HRTFDatabaseLoader is not an absolute condition to run audioContext

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.
  * 2.  Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 34 matching lines @@
     if (std::isnan(x) || std::isinf(x))
         x = 0.0;
 }
 
 PannerNode::PannerNode(AudioContext* context, float sampleRate)
     : AudioNode(context, sampleRate)
     , m_panningModel(Panner::PanningModelHRTF)
     , m_lastGain(-1.0)
     , m_connectionCount(0)
 {
+    // HRTFDatabaseLoader should be created and load database for pannerNode asynchronously.
+    m_hrtfDatabaseLoader = HRTFDatabaseLoader::createAndLoadAsynchronouslyIfNecessary(context->sampleRate());
+
     ScriptWrappable::init(this);
     addInput(adoptPtr(new AudioNodeInput(this)));
     addOutput(adoptPtr(new AudioNodeOutput(this, 2)));
 
     // Node-specific default mixing rules.
     m_channelCount = 2;
     m_channelCountMode = ClampedMax;
     m_channelInterpretation = AudioBus::Speakers;
 
     m_distanceGain = AudioParam::create(context, "distanceGain", 1.0, 0.0, 1.0);
@@ skipping 34 matching lines @@
 void PannerNode::process(size_t framesToProcess)
 {
     AudioBus* destination = output(0)->bus();
 
     if (!isInitialized() || !input(0)->isConnected() || !m_panner.get()) {
         destination->zero();
         return;
     }
 
     AudioBus* source = input(0)->bus();
-
     if (!source) {
         destination->zero();
         return;
     }
 
+    // HRTFDatabaseLoader and HRTFDatabase should be loaded before proceed.

[Raymond Toy (Google), 2014/02/24 23:01:22]

Comment seems incorrect.  Change "before proceed" to "before proceeding for an
offline audio context. "

Also, is it possible for the offline audio context to check for completion
instead of here?

[KhNo, 2014/02/25 02:00:25]

Yes. It seems to be not correct comment. I will fix it.

OfflineAudioDestination::offlinerender() had a wait loader completion logic, I
have moved it to here. This change means that checking routine of HRTFDatabase
on pannerNode itself be located before transferring processed buffers to next
node or destination on audio thread as previous code did. It just moves checking
time early.

+    if (!m_hrtfDatabaseLoader->isLoaded()) {
+        if (context()->isOfflineContext()) {
+            m_hrtfDatabaseLoader->waitForLoaderThreadCompletion();
+        } else {
+            destination->zero();
+            return;
+        }
+    }
+
     // The audio thread can't block on this lock, so we call tryLock() instead.
     MutexTryLocker tryLocker(m_pannerLock);
     if (tryLocker.locked()) {
         // Apply the panning effect.
         double azimuth;
         double elevation;
         getAzimuthElevation(&azimuth, &elevation);
         m_panner->pan(azimuth, elevation, source, destination, framesToProcess);
 
         // Get the distance and cone gain.
         double totalGain = distanceConeGain();
 
         // Snap to desired gain at the beginning.
         if (m_lastGain == -1.0)
             m_lastGain = totalGain;
 
         // Apply gain in-place with de-zippering.
         destination->copyWithGainFrom(*destination, &m_lastGain, totalGain);
     } else {
         // Too bad - The tryLock() failed. We must be in the middle of changing the panner.
         destination->zero();
     }
 }
 
 void PannerNode::initialize()
 {
     if (isInitialized())
         return;
 
-    m_panner = Panner::create(m_panningModel, sampleRate(), context()->hrtfDatabaseLoader());
+    m_panner = Panner::create(m_panningModel, sampleRate(), m_hrtfDatabaseLoader.get());
 
     AudioNode::initialize();
 }
 
 void PannerNode::uninitialize()
 {
     if (!isInitialized())
         return;
 
     m_panner.clear();
@@ skipping 34 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(), context()->hrtfDatabaseLoader());
+            OwnPtr<Panner> newPanner = Panner::create(model, sampleRate(), m_hrtfDatabaseLoader.get());
             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()->executionContext()->addConsoleMessage(JSMessageSource, WarningMessageLevel, "'soundfield' panning model not implemented.");
         break;
     default:
         return false;
@@ skipping 201 matching lines @@
                     notifyAudioSourcesConnectedToNode(connectedNode, visitedNodes); // recurse
                 }
             }
         }
     }
 }
 
 } // namespace WebCore
 
 #endif // ENABLE(WEB_AUDIO)