dom/media/webaudio/AudioBuffer.h
author Mike Hommey <mh+mozilla@glandium.org>
Fri, 11 Jan 2019 16:01:15 +0000
changeset 453570 daf50f25895db073e44d50fecf2e4f6fe873865d
parent 446960 0ceae9db9ec0be18daa1a279511ad305723185d4
permissions -rw-r--r--
Bug 1519307 - Add a new project to build useful parts of breakpad independently. r=froydnj With `ac_add_options --enable-project=tools/crashreporter` in a mozconfig, `./mach build` builds minidump_stackwalk, dump_syms and fileid. One caveat is that due to limitation in how the build system works currently, it's cumbersome to keep dump_syms as a host program for Gecko, and to make it a target program for this project. For now, keep it as a host program. We're not going to use it on automation, but it's still convenient to have for quick local builds (I've had to resort to awful hacks downstream). Differential Revision: https://phabricator.services.mozilla.com/D16299

/* -*- 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/. */

#ifndef AudioBuffer_h_
#define AudioBuffer_h_

#include "AudioSegment.h"
#include "nsWrapperCache.h"
#include "nsCycleCollectionParticipant.h"
#include "mozilla/Attributes.h"
#include "mozilla/StaticPtr.h"
#include "mozilla/StaticMutex.h"
#include "nsTArray.h"
#include "js/TypeDecls.h"
#include "mozilla/MemoryReporting.h"
#include "mozilla/dom/TypedArray.h"
#include "nsPIDOMWindow.h"
#include "nsIWeakReferenceUtils.h"

namespace mozilla {

class ErrorResult;
class ThreadSharedFloatArrayBufferList;

namespace dom {

struct AudioBufferOptions;

/**
 * An AudioBuffer keeps its data either in the mJSChannels objects, which
 * are Float32Arrays, or in mSharedChannels if the mJSChannels objects' buffers
 * are detached.
 */
class AudioBuffer final : public nsWrapperCache {
 public:
  // If non-null, aInitialContents must have number of channels equal to
  // aNumberOfChannels and their lengths must be at least aLength.
  static already_AddRefed<AudioBuffer> Create(
      nsPIDOMWindowInner* aWindow, uint32_t aNumberOfChannels, uint32_t aLength,
      float aSampleRate,
      already_AddRefed<ThreadSharedFloatArrayBufferList> aInitialContents,
      ErrorResult& aRv);

  static already_AddRefed<AudioBuffer> Create(nsPIDOMWindowInner* aWindow,
                                              uint32_t aNumberOfChannels,
                                              uint32_t aLength,
                                              float aSampleRate,
                                              ErrorResult& aRv) {
    return Create(aWindow, aNumberOfChannels, aLength, aSampleRate, nullptr,
                  aRv);
  }

  // Non-unit AudioChunk::mVolume is not supported
  static already_AddRefed<AudioBuffer> Create(nsPIDOMWindowInner* aWindow,
                                              float aSampleRate,
                                              AudioChunk&& aInitialContents);

  size_t SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;

  NS_INLINE_DECL_CYCLE_COLLECTING_NATIVE_REFCOUNTING(AudioBuffer)
  NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_NATIVE_CLASS(AudioBuffer)

  static already_AddRefed<AudioBuffer> Constructor(
      const GlobalObject& aGlobal, const AudioBufferOptions& aOptions,
      ErrorResult& aRv);

  nsPIDOMWindowInner* GetParentObject() const {
    nsCOMPtr<nsPIDOMWindowInner> parentObject = do_QueryReferent(mOwnerWindow);
    return parentObject;
  }

  JSObject* WrapObject(JSContext* aCx,
                       JS::Handle<JSObject*> aGivenProto) override;

  float SampleRate() const { return mSampleRate; }

  uint32_t Length() const { return mSharedChannels.mDuration; }

  double Duration() const {
    return Length() / static_cast<double>(mSampleRate);
  }

  uint32_t NumberOfChannels() const { return mJSChannels.Length(); }

  /**
   * If mSharedChannels is non-null, copies its contents to
   * new Float32Arrays in mJSChannels. Returns a Float32Array.
   */
  void GetChannelData(JSContext* aJSContext, uint32_t aChannel,
                      JS::MutableHandle<JSObject*> aRetval, ErrorResult& aRv);

  void CopyFromChannel(const Float32Array& aDestination,
                       uint32_t aChannelNumber, uint32_t aStartInChannel,
                       ErrorResult& aRv);
  void CopyToChannel(JSContext* aJSContext, const Float32Array& aSource,
                     uint32_t aChannelNumber, uint32_t aStartInChannel,
                     ErrorResult& aRv);

  /**
   * Returns a reference to an AudioChunk containing the sample data.
   * The AudioChunk can have a null buffer if there is no data.
   */
  const AudioChunk& GetThreadSharedChannelsForRate(JSContext* aContext);

 protected:
  AudioBuffer(nsPIDOMWindowInner* aWindow, uint32_t aNumberOfChannels,
              uint32_t aLength, float aSampleRate, ErrorResult& aRv);
  ~AudioBuffer();

  void SetSharedChannels(
      already_AddRefed<ThreadSharedFloatArrayBufferList> aBuffer);

  bool RestoreJSChannelData(JSContext* aJSContext);

  already_AddRefed<ThreadSharedFloatArrayBufferList>
  StealJSArrayDataIntoSharedChannels(JSContext* aJSContext);

  void ClearJSChannels();

  // Float32Arrays
  AutoTArray<JS::Heap<JSObject*>, 2> mJSChannels;
  // mSharedChannels aggregates the data from mJSChannels. This is non-null
  // if and only if the mJSChannels' buffers are detached, but its mDuration
  // member keeps the buffer length regardless of whether the buffer is
  // provided by mJSChannels or mSharedChannels.
  AudioChunk mSharedChannels;

  nsWeakPtr mOwnerWindow;
  float mSampleRate;
};

}  // namespace dom
}  // namespace mozilla

#endif