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diff --git a/Source/JavaScriptCore/runtime/Structure.h b/Source/JavaScriptCore/runtime/Structure.h
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+/*
+ * Copyright (C) 2008, 2009 Apple Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
+ */
+
+#ifndef Structure_h
+#define Structure_h
+
+#include "Identifier.h"
+#include "JSType.h"
+#include "JSValue.h"
+#include "PropertyMapHashTable.h"
+#include "PropertyNameArray.h"
+#include "Protect.h"
+#include "StructureChain.h"
+#include "StructureTransitionTable.h"
+#include "JSTypeInfo.h"
+#include "UString.h"
+#include "WeakGCPtr.h"
+#include <wtf/PassRefPtr.h>
+#include <wtf/RefCounted.h>
+
+#ifndef NDEBUG
+#define DUMP_PROPERTYMAP_STATS 0
+#else
+#define DUMP_PROPERTYMAP_STATS 0
+#endif
+
+namespace JSC {
+
+    class MarkStack;
+    class PropertyNameArray;
+    class PropertyNameArrayData;
+
+    enum EnumerationMode {
+        ExcludeDontEnumProperties,
+        IncludeDontEnumProperties
+    };
+
+    class Structure : public RefCounted<Structure> {
+    public:
+        friend class JIT;
+        friend class StructureTransitionTable;
+        static PassRefPtr<Structure> create(JSValue prototype, const TypeInfo& typeInfo, unsigned anonymousSlotCount)
+        {
+            return adoptRef(new Structure(prototype, typeInfo, anonymousSlotCount));
+        }
+
+        static void startIgnoringLeaks();
+        static void stopIgnoringLeaks();
+
+        static void dumpStatistics();
+
+        static PassRefPtr<Structure> addPropertyTransition(Structure*, const Identifier& propertyName, unsigned attributes, JSCell* specificValue, size_t& offset);
+        static PassRefPtr<Structure> addPropertyTransitionToExistingStructure(Structure*, const Identifier& propertyName, unsigned attributes, JSCell* specificValue, size_t& offset);
+        static PassRefPtr<Structure> removePropertyTransition(Structure*, const Identifier& propertyName, size_t& offset);
+        static PassRefPtr<Structure> changePrototypeTransition(Structure*, JSValue prototype);
+        static PassRefPtr<Structure> despecifyFunctionTransition(Structure*, const Identifier&);
+        static PassRefPtr<Structure> getterSetterTransition(Structure*);
+        static PassRefPtr<Structure> toCacheableDictionaryTransition(Structure*);
+        static PassRefPtr<Structure> toUncacheableDictionaryTransition(Structure*);
+
+        PassRefPtr<Structure> flattenDictionaryStructure(JSObject*);
+
+        ~Structure();
+
+        // These should be used with caution.  
+        size_t addPropertyWithoutTransition(const Identifier& propertyName, unsigned attributes, JSCell* specificValue);
+        size_t removePropertyWithoutTransition(const Identifier& propertyName);
+        void setPrototypeWithoutTransition(JSValue prototype) { m_prototype = prototype; }
+        
+        bool isDictionary() const { return m_dictionaryKind != NoneDictionaryKind; }
+        bool isUncacheableDictionary() const { return m_dictionaryKind == UncachedDictionaryKind; }
+
+        const TypeInfo& typeInfo() const { return m_typeInfo; }
+
+        JSValue storedPrototype() const { return m_prototype; }
+        JSValue prototypeForLookup(ExecState*) const;
+        StructureChain* prototypeChain(ExecState*) const;
+
+        Structure* previousID() const { return m_previous.get(); }
+
+        void growPropertyStorageCapacity();
+        unsigned propertyStorageCapacity() const { return m_propertyStorageCapacity; }
