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

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

content/media/webaudio/DelayNode.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 "DelayNode.h"
 #include "mozilla/dom/DelayNodeBinding.h"
 #include "AudioNodeEngine.h"
 #include "AudioNodeStream.h"
 #include "AudioDestinationNode.h"
 #include "WebAudioUtils.h"
 #include "DelayBuffer.h"
 #include "PlayingRefChangeHandler.h"
 namespace mozilla {
 namespace dom {
 NS_IMPL_CYCLE_COLLECTION_INHERITED(DelayNode, AudioNode,
                                    mDelay)
 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION_INHERITED(DelayNode)
 NS_INTERFACE_MAP_END_INHERITING(AudioNode)
 NS_IMPL_ADDREF_INHERITED(DelayNode, AudioNode)
 NS_IMPL_RELEASE_INHERITED(DelayNode, AudioNode)
 class DelayNodeEngine : public AudioNodeEngine
 {
   typedef PlayingRefChangeHandler PlayingRefChanged;
 public:
   DelayNodeEngine(AudioNode* aNode, AudioDestinationNode* aDestination,
                   double aMaxDelayTicks)
     : AudioNodeEngine(aNode)
     , mSource(nullptr)
     , mDestination(static_cast<AudioNodeStream*> (aDestination->Stream()))
     // Keep the default value in sync with the default value in DelayNode::DelayNode.
     , mDelay(0.f)
     // Use a smoothing range of 20ms
     , mBuffer(std::max(aMaxDelayTicks,
                        static_cast<double>(WEBAUDIO_BLOCK_SIZE)),
               WebAudioUtils::ComputeSmoothingRate(0.02,
                                                   mDestination->SampleRate()))
     , mMaxDelay(aMaxDelayTicks)
     , mLastOutputPosition(-1)
     , mLeftOverData(INT32_MIN)
   {
   }
   virtual DelayNodeEngine* AsDelayNodeEngine()
   {
     return this;
   }
   void SetSourceStream(AudioNodeStream* aSource)
   {
     mSource = aSource;
   }
   enum Parameters {
     DELAY,
   };
   void SetTimelineParameter(uint32_t aIndex,
                             const AudioParamTimeline& aValue,
                             TrackRate aSampleRate) MOZ_OVERRIDE
   {
     switch (aIndex) {
     case DELAY:
       MOZ_ASSERT(mSource && mDestination);
       mDelay = aValue;
       WebAudioUtils::ConvertAudioParamToTicks(mDelay, mSource, mDestination);
       break;
     default:
       NS_ERROR("Bad DelayNodeEngine TimelineParameter");
     }
   }
   virtual void ProcessBlock(AudioNodeStream* aStream,
                             const AudioChunk& aInput,
                             AudioChunk* aOutput,
                             bool* aFinished) MOZ_OVERRIDE
   {
     MOZ_ASSERT(mSource == aStream, "Invalid source stream");
     MOZ_ASSERT(aStream->SampleRate() == mDestination->SampleRate());
     if (!aInput.IsNull()) {
       if (mLeftOverData <= 0) {
         nsRefPtr<PlayingRefChanged> refchanged =
           new PlayingRefChanged(aStream, PlayingRefChanged::ADDREF);
         aStream->Graph()->
           DispatchToMainThreadAfterStreamStateUpdate(refchanged.forget());
       }
       mLeftOverData = mBuffer.MaxDelayTicks();
     } else if (mLeftOverData > 0) {
       mLeftOverData -= WEBAUDIO_BLOCK_SIZE;
     } else {
       if (mLeftOverData != INT32_MIN) {
         mLeftOverData = INT32_MIN;
         // Delete our buffered data now we no longer need it
         mBuffer.Reset();
         nsRefPtr<PlayingRefChanged> refchanged =
           new PlayingRefChanged(aStream, PlayingRefChanged::RELEASE);
         aStream->Graph()->
           DispatchToMainThreadAfterStreamStateUpdate(refchanged.forget());
       }
       *aOutput = aInput;
       return;
     }
     mBuffer.Write(aInput);
     UpdateOutputBlock(aOutput);
     mBuffer.NextBlock();
   }
   void UpdateOutputBlock(AudioChunk* aOutput)
   {
     TrackTicks tick = mSource->GetCurrentPosition();
     if (tick == mLastOutputPosition) {
       return; // mLastChunks is already set on the stream
     }
     mLastOutputPosition = tick;
