The Tor Browser: content/media/webaudio/GainNode.cpp@97036ab72558 (annotated)

content/media/webaudio/GainNode.cpp@97036ab72558 (annotated)

content/media/webaudio/GainNode.cpp

Tue, 06 Jan 2015 21:39:09 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Tue, 06 Jan 2015 21:39:09 +0100
branch: TOR_BUG_9701
changeset 8: 97036ab72558
permissions: -rw-r--r--

Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

 /* -*- 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 "GainNode.h"
 #include "mozilla/dom/GainNodeBinding.h"
 #include "AudioNodeEngine.h"
 #include "AudioNodeStream.h"
 #include "AudioDestinationNode.h"
 #include "WebAudioUtils.h"
 namespace mozilla {
 namespace dom {
 NS_IMPL_CYCLE_COLLECTION_INHERITED(GainNode, AudioNode,
                                    mGain)
 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION_INHERITED(GainNode)
 NS_INTERFACE_MAP_END_INHERITING(AudioNode)
 NS_IMPL_ADDREF_INHERITED(GainNode, AudioNode)
 NS_IMPL_RELEASE_INHERITED(GainNode, AudioNode)
 class GainNodeEngine : public AudioNodeEngine
 {
 public:
   GainNodeEngine(AudioNode* aNode, AudioDestinationNode* aDestination)
     : AudioNodeEngine(aNode)
     , mSource(nullptr)
     , mDestination(static_cast<AudioNodeStream*> (aDestination->Stream()))
     // Keep the default value in sync with the default value in GainNode::GainNode.
     , mGain(1.f)
   {
   }
   void SetSourceStream(AudioNodeStream* aSource)
   {
     mSource = aSource;
   }
   enum Parameters {
     GAIN
   };
   void SetTimelineParameter(uint32_t aIndex,
                             const AudioParamTimeline& aValue,
                             TrackRate aSampleRate) MOZ_OVERRIDE
   {
     switch (aIndex) {
     case GAIN:
       MOZ_ASSERT(mSource && mDestination);
       mGain = aValue;
       WebAudioUtils::ConvertAudioParamToTicks(mGain, mSource, mDestination);
       break;
     default:
       NS_ERROR("Bad GainNodeEngine TimelineParameter");
     }
   }
   virtual void ProcessBlock(AudioNodeStream* aStream,
                             const AudioChunk& aInput,
                             AudioChunk* aOutput,
                             bool* aFinished)
   {
     MOZ_ASSERT(mSource == aStream, "Invalid source stream");
     if (aInput.IsNull()) {
       // If input is silent, so is the output
       aOutput->SetNull(WEBAUDIO_BLOCK_SIZE);
     } else if (mGain.HasSimpleValue()) {
       // Optimize the case where we only have a single value set as the volume
       float gain = mGain.GetValue();
       if (gain == 0.0f) {
         aOutput->SetNull(WEBAUDIO_BLOCK_SIZE);
       } else {
         *aOutput = aInput;
         aOutput->mVolume *= gain;
       }
     } else {
       // First, compute a vector of gains for each track tick based on the
       // timeline at hand, and then for each channel, multiply the values
       // in the buffer with the gain vector.
       AllocateAudioBlock(aInput.mChannelData.Length(), aOutput);
       // Compute the gain values for the duration of the input AudioChunk
       // XXX we need to add a method to AudioEventTimeline to compute this buffer directly.
       float computedGain[WEBAUDIO_BLOCK_SIZE];
       for (size_t counter = 0; counter < WEBAUDIO_BLOCK_SIZE; ++counter) {
         TrackTicks tick = aStream->GetCurrentPosition();
         computedGain[counter] = mGain.GetValueAtTime(tick, counter) * aInput.mVolume;
       }
       // Apply the gain to the output buffer
       for (size_t channel = 0; channel < aOutput->mChannelData.Length(); ++channel) {
         const float* inputBuffer = static_cast<const float*> (aInput.mChannelData[channel]);
         float* buffer = static_cast<float*> (const_cast<void*>
                           (aOutput->mChannelData[channel]));
         AudioBlockCopyChannelWithScale(inputBuffer, computedGain, buffer);
       }
     }
   }
   virtual size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const MOZ_OVERRIDE
   {
     // Not owned:
     // - mSource (probably)
     // - mDestination (probably)
     // - mGain - Internal ref owned by AudioNode
     return AudioNodeEngine::SizeOfExcludingThis(aMallocSizeOf);
   }
   virtual size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const MOZ_OVERRIDE
   {
     return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
   }
   AudioNodeStream* mSource;
   AudioNodeStream* mDestination;
   AudioParamTimeline mGain;
 };
 GainNode::GainNode(AudioContext* aContext)
   : AudioNode(aContext,
 ,
               ChannelCountMode::Max,
               ChannelInterpretation::Speakers)
   , mGain(new AudioParam(MOZ_THIS_IN_INITIALIZER_LIST(),
                          SendGainToStream, 1.0f))
 {
   GainNodeEngine* engine = new GainNodeEngine(this, aContext->Destination());
   mStream = aContext->Graph()->CreateAudioNodeStream(engine, MediaStreamGraph::INTERNAL_STREAM);
   engine->SetSourceStream(static_cast<AudioNodeStream*> (mStream.get()));
 }
 size_t
 GainNode::SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const
 {
   size_t amount = AudioNode::SizeOfExcludingThis(aMallocSizeOf);
   amount += mGain->SizeOfIncludingThis(aMallocSizeOf);
   return amount;
 }
 size_t
 GainNode::SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const
 {
   return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
 }
 JSObject*
 GainNode::WrapObject(JSContext* aCx)
 {
   return GainNodeBinding::Wrap(aCx, this);
 }
 void
 GainNode::SendGainToStream(AudioNode* aNode)
 {
   GainNode* This = static_cast<GainNode*>(aNode);
   SendTimelineParameterToStream(This, GainNodeEngine::GAIN, *This->mGain);
 }
 }
 }

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content/media/webaudio/GainNode.cpp@97036ab72558 (annotated)

content/media/webaudio/GainNode.cpp