1374357 - stylo: ensure we match invalidation selectors in the "fast" order, whichever that is

Status: RESOLVED INCOMPLETE

(Core :: CSS Parsing and Computation, enhancement)

Description

[Boris Zbarsky [:bzbarsky]]

See bug 1373800 comment 13.  We should ensure that invalidation selectors are matches in the "fast" order, however that's implemented.  Ideally we can do this in such a way that future changes to underlying storage order don't involve changes to invalidation selector matching code....

Comment 1

[Boris Zbarsky [:bzbarsky]]

Bobby is this still a perf issue after the fix for bug 1373800?  That is, is there more perf work to be done here, or is this just a "make the code more robust" bug at this point?

Comment 2

[Bobby Holley (:bholley)]

I don't know if there's much we can do here. Unless we want to use separate storage for invalidation selectors vs the original selector (I believe right now we just use indices), we can't have the fast order in both left-to-right and right-to-left matching modes.

So I think this is probably WONTFIX, unless I'm misunderstanding one of the pieces. NI emilio to confirm.

Comment 3

[Emilio Cobos Álvarez (:emilio)]

Yeah, it's unclear if walking the whole partial selector and matching the other way would be faster. Intuitively it would not, but you never know.

I'd prefer not doing it if we don't know it's a bottleneck of any sort, given it would definitely make the invalidation stuff more complex (and I'd like to keep it as obvious as possible).

Comment 4

[Bobby Holley (:bholley)]

Ok, resolving until we have a clearer need.