C++ MediaDecoderOwner类代码示例

bool
WMFReader::InitializeDXVA()
{
    if (!Preferences::GetBool("media.windows-media-foundation.use-dxva", false)) {
        return false;
    }
    MOZ_ASSERT(mDecoder->GetImageContainer());

    // Extract the layer manager backend type so that we can determine
    // whether it's worthwhile using DXVA. If we're not running with a D3D
    // layer manager then the readback of decoded video frames from GPU to
    // CPU memory grinds painting to a halt, and makes playback performance
    // *worse*.
    MediaDecoderOwner* owner = mDecoder->GetOwner();
    NS_ENSURE_TRUE(owner, false);

    HTMLMediaElement* element = owner->GetMediaElement();
    NS_ENSURE_TRUE(element, false);

    nsRefPtr<LayerManager> layerManager =
        nsContentUtils::LayerManagerForDocument(element->OwnerDoc());
    NS_ENSURE_TRUE(layerManager, false);

    if (layerManager->GetBackendType() != LayersBackend::LAYERS_D3D9 &&
            layerManager->GetBackendType() != LayersBackend::LAYERS_D3D10) {
        return false;
    }

    mDXVA2Manager = DXVA2Manager::Create();

    return mDXVA2Manager != nullptr;
}

nsresult ChannelMediaResource::SetupChannelHeaders()
{
  // Always use a byte range request even if we're reading from the start
  // of the resource.
  // This enables us to detect if the stream supports byte range
  // requests, and therefore seeking, early.
  nsCOMPtr<nsIHttpChannel> hc = do_QueryInterface(mChannel);
  if (hc) {
    // Use |mOffset| if seeking in a complete file download.
    nsAutoCString rangeString("bytes=");
    rangeString.AppendInt(mOffset);
    rangeString.Append('-');
    nsresult rv = hc->SetRequestHeader(NS_LITERAL_CSTRING("Range"), rangeString, false);
    NS_ENSURE_SUCCESS(rv, rv);

    // Send Accept header for video and audio types only (Bug 489071)
    NS_ASSERTION(NS_IsMainThread(), "Don't call on non-main thread");
    MediaDecoderOwner* owner = mCallback->GetMediaOwner();
    NS_ENSURE_TRUE(owner, NS_ERROR_FAILURE);
    dom::HTMLMediaElement* element = owner->GetMediaElement();
    NS_ENSURE_TRUE(element, NS_ERROR_FAILURE);
    element->SetRequestHeaders(hc);
  } else {
    NS_ASSERTION(mOffset == 0, "Don't know how to seek on this channel type");
    return NS_ERROR_FAILURE;
  }
  return NS_OK;
}

void
MP4Reader::InitLayersBackendType()
{
  if (!IsVideoContentType(mDecoder->GetResource()->GetContentType())) {
    // Not playing video, we don't care about the layers backend type.
    return;
  }
  // Extract the layer manager backend type so that platform decoders
  // can determine whether it's worthwhile using hardware accelerated
  // video decoding.
  MediaDecoderOwner* owner = mDecoder->GetOwner();
  if (!owner) {
    NS_WARNING("MP4Reader without a decoder owner, can't get HWAccel");
    return;
  }

  dom::HTMLMediaElement* element = owner->GetMediaElement();
  NS_ENSURE_TRUE_VOID(element);

  nsRefPtr<LayerManager> layerManager =
    nsContentUtils::LayerManagerForDocument(element->OwnerDoc());
  NS_ENSURE_TRUE_VOID(layerManager);

  mLayersBackendType = layerManager->GetCompositorBackendType();
}

void ChannelMediaResource::Suspend(bool aCloseImmediately)
{
  NS_ASSERTION(NS_IsMainThread(), "Don't call on non-main thread");

  MediaDecoderOwner* owner = mCallback->GetMediaOwner();
  if (!owner) {
    // Shutting down; do nothing.
    return;
  }
  dom::HTMLMediaElement* element = owner->GetMediaElement();
  if (!element) {
    // Shutting down; do nothing.
    return;
  }

  if (mChannel && aCloseImmediately && mCacheStream.IsTransportSeekable()) {
    // Kill off our channel right now, but don't tell anyone about it.
    mIgnoreClose = true;
    CloseChannel();
    element->DownloadSuspended();
  }

  if (mSuspendAgent.Suspend()) {
    if (mChannel) {
      {
        MutexAutoLock lock(mLock);
        mChannelStatistics->Stop();
      }
      element->DownloadSuspended();
    }
  }
}

bool
WMFReader::InitializeDXVA()
{
  if (!gfxPlatform::GetPlatform()->CanUseHardwareVideoDecoding()) {
    return false;
  }

