firefox/dom/media/webaudio/AudioBuffer.cpp

/* -*- 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 "js/ArrayBuffer.h"             // JS::StealArrayBufferContents
#include "js/experimental/TypedData.h"  // JS_NewFloat32Array, JS_GetFloat32ArrayData, JS_GetTypedArrayLength, JS_GetArrayBufferViewBuffer
#include "mozilla/ErrorResult.h"
#include "AudioSegment.h"
#include "AudioChannelFormat.h"
#include "mozilla/PodOperations.h"
#include "mozilla/CheckedInt.h"
#include "mozilla/HoldDropJSObjects.h"
#include "mozilla/MemoryReporting.h"
#include "AudioNodeEngine.h"
#include "nsPrintfCString.h"
#include "nsTHashSet.h"
#include <numeric>

namespace mozilla::dom {

NS_IMPL_CYCLE_COLLECTION_CLASS(AudioBuffer)

NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(AudioBuffer)
  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_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

/**
 * AudioBuffers can be shared between AudioContexts, so we need a separate
 * mechanism to track their memory usage. This thread-safe class keeps track of
 * all the AudioBuffers, and gets called back by the memory reporting system
 * when a memory report is needed, reporting how much memory is used by the
 * buffers backing AudioBuffer objects. */
class AudioBufferMemoryTracker : public nsIMemoryReporter {
  NS_DECL_THREADSAFE_ISUPPORTS
  NS_DECL_NSIMEMORYREPORTER

 private:
  AudioBufferMemoryTracker();
  virtual ~AudioBufferMemoryTracker();

 public:
  /* Those methods can be called on any thread. */
  static void RegisterAudioBuffer(const AudioBuffer* aAudioBuffer);
  static void UnregisterAudioBuffer(const AudioBuffer* aAudioBuffer);

 private:
  static AudioBufferMemoryTracker* GetInstance();
  /* Those methods must be called with the lock held. */
  void RegisterAudioBufferInternal(const AudioBuffer* aAudioBuffer);
  /* Returns the number of buffers still present in the hash table. */
  uint32_t UnregisterAudioBufferInternal(const AudioBuffer* aAudioBuffer);
  void Init();

  /* This protects all members of this class. */
  static StaticMutex sMutex MOZ_UNANNOTATED;
  static StaticRefPtr<AudioBufferMemoryTracker> sSingleton;
  nsTHashSet<const AudioBuffer*> mBuffers;
};

StaticRefPtr<AudioBufferMemoryTracker> AudioBufferMemoryTracker::sSingleton;
StaticMutex AudioBufferMemoryTracker::sMutex;

NS_IMPL_ISUPPORTS(AudioBufferMemoryTracker, nsIMemoryReporter);

AudioBufferMemoryTracker* AudioBufferMemoryTracker::GetInstance() {
  sMutex.AssertCurrentThreadOwns();
  if (!sSingleton) {
    sSingleton = new AudioBufferMemoryTracker();
    sSingleton->Init();
  }
  return sSingleton;
}

AudioBufferMemoryTracker::AudioBufferMemoryTracker() = default;

void AudioBufferMemoryTracker::Init() { RegisterWeakMemoryReporter(this); }

AudioBufferMemoryTracker::~AudioBufferMemoryTracker() {
  UnregisterWeakMemoryReporter(this);
}

void AudioBufferMemoryTracker::RegisterAudioBuffer(
    const AudioBuffer* aAudioBuffer) {
  StaticMutexAutoLock lock(sMutex);
  AudioBufferMemoryTracker* tracker = AudioBufferMemoryTracker::GetInstance();
  tracker->RegisterAudioBufferInternal(aAudioBuffer);
}

void AudioBufferMemoryTracker::UnregisterAudioBuffer(
    const AudioBuffer* aAudioBuffer) {
  StaticMutexAutoLock lock(sMutex);
  AudioBufferMemoryTracker* tracker = AudioBufferMemoryTracker::GetInstance();
  uint32_t count;
  count = tracker->UnregisterAudioBufferInternal(aAudioBuffer);
  if (count == 0) {
    sSingleton = nullptr;
  }
}

void AudioBufferMemoryTracker::RegisterAudioBufferInternal(
    const AudioBuffer* aAudioBuffer) {
  sMutex.AssertCurrentThreadOwns();
  mBuffers.Insert(aAudioBuffer);
}

uint32_t AudioBufferMemoryTracker::UnregisterAudioBufferInternal(
    const AudioBuffer* aAudioBuffer) {
  sMutex.AssertCurrentThreadOwns();
  mBuffers.Remove(aAudioBuffer);
  return mBuffers.Count();
}

MOZ_DEFINE_MALLOC_SIZE_OF(AudioBufferMemoryTrackerMallocSizeOf)

