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 "base/callback.h"
   9 #include "base/memory/weak_ptr.h"
  10 #include "base/synchronization/lock.h"
  11 #include "media/base/audio_renderer_sink.h"
  12 #include "media/base/media_export.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 media {
  21
  22 // WebAudioSourceProviderImpl provides a bridge between classes:
  23 //     blink::WebAudioSourceProvider <---> 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 MEDIA_EXPORT WebAudioSourceProviderImpl
  32     : NON_EXPORTED_BASE(public blink::WebAudioSourceProvider),
  33       NON_EXPORTED_BASE(public AudioRendererSink) {
  34  public:
  35   explicit WebAudioSourceProviderImpl(
  36       const scoped_refptr<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   // AudioRendererSink implementation.
  44   void Start() override;
  45   void Stop() override;
  46   void Play() override;
  47   void Pause() override;
  48   bool SetVolume(double volume) override;
  49   void Initialize(const 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   // Closure that posts a task to call OnSetFormat() on the renderer thread.
  60   base::Closure set_format_cb_;
  61
  62   // Set to true when Initialize() is called.
  63   int channels_;
  64   int sample_rate_;
  65   double volume_;
  66
  67   // Tracks the current playback state.
  68   enum PlaybackState { kStopped, kStarted, kPlaying };
  69   PlaybackState state_;
  70
  71   // Where audio comes from.
  72   AudioRendererSink::RenderCallback* renderer_;
  73
  74   // When set via setClient() it overrides |sink_| for consuming audio.
  75   blink::WebAudioSourceProviderClient* client_;
  76
  77   // Where audio ends up unless overridden by |client_|.
  78   base::Lock sink_lock_;
  79   scoped_refptr<AudioRendererSink> sink_;
  80   scoped_ptr<AudioBus> bus_wrapper_;
  81
  82   // NOTE: Weak pointers must be invalidated before all other member variables.
  83   base::WeakPtrFactory<WebAudioSourceProviderImpl> weak_factory_;
  84
  85   DISALLOW_IMPLICIT_CONSTRUCTORS(WebAudioSourceProviderImpl);
  86 };
  87
  88 }  // namespace media
  89
  90 #endif  // MEDIA_BLINK_WEBAUDIOSOURCEPROVIDER_IMPL_H_