Merge 91801 - AudioContext is not correctly accounting for hardware resources

Source/WebCore/webaudio/AudioContext.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 75 matching lines @@
 // Don't allow more than this number of simultaneous AudioContexts talking to hardware.
 const unsigned MaxHardwareContexts = 4;
 unsigned AudioContext::s_hardwareContextCount = 0;
     
 PassRefPtr<AudioContext> AudioContext::create(Document* document)
 {
     ASSERT(document);
     ASSERT(isMainThread());
     if (s_hardwareContextCount >= MaxHardwareContexts)
         return 0;
-
-    ++s_hardwareContextCount;
         
     return adoptRef(new AudioContext(document));
 }
 
 PassRefPtr<AudioContext> AudioContext::createOfflineContext(Document* document, unsigned numberOfChannels, size_t numberOfFrames, double sampleRate, ExceptionCode& ec)
 {
     ASSERT(document);
 
     // FIXME: offline contexts have limitations on supported sample-rates.
     // Currently all AudioContexts must have the same sample-rate.
@@ skipping 20 matching lines @@
 {
     constructCommon();
 
     m_destinationNode = DefaultAudioDestinationNode::create(this);
 
     // This sets in motion an asynchronous loading mechanism on another thread.
     // We can check m_hrtfDatabaseLoader->isLoaded() to find out whether or not it has been fully loaded.
     // It's not that useful to have a callback function for this since the audio thread automatically starts rendering on the graph
     // when this has finished (see AudioDestinationNode).
     m_hrtfDatabaseLoader = HRTFDatabaseLoader::createAndLoadAsynchronouslyIfNecessary(sampleRate());
-
-    // FIXME: for now default AudioContext does not need an explicit startRendering() call.
-    // We may want to consider requiring it for symmetry with OfflineAudioContext
-    m_destinationNode->startRendering();
 }
 
 // Constructor for offline (non-realtime) rendering.
 AudioContext::AudioContext(Document* document, unsigned numberOfChannels, size_t numberOfFrames, double sampleRate)
     : ActiveDOMObject(document, this)
     , m_isInitialized(false)
     , m_isAudioThreadFinished(false)
     , m_document(document)
     , m_destinationNode(0)
     , m_connectionCount(0)
@@ skipping 35 matching lines @@
     ASSERT(!m_finishedNodes.size());
 }
 
 void AudioContext::lazyInitialize()
 {
     if (!m_isInitialized) {
         // Don't allow the context to initialize a second time after it's already been explicitly uninitialized.
         ASSERT(!m_isAudioThreadFinished);
         if (!m_isAudioThreadFinished) {
             if (m_destinationNode.get()) {
-                // This starts the audio thread.  The destination node's provideInput() method will now be called repeatedly to render audio.
-                // Each time provideInput() is called, a portion of the audio stream is rendered.  Let's call this time period a "render quantum".
                 m_destinationNode->initialize();
+
+                if (!isOfflineContext()) {
+                    // This starts the audio thread. The destination node's provideInput() method will now be called repeatedly to render audio.
+                    // Each time provideInput() is called, a portion of the audio stream is rendered. Let's call this time period a "render quantum".
+                    // NOTE: for now default AudioContext does not need an explicit startRendering() call from JavaScript.
+                    // We may want to consider requiring it for symmetry with OfflineAudioContext.
+                    m_destinationNode->startRendering();                    
+                    ++s_hardwareContextCount;
+                }
+
             }
             m_isInitialized = true;
         }
     }
 }
 
 void AudioContext::uninitialize()
 {
     ASSERT(isMainThread());
 
@@ skipping 474 matching lines @@
     // Avoid firing the event if the document has already gone away.
     if (hasDocument()) {
         // Call the offline rendering completion event listener.
         dispatchEvent(OfflineAudioCompletionEvent::create(renderedBuffer));
     }
 }
 
 } // namespace WebCore
 
 #endif // ENABLE(WEB_AUDIO)