Source/WebCore/style/ResolvedScopedName.h

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 * Copyright (C) 2025 Apple Inc. All rights reserved.
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 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
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#pragma once

#include "StyleScopeIdentifier.h"
#include <wtf/Forward.h>
#include <wtf/text/AtomString.h>

namespace WebCore {

class Element;

namespace Style {

class Scope;

struct ScopedName;

// A ScopedName that has been resolved to determine which specific scope it belongs to.
class ResolvedScopedName {
    WTF_DEPRECATED_MAKE_FAST_ALLOCATED(ResolvedScopedName);
public:
    ResolvedScopedName(AtomString, ScopeIdentifier);

    // Creates a ResolvedScopedName from a ScopedName by resolving the scope ordinal
    // into the concrete Style::Scope object.
    static ResolvedScopedName createFromScopedName(const Element&, const ScopedName&);

    AtomString name() const { return m_name; }
    ScopeIdentifier scopeIdentifier() const { return m_scopeIdentifier; }

    friend bool operator==(const ResolvedScopedName& lhs, const ResolvedScopedName& rhs) = default;

private:
    AtomString m_name;
    ScopeIdentifier m_scopeIdentifier;
};

inline void add(Hasher& hasher, const ResolvedScopedName& name)
{
    add(hasher, name.name(), name.scopeIdentifier());
}

} // namespace Style

} // namespace WebCore

namespace WTF {

template <>
struct DefaultHash<WebCore::Style::ResolvedScopedName> {
    static unsigned hash(const WebCore::Style::ResolvedScopedName& name) { return computeHash(name); }
    static bool equal(const WebCore::Style::ResolvedScopedName& a, const WebCore::Style::ResolvedScopedName& b) { return a == b; }
    static constexpr bool safeToCompareToEmptyOrDeleted = true;
};

template<>
struct HashTraits<WebCore::Style::ResolvedScopedName> : GenericHashTraits<WebCore::Style::ResolvedScopedName> {
    static const bool emptyValueIsZero = true;

    static WebCore::Style::ResolvedScopedName emptyValue()
    {
        return { WTF::nullAtom(), HashTraits<WebCore::Style::ScopeIdentifier>::emptyValue() };
    }

    static void constructDeletedValue(WebCore::Style::ResolvedScopedName& slot)
    {
        new (NotNull, std::addressof(slot)) WebCore::Style::ResolvedScopedName { HashTableDeletedValue, HashTableDeletedValue };
    }

    static bool isDeletedValue(const WebCore::Style::ResolvedScopedName& value)
    {
        return value.name().isHashTableDeletedValue() && value.scopeIdentifier().isHashTableDeletedValue();
    }
};

} // namespace WTF