1/*
2 * Copyright (C) 2008 Apple Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 *    notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 *    notice, this list of conditions and the following disclaimer in the
11 *    documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#ifndef StructureChain_h
27#define StructureChain_h
28
29#include "JSCell.h"
30#include "JSObject.h"
31#include "Structure.h"
32
33#include <wtf/PassRefPtr.h>
34#include <wtf/RefCounted.h>
35#include <wtf/RefPtr.h>
36#include <wtf/StdLibExtras.h>
37
38namespace JSC {
39
40    class LLIntOffsetsExtractor;
41    class Structure;
42
43    class StructureChain : public JSCell {
44        friend class JIT;
45
46    public:
47        typedef JSCell Base;
48
49        static StructureChain* create(VM& vm, Structure* head)
50        {
51            StructureChain* chain = new (NotNull, allocateCell<StructureChain>(vm.heap)) StructureChain(vm, vm.structureChainStructure.get());
52            chain->finishCreation(vm, head);
53            return chain;
54        }
55        WriteBarrier<Structure>* head() { return m_vector.get(); }
56        static void visitChildren(JSCell*, SlotVisitor&);
57
58        static Structure* createStructure(VM& vm, JSGlobalObject* globalObject, JSValue prototype)
59        {
60            return Structure::create(vm, globalObject, prototype, TypeInfo(CompoundType, StructureFlags), info());
61        }
62
63        DECLARE_INFO;
64
65        static const bool needsDestruction = true;
66        static const bool hasImmortalStructure = true;
67        static void destroy(JSCell*);
68
69    protected:
70        static const unsigned StructureFlags = OverridesVisitChildren | StructureIsImmortal;
71
72        void finishCreation(VM& vm, Structure* head)
73        {
74            Base::finishCreation(vm);
75            size_t size = 0;
76            for (Structure* current = head; current; current = current->storedPrototype().isNull() ? 0 : asObject(current->storedPrototype())->structure())
77                ++size;
78
79            m_vector = std::make_unique<WriteBarrier<Structure>[]>(size + 1);
80
81            size_t i = 0;
82            for (Structure* current = head; current; current = current->storedPrototype().isNull() ? 0 : asObject(current->storedPrototype())->structure())
83                m_vector[i++].set(vm, this, current);
84        }
85
86    private:
87        friend class LLIntOffsetsExtractor;
88
89        StructureChain(VM&, Structure*);
90        std::unique_ptr<WriteBarrier<Structure>[]> m_vector;
91    };
92
93} // namespace JSC
94
95#endif // StructureChain_h
96