C++ NotNull类代码示例

void WithSingleChunkDecode(const ImageTestCase& aTestCase,
                           const Maybe<IntSize>& aOutputSize,
                           Func aResultChecker)
{
  nsCOMPtr<nsIInputStream> inputStream = LoadFile(aTestCase.mPath);
  ASSERT_TRUE(inputStream != nullptr);

  // Figure out how much data we have.
  uint64_t length;
  nsresult rv = inputStream->Available(&length);
  ASSERT_TRUE(NS_SUCCEEDED(rv));

  // Write the data into a SourceBuffer.
  NotNull<RefPtr<SourceBuffer>> sourceBuffer = WrapNotNull(new SourceBuffer());
  sourceBuffer->ExpectLength(length);
  rv = sourceBuffer->AppendFromInputStream(inputStream, length);
  ASSERT_TRUE(NS_SUCCEEDED(rv));
  sourceBuffer->Complete(NS_OK);

  // Create a decoder.
  DecoderType decoderType =
    DecoderFactory::GetDecoderType(aTestCase.mMimeType);
  RefPtr<Decoder> decoder =
    DecoderFactory::CreateAnonymousDecoder(decoderType, sourceBuffer, aOutputSize,
                                           DefaultSurfaceFlags());
  ASSERT_TRUE(decoder != nullptr);
  RefPtr<IDecodingTask> task = new AnonymousDecodingTask(WrapNotNull(decoder));

  // Run the full decoder synchronously.
  task->Run();

  // Call the lambda to verify the expected results.
  aResultChecker(decoder);
}

/* static */ void
IDecodingTask::NotifyProgress(NotNull<RasterImage*> aImage,
                              NotNull<Decoder*> aDecoder)
{
  MOZ_ASSERT(aDecoder->HasProgress() && !aDecoder->IsMetadataDecode());

  // Capture the decoder's state. If we need to notify asynchronously, it's
  // important that we don't wait until the lambda actually runs to capture the
  // state that we're going to notify. That would both introduce data races on
  // the decoder's state and cause inconsistencies between the NotifyProgress()
  // calls we make off-main-thread and the notifications that RasterImage
  // actually receives, which would cause bugs.
  Progress progress = aDecoder->TakeProgress();
  IntRect invalidRect = aDecoder->TakeInvalidRect();
  Maybe<uint32_t> frameCount = aDecoder->TakeCompleteFrameCount();
  SurfaceFlags surfaceFlags = aDecoder->GetSurfaceFlags();

  // Synchronously notify if we can.
  if (NS_IsMainThread() &&
      !(aDecoder->GetDecoderFlags() & DecoderFlags::ASYNC_NOTIFY)) {
    aImage->NotifyProgress(progress, invalidRect,
                           frameCount, surfaceFlags);
    return;
  }

  // We're forced to notify asynchronously.
  NotNull<RefPtr<RasterImage>> image = aImage;
  NS_DispatchToMainThread(NS_NewRunnableFunction([=]() -> void {
    image->NotifyProgress(progress, invalidRect,
                          frameCount, surfaceFlags);
  }));
}

static void
NotifyProgress(NotNull<Decoder*> aDecoder)
{
  MOZ_ASSERT(aDecoder->HasProgress() && !aDecoder->IsMetadataDecode());

  Progress progress = aDecoder->TakeProgress();
  IntRect invalidRect = aDecoder->TakeInvalidRect();
  Maybe<uint32_t> frameCount = aDecoder->TakeCompleteFrameCount();
  SurfaceFlags surfaceFlags = aDecoder->GetSurfaceFlags();

  // Synchronously notify if we can.
  if (NS_IsMainThread() &&
      !(aDecoder->GetDecoderFlags() & DecoderFlags::ASYNC_NOTIFY)) {
    aDecoder->GetImage()->NotifyProgress(progress, invalidRect,
                                         frameCount, surfaceFlags);
    return;
  }

  // We're forced to notify asynchronously.
  NotNull<RefPtr<Decoder>> decoder = aDecoder;
  NS_DispatchToMainThread(NS_NewRunnableFunction([=]() -> void {
    decoder->GetImage()->NotifyProgress(progress, invalidRect,
                                        frameCount, surfaceFlags);
  }));
}

