Source/WebCore/style/StyleNameScope.h

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#pragma once

#include <WebCore/StyleScopeOrdinal.h>
#include <WebCore/StyleValueTypes.h>

namespace WebCore {
namespace Style {

// <name-scope> = none | all | <dashed-ident>#
// Used by:
// <'timeline-scope'>
// https://drafts.csswg.org/scroll-animations-1/#propdef-timeline-scope
// <'anchor-scope'>
// https://drafts.csswg.org/css-anchor-position-1/#propdef-anchor-scope

struct NameScope {
    enum class Type : uint8_t { None, All, Ident };

    NameScope(CSS::Keyword::None)
    {
    }

    NameScope(CSS::Keyword::All, ScopeOrdinal scopeOrdinal)
        : type { Type::All }
        , scopeOrdinal { scopeOrdinal }
    {
    }

    NameScope(CommaSeparatedListHashSet<CustomIdentifier>&& names, ScopeOrdinal scopeOrdinal)
        : type { Type::Ident }
        , names { WTF::move(names) }
        , scopeOrdinal { scopeOrdinal }
    {
    }

    Type type { Type::None };
    CommaSeparatedListHashSet<CustomIdentifier> names;
    ScopeOrdinal scopeOrdinal { ScopeOrdinal::Element };

    template<typename... F> constexpr decltype(auto) switchOn(F&&...) const;

    inline bool operator==(const NameScope&) const;
};

inline bool NameScope::operator==(const NameScope& other) const
{
    return type == other.type
        && scopeOrdinal == other.scopeOrdinal
        // Two name lists are equal if they contain the same values in the same order.
        // FIXME: This is not symmetrical in the case that other.names.isEmpty() is true, but names.isEmpty() is false.
        && (names.isEmpty() || std::ranges::equal(names, other.names));
}

template<typename... F> constexpr decltype(auto) NameScope::switchOn(F&&... f) const
{
    auto visitor = WTF::makeVisitor(std::forward<F>(f)...);

    switch (type) {
    case NameScope::Type::None:
        return visitor(CSS::Keyword::None { });
    case NameScope::Type::All:
        return visitor(CSS::Keyword::All { });
    case NameScope::Type::Ident:
        if (names.isEmpty())
            return visitor(CSS::Keyword::None { });
        return visitor(names);
    }
    RELEASE_ASSERT_NOT_REACHED();
}

// MARK: - Conversion

template<> struct CSSValueConversion<NameScope> { auto operator()(BuilderState&, const CSSValue&) -> NameScope; };

} // namespace Style
} // namespace WebCore

DEFINE_VARIANT_LIKE_CONFORMANCE(WebCore::Style::NameScope)