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

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

content/media/webaudio/AudioBuffer.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 "AudioBuffer.h"
 #include "mozilla/dom/AudioBufferBinding.h"
 #include "jsfriendapi.h"
 #include "mozilla/ErrorResult.h"
 #include "AudioSegment.h"
 #include "AudioChannelFormat.h"
 #include "mozilla/PodOperations.h"
 #include "mozilla/CheckedInt.h"
 #include "AudioNodeEngine.h"
 namespace mozilla {
 namespace dom {
 NS_IMPL_CYCLE_COLLECTION_CLASS(AudioBuffer)
 NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(AudioBuffer)
   NS_IMPL_CYCLE_COLLECTION_UNLINK(mContext)
   NS_IMPL_CYCLE_COLLECTION_UNLINK(mJSChannels)
   NS_IMPL_CYCLE_COLLECTION_UNLINK_PRESERVED_WRAPPER
   tmp->ClearJSChannels();
 NS_IMPL_CYCLE_COLLECTION_UNLINK_END
 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(AudioBuffer)
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mContext)
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE_SCRIPT_OBJECTS
 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
 NS_IMPL_CYCLE_COLLECTION_TRACE_BEGIN(AudioBuffer)
   NS_IMPL_CYCLE_COLLECTION_TRACE_PRESERVED_WRAPPER
   for (uint32_t i = 0; i < tmp->mJSChannels.Length(); ++i) {
     NS_IMPL_CYCLE_COLLECTION_TRACE_JS_MEMBER_CALLBACK(mJSChannels[i])
   }
 NS_IMPL_CYCLE_COLLECTION_TRACE_END
 NS_IMPL_CYCLE_COLLECTION_ROOT_NATIVE(AudioBuffer, AddRef)
 NS_IMPL_CYCLE_COLLECTION_UNROOT_NATIVE(AudioBuffer, Release)
 AudioBuffer::AudioBuffer(AudioContext* aContext, uint32_t aNumberOfChannels,
                          uint32_t aLength, float aSampleRate)
   : mContext(aContext),
     mLength(aLength),
     mSampleRate(aSampleRate)
 {
   mJSChannels.SetCapacity(aNumberOfChannels);
   SetIsDOMBinding();
   mozilla::HoldJSObjects(this);
 }
 AudioBuffer::~AudioBuffer()
 {
   ClearJSChannels();
 }
 void
 AudioBuffer::ClearJSChannels()
 {
   mJSChannels.Clear();
   mozilla::DropJSObjects(this);
 }
 /* static */ already_AddRefed<AudioBuffer>
 AudioBuffer::Create(AudioContext* aContext, uint32_t aNumberOfChannels,
                     uint32_t aLength, float aSampleRate,
                     JSContext* aJSContext, ErrorResult& aRv)
 {
   // Note that a buffer with zero channels is permitted here for the sake of
   // AudioProcessingEvent, where channel counts must match parameters passed
   // to createScriptProcessor(), one of which may be zero.
   if (aSampleRate < WebAudioUtils::MinSampleRate ||
       aSampleRate > WebAudioUtils::MaxSampleRate ||
       aNumberOfChannels > WebAudioUtils::MaxChannelCount ||
       !aLength || aLength > INT32_MAX) {
     aRv.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
     return nullptr;
   }
   nsRefPtr<AudioBuffer> buffer =
     new AudioBuffer(aContext, aNumberOfChannels, aLength, aSampleRate);
   for (uint32_t i = 0; i < aNumberOfChannels; ++i) {
     JS::Rooted<JSObject*> array(aJSContext,
                                 JS_NewFloat32Array(aJSContext, aLength));
     if (!array) {
       aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
       return nullptr;
     }
     buffer->mJSChannels.AppendElement(array.get());
   }
   return buffer.forget();
 }
 JSObject*
 AudioBuffer::WrapObject(JSContext* aCx)
 {
   return AudioBufferBinding::Wrap(aCx, this);
 }
 bool
 AudioBuffer::RestoreJSChannelData(JSContext* aJSContext)
 {
   if (mSharedChannels) {
     for (uint32_t i = 0; i < mJSChannels.Length(); ++i) {
       const float* data = mSharedChannels->GetData(i);
       // The following code first zeroes the array and then copies our data
       // into it. We could avoid this with additional JS APIs to construct
       // an array (or ArrayBuffer) containing initial data.
       JS::Rooted<JSObject*> array(aJSContext,
                                   JS_NewFloat32Array(aJSContext, mLength));
       if (!array) {
         return false;
       }
       memcpy(JS_GetFloat32ArrayData(array), data, sizeof(float)*mLength);
       mJSChannels[i] = array;
     }
     mSharedChannels = nullptr;
   }
   return true;
 }
 void
 AudioBuffer::CopyFromChannel(const Float32Array& aDestination, uint32_t aChannelNumber,
                              uint32_t aStartInChannel, ErrorResult& aRv)
 {
   aDestination.ComputeLengthAndData();
