1/*
2 * Copyright (C) 2008, 2009, 2015 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 SmallStrings_h
27#define SmallStrings_h
28
29#include "TypeofType.h"
30#include "WriteBarrier.h"
31#include <wtf/Noncopyable.h>
32
33#define JSC_COMMON_STRINGS_EACH_NAME(macro) \
34 macro(boolean) \
35 macro(false) \
36 macro(function) \
37 macro(number) \
38 macro(null) \
39 macro(object) \
40 macro(undefined) \
41 macro(string) \
42 macro(symbol) \
43 macro(true)
44
45namespace WTF {
46class StringImpl;
47}
48
49namespace JSC {
50
51class VM;
52class JSString;
53class SmallStringsStorage;
54class SlotVisitor;
55
56static const unsigned maxSingleCharacterString = 0xFF;
57
58class SmallStrings {
59 WTF_MAKE_NONCOPYABLE(SmallStrings);
60public:
61 SmallStrings();
62 ~SmallStrings();
63
64 JSString* emptyString()
65 {
66 return m_emptyString;
67 }
68
69 JSString* singleCharacterString(unsigned char character)
70 {
71 return m_singleCharacterStrings[character];
72 }
73
74 JS_EXPORT_PRIVATE WTF::StringImpl* singleCharacterStringRep(unsigned char character);
75
76 JSString** singleCharacterStrings() { return &m_singleCharacterStrings[0]; }
77
78 void initializeCommonStrings(VM&);
79 void visitStrongReferences(SlotVisitor&);
80
81#define JSC_COMMON_STRINGS_ACCESSOR_DEFINITION(name) \
82 JSString* name##String() const \
83 { \
84 return m_##name; \
85 }
86 JSC_COMMON_STRINGS_EACH_NAME(JSC_COMMON_STRINGS_ACCESSOR_DEFINITION)
87#undef JSC_COMMON_STRINGS_ACCESSOR_DEFINITION
88
89 JSString* typeString(TypeofType type) const
90 {
91 switch (type) {
92 case TypeofType::Undefined:
93 return undefinedString();
94 case TypeofType::Boolean:
95 return booleanString();
96 case TypeofType::Number:
97 return numberString();
98 case TypeofType::String:
99 return stringString();
100 case TypeofType::Symbol:
101 return symbolString();
102 case TypeofType::Object:
103 return objectString();
104 case TypeofType::Function:
105 return functionString();
106 }
107
108 RELEASE_ASSERT_NOT_REACHED();
109 return nullptr;
110 }
111
112 JSString* objectStringStart() const { return m_objectStringStart; }
113 JSString* nullObjectString() const { return m_nullObjectString; }
114 JSString* undefinedObjectString() const { return m_undefinedObjectString; }
115
116 bool needsToBeVisited(HeapOperation collectionType) const
117 {
118 if (collectionType == FullCollection)
119 return true;
120 return m_needsToBeVisited;
121 }
122
123private:
124 static const unsigned singleCharacterStringCount = maxSingleCharacterString + 1;
125
126 void createEmptyString(VM*);
127 void createSingleCharacterString(VM*, unsigned char);
128
129 void initialize(VM*, JSString*&, const char* value);
130
131 JSString* m_emptyString;
132#define JSC_COMMON_STRINGS_ATTRIBUTE_DECLARATION(name) JSString* m_##name;
133 JSC_COMMON_STRINGS_EACH_NAME(JSC_COMMON_STRINGS_ATTRIBUTE_DECLARATION)
134#undef JSC_COMMON_STRINGS_ATTRIBUTE_DECLARATION
135 JSString* m_objectStringStart;
136 JSString* m_nullObjectString;
137 JSString* m_undefinedObjectString;
138 JSString* m_singleCharacterStrings[singleCharacterStringCount];
139 std::unique_ptr<SmallStringsStorage> m_storage;
140 bool m_needsToBeVisited;
141};
142
143} // namespace JSC
144
145#endif // SmallStrings_h
146