     bool inCycle = mSource->AsProcessedStream()->InCycle();
     double minDelay = inCycle ? static_cast<double>(WEBAUDIO_BLOCK_SIZE) : 0.0;
     double maxDelay = mMaxDelay;
     double sampleRate = mSource->SampleRate();
     ChannelInterpretation channelInterpretation =
       mSource->GetChannelInterpretation();
     if (mDelay.HasSimpleValue()) {
       // If this DelayNode is in a cycle, make sure the delay value is at least
       // one block, even if that is greater than maxDelay.
       double delayFrames = mDelay.GetValue() * sampleRate;
       double delayFramesClamped =
         std::max(minDelay, std::min(delayFrames, maxDelay));
       mBuffer.Read(delayFramesClamped, aOutput, channelInterpretation);
     } else {
       // Compute the delay values for the duration of the input AudioChunk
       // If this DelayNode is in a cycle, make sure the delay value is at least
       // one block.
       double computedDelay[WEBAUDIO_BLOCK_SIZE];
       for (size_t counter = 0; counter < WEBAUDIO_BLOCK_SIZE; ++counter) {
         double delayAtTick = mDelay.GetValueAtTime(tick, counter) * sampleRate;
         double delayAtTickClamped =
           std::max(minDelay, std::min(delayAtTick, maxDelay));
         computedDelay[counter] = delayAtTickClamped;
       }
       mBuffer.Read(computedDelay, aOutput, channelInterpretation);
     }
   }
   virtual void ProduceBlockBeforeInput(AudioChunk* aOutput) MOZ_OVERRIDE
   {
     if (mLeftOverData <= 0) {
       aOutput->SetNull(WEBAUDIO_BLOCK_SIZE);
     } else {
       UpdateOutputBlock(aOutput);
     }
   }
   virtual size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const MOZ_OVERRIDE
   {
     size_t amount = AudioNodeEngine::SizeOfExcludingThis(aMallocSizeOf);
     // Not owned:
     // - mSource - probably not owned
     // - mDestination - probably not owned
     // - mDelay - shares ref with AudioNode, don't count
     amount += mBuffer.SizeOfExcludingThis(aMallocSizeOf);
     return amount;
   }
   virtual size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const MOZ_OVERRIDE
   {
     return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
   }
   AudioNodeStream* mSource;
   AudioNodeStream* mDestination;
   AudioParamTimeline mDelay;
   DelayBuffer mBuffer;
   double mMaxDelay;
   TrackTicks mLastOutputPosition;
   // How much data we have in our buffer which needs to be flushed out when our inputs
   // finish.
   int32_t mLeftOverData;
 };
 DelayNode::DelayNode(AudioContext* aContext, double aMaxDelay)
   : AudioNode(aContext,
 ,
               ChannelCountMode::Max,
               ChannelInterpretation::Speakers)
   , mDelay(new AudioParam(MOZ_THIS_IN_INITIALIZER_LIST(),
                           SendDelayToStream, 0.0f))
 {
   DelayNodeEngine* engine =
     new DelayNodeEngine(this, aContext->Destination(),
                         aContext->SampleRate() * aMaxDelay);
   mStream = aContext->Graph()->CreateAudioNodeStream(engine, MediaStreamGraph::INTERNAL_STREAM);
   engine->SetSourceStream(static_cast<AudioNodeStream*> (mStream.get()));
 }
 size_t
 DelayNode::SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const
 {
   size_t amount = AudioNode::SizeOfExcludingThis(aMallocSizeOf);
   amount += mDelay->SizeOfIncludingThis(aMallocSizeOf);
   return amount;
 }
 size_t
 DelayNode::SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const
 {
   return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
 }
 JSObject*
 DelayNode::WrapObject(JSContext* aCx)
 {
   return DelayNodeBinding::Wrap(aCx, this);
 }
 void
 DelayNode::SendDelayToStream(AudioNode* aNode)
 {
   DelayNode* This = static_cast<DelayNode*>(aNode);
   SendTimelineParameterToStream(This, DelayNodeEngine::DELAY, *This->mDelay);
 }
 }
 }

The Tor Browser / annotate

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

content/media/webaudio/DelayNode.cpp