   uint32_t length = aDestination.Length();
   CheckedInt<uint32_t> end = aStartInChannel;
   end += length;
   if (aChannelNumber >= NumberOfChannels() ||
       !end.isValid() || end.value() > mLength) {
     aRv.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
     return;
   }
   if (!mSharedChannels && JS_GetTypedArrayLength(mJSChannels[aChannelNumber]) != mLength) {
     // The array was probably neutered
     aRv.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
     return;
   }
   const float* sourceData = mSharedChannels ?
     mSharedChannels->GetData(aChannelNumber) :
     JS_GetFloat32ArrayData(mJSChannels[aChannelNumber]);
   PodMove(aDestination.Data(), sourceData + aStartInChannel, length);
 }
 void
 AudioBuffer::CopyToChannel(JSContext* aJSContext, const Float32Array& aSource,
                            uint32_t aChannelNumber, uint32_t aStartInChannel,
                            ErrorResult& aRv)
 {
   aSource.ComputeLengthAndData();
   uint32_t length = aSource.Length();
   CheckedInt<uint32_t> end = aStartInChannel;
   end += length;
   if (aChannelNumber >= NumberOfChannels() ||
       !end.isValid() || end.value() > mLength) {
     aRv.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
     return;
   }
   if (!mSharedChannels && JS_GetTypedArrayLength(mJSChannels[aChannelNumber]) != mLength) {
     // The array was probably neutered
     aRv.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
     return;
   }
   if (!RestoreJSChannelData(aJSContext)) {
     aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
     return;
   }
   PodMove(JS_GetFloat32ArrayData(mJSChannels[aChannelNumber]) + aStartInChannel,
           aSource.Data(), length);
 }
 void
 AudioBuffer::SetRawChannelContents(JSContext* aJSContext, uint32_t aChannel,
                                    float* aContents)
 {
   PodCopy(JS_GetFloat32ArrayData(mJSChannels[aChannel]), aContents, mLength);
 }
 void
 AudioBuffer::GetChannelData(JSContext* aJSContext, uint32_t aChannel,
                             JS::MutableHandle<JSObject*> aRetval,
                             ErrorResult& aRv)
 {
   if (aChannel >= NumberOfChannels()) {
     aRv.Throw(NS_ERROR_DOM_SYNTAX_ERR);
     return;
   }
   if (!RestoreJSChannelData(aJSContext)) {
     aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
     return;
   }
   if (mJSChannels[aChannel]) {
     JS::ExposeObjectToActiveJS(mJSChannels[aChannel]);
   }
   aRetval.set(mJSChannels[aChannel]);
 }
 static already_AddRefed<ThreadSharedFloatArrayBufferList>
 StealJSArrayDataIntoThreadSharedFloatArrayBufferList(JSContext* aJSContext,
                                                      const nsTArray<JSObject*>& aJSArrays)
 {
   nsRefPtr<ThreadSharedFloatArrayBufferList> result =
     new ThreadSharedFloatArrayBufferList(aJSArrays.Length());
   for (uint32_t i = 0; i < aJSArrays.Length(); ++i) {
     JS::Rooted<JSObject*> arrayBuffer(aJSContext,
                                       JS_GetArrayBufferViewBuffer(aJSContext, aJSArrays[i]));
     uint8_t* stolenData = arrayBuffer
                           ? (uint8_t*) JS_StealArrayBufferContents(aJSContext, arrayBuffer)
                           : nullptr;
     if (stolenData) {
       result->SetData(i, stolenData, reinterpret_cast<float*>(stolenData));
     } else {
       return nullptr;
     }
   }
   return result.forget();
 }
 ThreadSharedFloatArrayBufferList*
 AudioBuffer::GetThreadSharedChannelsForRate(JSContext* aJSContext)
 {
   if (!mSharedChannels) {
     for (uint32_t i = 0; i < mJSChannels.Length(); ++i) {
       if (mLength != JS_GetTypedArrayLength(mJSChannels[i])) {
         // Probably one of the arrays was neutered
         return nullptr;
       }
     }
     mSharedChannels =
       StealJSArrayDataIntoThreadSharedFloatArrayBufferList(aJSContext, mJSChannels);
   }
   return mSharedChannels;
 }
 size_t
 AudioBuffer::SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const
 {
   size_t amount = aMallocSizeOf(this);
   amount += mJSChannels.SizeOfExcludingThis(aMallocSizeOf);
   if (mSharedChannels) {
     amount += mSharedChannels->SizeOfExcludingThis(aMallocSizeOf);
   }
   return amount;
 }
 }
 }

The Tor Browser / annotate

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

content/media/webaudio/AudioBuffer.cpp