Source/JavaScriptCore/runtime/JSArrayIterator.h

/*
 * Copyright (C) 2020-2021 Apple Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    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 DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 */

#pragma once

#include "JSInternalFieldObjectImpl.h"

namespace JSC {

class JSArrayIterator final : public JSInternalFieldObjectImpl<3> {
public:
    using Base = JSInternalFieldObjectImpl<3>;

    enum class Field : uint8_t {
        Index = 0,
        IteratedObject,
        Kind,
    };
    static_assert(numberOfInternalFields == 3);

    static size_t allocationSize(Checked<size_t> inlineCapacity)
    {
        ASSERT_UNUSED(inlineCapacity, inlineCapacity == 0U);
        return sizeof(JSArrayIterator);
    }
    
    template<typename CellType, SubspaceAccess mode>
    static IsoSubspace* subspaceFor(VM& vm)
    {
        return vm.arrayIteratorSpace<mode>();
    }

    static std::array<JSValue, numberOfInternalFields> initialValues()
    {
        return { {
            jsNumber(0),
            jsNull(),
            jsNumber(0),
        } };
    }

    static constexpr int64_t doneIndex = -1;
    const WriteBarrier<Unknown>& internalField(Field field) const { return Base::internalField(static_cast<uint32_t>(field)); }
    WriteBarrier<Unknown>& internalField(Field field) { return Base::internalField(static_cast<uint32_t>(field)); }

    IterationKind kind() const { return static_cast<IterationKind>(internalField(Field::Kind).get().asUInt32AsAnyInt()); }
    JSObject* iteratedObject() const { return jsCast<JSObject*>(internalField(Field::IteratedObject).get()); }

    JS_EXPORT_PRIVATE static JSArrayIterator* create(VM&, Structure*, JSObject* iteratedObject, JSValue kind);
    static JSArrayIterator* create(VM& vm, Structure* structure, JSObject* iteratedObject, IterationKind kind)
    {
        return create(vm, structure, iteratedObject, jsNumber(static_cast<unsigned>(kind)));
    }
    static JSArrayIterator* createWithInitialValues(VM&, Structure*);
    static Structure* createStructure(VM&, JSGlobalObject*, JSValue);

    DECLARE_INFO;

    DECLARE_VISIT_CHILDREN;

private:
    JSArrayIterator(VM&, Structure*);
    void finishCreation(VM&);
};

} // namespace JSC