This doesn't have parsing support for multiple languages in the same
selector. Support for language subcodes is not great either. But it
does do the basics.
If the current Document is not attached to a Web::Page for whatever
reason, but we're trying to look up a color from the system palette,
let's just fail the lookup instead of crashing the process.
ID selectors need to be serialized as identifiers in the spec, but other
hash-values do not. This was causing hex colors that start with a
number, like `#54a3ff`, to serialize as `#\35 4a3ff`, which is silly
and unnecessary.
Selector serialization is done elsewhere, so this case in Token is
probably also unnecessary, but there might be situations I haven't
thought of where serializing an ID does need to happen while it's still
a Token.
`static const` variables can be computed and initialized at run-time
during initialization or the first time a function is called. Change
them to `static constexpr` to ensure they are computed at
compile-time.
This allows some removal of `strlen` because the length of the
`StringView` can be used which is pre-computed at compile-time.
- background properties
- box-shadow
- cursor
- SVG fill/stroke properties
- image-rendering
- outline properties
- pointer-events
- user-select
This should be basically all of them. I skipped `opacity` and
`transform` since establishing a stacking context feels like a
layout-affecting thing, but I could be very wrong on that!
In Selectors level 4, `:nth-child()` and `:nth-last-child()` can both
optionally take a selector-list argument. This selector-list acts as a
filter, so that only elements matching the list are counted. For
example, this means that the following are equivalent:
```css
:nth-child(2n+1 of p) {}
p:nth-of-type(2n+1) {}
```
This fixes the specificity for :not(), :is() and :where(). Also, we now
clamp the specificity numbers instead of letting them overflow, and I
sprinkled in some spec comments for good measure.
`<forgiving-selector-list>` and `<forgiving-relative-selector-list>` are
the same as regular selector-lists, except that an invalid selector
does not make the whole list invalid. The former is used by the `:is()`
pseudo-class.
For example:
```css
/* This entire selector-list is invalid */
.foo, .bar, !?invalid { }
/* This is valid, but the "!?invalid" selector is removed */
:is(.foo, .bar, !?invalid) { }
```
Also as part of this, I've removed the `parse_a_selector(TokenStream)`
and `parse_a_relative_selector(TokenStream)` methods as they don't add
anything useful.
As noted, this is not 100% to the spec, but effectively the same -
`no-preference` is only allowed to appear in features that evaluate it
as false in a boolean context. This is also the only identifier besides
`none` that evaluates to false. If other identifiers gain this property
in the future, we can make it more robust then.
This adds (or at least stubs-out) the following:
- display-mode
- dynamic-range
- environment-blending
- forced-colors
- horizontal-viewport-segments
- vertical-viewport-segments
- inverted-colors
- nav-controls
- prefers-contrast
- prefers-reduced-data
- prefers-reduced-motion
- prefers-reduced-transparency
- scripting
- video-color-gamut
- video-dynamic-range
The `@media (inverted-colors)` CSS that the spec requires we add to the
UA style sheet does not actually do anything for us yet since we don't
support `filter`, but it seemed sensible to include it now to avoid
forgetting later. :^)
This patch adds CSS::property_affects_layout(PropertyID) which tells us
whether a CSS property would affect layout if it were changed.
This will be used to avoid unnecessary relayout work when something
changes that really only requires us to repaint the page.
To mark a property as not affecting layout, set "affects-layout" to
false in the corresponding Properties.json entry. Note that all
properties affect layout by default.
Relative font-sizes like "2em" were previously resolved against the
fallback value (10px) which led to incorrect layouts in many places.
Fix this by resolving relative font-sizes against the absolutized
font-size of the parent or root element as appropriate.
Let's make it very clear that these are *computed* values, and not at
all the specified values. The specified values are currently discarded
by the CSS cascade algorithm.
Get rid of the old, roundabout way of invalidating the rule cache by
incrementing the StyleSheetList "generation".
Instead, when something wants to invalidate the rule cache, just have it
directly invalidate the rule cache. This makes it much easier to see
what's happening anyway.
Style computation always happens *before* layout, so we can't rely on
things having (or not having) layout nodes, as that information will
always be one step behind.
Instead, we have to use the DOM to find all the information we need.
Previously we were making a copy of the full set of custom properties
that applied to a DOM element. This was very costly and dominated the
profile when mousing around on GitHub.
Note that this may break custom properties on pseudo elements a little
bit, and that's something we'll have to look into.
Computing the pseudo element of a CSS::Selector was very hot when
mousing around on GitHub in Browser. A profile had it at ~10%.
After these changes, it's totally gone from the profile. :^)
For seletors whose subject is unversal (i.e selectors that end in "*")
we were not serializing the asterisk. Instead "foo bar *" came out as
"foo bar foo". This patch fixes that by correctly serializing the last
simple selector if it's universal.
Previously this queried the root layout-node's font, which was both
wrong and could crash if the layout wasn't ready yet. Now, it's just
wrong. But at least all the font-related wrongness is grouped together
in StyleComputer. :^)
This resolves the ambiguity between whether a single number is a number
or a ratio. :^)
Also removed the "no more tokens" checks from
deea129b8c - that logic was completely
wrong, since there are always tokens after a value in the `(123 < foo <
456)` syntax.
This data will be used to generate code for parsing media-queries. So
far, it includes all MEDIAQUERIES-4 features, and
`prefers-color-scheme` from MEDIAQUERIES-5 since we support that.
When rules are inserted or removed via the CSSOM API, we now invalidate
document style to ensure that any changes made are reflected.
1% progression on ACID3. :^)
We were handing out stale values from window.getComputedStyle() objects
after the first layout.
Fix this by always updating layout on property access. This is not
necessary for all properties, but for now let's go with the simplest
approach to make it work correctly.
