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