If a property is custom or contains a `var()` reference, it cannot be
parsed into a proper StyleValue immediately, so we store it as an
UnresolvedStyleValue until the property is compute. Then, at compute
time, we resolve them by expanding out any `var()` references, and
parsing the result.
The implementation here is very naive, and involves copying the
UnresolvedStyleValue's tree of StyleComponentValueRules while copying
the contents of any `var()`s it finds along the way. This is quite an
expensive operation to do every time that the style is computed.
Now that we can serialize CSS tokens, we can just hold a string and then
re-parse it when the Supports is evaluated. This feels a little weird,
but it only happens once so it's not going to slow it down much, and it
keep the API cleaner.
The changes in commit d462a6720a meant
that `CSSLoader::load_next_import_if_needed()` was no longer being
called, so no `@import` rules were loading.
The spec does not seem to mention when that loading should take place,
but WebKit does this at parse time, as each rule is added to the style
sheet. If it works for them, it's probably not that bad. :^)
So, that's what we now do here. The `CSSImportRule` creates a fetch
request when it is constructed, so each one is responsible for its own
contents.
Like the `background-foo` longhand properties (except
`background-color`), `background` allows multiple layers to be defined,
separated by commas. A layer does not necessarily contain something to
actually draw!
This parses as a `BackgroundStyleValue`, holding a `StyleValueList` for
each property. This is mostly to make expansion into longhands simpler -
if we had a list of `BackgroundStyleValue`s instead, one per layer, then
we would have to break it up per-property anyway when computing styles.
We now can parse lists of values for these properties:
- `background-attachment`
- `background-clip`
- `background-image`
- `background-origin`
- `background-position`
- `background-repeat`
- `background-size`
This uses two new Parser methods:
`parse_simple_comma_separated_value_list()` for the simple case when
each value is parsed from a single token; and
`parse_comma_separated_value_list()` which takes a lambda for when
parsing each value is more involved.
This also means that any unconsumed tokens at the end will make the
parsing fail as it should, where previously we just ignored them.
...as opposed to storing StyleValues, which we have to later check are
IdentifierStyleValues, which store identifiers that we can convert to
Repeat values later. It's fewer allocations, and we can't end up with
invalid values by mistake. :^)
This is step 1 in removing the two `background-repeat-x/y`
pseudo-properties. Since adding the concept of compound StyleValues, we
don't need `background-repeat` to be split in two any more.
This is done a bit differently from other properties: using a
TokenStream instead of just a Vector of ComponentValues. The reason for
this is, we can then use call the same function when parsing the
`background` shorthand. Otherwise, we would have to know in advance how
many values to pass down, which basically would involve duplicating the
`background-position` parsing code inside `background`.
The StyleValue is PositionStyleValue, since it represents a
`<position>`: https://www.w3.org/TR/css-values-4/#typedef-position
Unfortunately, background-position's parsing is a bit different from
`<position>`'s, (background-position allows 3-value syntax and
`<position>` doesn't) so we'll need to come back and write a different
parsing function for that later.
This accounts for cases like:
```css
.foo {
color: blue ! important ;
}
```
That's rare now that minifying is so popular, but does appear on some
websites.
I've added spec comments to `consume_a_declaration()` while I was at it.
Noticed this while checking some MediaWiki-based sites. It's not
obvious, but the spec does allow this, by not mentioning it in this list
of places whitespace is forbidden:
https://www.w3.org/TR/selectors-4/#white-space
The only reason it wasn't const before (and why we had a const_cast
hack) was to support ImageStyleValue's constructor taking it, which no
longer applies. `hack_count--;` :^)
This always felt awkward to me, and required a few other hacks to make
it work. Now, the request is only started when `load_bitmap()` is
called, which we do inside `NodeWithStyle::apply_style()`.
Previously, `box-shadow: none` would fail to parse, meaning that in this
example:
```css
p {
box-shadow: 20px 10px 5px magenta;
}
p.foo {
box-shadow: none;
}
```
... a `<p class="foo">` would still have a box-shadow, when it should
not have one. Now, we handle the `none` value. :^)
We can reduce the amount of padding the compiler adds in order to
ensure data alignment of member variables by ordering the types in
a struct by size in decending order.