NS_IMETHODIMP
AudioBufferMemoryTracker::CollectReports(nsIHandleReportCallback* aHandleReport,
                                         nsISupports* aData, bool) {
  StaticMutexAutoLock lock(sMutex);
  const size_t amount =
      std::accumulate(mBuffers.cbegin(), mBuffers.cend(), size_t(0),
                      [](size_t val, const AudioBuffer* buffer) {
                        return val + buffer->SizeOfIncludingThis(
                                         AudioBufferMemoryTrackerMallocSizeOf);
                      });

  MOZ_COLLECT_REPORT("explicit/webaudio/audiobuffer", KIND_HEAP, UNITS_BYTES,
                     amount, "Memory used by AudioBuffer objects (Web Audio).");

  return NS_OK;
}

AudioBuffer::AudioBuffer(nsPIDOMWindowInner* aWindow,
                         uint32_t aNumberOfChannels, uint32_t aLength,
                         float aSampleRate, ErrorResult& aRv)
    : mOwnerWindow(do_GetWeakReference(aWindow)), mSampleRate(aSampleRate) {
  // 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) {
    aRv.ThrowNotSupportedError(
        nsPrintfCString("Sample rate (%g) is out of range", aSampleRate));
    return;
  }

  if (aNumberOfChannels > WebAudioUtils::MaxChannelCount) {
    aRv.ThrowNotSupportedError(nsPrintfCString(
        "Number of channels (%u) is out of range", aNumberOfChannels));
    return;
  }

  if (!aLength || aLength > INT32_MAX) {
    aRv.ThrowNotSupportedError(
        nsPrintfCString("Length (%u) is out of range", aLength));
    return;
  }

  mSharedChannels.mDuration = aLength;
  mJSChannels.SetLength(aNumberOfChannels);
  mozilla::HoldJSObjects(this);
  AudioBufferMemoryTracker::RegisterAudioBuffer(this);
}

AudioBuffer::~AudioBuffer() {
  AudioBufferMemoryTracker::UnregisterAudioBuffer(this);
  ClearJSChannels();
  mozilla::DropJSObjects(this);
}

/* static */
already_AddRefed<AudioBuffer> AudioBuffer::Constructor(
    const GlobalObject& aGlobal, const AudioBufferOptions& aOptions,
    ErrorResult& aRv) {
  if (!aOptions.mNumberOfChannels) {
    aRv.ThrowNotSupportedError("Must have nonzero number of channels");
    return nullptr;
  }

  nsCOMPtr<nsPIDOMWindowInner> window =
      do_QueryInterface(aGlobal.GetAsSupports());

  return Create(window, aOptions.mNumberOfChannels, aOptions.mLength,
                aOptions.mSampleRate, aRv);
}

void AudioBuffer::ClearJSChannels() { mJSChannels.Clear(); }

void AudioBuffer::SetSharedChannels(
    already_AddRefed<ThreadSharedFloatArrayBufferList> aBuffer) {
  RefPtr<ThreadSharedFloatArrayBufferList> buffer = aBuffer;
  uint32_t channelCount = buffer->GetChannels();
  mSharedChannels.mChannelData.SetLength(channelCount);
  for (uint32_t i = 0; i < channelCount; ++i) {
    mSharedChannels.mChannelData[i] = buffer->GetData(i);
  }
  mSharedChannels.mBuffer = std::move(buffer);
  mSharedChannels.mBufferFormat = AUDIO_FORMAT_FLOAT32;
}

/* static */
already_AddRefed<AudioBuffer> AudioBuffer::Create(
    nsPIDOMWindowInner* aWindow, uint32_t aNumberOfChannels, uint32_t aLength,
    float aSampleRate,
    already_AddRefed<ThreadSharedFloatArrayBufferList> aInitialContents,
    ErrorResult& aRv) {
  RefPtr<ThreadSharedFloatArrayBufferList> initialContents = aInitialContents;
  RefPtr<AudioBuffer> buffer =
      new AudioBuffer(aWindow, aNumberOfChannels, aLength, aSampleRate, aRv);
  if (aRv.Failed()) {
    return nullptr;
  }

  if (initialContents) {
    MOZ_ASSERT(initialContents->GetChannels() == aNumberOfChannels);
    buffer->SetSharedChannels(initialContents.forget());
  }

  return buffer.forget();
}

/* static */
already_AddRefed<AudioBuffer> AudioBuffer::Create(
    nsPIDOMWindowInner* aWindow, float aSampleRate,
    AudioChunk&& aInitialContents) {
  AudioChunk initialContents = aInitialContents;
  ErrorResult rv;
  RefPtr<AudioBuffer> buffer =
      new AudioBuffer(aWindow, initialContents.ChannelCount(),
                      initialContents.mDuration, aSampleRate, rv);
  if (rv.Failed()) {
    return nullptr;
  }
  buffer->mSharedChannels = std::move(aInitialContents);