  MOZ_ASSERT(mDecoder->GetImageContainer());

  // Extract the layer manager backend type so that we can determine
  // whether it's worthwhile using DXVA. If we're not running with a D3D
  // layer manager then the readback of decoded video frames from GPU to
  // CPU memory grinds painting to a halt, and makes playback performance
  // *worse*.
  MediaDecoderOwner* owner = mDecoder->GetOwner();
  NS_ENSURE_TRUE(owner, false);

  dom::HTMLMediaElement* element = owner->GetMediaElement();
  NS_ENSURE_TRUE(element, false);

  nsRefPtr<LayerManager> layerManager =
    nsContentUtils::LayerManagerForDocument(element->OwnerDoc());
  NS_ENSURE_TRUE(layerManager, false);

  LayersBackend backend = layerManager->GetCompositorBackendType();
  if (backend != LayersBackend::LAYERS_D3D9 &&
      backend != LayersBackend::LAYERS_D3D10 &&
      backend != LayersBackend::LAYERS_D3D11) {
    return false;
  }

  mDXVA2Manager = DXVA2Manager::CreateD3D9DXVA();

  return mDXVA2Manager != nullptr;
}

already_AddRefed<KnowsCompositor>
MediaDecoder::GetCompositor()
{
  MediaDecoderOwner* owner = GetOwner();
  nsIDocument* ownerDoc = owner ? owner->GetDocument() : nullptr;
  RefPtr<LayerManager> layerManager =
    ownerDoc ? nsContentUtils::LayerManagerForDocument(ownerDoc) : nullptr;
  RefPtr<KnowsCompositor> knows =
    layerManager ? layerManager->AsKnowsCompositor() : nullptr;
  return knows ? knows->GetForMedia().forget() : nullptr;
}

nsresult
ChannelMediaResource::RecreateChannel()
{
  nsLoadFlags loadFlags =
    nsICachingChannel::LOAD_BYPASS_LOCAL_CACHE_IF_BUSY |
    nsIChannel::LOAD_CLASSIFY_URI |
    (mLoadInBackground ? nsIRequest::LOAD_BACKGROUND : 0);

  MediaDecoderOwner* owner = mCallback->GetMediaOwner();
  if (!owner) {
    // The decoder is being shut down, so don't bother opening a new channel
    return NS_OK;
  }
  dom::HTMLMediaElement* element = owner->GetMediaElement();
  if (!element) {
    // The decoder is being shut down, so don't bother opening a new channel
    return NS_OK;
  }
  nsCOMPtr<nsILoadGroup> loadGroup = element->GetDocumentLoadGroup();
  NS_ENSURE_TRUE(loadGroup, NS_ERROR_NULL_POINTER);

  nsSecurityFlags securityFlags = element->ShouldCheckAllowOrigin()
                                  ? nsILoadInfo::SEC_REQUIRE_CORS_DATA_INHERITS
                                  : nsILoadInfo::SEC_ALLOW_CROSS_ORIGIN_DATA_INHERITS;

  MOZ_ASSERT(element->IsAnyOfHTMLElements(nsGkAtoms::audio, nsGkAtoms::video));
  nsContentPolicyType contentPolicyType = element->IsHTMLElement(nsGkAtoms::audio) ?
    nsIContentPolicy::TYPE_INTERNAL_AUDIO : nsIContentPolicy::TYPE_INTERNAL_VIDEO;

  nsresult rv = NS_NewChannel(getter_AddRefs(mChannel),
                              mURI,
                              element,
                              securityFlags,
                              contentPolicyType,
                              loadGroup,
                              nullptr,  // aCallbacks
                              loadFlags);
  NS_ENSURE_SUCCESS(rv, rv);

  // We have cached the Content-Type, which should not change. Give a hint to
  // the channel to avoid a sniffing failure, which would be expected because we
  // are probably seeking in the middle of the bitstream, and sniffing relies
  // on the presence of a magic number at the beginning of the stream.
  NS_ASSERTION(!GetContentType().IsEmpty(),
      "When recreating a channel, we should know the Content-Type.");
  mChannel->SetContentType(GetContentType());
  mSuspendAgent.NotifyChannelOpened(mChannel);

