JavaScriptCore-7600.1.4.16.1.tar.gz

[apple/javascriptcore.git] / runtime / StructureChain.h

/*
 * Copyright (C) 2008 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. ``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
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
 */

#ifndef StructureChain_h
#define StructureChain_h

#include "JSCell.h"
#include "JSObject.h"
#include "Structure.h"

#include <wtf/PassRefPtr.h>
#include <wtf/RefCounted.h>
#include <wtf/RefPtr.h>
#include <wtf/StdLibExtras.h>

namespace JSC {

    class LLIntOffsetsExtractor;
    class Structure;

    class StructureChain : public JSCell {
        friend class JIT;

    public:
        typedef JSCell Base;

        static StructureChain* create(VM& vm, Structure* head)
        { 
            StructureChain* chain = new (NotNull, allocateCell<StructureChain>(vm.heap)) StructureChain(vm, vm.structureChainStructure.get());
            chain->finishCreation(vm, head);
            return chain;
        }
        WriteBarrier<Structure>* head() { return m_vector.get(); }
        static void visitChildren(JSCell*, SlotVisitor&);

        static Structure* createStructure(VM& vm, JSGlobalObject* globalObject, JSValue prototype)
        {
            return Structure::create(vm, globalObject, prototype, TypeInfo(CompoundType, StructureFlags), info());
        }
        
        DECLARE_INFO;

        static const bool needsDestruction = true;
        static const bool hasImmortalStructure = true;
        static void destroy(JSCell*);

    protected:
        static const unsigned StructureFlags = OverridesVisitChildren | StructureIsImmortal;

        void finishCreation(VM& vm, Structure* head)
        {
            Base::finishCreation(vm);
            size_t size = 0;
            for (Structure* current = head; current; current = current->storedPrototype().isNull() ? 0 : asObject(current->storedPrototype())->structure())
                ++size;
    
            m_vector = std::make_unique<WriteBarrier<Structure>[]>(size + 1);

            size_t i = 0;
            for (Structure* current = head; current; current = current->storedPrototype().isNull() ? 0 : asObject(current->storedPrototype())->structure())
                m_vector[i++].set(vm, this, current);
        }

    private:
        friend class LLIntOffsetsExtractor;
        
        StructureChain(VM&, Structure*);
        std::unique_ptr<WriteBarrier<Structure>[]> m_vector;
    };

} // namespace JSC

#endif // StructureChain_h