IPCResult
IPCResult::Fail(NotNull<IProtocol*> actor, const char* where, const char* why)
{
  // Calls top-level protocol to handle the error.
  nsPrintfCString errorMsg("%s::%s %s\n", actor->ProtocolName(), where, why);
  actor->GetIPCChannel()->Listener()->ProcessingError(
    HasResultCodes::MsgProcessingError, errorMsg.get());
  return IPCResult(false);
}

void
MsaaIdGenerator::ReleaseID(NotNull<AccessibleWrap*> aAccWrap)
{
  if (!ReleaseID(aAccWrap->GetExistingID())) {
    // This may happen if chrome holds a proxy whose ID was originally generated
    // by a content process. Since ReleaseID only has meaning in the process
    // that originally generated that ID, we ignore ReleaseID calls for any ID
    // that did not come from the current process.
    MOZ_ASSERT(aAccWrap->IsProxy());
  }
}

DecodedSurfaceProvider::DecodedSurfaceProvider(NotNull<RasterImage*> aImage,
                                               const SurfaceKey& aSurfaceKey,
                                               NotNull<Decoder*> aDecoder)
  : ISurfaceProvider(ImageKey(aImage.get()), aSurfaceKey,
                     AvailabilityState::StartAsPlaceholder())
  , mImage(aImage.get())
  , mMutex("mozilla::image::DecodedSurfaceProvider")
  , mDecoder(aDecoder.get())
{
  MOZ_ASSERT(!mDecoder->IsMetadataDecode(),
             "Use MetadataDecodingTask for metadata decodes");
  MOZ_ASSERT(mDecoder->IsFirstFrameDecode(),
             "Use AnimationSurfaceProvider for animation decodes");
}

/* static */ already_AddRefed<Decoder>
DecoderFactory::CreateDecoderForICOResource(DecoderType aType,
                                            SourceBufferIterator&& aIterator,
                                            NotNull<nsICODecoder*> aICODecoder,
                                            bool aIsMetadataDecode,
                                            const Maybe<IntSize>& aExpectedSize,
                                            const Maybe<uint32_t>& aDataOffset
                                              /* = Nothing() */)
{
  // Create the decoder.
  RefPtr<Decoder> decoder;
  switch (aType) {
    case DecoderType::BMP:
      MOZ_ASSERT(aDataOffset);
      decoder = new nsBMPDecoder(aICODecoder->GetImageMaybeNull(), *aDataOffset);
      break;

    case DecoderType::PNG:
      MOZ_ASSERT(!aDataOffset);
      decoder = new nsPNGDecoder(aICODecoder->GetImageMaybeNull());
      break;

    default:
      MOZ_ASSERT_UNREACHABLE("Invalid ICO resource decoder type");
      return nullptr;
  }

  MOZ_ASSERT(decoder);

  // Initialize the decoder, copying settings from @aICODecoder.
  decoder->SetMetadataDecode(aIsMetadataDecode);
  decoder->SetIterator(Forward<SourceBufferIterator>(aIterator));
  if (!aIsMetadataDecode) {
    decoder->SetOutputSize(aICODecoder->OutputSize());
  }
  if (aExpectedSize) {
    decoder->SetExpectedSize(*aExpectedSize);
  }
  decoder->SetDecoderFlags(aICODecoder->GetDecoderFlags());
  decoder->SetSurfaceFlags(aICODecoder->GetSurfaceFlags());
  decoder->SetFinalizeFrames(false);

  if (NS_FAILED(decoder->Init())) {
    return nullptr;
  }

  return decoder.forget();
}

/* static */ already_AddRefed<IDecodingTask>
DecoderFactory::CreateAnimationDecoder(DecoderType aType,
                                       NotNull<RasterImage*> aImage,
                                       NotNull<SourceBuffer*> aSourceBuffer,
                                       DecoderFlags aDecoderFlags,
                                       SurfaceFlags aSurfaceFlags)
{
  if (aType == DecoderType::UNKNOWN) {
    return nullptr;
  }

  MOZ_ASSERT(aType == DecoderType::GIF || aType == DecoderType::PNG,
             "Calling CreateAnimationDecoder for non-animating DecoderType");

  RefPtr<Decoder> decoder =
    GetDecoder(aType, aImage, /* aIsRedecode = */ true);
  MOZ_ASSERT(decoder, "Should have a decoder now");

  // Initialize the decoder.
  decoder->SetMetadataDecode(false);
  decoder->SetIterator(aSourceBuffer->Iterator());
  decoder->SetDecoderFlags(aDecoderFlags | DecoderFlags::IS_REDECODE);
  decoder->SetSurfaceFlags(aSurfaceFlags);

  decoder->Init();
  if (NS_FAILED(decoder->GetDecoderError())) {
    return nullptr;
  }

  RefPtr<IDecodingTask> task = new DecodingTask(WrapNotNull(decoder));
  return task.forget();
}

