1368229 - stylo: We have no style sharing for mapped attributes (aka presentation hints or preshints)

Status: RESOLVED FIXED

(Core :: CSS Parsing and Computation, enhancement)

Description

[Boris Zbarsky [:bzbarsky]]

In Gecko, these are explicitly coalesced on the DOM level just so we'll share the style side.  With stylo we share the _declaration_, but preshints immediately disable ComputedValues sharing.

I don't see why we need to do that.  As long as two elements have the same exact declaration pointer for their preshints, why can't we do style sharing for them?

Comment 1

[Bobby Holley (:bholley)]

(In reply to Boris Zbarsky [:bz] (work week until 5/26) (if a patch has no decent message, automatic r-) from comment #0)
> I don't see why we need to do that.  As long as two elements have the same
> exact declaration pointer for their preshints, why can't we do style sharing
> for them?

Yes, I think the current setup predates the caching we do now. Worth checking whether with works for Servo too. Either way, should be a simple patch.

Comment 2

[Emilio Cobos Álvarez (:emilio)]

Yeah, we can. Servo creates a new declaration each time, so should be fine too AFAICT.

Comment 3

[Emilio Cobos Álvarez (:emilio)]

It needs to change a bit the setup, but it shouldn't be hard, I'll write a patch for it.

Comment 4

[Emilio Cobos Álvarez (:emilio)]

Attachment: Patch

Comment 5

[Boris Zbarsky [:bzbarsky]]

> Servo creates a new declaration each time

We should probably file an issue on that...

Comment 6

[Bobby Holley (:bholley)]

Comment on attachment 8872041 [details] [review]
Patch

delegate+ on github. Next time please post patches to bugzilla. :-)

Comment 7

[Boris Zbarsky [:bzbarsky]]

Is this fixed now?

Comment 8

[Emilio Cobos Álvarez (:emilio)]

Yes, fixed in https://github.com/servo/servo/pull/17063