  return buffer.forget();
}

JSObject* AudioBuffer::WrapObject(JSContext* aCx,
                                  JS::Handle<JSObject*> aGivenProto) {
  return AudioBuffer_Binding::Wrap(aCx, this, aGivenProto);
}

static void CopyChannelDataToFloat(const AudioChunk& aChunk, uint32_t aChannel,
                                   uint32_t aSrcOffset, float* aOutput,
                                   uint32_t aLength) {
  MOZ_ASSERT(aChunk.mVolume == 1.0f);
  if (aChunk.mBufferFormat == AUDIO_FORMAT_FLOAT32) {
    mozilla::PodCopy(
        aOutput, aChunk.ChannelData<float>()[aChannel] + aSrcOffset, aLength);
  } else {
    MOZ_ASSERT(aChunk.mBufferFormat == AUDIO_FORMAT_S16);
    ConvertAudioSamples(aChunk.ChannelData<int16_t>()[aChannel] + aSrcOffset,
                        aOutput, aLength);
  }
}

bool AudioBuffer::RestoreJSChannelData(JSContext* aJSContext) {
  nsPIDOMWindowInner* global = GetParentObject();
  if (!global || !global->AsGlobal()->HasJSGlobal()) {
    return false;
  }

  JSAutoRealm ar(aJSContext, global->AsGlobal()->GetGlobalJSObject());

  for (uint32_t i = 0; i < mJSChannels.Length(); ++i) {
    if (mJSChannels[i]) {
      // Already have data in JS array.
      continue;
    }

    // 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, Length()));
    if (!array) {
      return false;
    }
    if (!mSharedChannels.IsNull()) {
      // "4. Attach ArrayBuffers containing copies of the data to the
      // AudioBuffer, to be returned by the next call to getChannelData."
      JS::AutoCheckCannotGC nogc;
      bool isShared;
      float* jsData = JS_GetFloat32ArrayData(array, &isShared, nogc);
      MOZ_ASSERT(!isShared);  // Was created as unshared above
      CopyChannelDataToFloat(mSharedChannels, i, 0, jsData, Length());
    }
    mJSChannels[i] = array;
  }

  mSharedChannels.SetNull(Length());

  return true;
}

void AudioBuffer::CopyFromChannel(const Float32Array& aDestination,
                                  uint32_t aChannelNumber,
                                  uint32_t aBufferOffset, ErrorResult& aRv) {
  if (aChannelNumber >= NumberOfChannels()) {
    aRv.ThrowIndexSizeError(
        nsPrintfCString("Channel number (%u) is out of range", aChannelNumber));
    return;
  }
  uint32_t length = Length();
  if (aBufferOffset >= length) {
    return;
  }
  JS::AutoCheckCannotGC nogc;
  MOZ_RELEASE_ASSERT(!JS_GetTypedArraySharedness(aDestination.Obj()));
  auto calculateCount = [=](uint32_t aLength) -> uint32_t {
    return std::min(length - aBufferOffset, aLength);
  };

  JSObject* channelArray = mJSChannels[aChannelNumber];
  if (channelArray) {
    if (JS_GetTypedArrayLength(channelArray) != length) {
      // The array's buffer was detached.
      return;
    }
    bool isShared = false;
    const float* sourceData =
        JS_GetFloat32ArrayData(channelArray, &isShared, nogc);
    // The sourceData arrays should all have originated in
    // RestoreJSChannelData, where they are created unshared.
    MOZ_ASSERT(!isShared);
    aDestination.ProcessData(
        [&](const Span<float>& aData, JS::AutoCheckCannotGC&&) {
          PodMove(aData.Elements(), sourceData + aBufferOffset,
                  calculateCount(aData.Length()));
        });
    return;
  }

  if (!mSharedChannels.IsNull()) {
    aDestination.ProcessData([&](const Span<float>& aData,
                                 JS::AutoCheckCannotGC&&) {
      CopyChannelDataToFloat(mSharedChannels, aChannelNumber, aBufferOffset,
                             aData.Elements(), calculateCount(aData.Length()));
    });
    return;
  }

  aDestination.ProcessData(
      [&](const Span<float>& aData, JS::AutoCheckCannotGC&&) {
        PodZero(aData.Elements(), calculateCount(aData.Length()));
      });
}

void AudioBuffer::CopyToChannel(JSContext* aJSContext,
                                const Float32Array& aSource,
                                uint32_t aChannelNumber, uint32_t aBufferOffset,
                                ErrorResult& aRv) {
  if (aChannelNumber >= NumberOfChannels()) {
    aRv.ThrowIndexSizeError(
        nsPrintfCString("Channel number (%u) is out of range", aChannelNumber));
    return;
  }

  if (!RestoreJSChannelData(aJSContext)) {
    aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
    return;
  }

