1/*
2 * Copyright (C) 2009 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 ParserArena_h
27#define ParserArena_h
28
29#include "Identifier.h"
30#include <array>
31#include <wtf/SegmentedVector.h>
32
33namespace JSC {
34
35    class ParserArenaDeletable;
36    class ParserArenaRefCounted;
37
38    class IdentifierArena {
39        WTF_MAKE_FAST_ALLOCATED;
40    public:
41        IdentifierArena()
42        {
43            clear();
44        }
45
46        template <typename T>
47        ALWAYS_INLINE const Identifier& makeIdentifier(VM*, const T* characters, size_t length);
48        ALWAYS_INLINE const Identifier& makeIdentifierLCharFromUChar(VM*, const UChar* characters, size_t length);
49
50        const Identifier& makeNumericIdentifier(VM*, double number);
51
52        bool isEmpty() const { return m_identifiers.isEmpty(); }
53
54    public:
55        static const int MaximumCachableCharacter = 128;
56        typedef SegmentedVector<Identifier, 64> IdentifierVector;
57        void clear()
58        {
59            m_identifiers.clear();
60            for (int i = 0; i < MaximumCachableCharacter; i++)
61                m_shortIdentifiers[i] = 0;
62            for (int i = 0; i < MaximumCachableCharacter; i++)
63                m_recentIdentifiers[i] = 0;
64        }
65
66    private:
67        IdentifierVector m_identifiers;
68        std::array<Identifier*, MaximumCachableCharacter> m_shortIdentifiers;
69        std::array<Identifier*, MaximumCachableCharacter> m_recentIdentifiers;
70    };
71
72    template <typename T>
73    ALWAYS_INLINE const Identifier& IdentifierArena::makeIdentifier(VM* vm, const T* characters, size_t length)
74    {
75        if (characters[0] >= MaximumCachableCharacter) {
76            m_identifiers.append(Identifier(vm, characters, length));
77            return m_identifiers.last();
78        }
79        if (length == 1) {
80            if (Identifier* ident = m_shortIdentifiers[characters[0]])
81                return *ident;
82            m_identifiers.append(Identifier(vm, characters, length));
83            m_shortIdentifiers[characters[0]] = &m_identifiers.last();
84            return m_identifiers.last();
85        }
86        Identifier* ident = m_recentIdentifiers[characters[0]];
87        if (ident && Identifier::equal(ident->impl(), characters, length))
88            return *ident;
89        m_identifiers.append(Identifier(vm, characters, length));
90        m_recentIdentifiers[characters[0]] = &m_identifiers.last();
91        return m_identifiers.last();
92    }
93
94    ALWAYS_INLINE const Identifier& IdentifierArena::makeIdentifierLCharFromUChar(VM* vm, const UChar* characters, size_t length)
95    {
96        if (characters[0] >= MaximumCachableCharacter) {
97            m_identifiers.append(Identifier::createLCharFromUChar(vm, characters, length));
98            return m_identifiers.last();
99        }
100        if (length == 1) {
101            if (Identifier* ident = m_shortIdentifiers[characters[0]])
102                return *ident;
103            m_identifiers.append(Identifier(vm, characters, length));
104            m_shortIdentifiers[characters[0]] = &m_identifiers.last();
105            return m_identifiers.last();
106        }
107        Identifier* ident = m_recentIdentifiers[characters[0]];
108        if (ident && Identifier::equal(ident->impl(), characters, length))
109            return *ident;
110        m_identifiers.append(Identifier::createLCharFromUChar(vm, characters, length));
111        m_recentIdentifiers[characters[0]] = &m_identifiers.last();
112        return m_identifiers.last();
113    }
114
115    inline const Identifier& IdentifierArena::makeNumericIdentifier(VM* vm, double number)
116    {
117        m_identifiers.append(Identifier(vm, String::numberToStringECMAScript(number)));
118        return m_identifiers.last();
119    }
120
121    class ParserArena {
122        WTF_MAKE_NONCOPYABLE(ParserArena);
123    public:
124        ParserArena();
125        ~ParserArena();
126
127        void swap(ParserArena& otherArena)
128        {
129            std::swap(m_freeableMemory, otherArena.m_freeableMemory);
130            std::swap(m_freeablePoolEnd, otherArena.m_freeablePoolEnd);
131            m_identifierArena.swap(otherArena.m_identifierArena);
132            m_freeablePools.swap(otherArena.m_freeablePools);
133            m_deletableObjects.swap(otherArena.m_deletableObjects);
134            m_refCountedObjects.swap(otherArena.m_refCountedObjects);
135        }
136
137        void* allocateFreeable(size_t size)
138        {
139            ASSERT(size);
140            ASSERT(size <= freeablePoolSize);
141            size_t alignedSize = alignSize(size);
142            ASSERT(alignedSize <= freeablePoolSize);
143            if (UNLIKELY(static_cast<size_t>(m_freeablePoolEnd - m_freeableMemory) < alignedSize))
144                allocateFreeablePool();
145            void* block = m_freeableMemory;
146            m_freeableMemory += alignedSize;
147            return block;
148        }
149
150        void* allocateDeletable(size_t size)
151        {
152            ParserArenaDeletable* deletable = static_cast<ParserArenaDeletable*>(allocateFreeable(size));
153            m_deletableObjects.append(deletable);
154            return deletable;
155        }
156
157        void derefWithArena(PassRefPtr<ParserArenaRefCounted>);
158        bool contains(ParserArenaRefCounted*) const;
159        ParserArenaRefCounted* last() const;
160        void removeLast();
161
162        bool isEmpty() const;
163        JS_EXPORT_PRIVATE void reset();
164
165        IdentifierArena& identifierArena()
166        {
167            if (UNLIKELY (!m_identifierArena))
168                m_identifierArena = adoptPtr(new IdentifierArena);
169            return *m_identifierArena;
170        }
171
172    private:
173        static const size_t freeablePoolSize = 8000;
174
175        static size_t alignSize(size_t size)
176        {
177            return (size + sizeof(WTF::AllocAlignmentInteger) - 1) & ~(sizeof(WTF::AllocAlignmentInteger) - 1);
178        }
179
180        void* freeablePool();
181        void allocateFreeablePool();
182        void deallocateObjects();
183
184        char* m_freeableMemory;
185        char* m_freeablePoolEnd;
186
187        OwnPtr<IdentifierArena> m_identifierArena;
188        Vector<void*> m_freeablePools;
189        Vector<ParserArenaDeletable*> m_deletableObjects;
190        Vector<RefPtr<ParserArenaRefCounted>> m_refCountedObjects;
191    };
192
193}
194
195#endif
196