We now do the proper thing in terms of:
- Allowing percentages
- Returning the computed value in getComputedStyle
- Handling values out of the [0,1] range
Gains us 13 WPT passes in the imported tests.
Add global registry for registered properties and partial support
for `@property` rule. Enables registering properties with initial
values. Also adds basic retrieval via `var()`.
Note: This is not a complete `@property` implementation.
`<syntax>` is a limited subset of the "value definition syntax" used in
CSS specs. It's used for `@property`'s `syntax` descriptor, and for the
`type()` function in `attr()`.
UnresolvedStyleValue::create() has one user where we know if there are
any arbitrary substitution functions in the list of CVs, and two users
where we don't know and just hope there aren't any. I'm about to add
another user that also doesn't know, and so it seems worth just making
UnresolvedStyleValue::create() do that work instead.
We keep the parameter, now Optional<>, so that we save some redundant
work in that one place where we do already know.
A couple of arbitrary substitution functions require us to get or
produce some style value, and then substitute its ComponentValues into
the original ComponentValue list. So this commit gives CSSStyleValue a
tokenize() method that does so.
Apart from a couple of unusual cases like the guaranteed-invalid value,
style values can all be converted into ComponentValues by serializing
them as a string, and then parsing that as a list of component values.
That feels unnecessarily inefficient in most cases though, so I've
implemented faster overrides for a lot of the basic style value
classes, but left that serialize-and-reparse method as the fallback.
`CSSColorValue`s which have unresolved `calc` components should be able
to be resolved. Previously we would always resolve them but with
incorrect values.
This is useful as we will now be able to now whether we should serialize
colors in their normalized form or not.
Slight regression in that we now serialize (RGB, HSL and HWB) colors
with components that rely on compute-time information as an empty
string, but that will be fixed in the next commit.
These new methods are built on top of the spec's
`simplify_a_calculation_tree` algorithm where the old methods were
ad-hoc.
These methods are not used anywhere yet as callers will need to be
migrated over from the deprecated methods one-by-one to account for
differences in behaviour.
No functionality changes.
The existing resolve methods are not to spec and we are working to
replace them with new ones based on the `simplify_a_calculation_tree`
method.
These are marked as deprecated rather than replaced outright as work
will need to be done on the caller side to be made compatible with the
new methods, for instance the new methods can fail to resolve (e.g.
if we are missing required context), where the existing methods will
always resolve (albeit sometimes with an incorrect value).
No functionality changes.
When setting a declaration for a property in a logical property group,
it should appear after all other declarations which belong to the same
property group but have different mapping logic (are/aren't a logical
alias).
Gains us 1 WPT pass.
We should not serialize a group of properties `longhands` as a single
shorthand if there is any property declared between the first and
last property in `longhands` which is not part of `longhands` but
belongs to the same logical property group, and has different mapping
logic to any of property in `longhands`
When parsing values in `process_a_keyframes_argument` we don't expand
properties using `StyleComputer::for_each_property_expanding_shorthands`
unlike most other places - this means that if we parse a `border` we end
up with the `border`'s sub-properties (`border-width`, `border-style`,
`border-color`) still in their unexpanded forms (`CSSKeywordValue`,
`LengthStyleValue`, `StyleValueList`, etc) rather than
`ShorthandStyleValue`s which causes a crash when serializing the
`border` value in `KeyframeEffect::get_keyframes`.
The proper fix here is to parse `border`'s sub-properties directly to
`ShorthandStyleValue`s instead of relying on
`StyleComputer::for_each_property_expanding_shorthand` to do this
conversion for us but this may be a while off.
This commit also imports the previously crashing tests.
We were previously handling this ad-hoc via logic in
`get_property_internal` but this didn't cover all contexts (for
instance `CSSStyleProperties::serialized`.
Gains us 9 more WPT tests as we now cover properties which weren't
included in the previous ad-hoc approach.
Some shorthand properties work differently to normal in that mapping of
provided values to longhands isn't necessarily 1-to-1 and depends on the
number of values provided, for example `margin`, `border-width`, `gap`,
etc.
