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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 <wtf/SegmentedVector.h>
31 
32 namespace JSC {
33 
34     class ParserArenaDeletable;
35     class ParserArenaRefCounted;
36 
37     class IdentifierArena {
38         WTF_MAKE_FAST_ALLOCATED;
39     public:
40         ALWAYS_INLINE const Identifier& makeIdentifier(JSGlobalData*, const UChar* characters, size_t length);
41         const Identifier& makeNumericIdentifier(JSGlobalData*, double number);
42 
clear()43         void clear() { m_identifiers.clear(); }
isEmpty()44         bool isEmpty() const { return m_identifiers.isEmpty(); }
45 
46     private:
47         typedef SegmentedVector<Identifier, 64> IdentifierVector;
48         IdentifierVector m_identifiers;
49     };
50 
makeIdentifier(JSGlobalData * globalData,const UChar * characters,size_t length)51     ALWAYS_INLINE const Identifier& IdentifierArena::makeIdentifier(JSGlobalData* globalData, const UChar* characters, size_t length)
52     {
53         m_identifiers.append(Identifier(globalData, characters, length));
54         return m_identifiers.last();
55     }
56 
makeNumericIdentifier(JSGlobalData * globalData,double number)57     inline const Identifier& IdentifierArena::makeNumericIdentifier(JSGlobalData* globalData, double number)
58     {
59         m_identifiers.append(Identifier(globalData, UString::number(number)));
60         return m_identifiers.last();
61     }
62 
63     class ParserArena {
64         WTF_MAKE_NONCOPYABLE(ParserArena);
65     public:
66         ParserArena();
67         ~ParserArena();
68 
swap(ParserArena & otherArena)69         void swap(ParserArena& otherArena)
70         {
71             std::swap(m_freeableMemory, otherArena.m_freeableMemory);
72             std::swap(m_freeablePoolEnd, otherArena.m_freeablePoolEnd);
73             m_identifierArena.swap(otherArena.m_identifierArena);
74             m_freeablePools.swap(otherArena.m_freeablePools);
75             m_deletableObjects.swap(otherArena.m_deletableObjects);
76             m_refCountedObjects.swap(otherArena.m_refCountedObjects);
77         }
78 
allocateFreeable(size_t size)79         void* allocateFreeable(size_t size)
80         {
81             ASSERT(size);
82             ASSERT(size <= freeablePoolSize);
83             size_t alignedSize = alignSize(size);
84             ASSERT(alignedSize <= freeablePoolSize);
85             if (UNLIKELY(static_cast<size_t>(m_freeablePoolEnd - m_freeableMemory) < alignedSize))
86                 allocateFreeablePool();
87             void* block = m_freeableMemory;
88             m_freeableMemory += alignedSize;
89             return block;
90         }
91 
allocateDeletable(size_t size)92         void* allocateDeletable(size_t size)
93         {
94             ParserArenaDeletable* deletable = static_cast<ParserArenaDeletable*>(fastMalloc(size));
95             m_deletableObjects.append(deletable);
96             return deletable;
97         }
98 
99         void derefWithArena(PassRefPtr<ParserArenaRefCounted>);
100         bool contains(ParserArenaRefCounted*) const;
101         ParserArenaRefCounted* last() const;
102         void removeLast();
103 
104         bool isEmpty() const;
105         void reset();
106 
identifierArena()107         IdentifierArena& identifierArena() { return *m_identifierArena; }
108 
109     private:
110         static const size_t freeablePoolSize = 8000;
111 
alignSize(size_t size)112         static size_t alignSize(size_t size)
113         {
114             return (size + sizeof(WTF::AllocAlignmentInteger) - 1) & ~(sizeof(WTF::AllocAlignmentInteger) - 1);
115         }
116 
117         void* freeablePool();
118         void allocateFreeablePool();
119         void deallocateObjects();
120 
121         char* m_freeableMemory;
122         char* m_freeablePoolEnd;
123 
124         OwnPtr<IdentifierArena> m_identifierArena;
125         Vector<void*> m_freeablePools;
126         Vector<ParserArenaDeletable*> m_deletableObjects;
127         Vector<RefPtr<ParserArenaRefCounted> > m_refCountedObjects;
128     };
129 
130 }
131 
132 #endif
133