1470099 - Make CSSStyleDeclaration's wrapper use nursery heap and make last Release call ClearComputedStyle();

Status: RESOLVED FIXED

(Core :: DOM: CSS Object Model, defect)

Comment 1

[Olli Pettay [:smaug][[e-mail]]]

Attachment: shortliving_cssstyledeclaration.diff

Make the wrapper nursery allocated, use faster mainthread-only refcounting (this way cycle collector uses main-thread only purple buffer nursery), call ClearComputedStyle() sooner.

remote: View the pushlog for these changes here:
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Comment 2

[Emilio Cobos Álvarez [:emilio]]

Comment on attachment 8986731 [details] [diff] [review]
shortliving_cssstyledeclaration.diff

Review of attachment 8986731 [details] [diff] [review]:
-----------------------------------------------------------------

::: dom/webidl/CSSStyleDeclaration.webidl
@@ +8,5 @@
>   */
>  
> + // Because of getComputedStyle, many CSSStyleDeclaration objects can be
> + // short-living.
> +[ProbablyShortLivingWrapper]

Disclaimer: I'm not totally familiar with all of the implications of this. I guess it makes sense for getComputedStyle, but not sure how much would this slow down or impact element.style / cssrule.style / etc.

I guess that if node lists have this it may make sense for this to have it as well.

::: layout/style/nsComputedDOMStyle.cpp
@@ +375,5 @@
>  NS_INTERFACE_MAP_END_INHERITING(nsDOMCSSDeclaration)
>  
>  
> +NS_IMPL_MAIN_THREAD_ONLY_CYCLE_COLLECTING_ADDREF(nsComputedDOMStyle)
> +NS_IMPL_MAIN_THREAD_ONLY_CYCLE_COLLECTING_RELEASE_WITH_LAST_RELEASE(

Maybe change the destructor to assert !mResolvedComputedStyle instead of calling ClearComputedStyle(), with a comment pointing here?

Comment 3

[Olli Pettay [:smaug][[e-mail]]]

Attachment: + assertion

Still compiling (a debug build) to see if it could fire. I can't see any reason why it would.

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/mozilla-inbound/rev/412d61652806
Make CSSStyleDeclaration's wrapper use nursery heap and make last Release call ClearComputedStyle(), r=emilio

Comment 5

[Natalia Csoregi [:nataliaCs]]

https://hg.mozilla.org/mozilla-central/rev/412d61652806