diff -r 000000000000 -r 6474c204b198 content/media/webaudio/AudioParam.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/content/media/webaudio/AudioParam.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,149 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et cindent: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "AudioParam.h"
+#include "mozilla/dom/AudioParamBinding.h"
+#include "AudioNodeEngine.h"
+#include "AudioNodeStream.h"
+#include "AudioContext.h"
+
+namespace mozilla {
+namespace dom {
+
+NS_IMPL_CYCLE_COLLECTION_CLASS(AudioParam)
+
+NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(AudioParam)
+  tmp->DisconnectFromGraphAndDestroyStream();
+  NS_IMPL_CYCLE_COLLECTION_UNLINK(mNode)
+  NS_IMPL_CYCLE_COLLECTION_UNLINK_PRESERVED_WRAPPER
+NS_IMPL_CYCLE_COLLECTION_UNLINK_END
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(AudioParam)
+  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mNode)
+  NS_IMPL_CYCLE_COLLECTION_TRAVERSE_SCRIPT_OBJECTS
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
+
+NS_IMPL_CYCLE_COLLECTION_TRACE_WRAPPERCACHE(AudioParam)
+
+NS_IMPL_CYCLE_COLLECTING_NATIVE_ADDREF(AudioParam)
+
+NS_IMETHODIMP_(MozExternalRefCountType)
+AudioParam::Release()
+{
+  if (mRefCnt.get() == 1) {
+    // We are about to be deleted, disconnect the object from the graph before
+    // the derived type is destroyed.
+    DisconnectFromGraphAndDestroyStream();
+  }
+  NS_IMPL_CC_NATIVE_RELEASE_BODY(AudioParam)
+}
+
+NS_IMPL_CYCLE_COLLECTION_ROOT_NATIVE(AudioParam, AddRef)
+NS_IMPL_CYCLE_COLLECTION_UNROOT_NATIVE(AudioParam, Release)
+
+AudioParam::AudioParam(AudioNode* aNode,
+                       AudioParam::CallbackType aCallback,
+                       float aDefaultValue)
+  : AudioParamTimeline(aDefaultValue)
+  , mNode(aNode)
+  , mCallback(aCallback)
+  , mDefaultValue(aDefaultValue)
+{
+  SetIsDOMBinding();
+}
+
+AudioParam::~AudioParam()
+{
+  MOZ_ASSERT(mInputNodes.IsEmpty());
+}
+
+JSObject*
+AudioParam::WrapObject(JSContext* aCx)
+{
+  return AudioParamBinding::Wrap(aCx, this);
+}
+
+void
+AudioParam::DisconnectFromGraphAndDestroyStream()
+{
+  // Addref this temporarily so the refcount bumping below doesn't destroy us
+  // prematurely
+  nsRefPtr<AudioParam> kungFuDeathGrip = this;
+
+  while (!mInputNodes.IsEmpty()) {
+    uint32_t i = mInputNodes.Length() - 1;
+    nsRefPtr<AudioNode> input = mInputNodes[i].mInputNode;
+    mInputNodes.RemoveElementAt(i);
+    input->RemoveOutputParam(this);
+  }
+
+  if (mNodeStreamPort) {
+    mNodeStreamPort->Destroy();
+    mNodeStreamPort = nullptr;
+  }
+
+  if (mStream) {
+    mStream->Destroy();
+    mStream = nullptr;
+  }
+}
+
+MediaStream*
+AudioParam::Stream()
+{
+  if (mStream) {
+    return mStream;
+  }
+
+  AudioNodeEngine* engine = new AudioNodeEngine(nullptr);
+  nsRefPtr<AudioNodeStream> stream =
+    mNode->Context()->Graph()->CreateAudioNodeStream(engine,
+                                                     MediaStreamGraph::INTERNAL_STREAM,
+                                                     Node()->Context()->SampleRate());
+
+  // Force the input to have only one channel, and make it down-mix using
+  // the speaker rules if needed.
+  stream->SetChannelMixingParametersImpl(1, ChannelCountMode::Explicit, ChannelInterpretation::Speakers);
+  // Mark as an AudioParam helper stream
+  stream->SetAudioParamHelperStream();
+
+  mStream = stream.forget();
+
+  // Setup the AudioParam's stream as an input to the owner AudioNode's stream
+  MediaStream* nodeStream = mNode->Stream();
+  MOZ_ASSERT(nodeStream->AsProcessedStream());
+  ProcessedMediaStream* ps = static_cast<ProcessedMediaStream*>(nodeStream);
+  mNodeStreamPort = ps->AllocateInputPort(mStream, MediaInputPort::FLAG_BLOCK_INPUT);
+
+  // Let the MSG's copy of AudioParamTimeline know about the change in the stream
+  mCallback(mNode);
+
+  return mStream;
+}
+
+float
+AudioParamTimeline::AudioNodeInputValue(size_t aCounter) const
+{
+  MOZ_ASSERT(mStream);
+
+  // If we have a chunk produced by the AudioNode inputs to the AudioParam,
+  // get its value now.  We use aCounter to tell us which frame of the last
+  // AudioChunk to look at.
+  float audioNodeInputValue = 0.0f;
+  const AudioChunk& lastAudioNodeChunk =
+    static_cast<AudioNodeStream*>(mStream.get())->LastChunks()[0];
+  if (!lastAudioNodeChunk.IsNull()) {
+    MOZ_ASSERT(lastAudioNodeChunk.GetDuration() == WEBAUDIO_BLOCK_SIZE);
+    audioNodeInputValue =
+      static_cast<const float*>(lastAudioNodeChunk.mChannelData[0])[aCounter];
+    audioNodeInputValue *= lastAudioNodeChunk.mVolume;
+  }
+
+  return audioNodeInputValue;
+}
+
+}
+}
+