Implementation of 'AudioContext.getOutputTimestamp' method

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

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "modules/webaudio/AudioContext.h"
 
 #include "bindings/core/v8/ExceptionMessages.h"
 #include "bindings/core/v8/ExceptionState.h"
 #include "bindings/core/v8/ScriptPromiseResolver.h"
 #include "core/dom/DOMException.h"
 #include "core/dom/ExceptionCode.h"
+#include "core/frame/LocalDOMWindow.h"
 #include "core/frame/UseCounter.h"
+#include "core/timing/DOMWindowPerformance.h"
+#include "core/timing/Performance.h"
 #include "modules/webaudio/AudioBufferCallback.h"
+#include "modules/webaudio/AudioTimestamp.h"
 #include "platform/Histogram.h"
 #include "platform/audio/AudioUtilities.h"
 
 #if DEBUG_AUDIONODE_REFERENCES
 #include <stdio.h>
 #endif
 
 namespace blink {
 
 // Don't allow more than this number of simultaneous AudioContexts
@@ skipping 120 matching lines @@
   // Save the resolver which will get resolved when the destination node starts
   // pulling on the graph again.
   {
     AutoLocker locker(this);
     m_resumeResolvers.append(resolver);
   }
 
   return promise;
 }
 
+void AudioContext::getOutputTimestamp(ScriptState* scriptState,
+                                      AudioTimestamp& result) {
+  DCHECK(isMainThread());
+  LocalDOMWindow* window = scriptState->domWindow();
+  if (!window)
+    return;
+
+  if (!destination()) {
+    result.setContextTime(0.0);
+    result.setPerformanceTime(0.0);
+    return;
+  }
+
+  Performance* performance = DOMWindowPerformance::performance(*window);
+  DCHECK(performance);
+
+  AudioIOPosition position = outputPosition();
+
+  double performanceTime =
+      performance->monotonicTimeToDOMHighResTimeStamp(position.timestamp);
+  if (performanceTime < 0.0)
+    performanceTime = 0.0;
+
+  result.setContextTime(position.position);
+  result.setPerformanceTime(performanceTime);
+}
+
 ScriptPromise AudioContext::closeContext(ScriptState* scriptState) {
   if (isContextClosed()) {
     // We've already closed the context previously, but it hasn't yet been
     // resolved, so just create a new promise and reject it.
     return ScriptPromise::rejectWithDOMException(
         scriptState,
         DOMException::create(InvalidStateError,
                              "Cannot close a context that is being closed or "
                              "has already been closed."));
   }
@@ skipping 35 matching lines @@
   DCHECK(destination());
 
   if (contextState() == Running) {
     destination()->audioDestinationHandler().stopRendering();
     setContextState(Suspended);
     deferredTaskHandler().clearHandlersToBeDeleted();
   }
 }
 
 }  // namespace blink