Implementation of 'AudioContext.getOutputTimestamp' method

third_party/WebKit/Source/modules/webaudio/AbstractAudioContext.cpp

Index: third_party/WebKit/Source/modules/webaudio/AbstractAudioContext.cpp
diff --git a/third_party/WebKit/Source/modules/webaudio/AbstractAudioContext.cpp b/third_party/WebKit/Source/modules/webaudio/AbstractAudioContext.cpp
index 36344db0f2263eac94c7836d70103eac6972a9b6..0766eeeb786c8526b093520cfd9275cb89371367 100644
--- a/third_party/WebKit/Source/modules/webaudio/AbstractAudioContext.cpp
+++ b/third_party/WebKit/Source/modules/webaudio/AbstractAudioContext.cpp
@@ -32,8 +32,11 @@
 #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"
@@ -43,6 +46,7 @@
 #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"
@@ -560,6 +564,53 @@ void AbstractAudioContext::recordUserGestureState()
     m_userGestureRequired = false;
 }
 
+static double toPerformanceTime(ExecutionContext* context, double seconds)
+{
+    if (!context)
+        return 0.0;
+
+    LocalDOMWindow* window = context->executingWindow();
+    if (!window)
+        return 0.0;
+
+    Performance* performance = DOMWindowPerformance::performance(*window);
+    if (!performance)
+        return 0.0;
+
+    return performance->monotonicTimeToDOMHighResTimeStamp(seconds);
+}
+
+void AbstractAudioContext::getOutputTimestamp(AudioTimestamp& result)
+{
+    DCHECK(isMainThread());
+    if (!m_destinationNode) {
+        result.setContextTime(0.0);
+        result.setPerformanceTime(0.0);
+        return;
+    }
+
+    WebAudioTimestamp outputTimestamp;
+    {
+        AutoLocker locker(this);
+        outputTimestamp = m_outputTimestamp;
+    }
+    AudioDestinationHandler& destinationHandler = m_destinationNode->audioDestinationHandler();
+    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);
+}
+
+void AbstractAudioContext::setWebAudioTimestamp(const WebAudioTimestamp& timestamp)
+{
+    DCHECK(isAudioThread());
+    if (tryLock()) {
+        m_outputTimestamp = timestamp;
+        unlock();
+    }
+}
+
 String AbstractAudioContext::state() const
 {
     // These strings had better match the strings for AudioContextState in AudioContext.idl.