  // Tell the cache to reset the download status when the channel is reopened.
  mCacheStream.NotifyChannelRecreated();

  return rv;
}

void RtspMediaResource::Suspend(bool aCloseImmediately)
{
  NS_ASSERTION(NS_IsMainThread(), "Don't call on non-main thread");

  MediaDecoderOwner* owner = mDecoder->GetMediaOwner();
  NS_ENSURE_TRUE_VOID(owner);
  dom::HTMLMediaElement* element = owner->GetMediaElement();
  NS_ENSURE_TRUE_VOID(element);

  mMediaStreamController->Suspend();
  element->DownloadSuspended();
}

void
ChannelMediaDecoder::ResourceCallback::NotifySuspendedStatusChanged(
  bool aSuspendedByCache)
{
  MOZ_ASSERT(NS_IsMainThread());
  DDLOGEX2("ChannelMediaDecoder::ResourceCallback",
           this,
           DDLogCategory::Log,
           "suspended_status_changed",
           aSuspendedByCache);
  MediaDecoderOwner* owner = GetMediaOwner();
  if (owner) {
    AbstractThread::AutoEnter context(owner->AbstractMainThread());
    owner->NotifySuspendedByCache(aSuspendedByCache);
  }
}

void ChannelMediaResource::Resume()
{
  NS_ASSERTION(NS_IsMainThread(), "Don't call on non-main thread");
  NS_ASSERTION(mSuspendCount > 0, "Too many resumes!");

  MediaDecoderOwner* owner = mDecoder->GetMediaOwner();
  if (!owner) {
    // Shutting down; do nothing.
    return;
  }
  dom::HTMLMediaElement* element = owner->GetMediaElement();
  if (!element) {
    // Shutting down; do nothing.
    return;
  }

  NS_ASSERTION(mSuspendCount > 0, "Resume without previous Suspend!");
  --mSuspendCount;
  if (mSuspendCount == 0) {
    if (mChannel) {
      // Just wake up our existing channel
      {
        MutexAutoLock lock(mLock);
        mChannelStatistics->Start();
      }
      // if an error occurs after Resume, assume it's because the server
      // timed out the connection and we should reopen it.
      mReopenOnError = true;
      PossiblyResume();
      element->DownloadResumed();
    } else {
      int64_t totalLength = mCacheStream.GetLength();
      // If mOffset is at the end of the stream, then we shouldn't try to
      // seek to it. The seek will fail and be wasted anyway. We can leave
      // the channel dead; if the media cache wants to read some other data
      // in the future, it will call CacheClientSeek itself which will reopen the
      // channel.
      if (totalLength < 0 || mOffset < totalLength) {
        // There is (or may be) data to read at mOffset, so start reading it.
        // Need to recreate the channel.
        CacheClientSeek(mOffset, false);
      }
      element->DownloadResumed();
    }
  }
}

void RtspMediaResource::Suspend(bool aCloseImmediately)
{
  NS_ASSERTION(NS_IsMainThread(), "Don't call on non-main thread");

  mIsSuspend = true;
  if (NS_WARN_IF(!mDecoder)) {
    return;
  }

  MediaDecoderOwner* owner = mDecoder->GetMediaOwner();
  NS_ENSURE_TRUE_VOID(owner);
  dom::HTMLMediaElement* element = owner->GetMediaElement();
  NS_ENSURE_TRUE_VOID(element);

  mMediaStreamController->Suspend();
  element->DownloadSuspended();
  mDecoder->NotifySuspendedStatusChanged();
}

nsresult
ChannelMediaResource::RecreateChannel()
{
  nsLoadFlags loadFlags =
    nsICachingChannel::LOAD_BYPASS_LOCAL_CACHE_IF_BUSY |
    (mLoadInBackground ? nsIRequest::LOAD_BACKGROUND : 0);

  MediaDecoderOwner* owner = mDecoder->GetMediaOwner();
  if (!owner) {
    // The decoder is being shut down, so don't bother opening a new channel
    return NS_OK;
  }
  dom::HTMLMediaElement* element = owner->GetMediaElement();
  if (!element) {
    // The decoder is being shut down, so don't bother opening a new channel
    return NS_OK;
  }
  nsCOMPtr<nsILoadGroup> loadGroup = element->GetDocumentLoadGroup();
  NS_ENSURE_TRUE(loadGroup, NS_ERROR_NULL_POINTER);

  nsCOMPtr<nsIChannel> channel;
  nsresult rv = NS_NewChannel(getter_AddRefs(channel),
                              mURI,
                              nullptr,
                              loadGroup,
                              nullptr,
                              loadFlags);
  mChannel = new nsMainThreadPtrHolder<nsIChannel>(channel);