Found By PVS-Studio: https://pvs-studio.com/en/docs/warnings/v802/
The main thing missing is that we don't serialize the supports clause,
but for actually using a `@supports (something: cool) {}` rule in CSS,
it works!
... according to
https://www.w3.org/TR/css-conditional-3/#typedef-supports-condition
This works very similarly to `@media`, but is different enough to
require its own parsing. (Though, the draft of Conditional-4 currently
mentions combining the two into a `@when` rule.)
Made some small changes to parsing code to make this work. Notably,
making `consume_a_declaration()` fail gracefully instead of
`VERIFY()`ing.
The name is a little awkward, but this corresponds to the condition of a
`@supports` rule or the `CSS.supports("")` function.
A supports query only gets evaluated once, since its condition cannot
change during runtime. (We either support something or we don't, and the
spec specifically mentions that user preferences that disable features
do not affect the result here.) We keep a representation of it around
though, so that it can be serialized if needed. This is a little awkward
since we hold onto a `StyleDeclarationRule` which should be an internal
Parser class. This means making some Parser functions more public.
Potentially we could evaluate the Supports inside the Parser, and have
it only store a String representation of itself. But this works for now.
:^)
Previously: CSSImportRule::loaded_style_sheet() (and others) depend on
the definition of class CSSStyleSheet. Meanwhile,
CSSStyleSheet::template for_each_effective_style_rule (and others)
depend on the definition of class CSSImportRule.
This hasn't caused any problems so far because CSSStyleSheet.h happened
to be always included after CSSImportRule.h (in part due to alphabetical
ordering).
However, a compilation unit that (for example) only contains
#include <Userland/Libraries/LibWeb/CSSImportRule.h>
would fail to compile.
This patch resolves this issue by pushing the inline definition of
Web::CSS::CSSStyleSheet::for_each_effective_style_rule and
for_first_not_loaded_import_rule into a different file, and adding the
missing headers.
While not complete by any means, we are now compatible with the [level 3
spec](https://www.w3.org/TR/css3-mediaqueries/#syntax) and some parts of
[level 4.](https://www.w3.org/TR/mediaqueries-4#mq-syntax)
Compatibility with level 4+ requires:
- Implementing the range syntax: `(800px <= width <= 1200px)`
- Parsing `<general-enclosed>`, which represents syntax that is not yet
used but they may use in the future.
Parsing media queries sometimes requires significant back-tracking, so
`reconsume_current_input_token()` was not good enough.
`rewind_to_position()` lets you reconsume an erbitrary number of tokens
to return to an earlier point in the stream, which you previously saved
from `TokenStream::position()`.
This now matches the spec, and fixes the situation where if it was given
a TokenStream of StyleComponentValueRules, it would drop any Blocks on
the floor instead of adding them to the result StyleRule.
When parsing a CSS value in the context of a CSSStyleDeclaration
camelCase property setter, we don't necessarily have a Document to
provide the CSS parser for context.
So the parser can't go assuming that there's always a Document in the
ParsingContext. And ImageStyleValue can't go assuming that there's
always a Document either. This will require some more work to get things
right, I'm just patching up the null dereference for now.
This brings us a few nice benefits:
- We only generate a `StyleValueList` for properties that accept
multiple values.
- We reject declarations that have too many values.
- We check the type of each value that is parsed, to make sure it's
acceptable to the property.
Probably there are some regressions here, since this is
Later, we can also replace many of the `is_foo()` functions and lambas
inside the Parser with more calls to `property_accepts_value()`. Also we
can remove some checks when resolving styles, since only valid types of
values will get to that point. But one step at a time. :^)
We don't want a property like `background` to fall back to parsing as a
single value or StyleValueList if `parse_background_style_value()`
fails. We just want it to fail.
Shorthand properties were only checking for `ColorStyleValue`s, which
excludes identifier colors. Now they accept them too, including the
various `-libweb-foo` colors. :^)
This namespace will be used for all interfaces defined in the URL
specification, like URL and URLSearchParams.
This has the unfortunate side-effect of requiring us to use the fully
qualified AK::URL name whenever we want to refer to the AK class, so
this commit also fixes all such references.