These properties have distinct behaviors in how they are parsed and
serialized, having them marked allows us to implement theses behaviors
in a generic way.
No functionality changes.
Make sure we have a parent element before trying to look at it!
I've also pulled out a stub function for getting a custom property's
initial value, so that there's only one place to change once we support
`@property` more.
Because we defined `th { text-align: center }` in our UA stylesheet, it
received a higher precedence than inherited (inline) styles. Firefox
deals with this by defining a custom `text-align` value that prioritizes
any inherited value before defaulting to `text-align: center`.
We now do this as well :^)
Previously if we encountered a keyword other than `fill` when parsing
`<border-image-slice` we would return a nullptr.
This could cause issues when we parse `<border-image-slice>` as part of
parsing `border-image`, for example `border-image: 100% none` would fail
as we would try parse `none` as part of the `<border-image-slice>`
instead of `<border-image-source>`.
This change makes it so that we don't consume the token and leave it to
be parsed as part of the next section of the grammar.
The attack unfortunately still slows us down, but this prevents us from
OOMing. Currently, we don't save the value of `var(--foo)` after
computing it once, so in this example, we end up computing `--prop1` 4
times to compute `--prop3`, but then we start again from scratch when
computing `--prop4`:
```css
--prop1: lol;
--prop2: var(--prop1) var(--prop1);
--prop3: var(--prop2) var(--prop2);
--prop4: var(--prop3) var(--prop3);
}
```
This should be solvable later if we update the computed values as we go.
"Arbitrary substitution functions" are a family of functions that
includes var() and attr(). All of them resolve to an arbitrary set of
component values that are not known at parse-time, so they have to be
substituted at computed-value time.
Besides it being nice to follow the spec closely, this means we'll be
able to implement the others (such as `if()` and `inherit()`) more
easily.
The main omission here is the new "spread syntax", which can be
implemented in the future.
This has an extra parameter to allow stopping at the first comma token,
which we need for var() and attr()'s "argument grammar".
Co-authored-by: Tim Ledbetter <tim.ledbetter@ladybird.org>
Custom properties are required to produce a computed value just like
regular properties. The computed value is defined in the spec as
"specified value with variables substituted, or the guaranteed-invalid
value", though in reality all arbitrary substitution functions should be
substituted, not just `var()`.
To support this, we parse the CSS-wide keywords normally in custom
properties, instead of ignoring them. We don't yet handle all of them
properly, and because that will require us to cascade them like regular
properties. This is just enough to prevent regressions when implementing
ASFs.
Our output in this new test is not quite correct, because of the awkward
way we handle whitespace in property values - so it has 3 spaces in the
middle instead of 1, until that's fixed.
It's possible this computed-value production should go in
cascade_custom_properties(), but I had issues with that. Hopefully once
we start cascading custom properties properly, it'll be clearer how
this should all work.
Treating these like any other ComponentValue means not having to convert
between different types of Vector, and that we will be able to use
TokenStream to parse the "argument grammars" of arbitrary substitution
functions.
Previously the type argument in attr() could be the name of a CSS type
on its own. This has changed, and now only `raw-string`
(previously `string`) or the name of a dimension unit is allowed. Other
types and more complex grammar use the `type()` function, which we
don't yet support.
I've updated the syntax comment, but not the algorithm itself, which
will be reimplemented in a later commit.
Add `create_foo()` static methods for the missing Token::Types, and use
them in the Tokenizer. This means we slightly deviate from the spec now:
it says "create foo token... set its bar to 32", but we now just wait
and construct the Token fully-formed. But those cases are short so it
should still be clear what we're doing.
This makes it possible to construct all kinds of Token elsewhere, such
as for testing purposes.
Before this change, we would never apply CSS rules where the selector
had a mixed-case tag name. This happened because our rule caches would
key them on the lowercased tag name, but we didn't lowercase the tag
name when fetching things from the cache.
This uncovered the fact that the SVG2 spec has a bunch of style applied
to non-rendered elements in a way that doesn't match other browsers.
Instead of blindly following the spec, we now match other browsers.
