[DO NOT SUBMIT] AudioWorklet FS2: audio thread

third_party/WebKit/Source/modules/webaudio/AudioDestinationNode.cpp

 /*
  * Copyright (C) 2010, 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
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 26 matching lines @@
     , m_currentSampleFrame(0)
 {
     addInput();
 }
 
 AudioDestinationHandler::~AudioDestinationHandler()
 {
     ASSERT(!isInitialized());
 }
 
-void AudioDestinationHandler::render(AudioBus* sourceBus, AudioBus* destinationBus, size_t numberOfFrames)
+void AudioDestinationHandler::render(AudioBus* sourceBus, AudioBus* destinationBus, size_t framesToProcess)
 {
-    // We don't want denormals slowing down any of the audio processing
-    // since they can very seriously hurt performance.
-    // This will take care of all AudioNodes because they all process within this scope.
+    // We don't want denormals slowing down any of the audio processing since
+    // they can very seriously hurt performance. This will take care of all
+    // AudioNodes because they all process within this scope.
     DenormalDisabler denormalDisabler;
 
     // Need to check if the context actually alive. Otherwise the subsequent
     // steps will fail. If the context is not alive somehow, return immediately
     // and do nothing.
     //
     // TODO(hongchan): because the context can go away while rendering, so this
     // check cannot guarantee the safe execution of the following steps.
     ASSERT(context());
     if (!context())
         return;
 
     context()->deferredTaskHandler().setAudioThreadToCurrentThread();
 
     // If the destination node is not initialized, pass the silence to the final
     // audio destination (one step before the FIFO). This check is for the case
     // where the destination is in the middle of tearing down process.
     if (!isInitialized()) {
         destinationBus->zero();
         return;
     }
 
-    // Let the context take care of any business at the start of each render quantum.
+    // Let the context take care of any business at the start of each render
+    // quantum.
     context()->handlePreRenderTasks();
 
     // Prepare the local audio input provider for this render quantum.
     if (sourceBus)
-        m_localAudioInputProvider.set(sourceBus);
+        m_localAudioInputProvider.setSourceBus(sourceBus);
 
     ASSERT(numberOfInputs() >= 1);
     if (numberOfInputs() < 1) {
         destinationBus->zero();
         return;
     }
-    // This will cause the node(s) connected to us to process, which in turn will pull on their input(s),
-    // all the way backwards through the rendering graph.
-    AudioBus* renderedBus = input(0).pull(destinationBus, numberOfFrames);
 
+    // This will cause the node(s) connected to us to process, which in turn
+    // will pull on their input(s), all the way backwards through the rendering
+    // graph.
+    AudioBus* renderedBus = input(0).pull(destinationBus, framesToProcess);
+
+    // TODO(hongchan): this logic should be a part of AudioNodeInput::pull().
     if (!renderedBus) {
         destinationBus->zero();
     } else if (renderedBus != destinationBus) {
-        // in-place processing was not possible - so copy
+        // If the destination node has multiple inputs, in-place processing is
+        // not possible. Thus the explicit copy is necessary.
         destinationBus->copyFrom(*renderedBus);
     }
 
-    // Process nodes which need a little extra help because they are not connected to anything, but still need to process.
-    context()->deferredTaskHandler().processAutomaticPullNodes(numberOfFrames);
+    // Process nodes which need a little extra help because they are not
+    // connected to anything, but still need to process.
+    context()->deferredTaskHandler().processAutomaticPullNodes(framesToProcess);
 
-    // Let the context take care of any business at the end of each render quantum.
+    // Let the context take care of any business at the end of each render
+    // quantum.
     context()->handlePostRenderTasks();
 
     // Advance current sample-frame.
-    size_t newSampleFrame = m_currentSampleFrame + numberOfFrames;
+    size_t newSampleFrame = m_currentSampleFrame + framesToProcess;
     releaseStore(&m_currentSampleFrame, newSampleFrame);
 }
 
 // ----------------------------------------------------------------
 
 AudioDestinationNode::AudioDestinationNode(AbstractAudioContext& context)
     : AudioNode(context)
 {
 }
 
 AudioDestinationHandler& AudioDestinationNode::audioDestinationHandler() const
 {
     return static_cast<AudioDestinationHandler&>(handler());
 }
 
 unsigned long AudioDestinationNode::maxChannelCount() const
 {
     return audioDestinationHandler().maxChannelCount();
 }
 
 } // namespace blink