For example, this CSS previously produced a lot of log spam about the
`display` properties having invalid values:
```css
.foo {
display: -webkit-box;
display: -moz-box;
display: -ms-flexbox;
display: -webkit-flex;
display: flex;
}
```
Now, it just ignores them, because we don't need to know about it. :^)
Our debug logging when we fail to parse a legitimate selector, is less
useful when it's hidden among selectors that don't parse because they
contain vendor-prefixed pseudo-elements and classes. So, now we
specifically ignore these and don't produce a log message.
This patch moves the CSS property+value storage down to a new subclass
of CSSStyleDeclaration called PropertyOwningCSSStyleDeclaration.
The JavaScript wrapper for CSSStyleDeclaration now calls virtual
functions on the C++ object.
This is preparation for supporting computed style CSSStyleDeclaration
objects which won't have internal property storage, but rather an
internal element pointer. :^)
The StyleProperties code for opacity existed before NumericStyleValue
was a thing, and was affected by over-enthusiastic unitless-length
parsing, so it assumed everything was a length. Now it matches the
Color4 spec instead, accepting either a number, or a percentage.
We also get to remove the hack! :^)
Previously, we applied the unitless length quirk to all numbers in
quirks mode. Now, we correctly only do so for the set of properties
listed in the quirks-mode spec:
https://quirks.spec.whatwg.org/#quirky-length-value
However, we do not yet prevent this quirk inside CSS expressions (like
`calc()`) as the spec directs.
After `parse_css_value(PropertyID, TokenStream)`, we only need to know
the current PropertyID when checking for property-specific quirks, which
will take place in only 2 places, which happen deep down. Making the
current PropertyID part of the context means that those places can check
it easily, without us having to pass it to every one of the parsing
functions, which otherwise do not care.
This fixes#9978.
When a TokenStream is empty, reading its `current_token()` still returns
a token (for EOF) so it makes sense to allow users to
`reconsume_current_input_token()` that token, so they do not have to
handle that themselves. Instead of VERIFY()ing, we can just no-op when
reconsuming token 0.
And also try_create<T> => try_make_ref_counted<T>.
A global "create" was a bit much. The new name matches make<T> better,
which we've used for making single-owner objects since forever.
This isn't 100% spec complaint, as it should use glyph_height()
depending on what the value of the writing-mode is, but we haven't
implemented it yet, so I think it'll be good enough for now.
This can be tested in https://wpt.live/css/css-values/ch-unit-008.html
Other css-unit tests fail as:
- 001 shows an issue related to a renderer (looks to me like you can't
pass a width and height property to a span -- adding `display: block`
to it passes the test),
- 002-004 and 009-012 use mentioned writing-mode,
- 016-017 loads custom fonts, which we also don't support (yet).
With the new parser, we started interpreting the `opacity` property as a
string value, which made it turn into `auto` and so anything with
opacity ended up not visible (e.g the header on google.com)
This patch restores our old behavior for `opacity` by interpreting it
as a numeric value with optional decimals.
Some properties, such as `margin`, take multiple values but are not
complicated enough to require special-case handling. These no longer
parsed after my previous StyleValue changes, so this fixes that.
In the future we may want to configure whether to allow this for each
property.
Apart from now gathering comma-separated font-family names into a
StyleValueList, this also corrects the logic for parsing a single
font-family. Previously, we did not handle unquoted font names at all,
and now they are handled including when they are several words separated
by whitespace.
Modified the logic for `font` to use `parse_font_family_value()`.
`FontStyleValue.font_families()` is now a StyleValueList instead of a
vector, so that it can be better handled in StyleResolver.
We also finally remove the CSS::ParsingContext in
set_property_expanding_shorthands(). :^)
This wraps an x and y background-repeat value. Potentially, we could use
this in place of the background-repeat-x and background-repeat-y
pseudo-properties, but for now StyleResolver splits it into those
properties, like it did before.
This parses the elliptical border-radius values, though currently we
only support circular ones. So, to_length() is overloaded to return the
horizontal-radius. This means the code in Layout/Node.cpp does not need
to change for now.
