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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