Move many calls of lazyInitialize() from AudioContext to AudioNode.

Source/modules/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 169 matching lines @@
 }
 
 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()) {
                 m_destinationNode->initialize();
-

[Raymond Toy, 2014/04/01 17:49:49]

Don't gratuitously delete (or add) blank lines. 

[KhNo, 2014/04/01 18:25:08]

Done.

                 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;
             }
-            m_isInitialized = true;

[Raymond Toy, 2014/04/01 17:49:49]

Why is this moved up?

[KhNo, 2014/04/01 18:25:08]

It should be inside if (m_destinationNode.get())
{m_destinationNode->initialize(); ........ }
Currently, if lazyInitialize() is called once without actual
m_destinationNode->initialize();
next calling is just return. When I create this patch, I meet this issue on
creating AudioDestinationNode.

[Raymond Toy, 2014/04/01 20:20:30]

Ah. So it's because the destination node is created but not initialized until
some audio node is created which calls lazyInitialize. 

Adding a comment would be useful here or near the if (m_destinationNode.get())
line.

         }
     }
 }
 
 void AudioContext::clear()
 {
     // We have to release our reference to the destination node before the context will ever be deleted since the destination node holds a reference to the context.
     if (m_destinationNode)
         m_destinationNode.clear();
 
@@ skipping 126 matching lines @@
         exceptionState.throwDOMException(
             SyntaxError,
             "invalid ArrayBuffer for audioData.");
         return;
     }
     m_audioDecoder.decodeAsync(audioData, sampleRate(), successCallback, errorCallback);
 }
 
 PassRefPtr<AudioBufferSourceNode> AudioContext::createBufferSource()
 {
     ASSERT(isMainThread());

[Raymond Toy, 2014/04/01 17:49:49]

Should the ASSERT be moved to lazyInitialize?

[KhNo, 2014/04/01 18:25:08]

It couldn't. Those function can be called internally with wrong use.

ASSERT(isMainThread()); gives to developer that should be called on main thread.
If we move it to lazyIntialize, readability might be less

[Raymond Toy, 2014/04/01 20:20:30]

Ok. Same could be said for lazyInitialize. Now some magic happens inside the
AudioNode to initialize the context. The current code makes it clear. Your
proposal hides that magic initialization. I'll have to think about this.

-    lazyInitialize();
     RefPtr<AudioBufferSourceNode> node = AudioBufferSourceNode::create(this, m_destinationNode->sampleRate());
 
     // Because this is an AudioScheduledSourceNode, the context keeps a reference until it has finished playing.
     // When this happens, AudioScheduledSourceNode::finish() calls AudioContext::notifyNodeFinishedProcessing().
     refNode(node.get());
 
     return node;
 }
 
 PassRefPtr<MediaElementAudioSourceNode> AudioContext::createMediaElementSource(HTMLMediaElement* mediaElement, ExceptionState& exceptionState)
 {
+    ASSERT(isMainThread());
     if (!mediaElement) {
         exceptionState.throwDOMException(
             InvalidStateError,
             "invalid HTMLMedialElement.");
         return nullptr;
     }
 
-    ASSERT(isMainThread());

[Raymond Toy, 2014/04/01 17:49:49]

This ASSERT should probably not have been removed.

[KhNo, 2014/04/01 18:25:08]

It doesn't removed, Just move to top of function same as others.
When "if (!mediaElement) ......" was added, it should have added under
ASSERT(thread checking)

-    lazyInitialize();
-
     // First check if this media element already has a source node.
     if (mediaElement->audioSourceNode()) {
         exceptionState.throwDOMException(
             InvalidStateError,
             "invalid HTMLMediaElement.");
         return nullptr;
     }
 
     RefPtr<MediaElementAudioSourceNode> node = MediaElementAudioSourceNode::create(this, mediaElement);
 
     mediaElement->setAudioSourceNode(node.get());
 
     refNode(node.get()); // context keeps reference until node is disconnected
     return node;
 }
 
 PassRefPtr<MediaStreamAudioSourceNode> AudioContext::createMediaStreamSource(MediaStream* mediaStream, ExceptionState& exceptionState)
 {
+    ASSERT(isMainThread());
     if (!mediaStream) {
         exceptionState.throwDOMException(
             InvalidStateError,
             "invalid MediaStream source");
         return nullptr;
     }
 
-    ASSERT(isMainThread());

[Raymond Toy, 2014/04/01 17:49:49]

This ASSERT should not have been removed.