/* static */ already_AddRefed<IDecodingTask>
DecoderFactory::CreateMetadataDecoder(DecoderType aType,
                                      NotNull<RasterImage*> aImage,
                                      NotNull<SourceBuffer*> aSourceBuffer,
                                      int aSampleSize)
{
  if (aType == DecoderType::UNKNOWN) {
    return nullptr;
  }

  RefPtr<Decoder> decoder =
    GetDecoder(aType, aImage, /* aIsRedecode = */ false);
  MOZ_ASSERT(decoder, "Should have a decoder now");

  // Initialize the decoder.
  decoder->SetMetadataDecode(true);
  decoder->SetIterator(aSourceBuffer->Iterator());
  decoder->SetSampleSize(aSampleSize);

  decoder->Init();
  if (NS_FAILED(decoder->GetDecoderError())) {
    return nullptr;
  }

  RefPtr<IDecodingTask> task = new MetadataDecodingTask(WrapNotNull(decoder));
  return task.forget();
}

static void
NotifyDecodeComplete(NotNull<Decoder*> aDecoder)
{
  // Synchronously notify if we can.
  if (NS_IsMainThread() &&
      !(aDecoder->GetDecoderFlags() & DecoderFlags::ASYNC_NOTIFY)) {
    aDecoder->GetImage()->FinalizeDecoder(aDecoder);
    return;
  }

  // We're forced to notify asynchronously.
  NotNull<RefPtr<Decoder>> decoder = aDecoder;
  NS_DispatchToMainThread(NS_NewRunnableFunction([=]() -> void {
    decoder->GetImage()->FinalizeDecoder(decoder.get());
  }));
}

IAccessibleHolder
CreateHolderFromAccessible(NotNull<Accessible*> aAccToWrap)
{
  MOZ_ASSERT(NS_IsMainThread());

  STAUniquePtr<IAccessible> iaToProxy;
  aAccToWrap->GetNativeInterface(mscom::getter_AddRefs(iaToProxy));
  MOZ_DIAGNOSTIC_ASSERT(iaToProxy);
  if (!iaToProxy) {
    return nullptr;
  }

  static const bool useHandler =
    Preferences::GetBool("accessibility.handler.enabled", false) &&
    IsHandlerRegistered();

  RefPtr<HandlerProvider> payload;
  if (useHandler) {
    payload = new HandlerProvider(IID_IAccessible,
                                  mscom::ToInterceptorTargetPtr(iaToProxy));
  }

  ProxyUniquePtr<IAccessible> intercepted;
  HRESULT hr = MainThreadHandoff::WrapInterface(Move(iaToProxy), payload,
                                                (IAccessible**) mscom::getter_AddRefs(intercepted));
  MOZ_ASSERT(SUCCEEDED(hr));
  if (FAILED(hr)) {
    return nullptr;
  }

  return IAccessibleHolder(Move(intercepted));
}

void
MsaaIdGenerator::ReleaseID(NotNull<sdnAccessible*> aSdnAcc)
{
  Maybe<uint32_t> id = aSdnAcc->ReleaseUniqueID();
  if (id.isSome()) {
    DebugOnly<bool> released = ReleaseID(id.value());
    MOZ_ASSERT(released);
  }
}

static void
CheckDecoderMultiChunk(const ImageTestCase& aTestCase)
{
  nsCOMPtr<nsIInputStream> inputStream = LoadFile(aTestCase.mPath);
  ASSERT_TRUE(inputStream != nullptr);

  // Figure out how much data we have.
  uint64_t length;
  nsresult rv = inputStream->Available(&length);
  ASSERT_TRUE(NS_SUCCEEDED(rv));

  // Create a SourceBuffer and a decoder.
  NotNull<RefPtr<SourceBuffer>> sourceBuffer = WrapNotNull(new SourceBuffer());
  sourceBuffer->ExpectLength(length);
  DecoderType decoderType =
    DecoderFactory::GetDecoderType(aTestCase.mMimeType);
  RefPtr<Decoder> decoder =
    DecoderFactory::CreateAnonymousDecoder(decoderType, sourceBuffer, Nothing(),
                                           DefaultSurfaceFlags());
  ASSERT_TRUE(decoder != nullptr);
  RefPtr<IDecodingTask> task = new AnonymousDecodingTask(WrapNotNull(decoder));

  for (uint64_t read = 0; read < length ; ++read) {
    uint64_t available = 0;
    rv = inputStream->Available(&available);
    ASSERT_TRUE(available > 0);
    ASSERT_TRUE(NS_SUCCEEDED(rv));

    rv = sourceBuffer->AppendFromInputStream(inputStream, 1);
    ASSERT_TRUE(NS_SUCCEEDED(rv));

    task->Run();
  }

  sourceBuffer->Complete(NS_OK);
  task->Run();
  
