Support multiple HRTFDatabases for different sample-rates

Source/modules/webaudio/PannerNode.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.
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  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 126 matching lines @@
 {
     m_lastGain = -1.0; // force to snap to initial gain
     if (m_panner.get())
         m_panner->reset();
 }
 
 void PannerNode::initialize()
 {
     if (isInitialized())
         return;
-        
-    m_panner = Panner::create(m_panningModel, sampleRate());
+
+    HRTFDatabase* database = context()->hrtfDatabaseLoader()->database();

[Ken Russell (switch to Gerrit), 2013/05/11 01:35:16]

There's a race condition in the fetching of the HRTFDatabase from the
HRTFDatabaseLoader. Since the HRTFDatabaseLoader creates the HRTFDatabase from
its database loader thread, there's a possibility that the database() method
call here will return NULL. To guard against this, it seems to me that the
Panner should probably take an HRTFDatabaseLoader as argument rather than an
HRTFDatabase. What do you think?

[Chris Rogers, 2013/05/13 20:05:22]

Good point, I'll switch this back to the previous behavior where the HRTFPanner
deals with the loader itself...

Fixed.

+    m_panner = Panner::create(m_panningModel, sampleRate(), database);
 
     AudioNode::initialize();
 }
 
 void PannerNode::uninitialize()
 {
     if (!isInitialized())
         return;
         
     m_panner.clear();
@@ skipping 33 matching lines @@
 }
 
 bool PannerNode::setPanningModel(unsigned model)
 {
     switch (model) {
     case EQUALPOWER:
     case HRTF:
         if (!m_panner.get() || model != m_panningModel) {
             // This synchronizes with process().
             MutexLocker processLocker(m_pannerLock);
-            
-            OwnPtr<Panner> newPanner = Panner::create(model, sampleRate());
+
+            HRTFDatabase* database = context()->hrtfDatabaseLoader()->database();
+            OwnPtr<Panner> newPanner = Panner::create(model, sampleRate(), database);
             m_panner = newPanner.release();
             m_panningModel = model;
         }
         break;
     case SOUNDFIELD:
         // FIXME: Implement sound field model. See // https://bugs.webkit.org/show_bug.cgi?id=77367.
         context()->scriptExecutionContext()->addConsoleMessage(JSMessageSource, WarningMessageLevel, "'soundfield' panning model not implemented.");
         break;
     default:
         return false;
@@ skipping 194 matching lines @@
                 AudioNode* connectedNode = connectedOutput->node();
                 notifyAudioSourcesConnectedToNode(connectedNode); // recurse
             }
         }
     }
 }
 
 } // namespace WebCore
 
 #endif // ENABLE(WEB_AUDIO)