[KhNo, 2014/04/01 18:25:08]

ditto

-    lazyInitialize();
-
     MediaStreamTrackVector audioTracks = mediaStream->getAudioTracks();
     if (audioTracks.isEmpty()) {
         exceptionState.throwDOMException(
             InvalidStateError,
             "MediaStream has no audio track");
         return nullptr;
     }
 
     // Use the first audio track in the media stream.
     RefPtr<MediaStreamTrack> audioTrack = audioTracks[0];
@@ skipping 27 matching lines @@
 
 PassRefPtr<ScriptProcessorNode> AudioContext::createScriptProcessor(size_t bufferSize, size_t numberOfInputChannels, ExceptionState& exceptionState)
 {
     // Set number of output channels to stereo by default.
     return createScriptProcessor(bufferSize, numberOfInputChannels, 2, exceptionState);
 }
 
 PassRefPtr<ScriptProcessorNode> AudioContext::createScriptProcessor(size_t bufferSize, size_t numberOfInputChannels, size_t numberOfOutputChannels, ExceptionState& exceptionState)
 {
     ASSERT(isMainThread());
-    lazyInitialize();
     RefPtr<ScriptProcessorNode> node = ScriptProcessorNode::create(this, m_destinationNode->sampleRate(), bufferSize, numberOfInputChannels, numberOfOutputChannels);
 
     if (!node.get()) {
         if (!numberOfInputChannels && !numberOfOutputChannels) {
             exceptionState.throwDOMException(
                 IndexSizeError,
                 "number of input channels and output channels cannot both be zero.");
         } else if (numberOfInputChannels > AudioContext::maxNumberOfChannels()) {
             exceptionState.throwDOMException(
                 IndexSizeError,
@@ skipping 15 matching lines @@
         return nullptr;
     }
 
     refNode(node.get()); // context keeps reference until we stop making javascript rendering callbacks
     return node;
 }
 
 PassRefPtr<BiquadFilterNode> AudioContext::createBiquadFilter()
 {
     ASSERT(isMainThread());
-    lazyInitialize();
     return BiquadFilterNode::create(this, m_destinationNode->sampleRate());
 }
 
 PassRefPtr<WaveShaperNode> AudioContext::createWaveShaper()
 {
     ASSERT(isMainThread());
-    lazyInitialize();
     return WaveShaperNode::create(this);
 }
 
 PassRefPtr<PannerNode> AudioContext::createPanner()
 {
     ASSERT(isMainThread());
-    lazyInitialize();
     return PannerNode::create(this, m_destinationNode->sampleRate());
 }
 
 PassRefPtr<ConvolverNode> AudioContext::createConvolver()
 {
     ASSERT(isMainThread());
-    lazyInitialize();
     return ConvolverNode::create(this, m_destinationNode->sampleRate());
 }
 
 PassRefPtr<DynamicsCompressorNode> AudioContext::createDynamicsCompressor()
 {
     ASSERT(isMainThread());
-    lazyInitialize();
     return DynamicsCompressorNode::create(this, m_destinationNode->sampleRate());
 }
 
 PassRefPtr<AnalyserNode> AudioContext::createAnalyser()
 {
     ASSERT(isMainThread());
-    lazyInitialize();
     return AnalyserNode::create(this, m_destinationNode->sampleRate());
 }
 
 PassRefPtr<GainNode> AudioContext::createGain()
 {
     ASSERT(isMainThread());
-    lazyInitialize();
     return GainNode::create(this, m_destinationNode->sampleRate());
 }
 
 PassRefPtr<DelayNode> AudioContext::createDelay(ExceptionState& exceptionState)
 {
     const double defaultMaxDelayTime = 1;
     return createDelay(defaultMaxDelayTime, exceptionState);
 }
 
 PassRefPtr<DelayNode> AudioContext::createDelay(double maxDelayTime, ExceptionState& exceptionState)
 {
     ASSERT(isMainThread());
-    lazyInitialize();
     RefPtr<DelayNode> node = DelayNode::create(this, m_destinationNode->sampleRate(), maxDelayTime, exceptionState);
     if (exceptionState.hadException())
         return nullptr;
     return node;
 }
 