  CheckDecoderResults(aTestCase, decoder);
}

/* static */ already_AddRefed<IDecodingTask>
DecoderFactory::CreateDecoder(DecoderType aType,
                              NotNull<RasterImage*> aImage,
                              NotNull<SourceBuffer*> aSourceBuffer,
                              const IntSize& aIntrinsicSize,
                              const IntSize& aOutputSize,
                              DecoderFlags aDecoderFlags,
                              SurfaceFlags aSurfaceFlags)
{
  if (aType == DecoderType::UNKNOWN) {
    return nullptr;
  }

  // Create an anonymous decoder. Interaction with the SurfaceCache and the
  // owning RasterImage will be mediated by DecodedSurfaceProvider.
  RefPtr<Decoder> decoder =
    GetDecoder(aType, nullptr, bool(aDecoderFlags & DecoderFlags::IS_REDECODE));
  MOZ_ASSERT(decoder, "Should have a decoder now");

  // Initialize the decoder.
  decoder->SetMetadataDecode(false);
  decoder->SetIterator(aSourceBuffer->Iterator());
  decoder->SetOutputSize(aOutputSize);
  decoder->SetDecoderFlags(aDecoderFlags | DecoderFlags::FIRST_FRAME_ONLY);
  decoder->SetSurfaceFlags(aSurfaceFlags);

  if (NS_FAILED(decoder->Init())) {
    return nullptr;
  }

  // Create a DecodedSurfaceProvider which will manage the decoding process and
  // make this decoder's output available in the surface cache.
  SurfaceKey surfaceKey =
    RasterSurfaceKey(aOutputSize, aSurfaceFlags, PlaybackType::eStatic);
  auto provider = MakeNotNull<RefPtr<DecodedSurfaceProvider>>(
    aImage, surfaceKey, WrapNotNull(decoder));
  if (aDecoderFlags & DecoderFlags::CANNOT_SUBSTITUTE) {
    provider->Availability().SetCannotSubstitute();
  }

  // Attempt to insert the surface provider into the surface cache right away so
  // we won't trigger any more decoders with the same parameters.
  if (SurfaceCache::Insert(provider) != InsertOutcome::SUCCESS) {
    return nullptr;
  }

  // Return the surface provider in its IDecodingTask guise.
  RefPtr<IDecodingTask> task = provider.get();
  return task.forget();
}

/* static */ already_AddRefed<IDecodingTask>
DecoderFactory::CreateAnimationDecoder(DecoderType aType,
                                       NotNull<RasterImage*> aImage,
                                       NotNull<SourceBuffer*> aSourceBuffer,
                                       const IntSize& aIntrinsicSize,
                                       DecoderFlags aDecoderFlags,
                                       SurfaceFlags aSurfaceFlags)
{
  if (aType == DecoderType::UNKNOWN) {
    return nullptr;
  }

  MOZ_ASSERT(aType == DecoderType::GIF || aType == DecoderType::PNG,
             "Calling CreateAnimationDecoder for non-animating DecoderType");

  // Create an anonymous decoder. Interaction with the SurfaceCache and the
  // owning RasterImage will be mediated by AnimationSurfaceProvider.
  RefPtr<Decoder> decoder = GetDecoder(aType, nullptr, /* aIsRedecode = */ true);
  MOZ_ASSERT(decoder, "Should have a decoder now");

  // Initialize the decoder.
  decoder->SetMetadataDecode(false);
  decoder->SetIterator(aSourceBuffer->Iterator());
  decoder->SetDecoderFlags(aDecoderFlags | DecoderFlags::IS_REDECODE);
  decoder->SetSurfaceFlags(aSurfaceFlags);

  if (NS_FAILED(decoder->Init())) {
    return nullptr;
  }

  // Create an AnimationSurfaceProvider which will manage the decoding process
  // and make this decoder's output available in the surface cache.
  SurfaceKey surfaceKey =
    RasterSurfaceKey(aIntrinsicSize, aSurfaceFlags, PlaybackType::eAnimated);
  auto provider = MakeNotNull<RefPtr<AnimationSurfaceProvider>>(
    aImage, surfaceKey, WrapNotNull(decoder));

  // Attempt to insert the surface provider into the surface cache right away so
  // we won't trigger any more decoders with the same parameters.
  if (SurfaceCache::Insert(provider) != InsertOutcome::SUCCESS) {
    return nullptr;
  }

  // Return the surface provider in its IDecodingTask guise.
  RefPtr<IDecodingTask> task = provider.get();
  return task.forget();
}