Bug 173403 – ImageDecoder: Gifs with infinite animation only play once very often

• Status: RESOLVED
• Resolution: FIXED
• Component: Platform

[Carlos Garcia Campos]

It doesn't always happen, it's easier to reproduce when loading big files from the network, but it also depends on every file. The problem is that ImageFrameCache is caching the repetition count value always when the size is already available. In the case of gif files, the loop count value can be at any point of the image stream, so having the size available doesn't mean we also have the loop count. So, if the value is queried before it's available, the default value is cached (repeat once) and then always used. So, we need a way to only cache that value when it's really available.

[Carlos Garcia Campos]

Created attachment 312958 [details]
Patch

[Carlos Garcia Campos]

Created attachment 312959 [details]
Patch

[Carlos Garcia Campos]

Ping reviewers.

[Michael Catanzaro]

Said, is there another way you would prefer to do this?

[Said Abou-Hallawa]

(In reply to Michael Catanzaro from comment #4)
> Said, is there another way you would prefer to do this?

I think this issue can be fixed by clearing m_repetitionCount in ImageFrameCache::clearMetadata(). This method is called from ImageSource::dataChanged() every time new data is incrementally added to the image source. ImageFrameCache::clearMetadata() clears all the cached metadata that may change their values with new data added to the image source.

[Carlos Garcia Campos]

(In reply to Said Abou-Hallawa from comment #5)
> (In reply to Michael Catanzaro from comment #4)
> > Said, is there another way you would prefer to do this?
> 
> I think this issue can be fixed by clearing m_repetitionCount in
> ImageFrameCache::clearMetadata(). This method is called from
> ImageSource::dataChanged() every time new data is incrementally added to the
> image source. ImageFrameCache::clearMetadata() clears all the cached
> metadata that may change their values with new data added to the image
> source.

Ah!, good point, I didn't know that, it's indeed a much simpler solution. I'll submit a new patch. Thanks!

[Carlos Garcia Campos]

Created attachment 315102 [details]
Patch

[Michael Catanzaro]

Comment on attachment 315102 [details]
Patch

Much nicer! Thanks, Said.

[Carlos Garcia Campos]

Committed r219389: <http://trac.webkit.org/changeset/219389>