Enable -Wexit-time-destructors for all in-tree library targets and
update process-lifetime library statics so they no longer register
exit-time destructors. Long-lived caches, lookup tables, singleton
registries, and generated constants now use NeverDestroyed or leaked
references where the data is intended to live until process exit.
Update LibWeb, LibLine, and the binding generators so regenerated
sources follow the same rule instead of reintroducing destructed
statics.
`@scope (a) to (b) {}` applies its contained style rules to elements
that have `a` as a parent, and do not have `a b` as a parent. Both the
`a` and `b` selector lists are optional.
Because it's situational whether a `@scope` will apply to a given
element, we store the ancestor scope on the `MatchingRule`, similar to
`@container`, and then determine during matching whether all the parent
`@scope`s match or not.
The rules for how selectors inside `@scope` are adjusted and interpreted
are a bit confusing. Unlike for other at-rules, nested style rules
inside `@scope` do not get a leading `&` added during parsing. To
support this, `adapt_nested_relative_selector_list()` now takes a flag
for whether its parent is a `@scope` or not.
`@scope` can also contain nested declarations without itself being
nested inside a style rule.
When determining their selectors, nested declarations rules adopt the
`@scope`'s scoping root if it has one, or otherwise fall back to the
parent element of the `<style>` element (not implemented here,) or the
`:root`. These are required to have zero specificity, so we wrap the
selector in `:where()`.
We previously just ignored `&` when absolutizing it would become
`:scope`, because of specificity, but we can actually directly replace
it with `:where(:scope)` in that situation instead.
This commit also renames parent_style_rule() to nesting_parent_rule()
and it doesn't just return CSSStyleRules - in a later commit, we'll
also detect CSSScopeRules here.
Just a move with very minor adjustments. We're going to need to run the
absolutization process on other selectors besides those in a
CSSStyleRule - specifically the scope target of CSSScopeRule. So put the
code where it's accessible.
Previously, and according to the spec, `a::part(foo)::before` would be a
single CompoundSelector, even though it matches against 3 different
targets. This meant some awkward swapping of targets in the middle of
matching, and in particular it made `::part()` and `::slotted()` quite
hacky, requiring them to track extra data on the MatchContext to then
use later. This was scattered around and difficult to follow.
Partly inspired by Gecko, this commit instead introduces an invisible
PseudoElement combinator. After parsing a selector, we find any
CompoundSelectors that contain a pseudo-element and split them up, so
that each CompoundSelector only has a single target in the end. Where
the pseudo-element was at the start of a CompoundSelector, we insert an
invisible universal selector before it to represent its originating
element.
So now, a CompoundSelector deals with one target, and switching targets
is done at the combinator.
The one inconsistency is that we match the target of ::slotted()
and ::part() in pseudo_element_transition_target(), instead of before
then when processing the SimpleSelector. This is to avoid repeating the
same computations twice.
No outward-facing behaviour changes, though the invalidation metrics
have changed.
Apart from making the code a bit easier to follow, we'll need to
distinguish between the two in order to insert a pseudo-element
combinator in front of pseudo-elements (including the single-colon
legacy ones).
next_is_pseudo_element() is its own function because it'll be needed in
a couple of other places, again to support pseudo-element combinators.
This really represents the final pseudo-element, the one that style
actually applies to. We'll want to know that even once we fully support
having multiple pseudo-elements in a selector.
Allow CSS pseudo-element chaining with ::part() so that
selectors like ::part(title)::before can style pseudo-elements
within shadow DOM parts.
Parser changes (SelectorParsing.cpp): The pseudo-element
validation logic now tracks which pseudo-element appears first
and second in a compound selector. When multiple pseudo-elements
are found, the parser permits the selector only if the first is
::part() and the second is NOT ::part(). A maximum of two
pseudo-elements is enforced.
Selector changes (Selector.cpp, Selector.h): The Selector
constructor now stores the last pseudo-element (the styling
target) rather than the first. For ::part(foo)::before, the
selector reports ::before as its target. A new
m_contains_part_pseudo_element flag separately tracks whether
::part() is present for the selector engine.
Fixes 9 WPT tests: 6 in css/selectors/parsing/parse-part.html
for chained selector parsing, and 3 in
css/css-shadow-parts/multiple-scopes.html for correct scoping
of exported, middle-scope, and non-exported part selectors.
Before this change, we'd stop collecting must-be-present identifiers
from the selector once we crossed a combinator that wasn't ' ' or '>'.
However, we can simply skip over sibling combinators and continue
collecting ancestor identifiers on the "other side" of them, since
siblings always have a shared parent.
This allows us to use the ancestor filter to quickly reject more
selectors. It also fixes a harmless bug where we believed the ancestor
filter to be useful while there were 0 ancestor hashes in the selector.
The corresponding WPT test was not imported since it still fails
for unrelated reasons. As it stands right now, we have no way of
testing this behavior.
Implements `::slotted()` to enough extent we could pass the imported WPT
test and make substantial layout correctness improvement on
https://www.rottentomatoes.com/
This reverts e7890429aa and partly reverts
a59c15481f.
The one pseudo-class that accepted multiple of these was :heading(), and
since that got changed to take integers instead, there's no need to keep
this extra complexity (and memory usage) around.
