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The Tor Browser
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AudioBuffer.h (4888B)

      1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
      2 /* vim:set ts=2 sw=2 sts=2 et cindent: */
      3 /* This Source Code Form is subject to the terms of the Mozilla Public
      4 * License, v. 2.0. If a copy of the MPL was not distributed with this
      5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
      6 
      7 #ifndef AudioBuffer_h_
      8 #define AudioBuffer_h_
      9 
     10 #include "AudioSegment.h"
     11 #include "js/TypeDecls.h"
     12 #include "mozilla/MemoryReporting.h"
     13 #include "mozilla/StaticMutex.h"
     14 #include "mozilla/StaticPtr.h"
     15 #include "mozilla/dom/TypedArray.h"
     16 #include "nsCycleCollectionParticipant.h"
     17 #include "nsIWeakReferenceUtils.h"
     18 #include "nsPIDOMWindow.h"
     19 #include "nsTArray.h"
     20 #include "nsWrapperCache.h"
     21 
     22 namespace mozilla {
     23 
     24 class ErrorResult;
     25 class ThreadSharedFloatArrayBufferList;
     26 
     27 namespace dom {
     28 
     29 struct AudioBufferOptions;
     30 
     31 /**
     32 * An AudioBuffer keeps its data either in the mJSChannels objects, which
     33 * are Float32Arrays, or in mSharedChannels if the mJSChannels objects' buffers
     34 * are detached.
     35 */
     36 class AudioBuffer final : public nsWrapperCache {
     37 public:
     38  // If non-null, aInitialContents must have number of channels equal to
     39  // aNumberOfChannels and their lengths must be at least aLength.
     40  static already_AddRefed<AudioBuffer> Create(
     41      nsPIDOMWindowInner* aWindow, uint32_t aNumberOfChannels, uint32_t aLength,
     42      float aSampleRate,
     43      already_AddRefed<ThreadSharedFloatArrayBufferList> aInitialContents,
     44      ErrorResult& aRv);
     45 
     46  static already_AddRefed<AudioBuffer> Create(nsPIDOMWindowInner* aWindow,
     47                                              uint32_t aNumberOfChannels,
     48                                              uint32_t aLength,
     49                                              float aSampleRate,
     50                                              ErrorResult& aRv) {
     51    return Create(aWindow, aNumberOfChannels, aLength, aSampleRate, nullptr,
     52                  aRv);
     53  }
     54 
     55  // Non-unit AudioChunk::mVolume is not supported
     56  static already_AddRefed<AudioBuffer> Create(nsPIDOMWindowInner* aWindow,
     57                                              float aSampleRate,
     58                                              AudioChunk&& aInitialContents);
     59 
     60  size_t SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
     61 
     62  NS_INLINE_DECL_CYCLE_COLLECTING_NATIVE_REFCOUNTING(AudioBuffer)
     63  NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_NATIVE_CLASS(AudioBuffer)
     64 
     65  static already_AddRefed<AudioBuffer> Constructor(
     66      const GlobalObject& aGlobal, const AudioBufferOptions& aOptions,
     67      ErrorResult& aRv);
     68 
     69  nsPIDOMWindowInner* GetParentObject() const {
     70    nsCOMPtr<nsPIDOMWindowInner> parentObject = do_QueryReferent(mOwnerWindow);
     71    return parentObject;
     72  }
     73 
     74  JSObject* WrapObject(JSContext* aCx,
     75                       JS::Handle<JSObject*> aGivenProto) override;
     76 
     77  float SampleRate() const { return mSampleRate; }
     78 
     79  uint32_t Length() const { return mSharedChannels.mDuration; }
     80 
     81  double Duration() const {
     82    return Length() / static_cast<double>(mSampleRate);
     83  }
     84 
     85  uint32_t NumberOfChannels() const { return mJSChannels.Length(); }
     86 
     87  /**
     88   * If mSharedChannels is non-null, copies its contents to
     89   * new Float32Arrays in mJSChannels. Returns a Float32Array.
     90   */
     91  void GetChannelData(JSContext* aJSContext, uint32_t aChannel,
     92                      JS::MutableHandle<JSObject*> aRetval, ErrorResult& aRv);
     93 
     94  void CopyFromChannel(const Float32Array& aDestination,
     95                       uint32_t aChannelNumber, uint32_t aBufferOffset,
     96                       ErrorResult& aRv);
     97  void CopyToChannel(JSContext* aJSContext, const Float32Array& aSource,
     98                     uint32_t aChannelNumber, uint32_t aBufferOffset,
     99                     ErrorResult& aRv);
    100 
    101  /**
    102   * Returns a reference to an AudioChunk containing the sample data.
    103   * The AudioChunk can have a null buffer if there is no data.
    104   */
    105  const AudioChunk& GetThreadSharedChannelsForRate(JSContext* aContext);
    106 
    107 protected:
    108  AudioBuffer(nsPIDOMWindowInner* aWindow, uint32_t aNumberOfChannels,
    109              uint32_t aLength, float aSampleRate, ErrorResult& aRv);
    110  ~AudioBuffer();
    111 
    112  void SetSharedChannels(
    113      already_AddRefed<ThreadSharedFloatArrayBufferList> aBuffer);
    114 
    115  bool RestoreJSChannelData(JSContext* aJSContext);
    116 
    117  already_AddRefed<ThreadSharedFloatArrayBufferList>
    118  StealJSArrayDataIntoSharedChannels(JSContext* aJSContext);
    119 
    120  void ClearJSChannels();
    121 
    122  // Float32Arrays
    123  AutoTArray<JS::Heap<JSObject*>, 2> mJSChannels;
    124  // mSharedChannels aggregates the data from mJSChannels. This is non-null
    125  // if and only if the mJSChannels' buffers are detached, but its mDuration
    126  // member keeps the buffer length regardless of whether the buffer is
    127  // provided by mJSChannels or mSharedChannels.
    128  AudioChunk mSharedChannels;
    129 
    130  nsWeakPtr mOwnerWindow;
    131  float mSampleRate;
    132 };
    133 
    134 }  // namespace dom
    135 }  // namespace mozilla
    136 
    137 #endif