Bug 181391 – When decoding thread fails to generate a new NativeImage, the main thread has to remove the ImageFrameRequest from commit queue

• Component: Images
• Status: NEW

[Said Abou-Hallawa]

This is a follow up for <http://trac.webkit.org/changeset/216998>. See the comment https://bugs.webkit.org/show_bug.cgi?id=171614#c20.

ImageSource keeps two queues of ImageFrameRequest. The first one, 'm_frameRequestQueue", is shared between the main thread and the decoding thread. The second one, 'm_frameCommitQueue', is only accessible by the main thread. The m_frameCommitQueue is used to keep track of the pending requests. An item is removed only when the main thread caches it. It is also used to tell whether the decoding thread is busy or not without having to have another synchronized object.

If the decoding thread fails to generate the NativeImage. We should be doing the following:

-- The ImageFrameRequest should be removed from m_frameCommitQueue.
-- The Image object should be notified the decoding was finished (even it failed).
-- The HTMLImageElement::decode() promise should be rejected.
-- BitmapImage::draw() should fall back to synchronous decoding mode.

[Said Abou-Hallawa]

Created attachment 330733 [details]
Patch

[Maciej Stachowiak]

Comment on attachment 330733 [details]
Patch

Unfortunately, this old patch fails to apply.