We originally had special handling for `:host()` as that had been the
only pseudo-class that could be both an identifier or a function.
However, this meant duplicating the serialization logic, and also we
had to manually remember to add the same hack for any other
identifier-and-function cases. Which I forgot to do with `:heading()`!
So instead, for these cases, detect if they actually have arguments
specified and use that to determine which form to serialize as. We do
still have to write a check for each one of these pseudo-classes, but
the VERIFY should make it easier to remember.
The upcoming `:heading()` pseudo-class takes multiple comma-separated
An+Bs. Also rename this field as the `:nth-[last-]child()`
pseudo-classes are only a subset of the users.
Previusly the implementation only was serializing PseudoElements if they
were the last element in the CompoundSelector. This caused bugs on
Javascript code that referenced their selectorText, where it would be
wrong.
Selector::serialize() is used for both normal and relative selectors.
For the latter, we need to serialize their initial combinator, and for
the former, we always set the initial combinator as None anyway, so
this would be a no-op there.
Gets us 3 WPT passes.
The spec requires us to accept any ident here, not just ltr/rtl, and
also serialize it back out. That means we need to keep the original
string around.
In order to not call keyword_from_string() every time we want to match
a :dir() selector, we still attempt to parse the keyword and keep it
around.
A small behaviour change is that now we'll serialize the ident with its
original casing, instead of always lowercase. Chrome and Firefox
disagree on this, so I think either is fine until that can be
officially decided.
Gets us 2 WPT passes (including 1 from the as-yet-unmerged :dir() test).
The spec gives us a hard-coded list of functional pseudo-classes and how
to serialize them - but this list is incomplete and likely to always be
outdated compared to the list of pseudo-classes that exist. So instead,
use the generated metadata we already have to serialize their arguments
based on their type.
This fixes :dir() and :has(), which previously did not serialize their
arguments.
Gets us 26 passes (including 6 from that as-yet-unmerged :dir() test).
We achieve this by keeping track of all checked pseudo class selectors
in the SelectorEngine code. We also give StyleComputer per-pseudo-class
rule caches.
"Functional" as in "it's a function token" and not "it works", because
the behaviour for these is unimplemented. :^)
This is modeled after the pseudo-class parsing, but with some changes
based on things I don't like about that implementation. I've
implemented the `<pt-name-selector>` parameter used by view-transitions
for now, but nothing else.
The upcoming generated types will match those for pseudo-classes: A
PseudoElementSelector type, that then holds a PseudoElement enum
defining what it is. That enum will be at the top level in the Web::CSS
namespace.
In order to keep the diffs clearer, this commit renames and moves the
types, and then a following one will replace the handwritten enum with
a generated one.
This also implements the `:high-value` and `:low-value` that are in the
spec.
Same note as before about this being based on the very-drafty CSS Forms
spec. In fact, some of this isn't even in that spec yet. Specifically,
the `:suboptimal-value` and `:even-less-good-value` names are undecided
and subject to change. However, it's clear that this is a pseudo-class
situation, not a pseudo-element one, so I think this is still an
improvement, as it allows styling of the `::fill` pseudo-element
regardless of what state it is in.
Relevant spec issue: https://github.com/openui/open-ui/issues/1130
This spec is very early on, and likely to change. However, it still
feels preferable to use these rather than the prefixed -webkit ones.
Plus, as we have a `::fill` on range inputs, we can use that for styling
the bar instead of inserting CSS from C++.
A couple of fixes here:
- Parse a `<complex-selector>` instead of a `<selector-list>`
- Don't match if any unknown `::-webkit-*` pseudo-elements are found
If an element is affected only by selectors using the direct sibling
combinator `+`, we can calculate the maximum invalidation distance and
use it to limit style invalidation. For example, the selector
`.a + .b + .c` has a maximum invalidation distance of 2, meaning we can
skip invalidating any element affected by this selector if it's more
than two siblings away from the element that triggered the style
invalidation.
This change results in visible performance improvement when hovering
PR list on GitHub.
If selector does not have any descendant combinators then we know for
sure it won't be filtered out by ancestor filter, which means there is
no need to check for it.
This change makes hover style invalidation go faster on Discord where
with this change we spend 4-5% in `should_reject_with_ancestor_filter()`
instead of 20%.
Before this change, checking if fast selector matching could be used was
only enabled in style recalculation and hover invalidation. With this
change it's enabled for all callers of SelectorEngine::matches() by
default. This way APIs like `Element.matches()` and `querySelector()`
could take advantage of this optimization.
Previously, we optimized hover style invalidation to mark for style
updates only those elements that were matched by :hover selectors in the
last style calculation.
This change takes it a step further by invalidating only the elements
where the set of selectors that use :hover changes after hovered element
is modified. The implementation is as follows:
1. Collect all elements whose styles might be affected by a change in
the hovered element.
2. Retrieve a list of all selectors that use :hover.
3. Test each selector against each element and record which selectors
match.
4. Update m_hovered_node to the newly hovered element.
5. Repeat step 3.
6. For each element, compare the previous and current sets of matched
selectors. If they differ, mark the element for style recalculation.
Details' contents matches a new details-content pseudo element.
Further work is required to make this pseudo-element behave per spec.
This pseudo should be element-backed per
https://drafts.csswg.org/css-pseudo/#element-backed