 PassRefPtr<ChannelSplitterNode> AudioContext::createChannelSplitter(ExceptionState& exceptionState)
 {
     const unsigned ChannelSplitterDefaultNumberOfOutputs = 6;
     return createChannelSplitter(ChannelSplitterDefaultNumberOfOutputs, exceptionState);
 }
 
 PassRefPtr<ChannelSplitterNode> AudioContext::createChannelSplitter(size_t numberOfOutputs, ExceptionState& exceptionState)
 {
     ASSERT(isMainThread());
-    lazyInitialize();
-
     RefPtr<ChannelSplitterNode> node = ChannelSplitterNode::create(this, m_destinationNode->sampleRate(), numberOfOutputs);
 
     if (!node.get()) {
         exceptionState.throwDOMException(
             IndexSizeError,
             "number of outputs (" + String::number(numberOfOutputs)
             + ") must be between 1 and "
             + String::number(AudioContext::maxNumberOfChannels()) + ".");
         return nullptr;
     }
 
     return node;
 }
 
 PassRefPtr<ChannelMergerNode> AudioContext::createChannelMerger(ExceptionState& exceptionState)
 {
     const unsigned ChannelMergerDefaultNumberOfInputs = 6;
     return createChannelMerger(ChannelMergerDefaultNumberOfInputs, exceptionState);
 }
 
 PassRefPtr<ChannelMergerNode> AudioContext::createChannelMerger(size_t numberOfInputs, ExceptionState& exceptionState)
 {
     ASSERT(isMainThread());
-    lazyInitialize();
-
     RefPtr<ChannelMergerNode> node = ChannelMergerNode::create(this, m_destinationNode->sampleRate(), numberOfInputs);
 
     if (!node.get()) {
         exceptionState.throwDOMException(
             IndexSizeError,
             "number of inputs (" + String::number(numberOfInputs)
             + ") must be between 1 and "
             + String::number(AudioContext::maxNumberOfChannels()) + ".");
         return nullptr;
     }
 
     return node;
 }
 
 PassRefPtr<OscillatorNode> AudioContext::createOscillator()
 {
     ASSERT(isMainThread());
-    lazyInitialize();
-
     RefPtr<OscillatorNode> node = OscillatorNode::create(this, m_destinationNode->sampleRate());
 
     // Because this is an AudioScheduledSourceNode, the context keeps a reference until it has finished playing.
     // When this happens, AudioScheduledSourceNode::finish() calls AudioContext::notifyNodeFinishedProcessing().
     refNode(node.get());
 
     return node;
 }
 
 PassRefPtr<PeriodicWave> AudioContext::createPeriodicWave(Float32Array* real, Float32Array* imag, ExceptionState& exceptionState)
 {
     ASSERT(isMainThread());
-

[Raymond Toy, 2014/04/01 17:49:49]

Don't gratuitously delete (or add) blank lines.

[KhNo, 2014/04/01 18:25:08]

Done.

     if (!real) {
         exceptionState.throwDOMException(
             SyntaxError,
             "invalid real array");
         return nullptr;
     }
 
     if (!imag) {
         exceptionState.throwDOMException(
             SyntaxError,
@@ skipping 19 matching lines @@
     }
 
     if (imag->length() > 4096) {
         exceptionState.throwDOMException(
             IndexSizeError,
             "length of imaginary array (" + String::number(imag->length())
             + ") exceeds allowed maximum of 4096");
         return nullptr;
     }
 
-    lazyInitialize();
     return PeriodicWave::create(sampleRate(), real, imag);
 }
 
 void AudioContext::notifyNodeFinishedProcessing(AudioNode* node)
 {
     ASSERT(isAudioThread());
     m_finishedNodes.append(node);
 }
 
 void AudioContext::derefFinishedSourceNodes()
@@ skipping 376 matching lines @@
 }
 
 void AudioContext::decrementActiveSourceCount()
 {
     atomicDecrement(&m_activeSourceCount);
 }
 
 } // namespace WebCore
 
 #endif // ENABLE(WEB_AUDIO)