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LibWeb: Implement @supports selector(.foo)

This is defined in
https://www.w3.org/TR/css-conditional-4/#at-supports-ext which just
became a CR. :^)
This commit is contained in:
Sam Atkins 2022-02-19 17:22:05 +00:00 committed by Andreas Kling
parent c50ea8c1dd
commit 7880718fa8
4 changed files with 93 additions and 9 deletions

View file

@ -1,7 +1,7 @@
/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
* Copyright (c) 2020-2021, the SerenityOS developers.
* Copyright (c) 2021, Sam Atkins <atkinssj@serenityos.org>
* Copyright (c) 2021-2022, Sam Atkins <atkinssj@serenityos.org>
* Copyright (c) 2021, Tobias Christiansen <tobyase@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
@ -1309,12 +1309,23 @@ Optional<Supports::Feature> Parser::parse_supports_feature(TokenStream<StyleComp
// `<supports-decl>`
if (first_token.is_block() && first_token.block().is_paren()) {
TokenStream block_tokens { first_token.block().values() };
// FIXME: Parsing and then converting back to a string is weird.
if (auto declaration = consume_a_declaration(block_tokens); declaration.has_value()) {
return Supports::Feature {
.declaration = declaration->to_string()
Supports::Declaration { declaration->to_string() }
};
}
}
// `<supports-selector-fn>`
if (first_token.is_function() && first_token.function().name().equals_ignoring_case("selector"sv)) {
// FIXME: Parsing and then converting back to a string is weird.
StringBuilder builder;
for (auto const& item : first_token.function().values())
builder.append(item.to_string());
return Supports::Feature {
Supports::Selector { builder.to_string() }
};
}
tokens.rewind_to_position(start_position);
return {};

View file

@ -1,5 +1,5 @@
/*
* Copyright (c) 2021, Sam Atkins <atkinssj@serenityos.org>
* Copyright (c) 2021-2022, Sam Atkins <atkinssj@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
@ -50,10 +50,27 @@ bool Supports::InParens::evaluate() const
});
}
bool Supports::Feature::evaluate() const
bool Supports::Declaration::evaluate() const
{
auto style_property = Parser({}, declaration).parse_as_declaration();
return style_property.has_value();
}
bool Supports::Selector::evaluate() const
{
auto style_property = Parser({}, selector).parse_as_selector();
return style_property.has_value();
}
bool Supports::Feature::evaluate() const
{
return value.visit(
[&](Declaration const& declaration) {
return declaration.evaluate();
},
[&](Selector const& selector) {
return selector.evaluate();
});
}
}

View file

@ -1,5 +1,5 @@
/*
* Copyright (c) 2021, Sam Atkins <atkinssj@serenityos.org>
* Copyright (c) 2021-2022, Sam Atkins <atkinssj@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
@ -16,16 +16,26 @@
namespace Web::CSS {
// https://www.w3.org/TR/css-conditional-3/#at-supports
// https://www.w3.org/TR/css-conditional-4/#at-supports
class Supports final : public RefCounted<Supports> {
friend class Parser;
public:
struct Feature {
struct Declaration {
String declaration;
bool evaluate() const;
};
struct Selector {
String selector;
bool evaluate() const;
};
struct Feature {
Variant<Declaration, Selector> value;
bool evaluate() const;
};
struct Condition;
struct InParens {
Variant<NonnullOwnPtr<Condition>, Feature, GeneralEnclosed> value;