Previous multi-value properties use a ValueListStyleValue, which then
gets parsed into its sub-properties in the StyleResolver. However, that
is not ideal, especially as it exposes StyleResolver to the inner
workings of the Parser and Tokenizer, which it should not need to know
about.
The way `box-shadow` was implemented as a StyleValue subclass means that
the parsing can happen inside the Parser instead, which seems like a
better solution. Converting the other complicated cases (background,
font, list-style) is on my todo list for later.
This lets us get the Length and Color values directly, without having to
create a StyleValue object and then throw it away again, when parsing
the box-shadow property in the next commit.
This is three small, related changes:
1. Element::has_attribute() now returns true if the attribute exists but
has no value. (eg, `<div foo />` -> `has_attribute("foo")`)
2. SelectorEngine::matches_attribute() now makes sure there is a first
segment before comparing it, fixing a crash.
3. CSS::Parser now converts attribute names in attribute selectors to
lowercase, to match the expectations of the rest of the system.
Converting to lowercase is not always correct, depending on language,
but since we only currently support HTML, and that expects them to be
case-insensitive, it is fine for now.
Parsing this pattern from CSS tokens turns out to be slightly crazy, but
thankfully well documented in the spec.
The spec lists the cases in order of simple -> complicated, but this
would cause problems in code, since `<n-dimension> <signed-.integer>`
would never by reached, as `<n-dimension>` comes before. Instead, I
have grouped them by their first token.
Also renamed the NthChildPattern class to ANPlusBPattern, to match spec
terminology.
The spec does not directly tell us how to parse selectors, so there are
likely some bugs here, but I've used the spec language where possible.
This is very much based on the previous selector parsing code.
Any parse error inside a selector makes the entire SelectorList
invalid, so nothing is returned.
- CompoundSelector -> *deleted*
- ComplexSelector -> CompoundSelector
- Relation -> Combinator
Our Selector is really a ComplexSelector, but only the Parser and
SelectorEngine need to know that, so keeping it named Selector makes it
more understandable for users.
Our CompoundSelector is really a CompoundSelectorAndCombinator.
Combining the two makes sense in our codebase, but the accurate name is
so long that I think it makes the code less readable.
Renamed some Combinators to also match the spec terminology:
- AdjacentSibling -> NextSibling
- GeneralSibling -> SubsequentSibling
The previous names are somewhat ambiguous, so hopefully this is clearer.
This was a hack copied over from the old parser, but it was causing
problems with flex-grow, and probably other properties that accept
numbers. Removing it does not seem to break anything, so lets' remove
it! :^)
Also added css-import.html, which tests the 3 syntax variations on
`@import` statements. Note that the optional media-query parameter to
`@import` is not handled yet.
This resolves the three sub-properties, appearing in any order:
- list-style-image
- list-style-position
- list-style-type
Added `list-style-position` values to support this, though they are not
yet used in rendering.
This was broken when we switched away from using StringStyleValues.
While I was at it, I have implemented hsl/a() and the percentage
syntax for rgb/a().
As a bonus, added `colors.html` as a test page for the various CSS
color syntaxes, since nothing was testing rgb() or rgba() before.
Much of the parsing code in LibGFX/Color.h seems to be centered
around CSS color values, but this is not used by the new Parser.
(And can't be used, because it requires a String value and we have
a list of Tokens of some kind instead.) Maybe that should be removed
from there when the new CSS parser is operational.
Now that StyleResolver is going to deal with StyleComponentValueRules,
it will need to be able to parse those into StyleValues, using
`parse_css_value()`.
Also added StyleValue::is_builtin_or_dynamic(), which returns true for
values that are valid anywhere - things like `initial` and `inherit`,
along with `var()`, `attr()` and `calc()` - which we want to test for
easily.
We skip whitespace tokens while doing this. As far as I can tell,
whitespace is not useful once we get to this point, and it legally
may or may not appear between any two tokens. By not including it
in the ValueListStyleValue, we make the "if it has 3 parts"-type
checks a lot more straightforward.
Rather than parsing the selector every time we want to check it, we
now parse it once at the beginning.
A bonus effect of this is that we now support a selector list in
:not(), instead of just a single selector, though only when using
the new parser.
The end goal is to make the PseudoClass::not_selector be a Selector
instead of a String that is repeatedly re-parsed. But since Selector
contains a Vector of ComplexSelectors, which each have a Vector of
SimpleSelectors, it's probably a good idea to not be passing them
around by value anyway. :^)
Same reasoning again! This is the last one.
While I was at it, I added the two remaining CSS2.2 pseudo-elements,
::first-line and ::first-letter. All 4 are handled in the new CSS
parser, including with the compatibility single-colon syntax. I have
not added support to the old parser.
Previously, SimpleSelectors optionally had Attribute-selector data
as well as their main type. Now, they're either one or the other,
which better matches the spec, and makes parsing and matching more
straightforward.
Had to adjust some places that were using Token.to_string() for
non-debug-logging purposes. Changed its name to to_debug_string()
to make the usage clearer.
Whitespace marks the end of a compound-selector, no matter where
it occurs. `check_for_eof_or_whitespace()` reconsumes the whitespace
token for convenience.
The entry points for CSS parsing in the spec are defined as accepting
any of a stream of Tokens, or a stream of ComponentValues, or a String.
TokenStream is an attempt to reduce the duplication of code for that.
The end goal here is to make the two classes mostly interchangeable, as
the CSS spec requires that the various parser algorithms can take a
stream of either class, and we want to have that functionality without
needing to duplicate all of the code.
Rather than passing a ComponentType, and then manually modifying the
data fields, we now create them initialized.
The constructor that takes a Token is intentionally left implicit,
so that we can automatically convert when using the TokenStream later.
AtStyleRule being a subclass of QualifiedStyleRule was causing
problems when trying to distinguish between them. Combining them
and then distinguishing between them with a Type enum makes that
check simpler, and is in line with how similar checks are done
elsewhere in the parser.
The new one is the same as the old one, just in the new Parser's
source files. This isn't the most elegant solution but it seemed
like the best option. And it's all temporary, after all.
Previous implementation was returning everything in a single Vector,
when what we really want is a Vector of Vectors, one for each comma-
separated part of the list.
This is very much stubbed out for now. Most notably is
Parser::convert_rule() where most of the conversion will happen
from the parser's internal rule classes to CSSRule and its children.
