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https://github.com/LadybirdBrowser/ladybird.git
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0f5e054f97
CSS Values 5 now defines a `<boolean-expr[]>` type that is used in place of the bespoke grammar that previously existed for `@media` and `@supports` queries. This commit implements some BooleanExpression types to represent the nodes in a `<boolean-expr[]>`, and reimplements `@media` and `@supports` queries using this. The one part of this implementation I'm not convinced on is that the `evaluate()` methods take a `HTML::Window*`. This is a compromise because `@media` requires a Window, and `@supports` does not require anything at all. As more users of `<boolean-expr[]>` get implemented in the future, it will become clear if this is sufficient, or if we need to do something smarter. As a bonus, this actually improves our serialization of media queries!
136 lines
4.1 KiB
C++
136 lines
4.1 KiB
C++
/*
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* Copyright (c) 2021-2025, Sam Atkins <sam@ladybird.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include <AK/StringBuilder.h>
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#include <LibWeb/CSS/BooleanExpression.h>
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namespace Web::CSS {
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bool BooleanExpression::evaluate_to_boolean(HTML::Window const* window) const
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{
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return evaluate(window) == MatchResult::True;
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}
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void BooleanExpression::indent(StringBuilder& builder, int levels)
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{
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builder.append_repeated(" "sv, levels);
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}
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void GeneralEnclosed::dump(StringBuilder& builder, int indent_levels) const
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{
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indent(builder, indent_levels);
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builder.appendff("GeneralEnclosed: {}\n", to_string());
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}
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MatchResult BooleanNotExpression::evaluate(HTML::Window const* window) const
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{
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// https://drafts.csswg.org/css-values-5/#boolean-logic
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// `not test` evaluates to true if its contained test is false, false if it’s true, and unknown if it’s unknown.
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switch (m_child->evaluate(window)) {
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case MatchResult::False:
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return MatchResult::True;
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case MatchResult::True:
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return MatchResult::False;
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case MatchResult::Unknown:
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return MatchResult::Unknown;
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}
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VERIFY_NOT_REACHED();
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}
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String BooleanNotExpression::to_string() const
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{
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return MUST(String::formatted("not {}", m_child->to_string()));
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}
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void BooleanNotExpression::dump(StringBuilder& builder, int indent_levels) const
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{
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indent(builder, indent_levels);
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builder.append("NOT:\n"sv);
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m_child->dump(builder, indent_levels + 1);
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}
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MatchResult BooleanExpressionInParens::evaluate(HTML::Window const* window) const
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{
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return m_child->evaluate(window);
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}
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String BooleanExpressionInParens::to_string() const
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{
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return MUST(String::formatted("({})", m_child->to_string()));
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}
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void BooleanExpressionInParens::dump(StringBuilder& builder, int indent_levels) const
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{
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indent(builder, indent_levels);
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builder.append("(\n"sv);
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m_child->dump(builder, indent_levels + 1);
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indent(builder, indent_levels);
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builder.append(")\n"sv);
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}
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MatchResult BooleanAndExpression::evaluate(HTML::Window const* window) const
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{
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// https://drafts.csswg.org/css-values-5/#boolean-logic
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// Multiple tests connected with `and` evaluate to true if all of those tests are true, false if any of them are
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// false, and unknown otherwise (i.e. if at least one unknown, but no false).
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size_t true_results = 0;
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for (auto const& child : m_children) {
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auto child_match = child->evaluate(window);
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if (child_match == MatchResult::False)
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return MatchResult::False;
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if (child_match == MatchResult::True)
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true_results++;
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}
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if (true_results == m_children.size())
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return MatchResult::True;
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return MatchResult::Unknown;
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}
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String BooleanAndExpression::to_string() const
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{
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return MUST(String::join(" and "sv, m_children));
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}
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void BooleanAndExpression::dump(StringBuilder& builder, int indent_levels) const
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{
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indent(builder, indent_levels);
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builder.append("AND:\n"sv);
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for (auto const& child : m_children)
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child->dump(builder, indent_levels + 1);
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}
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MatchResult BooleanOrExpression::evaluate(HTML::Window const* window) const
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{
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// https://drafts.csswg.org/css-values-5/#boolean-logic
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// Multiple tests connected with `or` evaluate to true if any of those tests are true, false if all of them are
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// false, and unknown otherwise (i.e. at least one unknown, but no true).
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size_t false_results = 0;
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for (auto const& child : m_children) {
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auto child_match = child->evaluate(window);
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if (child_match == MatchResult::True)
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return MatchResult::True;
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if (child_match == MatchResult::False)
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false_results++;
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}
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if (false_results == m_children.size())
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return MatchResult::False;
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return MatchResult::Unknown;
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}
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String BooleanOrExpression::to_string() const
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{
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return MUST(String::join(" or "sv, m_children));
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}
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void BooleanOrExpression::dump(StringBuilder& builder, int indent_levels) const
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{
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indent(builder, indent_levels);
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builder.append("OR:\n"sv);
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for (auto const& child : m_children)
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child->dump(builder, indent_levels + 1);
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}
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}
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