     66   int sample_rate_;
     67   double volume_;
     68 
     69   // Tracks the current playback state.
     70   enum PlaybackState { kStopped, kStarted, kPlaying };
     71   PlaybackState state_;
     72 
     73   // Where audio comes from.
     74   media::AudioRendererSink::RenderCallback* renderer_;
     75 
     76   // When set via setClient() it overrides |sink_| for consuming audio.
     77   blink::WebAudioSourceProviderClient* client_;
     78 
     79   // Where audio ends up unless overridden by |client_|.
     80   base::Lock sink_lock_;
     81   scoped_refptr<media::AudioRendererSink> sink_;
     82   scoped_ptr<media::AudioBus> bus_wrapper_;
     83 
     84   DISALLOW_IMPLICIT_CONSTRUCTORS(WebAudioSourceProviderImpl);
     85 };
     86 
     87 }  // namespace content
     88 
     89 #endif  // CONTENT_RENDERER_MEDIA_WEBAUDIOSOURCEPROVIDER_IMPL_H_
     90