media/blink/webaudiosourceprovider_impl.h

   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 MEDIA_BLINK_WEBAUDIOSOURCEPROVIDER_IMPL_H_
   6 #define MEDIA_BLINK_WEBAUDIOSOURCEPROVIDER_IMPL_H_
   7
   8 #include <string>
   9
  10 #include "base/callback.h"
  11 #include "base/memory/weak_ptr.h"
  12 #include "base/synchronization/lock.h"
  13 #include "media/base/audio_renderer_sink.h"
  14 #include "media/base/media_export.h"
  15 #include "third_party/WebKit/public/platform/WebAudioSourceProvider.h"
  16 #include "third_party/WebKit/public/platform/WebVector.h"
  17
  18 namespace blink {
  19 class WebAudioSourceProviderClient;
  20 }
  21
  22 namespace media {
  23
  24 // WebAudioSourceProviderImpl provides a bridge between classes:
  25 //     blink::WebAudioSourceProvider <---> AudioRendererSink
  26 //
  27 // WebAudioSourceProviderImpl wraps an existing audio sink that is used unless
  28 // WebKit has set a client via setClient(). While a client is set WebKit will
  29 // periodically call provideInput() to render a certain number of audio
  30 // sample-frames using the sink's RenderCallback to get the data.
  31 //
  32 // All calls are protected by a lock.
  33 class MEDIA_EXPORT WebAudioSourceProviderImpl
  34     : NON_EXPORTED_BASE(public blink::WebAudioSourceProvider),
  35       NON_EXPORTED_BASE(public AudioRendererSink) {
  36  public:
  37   explicit WebAudioSourceProviderImpl(
  38       const scoped_refptr<AudioRendererSink>& sink);
  39
  40   // blink::WebAudioSourceProvider implementation.
  41   virtual void setClient(blink::WebAudioSourceProviderClient* client);
  42   virtual void provideInput(const blink::WebVector<float*>& audio_data,
  43                             size_t number_of_frames);
  44
  45   // AudioRendererSink implementation.
  46   void Start() override;
  47   void Stop() override;
  48   void Play() override;
  49   void Pause() override;
  50   bool SetVolume(double volume) override;
  51   OutputDevice* GetOutputDevice() override;
  52   void Initialize(const AudioParameters& params,
  53                   RenderCallback* renderer) override;
  54
  55  protected:
  56   virtual ~WebAudioSourceProviderImpl();
  57
  58  private:
  59   // Calls setFormat() on |client_| from the Blink renderer thread.
  60   void OnSetFormat();
  61
  62   // Closure that posts a task to call OnSetFormat() on the renderer thread.
  63   base::Closure set_format_cb_;
  64
  65   // Set to true when Initialize() is called.
  66   int channels_;
  67   int sample_rate_;
  68   double volume_;
  69
  70   // Tracks the current playback state.
  71   enum PlaybackState { kStopped, kStarted, kPlaying };
  72   PlaybackState state_;
  73
  74   // Where audio comes from.
  75   AudioRendererSink::RenderCallback* renderer_;
  76
  77   // When set via setClient() it overrides |sink_| for consuming audio.
  78   blink::WebAudioSourceProviderClient* client_;
  79
  80   // Where audio ends up unless overridden by |client_|.
  81   base::Lock sink_lock_;
  82   scoped_refptr<AudioRendererSink> sink_;
  83   scoped_ptr<AudioBus> bus_wrapper_;
  84
  85   // NOTE: Weak pointers must be invalidated before all other member variables.
  86   base::WeakPtrFactory<WebAudioSourceProviderImpl> weak_factory_;
  87
  88   DISALLOW_IMPLICIT_CONSTRUCTORS(WebAudioSourceProviderImpl);
  89 };
  90
  91 }  // namespace media
  92
  93 #endif  // MEDIA_BLINK_WEBAUDIOSOURCEPROVIDER_IMPL_H_