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