1371976 - stylo: Need to implement sane comparisons between old and new counter styles

Status: RESOLVED FIXED

(Core :: CSS Parsing and Computation, enhancement, P1)

Description

[Boris Zbarsky [:bzbarsky]]

Right now we always detect a difference for styles other than "none", because the equality comparison between resolved and unresolved counter styles always says "not equal", the old struct always has a resolved style, and the new struct always has an unresolved one.

See bug 1371955 comment 4 and bug 1371955 comment 5.  As Cameron says, we should be able to do a readonly lookup for the case when we know we want to compare to an already-resolved style.  If the lookup returns nothing, we're not equal.

Comment 1

[Xidorn Quan [:xidorn] UTC+10]

See my comment in bug 1371955 comment 11, basically I don't think we want to do comparison between resolve and unresolved counter styles.

Comment 2

[Boris Zbarsky [:bzbarsky]]

OK, let's retitle to the real problem we want to solve.

Comment 3

[Xidorn Quan [:xidorn] UTC+10]

I can take this. I actually pretty much like my idea that we do the hashtable lookup during parallel traversal and only leave counter style unresolved when lookup doesn't find any existing item.

Comment 4

[Xidorn Quan [:xidorn] UTC+10]

(ni? myself in case I forgot.)

Comment 5

[Bobby Holley (:bholley)]

IIUC, this is causing spurious reflows after restyles, which can significantly hurt perf. P1.

Comment 6

[Xidorn Quan [:xidorn] UTC+10]

Attachment: Bug 1371976 - Resolve counter style during parallel traversal when possible.

Review commit: https://reviewboard.mozilla.org/r/148844/diff/#index_header
See other reviews: https://reviewboard.mozilla.org/r/148844/

Comment 7

[Xidorn Quan [:xidorn] UTC+10]

This would work only with both bug 1372488 and bug 1372549 fixed, otherwise there could still be unnecessary reflows.

Comment 8

[Xidorn Quan [:xidorn] UTC+10]

Comment on attachment 8877429 [details]
Bug 1371976 - Resolve counter style during parallel traversal when possible.

Review request updated; see interdiff: https://reviewboard.mozilla.org/r/148844/diff/1-2/

Comment 9

[Cameron McCormack (:heycam)]

Comment on attachment 8877429 [details]
Bug 1371976 - Resolve counter style during parallel traversal when possible.

https://reviewboard.mozilla.org/r/148844/#review153336

Comment 10

[Xidorn Quan [:xidorn] UTC+10]

Servo PR: servo/servo#17316

Comment 11

[Xidorn Quan [:xidorn] UTC+10]

Comment on attachment 8877429 [details]
Bug 1371976 - Resolve counter style during parallel traversal when possible.

Review request updated; see interdiff: https://reviewboard.mozilla.org/r/148844/diff/2-3/

Comment 12

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/eec8e0b192a8
Resolve counter style during parallel traversal when possible. r=heycam

Comment 13

[Sebastian Hengst [:aryx] (needinfo me if it's about an intermittent or backout)]

https://hg.mozilla.org/mozilla-central/rev/eec8e0b192a8