  JS::AutoCheckCannotGC nogc;
  JSObject* channelArray = mJSChannels[aChannelNumber];
  // This may differ from Length() if the buffer has been detached.
  uint32_t length = JS_GetTypedArrayLength(channelArray);
  if (aBufferOffset >= length) {
    return;
  }

  int64_t offset = aBufferOffset;
  aSource.ProcessData([&](const Span<float>& aData, JS::AutoCheckCannotGC&&) {
    MOZ_ASSERT_IF(std::numeric_limits<decltype(aData.Length())>::max() >
                      std::numeric_limits<int64_t>::max(),
                  aData.Length() <= std::numeric_limits<int64_t>::max());
    int64_t srcLength = int64_t(aData.Length());
    size_t count = std::max(int64_t(0), std::min(length - offset, srcLength));
    bool isShared = false;
    float* channelData = JS_GetFloat32ArrayData(channelArray, &isShared, nogc);
    // The channelData arrays should all have originated in
    // RestoreJSChannelData, where they are created unshared.
    MOZ_ASSERT(!isShared);
    PodMove(channelData + aBufferOffset, aData.Elements(), count);
  });
}

void AudioBuffer::GetChannelData(JSContext* aJSContext, uint32_t aChannel,
                                 JS::MutableHandle<JSObject*> aRetval,
                                 ErrorResult& aRv) {
  if (aChannel >= NumberOfChannels()) {
    aRv.ThrowIndexSizeError(
        nsPrintfCString("Channel number (%u) is out of range", aChannel));
    return;
  }

  if (!RestoreJSChannelData(aJSContext)) {
    aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
    return;
  }

  aRetval.set(mJSChannels[aChannel]);
}

already_AddRefed<ThreadSharedFloatArrayBufferList>
AudioBuffer::StealJSArrayDataIntoSharedChannels(JSContext* aJSContext) {
  nsPIDOMWindowInner* global = GetParentObject();
  if (!global || !global->AsGlobal()->HasJSGlobal()) {
    return nullptr;
  }

  JSAutoRealm ar(aJSContext, global->AsGlobal()->GetGlobalJSObject());

  // "1. If any of the AudioBuffer's ArrayBuffer have been detached, abort
  // these steps, and return a zero-length channel data buffers to the
  // invoker."
  for (uint32_t i = 0; i < mJSChannels.Length(); ++i) {
    JSObject* channelArray = mJSChannels[i];
    if (!channelArray || Length() != JS_GetTypedArrayLength(channelArray)) {
      // Either empty buffer or one of the arrays' buffers was detached.
      return nullptr;
    }
  }

  // "2. Detach all ArrayBuffers for arrays previously returned by
  // getChannelData on this AudioBuffer."
  // "3. Retain the underlying data buffers from those ArrayBuffers and return
  // references to them to the invoker."
  RefPtr<ThreadSharedFloatArrayBufferList> result =
      new ThreadSharedFloatArrayBufferList(mJSChannels.Length());
  for (uint32_t i = 0; i < mJSChannels.Length(); ++i) {
    JS::Rooted<JSObject*> arrayBufferView(aJSContext, mJSChannels[i]);
    bool isSharedMemory;
    JS::Rooted<JSObject*> arrayBuffer(
        aJSContext, JS_GetArrayBufferViewBuffer(aJSContext, arrayBufferView,
                                                &isSharedMemory));
    // The channel data arrays should all have originated in
    // RestoreJSChannelData, where they are created unshared.
    MOZ_ASSERT(!isSharedMemory);
    auto stolenData = arrayBuffer
                          ? static_cast<float*>(JS::StealArrayBufferContents(
                                aJSContext, arrayBuffer))
                          : nullptr;
    if (stolenData) {
      result->SetData(i, stolenData, js_free, stolenData);
    } else {
      NS_ASSERTION(i == 0, "some channels lost when contents not acquired");
      return nullptr;
    }
  }

  for (uint32_t i = 0; i < mJSChannels.Length(); ++i) {
    mJSChannels[i] = nullptr;
  }

  return result.forget();
}

const AudioChunk& AudioBuffer::GetThreadSharedChannelsForRate(
    JSContext* aJSContext) {
  if (mSharedChannels.IsNull()) {
    // mDuration is set in constructor
    RefPtr<ThreadSharedFloatArrayBufferList> buffer =
        StealJSArrayDataIntoSharedChannels(aJSContext);

    if (buffer) {
      SetSharedChannels(buffer.forget());
    }
  }

  return mSharedChannels;
}

size_t AudioBuffer::SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const {
  size_t amount = aMallocSizeOf(this);
  amount += mJSChannels.ShallowSizeOfExcludingThis(aMallocSizeOf);
  amount += mSharedChannels.SizeOfExcludingThis(aMallocSizeOf, false);
  return amount;
}

}  // namespace mozilla::dom