Support for AudioContextOptions latencyHint.

third_party/WebKit/Source/modules/webaudio/BaseAudioContext.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 @@
 #include "core/frame/Settings.h"
 #include "core/html/HTMLMediaElement.h"
 #include "core/inspector/ConsoleMessage.h"
 #include "core/inspector/ConsoleTypes.h"
 #include "modules/mediastream/MediaStream.h"
 #include "modules/webaudio/AnalyserNode.h"
 #include "modules/webaudio/AudioBuffer.h"
 #include "modules/webaudio/AudioBufferCallback.h"
 #include "modules/webaudio/AudioBufferSourceNode.h"
 #include "modules/webaudio/AudioContext.h"
+#include "modules/webaudio/AudioContextOptions.h"
 #include "modules/webaudio/AudioListener.h"
 #include "modules/webaudio/AudioNodeInput.h"
 #include "modules/webaudio/AudioNodeOutput.h"
 #include "modules/webaudio/BiquadFilterNode.h"
 #include "modules/webaudio/ChannelMergerNode.h"
 #include "modules/webaudio/ChannelSplitterNode.h"
 #include "modules/webaudio/ConstantSourceNode.h"
 #include "modules/webaudio/ConvolverNode.h"
 #include "modules/webaudio/DefaultAudioDestinationNode.h"
 #include "modules/webaudio/DelayNode.h"
@@ skipping 11 matching lines @@
 #include "modules/webaudio/PeriodicWave.h"
 #include "modules/webaudio/PeriodicWaveConstraints.h"
 #include "modules/webaudio/ScriptProcessorNode.h"
 #include "modules/webaudio/StereoPannerNode.h"
 #include "modules/webaudio/WaveShaperNode.h"
 #include "platform/CrossThreadFunctional.h"
 #include "platform/Histogram.h"
 #include "platform/UserGestureIndicator.h"
 #include "platform/audio/IIRFilter.h"
 #include "public/platform/Platform.h"
+#include "public/platform/WebAudioLatencyHint.h"
 #include "wtf/text/WTFString.h"
 
 namespace blink {
 
-BaseAudioContext* BaseAudioContext::create(Document& document,
-                                           ExceptionState& exceptionState) {
-  return AudioContext::create(document, exceptionState);
+BaseAudioContext* BaseAudioContext::create(
+    Document& document,
+    const WebAudioLatencyHint& latencyHint,
+    ExceptionState& exceptionState) {
+  return AudioContext::create(document, latencyHint, exceptionState);
 }
 
 // FIXME(dominicc): Devolve these constructors to AudioContext
 // and OfflineAudioContext respectively.
 
 // Constructor for rendering to the audio hardware.
-BaseAudioContext::BaseAudioContext(Document* document)
+BaseAudioContext::BaseAudioContext(Document* document,
+                                   const WebAudioLatencyHint& latencyHint)
     : ActiveScriptWrappable(this),
       ActiveDOMObject(document),
       m_destinationNode(nullptr),
       m_isCleared(false),
       m_isResolvingResumePromises(false),
       m_userGestureRequired(false),
       m_connectionCount(0),
       m_deferredTaskHandler(DeferredTaskHandler::create()),
       m_contextState(Suspended),
       m_closedContextSampleRate(-1),
       m_periodicWaveSine(nullptr),
       m_periodicWaveSquare(nullptr),
       m_periodicWaveSawtooth(nullptr),
       m_periodicWaveTriangle(nullptr) {
   // If mediaPlaybackRequiresUserGesture is enabled, cross origin iframes will
   // require user gesture for the AudioContext to produce sound.
   if (document->settings() &&
       document->settings()->mediaPlaybackRequiresUserGesture() &&
       document->frame() && document->frame()->isCrossOriginSubframe()) {
     m_autoplayStatus = AutoplayStatus::AutoplayStatusFailed;
     m_userGestureRequired = true;
   }
 
-  m_destinationNode = DefaultAudioDestinationNode::create(this);
+  m_destinationNode = DefaultAudioDestinationNode::create(this, latencyHint);
 
   initialize();
 }
 
 // Constructor for offline (non-realtime) rendering.
 BaseAudioContext::BaseAudioContext(Document* document,
                                    unsigned numberOfChannels,
                                    size_t numberOfFrames,
                                    float sampleRate)
     : ActiveScriptWrappable(this),
@@ skipping 457 matching lines @@
       return "suspended";
     case Running:
       return "running";
     case Closed:
       return "closed";
   }
   NOTREACHED();
   return "";
 }
 
+double BaseAudioContext::baseLatency() const {
+  return framesPerBuffer() * 2 / sampleRate();

[Raymond Toy, 2016/11/30 21:50:27]

Cast sampleRate() to double so that we get double arithmetic here.

[Andrew MacPherson, 2016/12/01 12:11:56]

Done.

+}
+
 void BaseAudioContext::setContextState(AudioContextState newState) {
   DCHECK(isMainThread());
 
   // Validate the transitions.  The valid transitions are Suspended->Running,
   // Running->Suspended, and anything->Closed.
   switch (newState) {
     case Suspended:
       DCHECK_EQ(m_contextState, Running);
       break;
     case Running:
@@ skipping 278 matching lines @@
 }
 
 SecurityOrigin* BaseAudioContext::getSecurityOrigin() const {
   if (getExecutionContext())
     return getExecutionContext()->getSecurityOrigin();
 
   return nullptr;
 }
 
 }  // namespace blink