+        unsigned propertyStorageSize() const { return m_anonymousSlotCount + (m_propertyTable ? m_propertyTable->keyCount + (m_propertyTable->deletedOffsets ? m_propertyTable->deletedOffsets->size() : 0) : static_cast<unsigned>(m_offset + 1)); }
+        bool isUsingInlineStorage() const;
+
+        size_t get(const Identifier& propertyName);
+        size_t get(const StringImpl* rep, unsigned& attributes, JSCell*& specificValue);
+        size_t get(const Identifier& propertyName, unsigned& attributes, JSCell*& specificValue)
+        {
+            ASSERT(!propertyName.isNull());
+            return get(propertyName.impl(), attributes, specificValue);
+        }
+        bool transitionedFor(const JSCell* specificValue)
+        {
+            return m_specificValueInPrevious == specificValue;
+        }
+        bool hasTransition(StringImpl*, unsigned attributes);
+        bool hasTransition(const Identifier& propertyName, unsigned attributes)
+        {
+            return hasTransition(propertyName.impl(), attributes);
+        }
+
+        bool hasGetterSetterProperties() const { return m_hasGetterSetterProperties; }
+        void setHasGetterSetterProperties(bool hasGetterSetterProperties) { m_hasGetterSetterProperties = hasGetterSetterProperties; }
+
+        bool hasNonEnumerableProperties() const { return m_hasNonEnumerableProperties; }
+
+        bool hasAnonymousSlots() const { return !!m_anonymousSlotCount; }
+        unsigned anonymousSlotCount() const { return m_anonymousSlotCount; }
+        
+        bool isEmpty() const { return m_propertyTable ? !m_propertyTable->keyCount : m_offset == noOffset; }
+
+        void despecifyDictionaryFunction(const Identifier& propertyName);
+        void disableSpecificFunctionTracking() { m_specificFunctionThrashCount = maxSpecificFunctionThrashCount; }
+
+        void setEnumerationCache(JSPropertyNameIterator* enumerationCache); // Defined in JSPropertyNameIterator.h.
+        void clearEnumerationCache(JSPropertyNameIterator* enumerationCache); // Defined in JSPropertyNameIterator.h.
+        JSPropertyNameIterator* enumerationCache(); // Defined in JSPropertyNameIterator.h.
+        void getPropertyNames(PropertyNameArray&, EnumerationMode mode);
+        
+    private:
+
+        Structure(JSValue prototype, const TypeInfo&, unsigned anonymousSlotCount);
+        
+        typedef enum { 
+            NoneDictionaryKind = 0,
+            CachedDictionaryKind = 1,
+            UncachedDictionaryKind = 2
+        } DictionaryKind;
+        static PassRefPtr<Structure> toDictionaryTransition(Structure*, DictionaryKind);
+
+        size_t put(const Identifier& propertyName, unsigned attributes, JSCell* specificValue);
+        size_t remove(const Identifier& propertyName);
+
+        void expandPropertyMapHashTable();
+        void rehashPropertyMapHashTable();
+        void rehashPropertyMapHashTable(unsigned newTableSize);
+        void createPropertyMapHashTable();
+        void createPropertyMapHashTable(unsigned newTableSize);
+        void insertIntoPropertyMapHashTable(const PropertyMapEntry&);
+        void checkConsistency();
+
+        bool despecifyFunction(const Identifier&);
+        void despecifyAllFunctions();
+
+        PropertyMapHashTable* copyPropertyTable();
+        void materializePropertyMap();
+        void materializePropertyMapIfNecessary()
+        {
+            if (m_propertyTable || !m_previous)             
+                return;
+            materializePropertyMap();
+        }
+
+        signed char transitionCount() const
+        {
+            // Since the number of transitions is always the same as m_offset, we keep the size of Structure down by not storing both.
