Source/WebCore/style/CustomFunctionRegistry.h

/*
 * Copyright (C) 2026 Apple Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
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 * 1.  Redistributions of source code must retain the above copyright
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 * 2.  Redistributions in binary form must reproduce the above copyright
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 *     documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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#pragma once

#include "StyleRuleFunction.h"

namespace WebCore {
namespace Style {

// CustomFunction registration represents @function after things like @media and cascade layers have
// been resolved.
// https://drafts.csswg.org/css-mixins/#evaluating-custom-functions

struct CustomFunction : CanMakeCheckedPtr<CustomFunction> {
    struct DeclarationsBlock {
        Ref<const StyleProperties> properties;
        Vector<Ref<const StyleRuleContainer>> containerQueries;
    };

    // A function body without conditional group rules is a single block.
    using DeclarationsBlocks = Vector<DeclarationsBlock, 1>;

    AtomString name;
    const Vector<StyleRuleFunction::Parameter> parameters;
    const CSSCustomPropertySyntax returnType;
    DeclarationsBlocks declarationBlocks;

    CustomFunction(const AtomString&, const Vector<StyleRuleFunction::Parameter>&, const CSSCustomPropertySyntax& returnType, DeclarationsBlocks&&);

    WTF_MAKE_STRUCT_TZONE_ALLOCATED(CustomFunction);
    WTF_STRUCT_OVERRIDE_DELETE_FOR_CHECKED_PTR(CustomFunction);
};

class CustomFunctionRegistry : public CanMakeCheckedPtr<CustomFunctionRegistry> {
    WTF_MAKE_TZONE_ALLOCATED(CustomFunctionRegistry);
    WTF_OVERRIDE_DELETE_FOR_CHECKED_PTR(CustomFunctionRegistry);
public:
    CustomFunctionRegistry() = default;

    const CustomFunction* NODELETE functionForName(const AtomString&) const;
    void registerFunction(const StyleRuleFunction&, CustomFunction::DeclarationsBlocks&&);

private:
    HashMap<AtomString, UniqueRef<const CustomFunction>> m_functions;
};

}

}