1/*
2 * Copyright (C) 2014-2017 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. AND ITS CONTRIBUTORS ``AS IS''
14 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
15 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
17 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
18 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
19 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
20 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
21 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
22 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
23 * THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#pragma once
27
28#include "JSCast.h"
29#include "Operations.h"
30#include "PropertyNameArray.h"
31#include "Structure.h"
32
33namespace JSC {
34
35class JSPropertyNameEnumerator final : public JSCell {
36public:
37 typedef JSCell Base;
38 static const unsigned StructureFlags = Base::StructureFlags | StructureIsImmortal;
39
40 static JSPropertyNameEnumerator* create(VM&);
41 static JSPropertyNameEnumerator* create(VM&, Structure*, uint32_t, uint32_t, PropertyNameArray&&);
42
43 static const bool needsDestruction = true;
44 static void destroy(JSCell*);
45
46 static Structure* createStructure(VM& vm, JSGlobalObject* globalObject, JSValue prototype)
47 {
48 return Structure::create(vm, globalObject, prototype, TypeInfo(CellType, StructureFlags), info());
49 }
50
51 DECLARE_EXPORT_INFO;
52
53 JSString* propertyNameAtIndex(uint32_t index) const
54 {
55 if (index >= m_propertyNames.size())
56 return nullptr;
57 return m_propertyNames[index].get();
58 }
59
60 StructureChain* cachedPrototypeChain() const { return m_prototypeChain.get(); }
61 void setCachedPrototypeChain(VM& vm, StructureChain* prototypeChain) { return m_prototypeChain.set(vm, this, prototypeChain); }
62
63 Structure* cachedStructure(VM& vm) const
64 {
65 if (!m_cachedStructureID)
66 return nullptr;
67 return vm.heap.structureIDTable().get(m_cachedStructureID);
68 }
69 StructureID cachedStructureID() const { return m_cachedStructureID; }
70 uint32_t indexedLength() const { return m_indexedLength; }
71 uint32_t endStructurePropertyIndex() const { return m_endStructurePropertyIndex; }
72 uint32_t endGenericPropertyIndex() const { return m_endGenericPropertyIndex; }
73 uint32_t cachedInlineCapacity() const { return m_cachedInlineCapacity; }
74 static ptrdiff_t cachedStructureIDOffset() { return OBJECT_OFFSETOF(JSPropertyNameEnumerator, m_cachedStructureID); }
75 static ptrdiff_t indexedLengthOffset() { return OBJECT_OFFSETOF(JSPropertyNameEnumerator, m_indexedLength); }
76 static ptrdiff_t endStructurePropertyIndexOffset() { return OBJECT_OFFSETOF(JSPropertyNameEnumerator, m_endStructurePropertyIndex); }
77 static ptrdiff_t endGenericPropertyIndexOffset() { return OBJECT_OFFSETOF(JSPropertyNameEnumerator, m_endGenericPropertyIndex); }
78 static ptrdiff_t cachedInlineCapacityOffset() { return OBJECT_OFFSETOF(JSPropertyNameEnumerator, m_cachedInlineCapacity); }
79 static ptrdiff_t cachedPropertyNamesVectorOffset()
80 {
81 return OBJECT_OFFSETOF(JSPropertyNameEnumerator, m_propertyNames) + Vector<WriteBarrier<JSString>>::dataMemoryOffset();
82 }
83
84 static void visitChildren(JSCell*, SlotVisitor&);
85
86private:
87 JSPropertyNameEnumerator(VM&, StructureID, uint32_t);
88 void finishCreation(VM&, uint32_t, uint32_t, RefPtr<PropertyNameArrayData>&&);
89
90 Vector<WriteBarrier<JSString>> m_propertyNames;
91 StructureID m_cachedStructureID;
92 WriteBarrier<StructureChain> m_prototypeChain;
93 uint32_t m_indexedLength;
94 uint32_t m_endStructurePropertyIndex;
95 uint32_t m_endGenericPropertyIndex;
96 uint32_t m_cachedInlineCapacity;
97};
98
99inline JSPropertyNameEnumerator* propertyNameEnumerator(ExecState* exec, JSObject* base)
100{
101 VM& vm = exec->vm();
102 auto scope = DECLARE_THROW_SCOPE(vm);
103
104 uint32_t indexedLength = base->methodTable(vm)->getEnumerableLength(exec, base);
105
106 JSPropertyNameEnumerator* enumerator = nullptr;
107
108 Structure* structure = base->structure(vm);
109 if (!indexedLength
110 && (enumerator = structure->cachedPropertyNameEnumerator())
111 && enumerator->cachedPrototypeChain() == structure->prototypeChain(exec, base))
112 return enumerator;
113
114 uint32_t numberStructureProperties = 0;
115
116 PropertyNameArray propertyNames(&vm, PropertyNameMode::Strings, PrivateSymbolMode::Exclude);
117
118 if (structure->canAccessPropertiesQuicklyForEnumeration() && indexedLength == base->getArrayLength()) {
119 base->methodTable(vm)->getStructurePropertyNames(base, exec, propertyNames, EnumerationMode());
120 scope.assertNoException();
121
122 numberStructureProperties = propertyNames.size();
123
124 base->methodTable(vm)->getGenericPropertyNames(base, exec, propertyNames, EnumerationMode());
125 } else {
126 // Generic property names vector contains all indexed property names.
127 // So disable indexed property enumeration phase by setting |indexedLength| to 0.
128 indexedLength = 0;
129 base->methodTable(vm)->getPropertyNames(base, exec, propertyNames, EnumerationMode());
130 }
131 RETURN_IF_EXCEPTION(scope, nullptr);
132
133 ASSERT(propertyNames.size() < UINT32_MAX);
134
135 bool sawPolyProto;
136 bool successfullyNormalizedChain = normalizePrototypeChain(exec, base, sawPolyProto) != InvalidPrototypeChain;
137
138 Structure* structureAfterGettingPropertyNames = base->structure(vm);
139 enumerator = JSPropertyNameEnumerator::create(vm, structureAfterGettingPropertyNames, indexedLength, numberStructureProperties, WTFMove(propertyNames));
140 if (!indexedLength && successfullyNormalizedChain && structureAfterGettingPropertyNames == structure) {
141 enumerator->setCachedPrototypeChain(vm, structure->prototypeChain(exec, base));
142 if (structure->canCachePropertyNameEnumerator())
143 structure->setCachedPropertyNameEnumerator(vm, enumerator);
144 }
145 return enumerator;
146}
147
148} // namespace JSC
149