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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 
     43         void clear() { m_identifiers.clear(); }
     44         bool isEmpty() const { return m_identifiers.isEmpty(); }
     45 
     46     private:
     47         typedef SegmentedVector<Identifier, 64> IdentifierVector;
     48         IdentifierVector m_identifiers;
     49     };
     50 
     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 
     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 
     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 
     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 
     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 
    107         IdentifierArena& identifierArena() { return *m_identifierArena; }
    108 
    109     private:
    110         static const size_t freeablePoolSize = 8000;
    111 
    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