1/*
2 * Copyright (C) 2008-2009, 2015-2016 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#pragma once
27
28#include "CollectionScope.h"
29#include "TypeofType.h"
30#include <wtf/Noncopyable.h>
31
32#define JSC_COMMON_STRINGS_EACH_NAME(macro) \
33 macro(default) \
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(bigint) \
44 macro(true)
45
46namespace WTF {
47class StringImpl;
48}
49
50namespace JSC {
51
52class VM;
53class JSString;
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 Ref<StringImpl> singleCharacterStringRep(unsigned char character);
75
76 void setIsInitialized(bool isInitialized) { m_isInitialized = isInitialized; }
77
78 JSString** singleCharacterStrings() { return &m_singleCharacterStrings[0]; }
79
80 void initializeCommonStrings(VM&);
81 void visitStrongReferences(SlotVisitor&);
82
83#define JSC_COMMON_STRINGS_ACCESSOR_DEFINITION(name) \
84 JSString* name##String() const \
85 { \
86 return m_##name; \
87 }
88 JSC_COMMON_STRINGS_EACH_NAME(JSC_COMMON_STRINGS_ACCESSOR_DEFINITION)
89#undef JSC_COMMON_STRINGS_ACCESSOR_DEFINITION
90
91 JSString* typeString(TypeofType type) const
92 {
93 switch (type) {
94 case TypeofType::Undefined:
95 return undefinedString();
96 case TypeofType::Boolean:
97 return booleanString();
98 case TypeofType::Number:
99 return numberString();
100 case TypeofType::String:
101 return stringString();
102 case TypeofType::Symbol:
103 return symbolString();
104 case TypeofType::Object:
105 return objectString();
106 case TypeofType::Function:
107 return functionString();
108 case TypeofType::BigInt:
109 return bigintString();
110 }
111
112 RELEASE_ASSERT_NOT_REACHED();
113 return nullptr;
114 }
115
116 JSString* objectStringStart() const { return m_objectStringStart; }
117 JSString* nullObjectString() const { return m_nullObjectString; }
118 JSString* undefinedObjectString() const { return m_undefinedObjectString; }
119
120 bool needsToBeVisited(CollectionScope scope) const
121 {
122 if (scope == CollectionScope::Full)
123 return true;
124 return m_needsToBeVisited;
125 }
126
127private:
128 static const unsigned singleCharacterStringCount = maxSingleCharacterString + 1;
129
130 void initialize(VM*, JSString*&, const char* value);
131
132 JSString* m_emptyString { nullptr };
133#define JSC_COMMON_STRINGS_ATTRIBUTE_DECLARATION(name) JSString* m_##name { nullptr };
134 JSC_COMMON_STRINGS_EACH_NAME(JSC_COMMON_STRINGS_ATTRIBUTE_DECLARATION)
135#undef JSC_COMMON_STRINGS_ATTRIBUTE_DECLARATION
136 JSString* m_objectStringStart { nullptr };
137 JSString* m_nullObjectString { nullptr };
138 JSString* m_undefinedObjectString { nullptr };
139 JSString* m_singleCharacterStrings[singleCharacterStringCount] { nullptr };
140 bool m_needsToBeVisited { true };
141 bool m_isInitialized { false };
142};
143
144} // namespace JSC
145