  // We have cached the Content-Type, which should not change. Give a hint to
  // the channel to avoid a sniffing failure, which would be expected because we
  // are probably seeking in the middle of the bitstream, and sniffing relies
  // on the presence of a magic number at the beginning of the stream.
  NS_ASSERTION(!GetContentType().IsEmpty(),
      "When recreating a channel, we should know the Content-Type.");
  mChannel->SetContentType(GetContentType());

  return rv;
}

void ChannelMediaResource::SetupChannelHeaders()
{
  // Always use a byte range request even if we're reading from the start
  // of the resource.
  // This enables us to detect if the stream supports byte range
  // requests, and therefore seeking, early.
  nsCOMPtr<nsIHttpChannel> hc = do_QueryInterface(mChannel);
  if (hc) {
    // Use |mByteRange| for a specific chunk, or |mOffset| if seeking in a
    // complete file download.
    nsAutoCString rangeString("bytes=");
    if (!mByteRange.IsNull()) {
      rangeString.AppendInt(mByteRange.mStart);
      mOffset = mByteRange.mStart;
    } else {
      rangeString.AppendInt(mOffset);
    }
    rangeString.Append("-");
    if (!mByteRange.IsNull()) {
      rangeString.AppendInt(mByteRange.mEnd);
    }
    hc->SetRequestHeader(NS_LITERAL_CSTRING("Range"), rangeString, false);

    // Send Accept header for video and audio types only (Bug 489071)
    NS_ASSERTION(NS_IsMainThread(), "Don't call on non-main thread");
    MediaDecoderOwner* owner = mDecoder->GetMediaOwner();
    if (!owner) {
      return;
    }
    dom::HTMLMediaElement* element = owner->GetMediaElement();
    if (!element) {
      return;
    }
    element->SetRequestHeaders(hc);
  } else {
    NS_ASSERTION(mOffset == 0, "Don't know how to seek on this channel type");
  }
}

void BaseMediaResource::SetLoadInBackground(bool aLoadInBackground) {
  if (aLoadInBackground == mLoadInBackground) {
    return;
  }
  mLoadInBackground = aLoadInBackground;
  if (!mChannel) {
    // No channel, resource is probably already loaded.
    return;
  }

  MediaDecoderOwner* owner = mCallback->GetMediaOwner();
  if (!owner) {
    NS_WARNING("Null owner in MediaResource::SetLoadInBackground()");
    return;
  }
  dom::HTMLMediaElement* element = owner->GetMediaElement();
  if (!element) {
    NS_WARNING("Null element in MediaResource::SetLoadInBackground()");
    return;
  }

  bool isPending = false;
  if (NS_SUCCEEDED(mChannel->IsPending(&isPending)) &&
      isPending) {
    nsLoadFlags loadFlags;
    DebugOnly<nsresult> rv = mChannel->GetLoadFlags(&loadFlags);
    NS_ASSERTION(NS_SUCCEEDED(rv), "GetLoadFlags() failed!");

    if (aLoadInBackground) {
      loadFlags |= nsIRequest::LOAD_BACKGROUND;
    } else {
      loadFlags &= ~nsIRequest::LOAD_BACKGROUND;
    }
    ModifyLoadFlags(loadFlags);
  }
}

void
ChannelMediaDecoder::ResourceCallback::NotifyDataEnded(nsresult aStatus)
{
  RefPtr<ResourceCallback> self = this;
  nsCOMPtr<nsIRunnable> r = NS_NewRunnableFunction(
    "ChannelMediaDecoder::ResourceCallback::NotifyDataEnded",
    [=]() {
    if (!self->mDecoder) {
      return;
    }
    self->mDecoder->NotifyDownloadEnded(aStatus);
    if (NS_SUCCEEDED(aStatus)) {
      MediaDecoderOwner* owner = self->GetMediaOwner();
      MOZ_ASSERT(owner);
      owner->DownloadSuspended();

      // NotifySuspendedStatusChanged will tell the element that download
      // has been suspended "by the cache", which is true since we never
      // download anything. The element can then transition to HAVE_ENOUGH_DATA.
      self->mDecoder->NotifySuspendedStatusChanged();
    }
  });
  mAbstractMainThread->Dispatch(r.forget());
}