D29542 fixed the bogus checks that was making nested pseudo-elements match
author rules. This adds tests and ends up being just a cleanup, though as it
turns out we it also fixes an issue with ::slotted() matched from
Element.matches.
Differential Revision: https://phabricator.services.mozilla.com/D27529
This fixes a couple fuzz bugs and prevents special-casing <svg:use> even more in
bug 1431255.
Unfortunately not as many hacks went away as I'd have hoped, since we still need
to match document rules, see the linked SVGWG issues.
But blocks_ancestor_combinators goes away, which is nice since it's on a very
hot path.
Bug: 1450250
Reviewed-by: heycam
Differential Revision: https://phabricator.services.mozilla.com/D2154
MozReview-Commit-ID: C4mthjoSNFh
Without turning it on yet, of course.
The reason why I didn't use the general PseudoElement mechanism is because this
pseudo is a bit of its own thing, and I found easier to make ::selectors know
about it (because you need to jump to the assigned slot) than the other way
around.
Also, we need to support ::slotted(..)::before and such, and supporting multiple
pseudo-elements like that breaks some other invariants around the SelectorMap,
and fixing those would require special-casing slotted a lot more in other parts
of the code.
Let me know if you think otherwise.
I also don't like much the boolean tuple return value, but I plan to do some
cleanup in the area in a bit, so it should go away soon, I'd hope.
Right now we go through a lot of hoops to see if we ever see a relevant link.
However, that information is not needed: if the element is a link, we'll always
need to compute its visited style because its its own relevant link.
If the element inherits from a link, we need to also compute the visited style
anyway.
So the "has a relevant link been found" is pretty useless when we know what are
we inheriting from.
The branches at the beginning of matches_complex_selector_internal were
affecting performance, and there are no good reasons to keep them.
I've verified that this passes all the visited tests in mozilla central, and
that the test-cases too-flaky to be landed still pass.
This type is a lot of complexity related to a very specific thing such as the
hover and active quirk.
Instead of that, move `nesting_level` to `MatchingContext`, and simplify all
this computing whether the quirk applies upfront, for each complex selector we
test.
This is less error-prone, and also allows simplifying more stuff in a bit.
Adjust the matching process to look for a "relevant link" while matching. A
"relevant link" is the element being matched if it is a link or the nearest
ancestor link.
Matching for links now depends on the `VisitedHandlingMode`, which determines
whether all links match as if they are unvisited (the default) or if the
relevant link matches as visited (and all others remain unvisited).
If a relevant link is ever found for any selector, track this as part of the
`MatchingContext` object. This is used in the next patch to determine if an
additional match and cascade should be performed to compute the styles when
visited.
MozReview-Commit-ID: 3xUbRo7vpuD
