style: Slim down SharedStyleContext, and do various other cleanups around the style crate.
This slims down SharedStyleContext, in preparation for a few things.
First, I would like to eventually move the stylist to the document in Servo, in
order for it to hold the StyleSheetSet.
Also, this gets rid of a fair amount of overhead while creating it in stylo.
Fixes bug 1363245.
<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/16802)
<!-- Reviewable:end -->
Fix typo and simplify for PresentationalHintsSynthesizer
<!-- Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `__` with appropriate data: -->
- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes do not require tests because it only affects build.
<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/16785)
<!-- Reviewable:end -->
Allow stylo to do lazier stylist rebuilds
---
<!-- Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `__` with appropriate data: -->
- [ ] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [ ] These changes fix https://bugzilla.mozilla.org/show_bug.cgi?id=1361843 (github issue number if applicable).
<!-- Either: -->
- [ ] There are tests for these changes OR
- [X] These changes do not require tests because it's optimization, which should have no observable behavior difference.
<!-- Also, please make sure that "Allow edits from maintainers" checkbox is checked, so that we can help you if you get stuck somewhere along the way.-->
<!-- Pull requests that do not address these steps are welcome, but they will require additional verification as part of the review process. -->
<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/16798)
<!-- Reviewable:end -->
I've chosen this approach mainly because there's no other good way to guarantee
the model is correct than holding the snapshots alive until a style refresh.
What I tried before this (storing them in a sort of "immutable element data") is
a pain, since we call into style from the frame constructor and other content
notifications, which makes keeping track of which snapshots should be cleared an
which shouldn't an insane task.
Ideally we'd have a single entry-point for style, but that's not the case right
now, and changing that requires pretty non-trivial changes to the frame
constructor.
MozReview-Commit-ID: FF1KWZv2iBM
Signed-off-by: Emilio Cobos Álvarez <emilio@crisal.io>
Right now in the common case we're doing twice the work during stylist update,
and also checking is_html_element_in_html_document twice during lookup. This
patch aligns us with what Gecko does.
MozReview-Commit-ID: D4TyG30BP8C
This makes things more readable, and easier to profile (since the Gecko
profiler doesn't have any intra-function granularity, so I tend to make
helpers non-inline when drilling down into what's expensive).
It allows us to iterate the selector list once, which could help cache locality
for rules with many selectors.
MozReview-Commit-ID: GdFtgrbYCIu
Text style is always resolved via ServoStyleSet::ResolveStyleForText, either
from the frame constructor initially, or from
ServoRestyleManager::ProcessPostTraversalForText.
So text-only adjustments should go there instead. Since that doesn't call into
cascade(), all the code that passes `pseudo` there is dead code we can remove.
MozReview-Commit-ID: jpbBYpLlUL
Signed-off-by: Emilio Cobos Álvarez <emilio@crisal.io>
It's unfortunate, but it's a correctness issue. I was looking at the
expectations update here:
* https://hg.mozilla.org/integration/autoland/rev/659cddddd434
And investigating it I realised that it's wrong to coalesce selectors like that,
because we keep the bloom filter flags.
So in the test cases disabled, we have a selector that looks like this:
msub > :not(:first-child),
msup > :not(:first-child),
msubsup > :not(:first-child),
mmultiscripts > :not(:first-child) {
-moz-script-level: +1;
-moz-math-display: inline;
}
And an element that looks like this:
<msubsup><mi></mi><mi></mi></msubsup>
We're only inserting the first selector msub > :not(:first-child) into the set,
so when we're going to match the <mi> elements we fast-reject it in both cases
due to the bloom filter, so they share style.
I can't see an easy way to fix this keeping the deduplication. If we keep it, we
need to remove the bloom filter optimization, which means that we'd trash the
cache for every first-child in the document (the :not(:first-child) effectively
becomes a global rule).
MozReview-Commit-ID: 9VPkmdj9zDg
Signed-off-by: Emilio Cobos Álvarez <emilio@crisal.io>
We have a fast path to return None if we have no rules for the pseudo-element at
all, but we should also return None if we have no _matching_ rules for it for
the given originating element. This is relied on by consumers like
Servo_ResolvePseudoStyle, which needs to be able to detect the "no styles for
this pseudo-element for this originating element case", to support probing for
whether work for a specific pseudo-element should be done at all.
Note that, while the comment is correct that there is a fair amount of -moz-any
usage in the UA sheet, it's always used as an ancestor selector, and thus ignored
for our purposes. Nevertheless, it's straightforward enough to support properly,
so we do that here.
MozReview-Commit-ID: Kz1yNfPUIaP
Ports the Gecko fixup for text-combine-upright writing mode to Servo. In
addition, this passes the current pseudo element (if any) down to the cascade
for use during the fixup process.
MozReview-Commit-ID: BkHd4AvSsOt
If there are multiple prefixed/non-prefixed @keyframes with the same name;
* non-prefixed rule overrides earlier rules.
* prefixed rule overrides earlier prefixed rules.
This improves cache locality and reduces allocations during parsing.
Note that this reverses the iteration order within a sequence of simple selectors,
but that shouldn't matter.
stylo: Centralize stylesheet handling.
This is needed for both bug 1357461 and bug 1273303, where I plan to add smarter
invalidations than what we have now.
Also, it's cleaner.
Ideally I'll move this onto stylist, though that may require extra work to make
it work fine for Servo, so for now let's just do the obvious thing.
<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/16516)
<!-- Reviewable:end -->
