[DO NOT SUBMIT] AudioWorklet FS2: audio thread

third_party/WebKit/Source/platform/audio/AudioPullFIFO.h

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 18 matching lines @@
 #ifndef AudioPullFIFO_h
 #define AudioPullFIFO_h
 
 #include "platform/audio/AudioBus.h"
 #include "platform/audio/AudioFIFO.h"
 #include "platform/audio/AudioSourceProvider.h"
 #include "wtf/Allocator.h"
 
 namespace blink {
 
-// A FIFO (First In First Out) buffer to handle mismatches in buffer sizes between a provider and
-// receiver. The receiver will "pull" data from this FIFO. If data is already available in the
-// FIFO, it is provided to the receiver. If insufficient data is available to satisfy the request,
-// the FIFO will ask the provider for more data when necessary to fulfill a request. Contrast this
-// with a "push" FIFO, where the sender pushes data to the FIFO which will itself push the data to
-// the receiver when the FIFO is full.
+// A FIFO (First In First Out) buffer to handle mismatches in buffer sizes
+// between a provider and consumer. The consumer will "pull" data from this
+// FIFO. If data is already available in the FIFO, it is provided to the
+// consumer. If available data is insufficient to satisfy the request, the FIFO
+// will ask the provider for more data until it is enough to fulfill a request.
+//
+//                 Provider           (e.g destination node)
+//                    | (pull)
+//                    v
+//              AudioPullFIFO
+//                    | (consume)
+//                    v
+//                 Consumer           (e.g. AudioRenderSink)
+//
 class PLATFORM_EXPORT AudioPullFIFO {
     USING_FAST_MALLOC(AudioPullFIFO);
     WTF_MAKE_NONCOPYABLE(AudioPullFIFO);
+
 public:
-    // Create a FIFO that gets data from |provider|. The FIFO will be large enough to hold
-    // |fifoLength| frames of data of |numberOfChannels| channels. The AudioSourceProvider will be
-    // asked to produce |providerSize| frames when the FIFO needs more data.
-    AudioPullFIFO(AudioSourceProvider& audioProvider, unsigned numberOfChannels, size_t fifoLength, size_t providerSize);
+    // Create a FIFO that gets data from |provider|. The FIFO will be large
+    // enough to hold |fifoBufferLength| frames of data of |numberOfChannels|
+    // channels. The AudioSourceProvider will be asked to produce
+    // |providerRenderBlockSize| frames when the FIFO needs more data.
+    AudioPullFIFO(unsigned numberOfChannels, size_t fifoBufferLength, AudioSourceProvider&, size_t providerRenderBlockSize);
 
-    // Read |framesToConsume| frames from the FIFO into the destination. If the FIFO does not have
-    // enough data, we ask the |provider| to get more data to fulfill the request.
+    // Read |framesToConsume| frames from the FIFO into the destination. If the
+    // FIFO does not have enough data, it asks the |provider| to get more data
+    // to fulfill the request.
     void consume(AudioBus* destination, size_t framesToConsume);
 
 private:
-    // Fill the FIFO buffer with at least |numberOfFrames| more data.
-    void fillBuffer(size_t numberOfFrames);
+    // Request more data of |numberOfFrames| from provider to fill the FIFO
+    // buffer.
+    void requestDataFromProvider(size_t numberOfFrames);
+
+    // Number of frames of data that the provider will produce per call.
+    unsigned m_providerRenderBlockSize;
 
     // The provider of the data in our FIFO.
     AudioSourceProvider& m_provider;
 
-    // The actual FIFO
+    // Temporary audio bus reference to transfer the data from the provider.
+    RefPtr<AudioBus> m_tempBus;
+
+    // The actual FIFO.
     AudioFIFO m_fifo;
-
-    // Number of frames of data that the provider will produce per call.
-    unsigned m_providerSize;
-
-    // Temporary workspace to hold the data from the provider.
-    RefPtr<AudioBus> m_tempBus;
 };
 
 } // namespace blink
 
 #endif // AudioPullFIFO.h