Implementation of 'AudioContext.getOutputTimestamp' method

third_party/WebKit/Source/modules/webaudio/AbstractAudioContext.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 14 matching lines @@
 #include "modules/webaudio/AbstractAudioContext.h"
 #include "bindings/core/v8/Dictionary.h"
 #include "bindings/core/v8/ExceptionMessages.h"
 #include "bindings/core/v8/ExceptionState.h"
 #include "bindings/core/v8/ScriptPromiseResolver.h"
 #include "bindings/core/v8/ScriptState.h"
 #include "core/dom/DOMException.h"
 #include "core/dom/Document.h"
 #include "core/dom/ExceptionCode.h"
 #include "core/dom/ExecutionContextTask.h"
+#include "core/frame/LocalDOMWindow.h"
 #include "core/frame/Settings.h"
 #include "core/html/HTMLMediaElement.h"
+#include "core/timing/DOMWindowPerformance.h"
+#include "core/timing/Performance.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/AudioListener.h"
 #include "modules/webaudio/AudioNodeInput.h"
 #include "modules/webaudio/AudioNodeOutput.h"
+#include "modules/webaudio/AudioTimestamp.h"
 #include "modules/webaudio/BiquadFilterNode.h"
 #include "modules/webaudio/ChannelMergerNode.h"
 #include "modules/webaudio/ChannelSplitterNode.h"
 #include "modules/webaudio/ConvolverNode.h"
 #include "modules/webaudio/DefaultAudioDestinationNode.h"
 #include "modules/webaudio/DelayNode.h"
 #include "modules/webaudio/DynamicsCompressorNode.h"
 #include "modules/webaudio/GainNode.h"
 #include "modules/webaudio/IIRFilterNode.h"
 #include "modules/webaudio/MediaElementAudioSourceNode.h"
@@ skipping 497 matching lines @@
         return;
     }
     if (!UserGestureIndicator::processingUserGesture()) {
         userGestureHistogram.count(UserGestureRequiredAndNotAvailable);
         return;
     }
     userGestureHistogram.count(UserGestureRequiredAndAvailable);
     m_userGestureRequired = false;
 }
 
+static double toPerformanceTime(ExecutionContext* context, double seconds)
+{
+    LocalDOMWindow* window = context ? context->executingWindow() : nullptr;

[Raymond Toy, 2016/06/14 16:42:40]

Why not just early return with 0.0 if the context doesn't exist? Similarly if
the window doesn't exist.

[Mikhail, 2016/06/17 09:36:57]

Done.

+    Performance* performance = window ? DOMWindowPerformance::performance(*window) : nullptr;
+    return performance ? performance->monotonicTimeToDOMHighResTimeStamp(seconds) : 0.0;
+}
+
+void AbstractAudioContext::getOutputTimestamp(AudioTimestamp& result)
+{
+    if (!m_destinationNode) {
+        result.setContextTime(0.0);
+        result.setPerformanceTime(0.0);
+        return;
+    }
+    AudioDestinationHandler& destinationHandler = m_destinationNode->audioDestinationHandler();
+
+    WebAudioTimestamp outputTimestamp = destinationHandler.outputTimestamp();
+    double contextTime = outputTimestamp.frames / static_cast<double>(destinationHandler.sampleRate());
+    double performanceTime = outputTimestamp.seconds ? toPerformanceTime(getExecutionContext(), outputTimestamp.seconds) : 0.0;
+
+    result.setContextTime(contextTime);
+    result.setPerformanceTime(performanceTime);
+}
+
 String AbstractAudioContext::state() const
 {
     // These strings had better match the strings for AudioContextState in AudioContext.idl.
     switch (m_contextState) {
     case Suspended:
         return "suspended";
     case Running:
         return "running";
     case Closed:
         return "closed";
@@ skipping 257 matching lines @@
 
 SecurityOrigin* AbstractAudioContext::getSecurityOrigin() const
 {
     if (getExecutionContext())
         return getExecutionContext()->getSecurityOrigin();
 
     return nullptr;
 }
 
 } // namespace blink