Bug 20315 – Memory leak with Canvas getImageData

• Status: RESOLVED
• Resolution: FIXED
• Component: JavaScriptCore

[James Urquhart]

I seem to be getting a rather predictable memory "leak" when using getImageData() on a 2d Canvas Rendering Context.

Basically in my test case, i am calling putImageData(getImageData(...), ...) every chance i can get. Memory usage climbs well into the 1 <-> 2gb range.

It should be noted that this occurs in other browsers too, though with varying cut-off points (presumably when the garbage collection finally kicks in).

However it should also be noted that i am essentially running the same code in a real app, i don't seem to encounter this issue (in WebKit r35620). For reference, i have put a copy of this up at the following URL:

http://www.cuppadev.co.uk/hiscumm/webkit-canvas-mem/js_test.html

(search for "fastPaletteRemap" if you want the meat of it)

As for why this is, i am really stumped. So i can't really rely on it.

Any insight would be appreciated of course. :)

[Eric Seidel (no email)]

Ouch.

[Geoffrey Garen]

JSImageData::JSImageData just needs to call JSC::Heap::reportExtraCost.

[Oliver Hunt]

JSCanvasPixelArrayCustom already does that -- i suppose if you never used the CPA that would achieve this result but, if you ever did touch it it would report...

Hmmmm -- i wonder if we ever get rid of the cached wrapper though?

[Oliver Hunt]

Created attachment 24004 [details]
Fixeration

Fix

[Maciej Stachowiak]

Comment on attachment 24004 [details]
Fixeration

r=me

[Oliver Hunt]

Committing to http://svn.webkit.org/repository/webkit/trunk ...
	D	WebCore/bindings/js/JSCanvasPixelArrayCustom.cpp
	M	WebCore/ChangeLog
	M	WebCore/WebCore.xcodeproj/project.pbxproj
	A	WebCore/bindings/js/JSImageDataCustom.cpp
	M	WebCore/bindings/scripts/CodeGeneratorJS.pm
	M	WebCore/html/CanvasPixelArray.idl
	M	WebCore/html/ImageData.idl
Committed r37181