+            return m_offset == noOffset ? 0 : m_offset + 1;
+        }
+
+        typedef std::pair<Structure*, Structure*> Transition;
+        typedef HashMap<StructureTransitionTableHash::Key, Transition, StructureTransitionTableHash, StructureTransitionTableHashTraits> TransitionTable;
+
+        inline bool transitionTableContains(const StructureTransitionTableHash::Key& key, JSCell* specificValue);
+        inline void transitionTableRemove(const StructureTransitionTableHash::Key& key, JSCell* specificValue);
+        inline void transitionTableAdd(const StructureTransitionTableHash::Key& key, Structure* structure, JSCell* specificValue);
+        inline bool transitionTableHasTransition(const StructureTransitionTableHash::Key& key) const;
+        inline Structure* transitionTableGet(const StructureTransitionTableHash::Key& key, JSCell* specificValue) const;
+
+        TransitionTable* transitionTable() const { ASSERT(!m_isUsingSingleSlot); return m_transitions.m_table; }
+        inline void setTransitionTable(TransitionTable* table);
+        Structure* singleTransition() const { ASSERT(m_isUsingSingleSlot); return m_transitions.m_singleTransition; }
+        void setSingleTransition(Structure* structure) { ASSERT(m_isUsingSingleSlot); m_transitions.m_singleTransition = structure; }
+        
+        bool isValid(ExecState*, StructureChain* cachedPrototypeChain) const;
+
+        static const unsigned emptyEntryIndex = 0;
+    
+        static const signed char s_maxTransitionLength = 64;
+
+        static const signed char noOffset = -1;
+
+        static const unsigned maxSpecificFunctionThrashCount = 3;
+
+        TypeInfo m_typeInfo;
+
+        JSValue m_prototype;
+        mutable RefPtr<StructureChain> m_cachedPrototypeChain;
+
+        RefPtr<Structure> m_previous;
+        RefPtr<StringImpl> m_nameInPrevious;
+        JSCell* m_specificValueInPrevious;
+
+        // 'm_isUsingSingleSlot' indicates whether we are using the single transition optimisation.
+        union {
+            TransitionTable* m_table;
+            Structure* m_singleTransition;
+        } m_transitions;
+
+        WeakGCPtr<JSPropertyNameIterator> m_enumerationCache;
+
+        PropertyMapHashTable* m_propertyTable;
+
+        uint32_t m_propertyStorageCapacity;
+
+        // m_offset does not account for anonymous slots
+        signed char m_offset;
+
+        unsigned m_dictionaryKind : 2;
+        bool m_isPinnedPropertyTable : 1;
+        bool m_hasGetterSetterProperties : 1;
+        bool m_hasNonEnumerableProperties : 1;
+#if COMPILER(WINSCW)
+        // Workaround for Symbian WINSCW compiler that cannot resolve unsigned type of the declared 
+        // bitfield, when used as argument in make_pair() function calls in structure.ccp.
+        // This bitfield optimization is insignificant for the Symbian emulator target.
+        unsigned m_attributesInPrevious;
+#else
+        unsigned m_attributesInPrevious : 7;
+#endif
+        unsigned m_specificFunctionThrashCount : 2;
+        unsigned m_anonymousSlotCount : 5;
+        unsigned m_isUsingSingleSlot : 1;
+        // 4 free bits
+    };
+
+    inline size_t Structure::get(const Identifier& propertyName)
+    {
+        ASSERT(!propertyName.isNull());
+
+        materializePropertyMapIfNecessary();
+        if (!m_propertyTable)
+            return WTF::notFound;
+
+        StringImpl* rep = propertyName.impl();
+
+        unsigned i = rep->existingHash();
+
+#if DUMP_PROPERTYMAP_STATS
+        ++numProbes;
+#endif
+
+        unsigned entryIndex = m_propertyTable->entryIndices[i & m_propertyTable->sizeMask];
+        if (entryIndex == emptyEntryIndex)
+            return WTF::notFound;
+
+        if (rep == m_propertyTable->entries()[entryIndex - 1].key)
+            return m_propertyTable->entries()[entryIndex - 1].offset;
+
+#if DUMP_PROPERTYMAP_STATS
+        ++numCollisions;
+#endif
+
+        unsigned k = 1 | WTF::doubleHash(rep->existingHash());
+
+        while (1) {
+            i += k;
+
+#if DUMP_PROPERTYMAP_STATS
+            ++numRehashes;
+#endif
+
+            entryIndex = m_propertyTable->entryIndices[i & m_propertyTable->sizeMask];
+            if (entryIndex == emptyEntryIndex)
+                return WTF::notFound;
+
+            if (rep == m_propertyTable->entries()[entryIndex - 1].key)
+                return m_propertyTable->entries()[entryIndex - 1].offset;
+        }
+    }
+
+} // namespace JSC
+
+#endif // Structure_h