JavaScriptCore/kjs/StructureID.cpp

   1 /*
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  10  *    notice, this list of conditions and the following disclaimer in the
  11  *    documentation and/or other materials provided with the distribution.
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  24  */
  25
  26 #include "config.h"
  27 #include "StructureID.h"
  28
  29 #include "identifier.h"
  30 #include "JSObject.h"
  31 #include <wtf/RefPtr.h>
  32
  33 using namespace std;
  34
  35 namespace JSC {
  36
  37     StructureID::StructureID(JSValue* prototype, JSType type)
  38     : m_isDictionary(false)
  39     , m_type(type)
  40     , m_prototype(prototype)
  41     , m_cachedPrototypeChain(0)
  42     , m_previous(0)
  43     , m_nameInPrevious(0)
  44     , m_transitionCount(0)
  45 {
  46     ASSERT(m_prototype);
  47     ASSERT(m_prototype->isObject() || m_prototype->isNull());
  48 }
  49
  50 void StructureID::transitionTo(StructureID* oldStructureID, StructureID* newStructureID, JSObject* slotBase)
  51 {
  52     if (!slotBase->usingInlineStorage() && oldStructureID->m_propertyMap.size() != newStructureID->m_propertyMap.size())
  53         slotBase->allocatePropertyStorage(oldStructureID->m_propertyMap.size(), newStructureID->m_propertyMap.size());
  54 }
  55
  56 PassRefPtr<StructureID> StructureID::addPropertyTransition(StructureID* structureID, const Identifier& propertyName, JSValue* value, unsigned attributes, JSObject* slotBase, PutPropertySlot& slot, PropertyStorage& propertyStorage)
  57 {
  58     ASSERT(!structureID->m_isDictionary);
  59     ASSERT(structureID->m_type == ObjectType);
  60
  61     if (StructureID* existingTransition = structureID->m_transitionTable.get(make_pair(propertyName.ustring().rep(), attributes))) {
  62         if (!slotBase->usingInlineStorage() && structureID->m_propertyMap.size() != existingTransition->m_propertyMap.size())
  63             slotBase->allocatePropertyStorage(structureID->m_propertyMap.size(), existingTransition->m_propertyMap.size());
  64
  65         size_t offset = existingTransition->propertyMap().getOffset(propertyName);
  66         ASSERT(offset != WTF::notFound);
  67         propertyStorage[offset] = value;
  68         slot.setNewProperty(slotBase, offset);
  69
  70         return existingTransition;
  71     }
  72
  73     if (structureID->m_transitionCount > s_maxTransitionLength) {
  74         RefPtr<StructureID> transition = toDictionaryTransition(structureID);
  75         transition->m_propertyMap.put(propertyName, value, attributes, false, slotBase, slot, propertyStorage);
  76         return transition.release();
  77     }
  78
  79     RefPtr<StructureID> transition = create(structureID->m_prototype);
  80     transition->m_cachedPrototypeChain = structureID->m_cachedPrototypeChain;
  81     transition->m_previous = structureID;
  82     transition->m_nameInPrevious = propertyName.ustring().rep();
  83     transition->m_attributesInPrevious = attributes;
  84     transition->m_transitionCount = structureID->m_transitionCount + 1;
  85     transition->m_propertyMap = structureID->m_propertyMap;
  86
  87     transition->m_propertyMap.put(propertyName, value, attributes, false, slotBase, slot, propertyStorage);
  88
  89     structureID->m_transitionTable.add(make_pair(propertyName.ustring().rep(), attributes), transition.get());
  90     return transition.release();
  91 }
  92
  93 PassRefPtr<StructureID> StructureID::toDictionaryTransition(StructureID* structureID)
  94 {
  95     ASSERT(!structureID->m_isDictionary);
  96
  97     RefPtr<StructureID> transition = create(structureID->m_prototype);
  98     transition->m_isDictionary = true;
  99     transition->m_propertyMap = structureID->m_propertyMap;
 100     return transition.release();
 101 }
 102
 103 PassRefPtr<StructureID> StructureID::fromDictionaryTransition(StructureID* structureID)
 104 {
 105     ASSERT(structureID->m_isDictionary);
 106
 107     // Since dictionary StructureIDs are not shared, and no opcodes specialize
 108     // for them, we don't need to allocate a new StructureID when transitioning
 109     // to non-dictionary status.
 110     structureID->m_isDictionary = false;
 111     return structureID;
 112 }
 113
 114 PassRefPtr<StructureID> StructureID::changePrototypeTransition(StructureID* structureID, JSValue* prototype)
 115 {
 116     RefPtr<StructureID> transition = create(prototype);
 117     transition->m_transitionCount = structureID->m_transitionCount + 1;
 118     transition->m_propertyMap = structureID->m_propertyMap;
 119     return transition.release();
 120 }
 121
 122 PassRefPtr<StructureID> StructureID::getterSetterTransition(StructureID* structureID)
 123 {
 124     RefPtr<StructureID> transition = create(structureID->storedPrototype());
 125     transition->m_transitionCount = structureID->m_transitionCount + 1;
 126     transition->m_propertyMap = structureID->m_propertyMap;
 127     return transition.release();
 128 }
 129
 130 StructureID::~StructureID()
 131 {
 132     if (m_previous) {
 133         ASSERT(m_previous->m_transitionTable.contains(make_pair(m_nameInPrevious, m_attributesInPrevious)));
 134         m_previous->m_transitionTable.remove(make_pair(m_nameInPrevious, m_attributesInPrevious));
 135     }
 136 }
 137
 138 StructureIDChain::StructureIDChain(StructureID* structureID)
 139 {
 140     size_t size = 1;
 141
 142     StructureID* tmp = structureID;
 143     while (!tmp->storedPrototype()->isNull()) {
 144         ++size;
 145         tmp = static_cast<JSCell*>(tmp->storedPrototype())->structureID();
 146     }
 147
 148     m_vector.set(new RefPtr<StructureID>[size + 1]);
 149
 150     size_t i;
 151     for (i = 0; i < size - 1; ++i) {
 152         m_vector[i] = structureID;
 153         structureID = static_cast<JSObject*>(structureID->storedPrototype())->structureID();
 154     }
 155     m_vector[i] = structureID;
 156     m_vector[i + 1] = 0;
 157 }
 158
 159 } // namespace JSC