C++ AutoTArray::LastElement方法代码示例

void VideoFrameContainer::SetCurrentFrames(const VideoSegment& aSegment)
{
  if (aSegment.IsEmpty()) {
    return;
  }

  MutexAutoLock lock(mMutex);

  // Collect any new frames produced in this iteration.
  AutoTArray<ImageContainer::NonOwningImage,4> newImages;
  PrincipalHandle lastPrincipalHandle = PRINCIPAL_HANDLE_NONE;

  VideoSegment::ConstChunkIterator iter(aSegment);
  while (!iter.IsEnded()) {
    VideoChunk chunk = *iter;

    const VideoFrame* frame = &chunk.mFrame;
    if (*frame == mLastPlayedVideoFrame) {
      iter.Next();
      continue;
    }

    Image* image = frame->GetImage();
    CONTAINER_LOG(LogLevel::Verbose,
                  ("VideoFrameContainer %p writing video frame %p (%d x %d)",
                  this, image, frame->GetIntrinsicSize().width,
                  frame->GetIntrinsicSize().height));

    if (frame->GetForceBlack()) {
      if (!mBlackImage) {
        mBlackImage = GetImageContainer()->CreatePlanarYCbCrImage();
        if (mBlackImage) {
          // Sets the image to a single black pixel, which will be scaled to
          // fill the rendered size.
          SetImageToBlackPixel(mBlackImage->AsPlanarYCbCrImage());
        }
      }
      if (mBlackImage) {
        image = mBlackImage;
      }
    }
    // Don't append null image to the newImages.
    if (!image) {
      iter.Next();
      continue;
    }
    newImages.AppendElement(ImageContainer::NonOwningImage(image, chunk.mTimeStamp));

    lastPrincipalHandle = chunk.GetPrincipalHandle();

    mLastPlayedVideoFrame = *frame;
    iter.Next();
  }

  // Don't update if there are no changes.
  if (newImages.IsEmpty()) {
    return;
  }

  AutoTArray<ImageContainer::NonOwningImage,4> images;

  bool principalHandleChanged =
     lastPrincipalHandle != PRINCIPAL_HANDLE_NONE &&
     lastPrincipalHandle != GetLastPrincipalHandleLocked();

  // Add the frames from this iteration.
  for (auto& image : newImages) {
    image.mFrameID = NewFrameID();
    images.AppendElement(image);
  }

  if (principalHandleChanged) {
    UpdatePrincipalHandleForFrameIDLocked(lastPrincipalHandle,
                                          newImages.LastElement().mFrameID);
  }

  SetCurrentFramesLocked(mLastPlayedVideoFrame.GetIntrinsicSize(), images);
  nsCOMPtr<nsIRunnable> event =
    new VideoFrameContainerInvalidateRunnable(this);
  mMainThread->Dispatch(event.forget());

  images.ClearAndRetainStorage();
}

bool
IsInterfaceEqualToOrInheritedFrom(REFIID aInterface, REFIID aFrom,
                                  unsigned long aVtableIndexHint)
{
  if (aInterface == aFrom) {
    return true;
  }

  // We expect this array to be length 1 but that is not guaranteed by the API.
  AutoTArray<RefPtr<ITypeInfo>, 1> typeInfos;

  // Grab aInterface's ITypeInfo so that we may obtain information about its
  // inheritance hierarchy.
  RefPtr<ITypeInfo> typeInfo;
  if (RegisteredProxy::Find(aInterface, getter_AddRefs(typeInfo))) {
    typeInfos.AppendElement(Move(typeInfo));
  }

  /**
   * The main loop of this function searches the hierarchy of aInterface's
   * parent interfaces, searching for aFrom.
   */
  while (!typeInfos.IsEmpty()) {
    RefPtr<ITypeInfo> curTypeInfo(Move(typeInfos.LastElement()));
    typeInfos.RemoveElementAt(typeInfos.Length() - 1);

    TYPEATTR* typeAttr = nullptr;
    HRESULT hr = curTypeInfo->GetTypeAttr(&typeAttr);
    if (FAILED(hr)) {
      break;
    }

    bool isFromParentVtable = IsVtableIndexFromParentInterface(typeAttr,
                                                               aVtableIndexHint);
    WORD numParentInterfaces = typeAttr->cImplTypes;

    curTypeInfo->ReleaseTypeAttr(typeAttr);
    typeAttr = nullptr;

    if (!isFromParentVtable) {
      // The vtable index cannot belong to this interface (otherwise the IIDs
      // would already have matched and we would have returned true). Since we
      // now also know that the vtable index cannot possibly be contained inside
      // curTypeInfo's parent interface, there is no point searching any further
      // up the hierarchy from here. OTOH we still should check any remaining
      // entries that are still in the typeInfos array, so we continue.
      continue;
    }

    for (WORD i = 0; i < numParentInterfaces; ++i) {
      HREFTYPE refCookie;
      hr = curTypeInfo->GetRefTypeOfImplType(i, &refCookie);
      if (FAILED(hr)) {
        continue;
      }

      RefPtr<ITypeInfo> nextTypeInfo;
      hr = curTypeInfo->GetRefTypeInfo(refCookie,
                                       getter_AddRefs(nextTypeInfo));
      if (FAILED(hr)) {
        continue;
      }

      hr = nextTypeInfo->GetTypeAttr(&typeAttr);
      if (FAILED(hr)) {
        continue;
      }

      IID nextIid = typeAttr->guid;

      nextTypeInfo->ReleaseTypeAttr(typeAttr);
      typeAttr = nullptr;

      if (nextIid == aFrom) {
        return true;
      }

      typeInfos.AppendElement(Move(nextTypeInfo));
    }
  }

  return false;
}