JavaScriptCore/kjs/StructureID.cpp

   1 /*
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  11  *    documentation and/or other materials provided with the distribution.
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  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 PassRefPtr<StructureID> StructureID::addPropertyTransition(StructureID* structureID, const Identifier& propertyName, JSValue* value, unsigned attributes, JSObject* slotBase, PutPropertySlot& slot, PropertyStorage& propertyStorage)
  51 {
  52     ASSERT(!structureID->m_isDictionary);
  53     ASSERT(structureID->m_type == ObjectType);
  54
  55     if (StructureID* existingTransition = structureID->m_transitionTable.get(make_pair(propertyName.ustring().rep(), attributes))) {
  56         if (!slotBase->usingInlineStorage() && structureID->m_propertyMap.size() != existingTransition->m_propertyMap.size())
  57             slotBase->allocatePropertyStorage(structureID->m_propertyMap.size(), existingTransition->m_propertyMap.size());
  58
  59         size_t offset = existingTransition->propertyMap().getOffset(propertyName);
  60         ASSERT(offset != WTF::notFound);
  61         propertyStorage[offset] = value;
  62         slot.setNewProperty(slotBase, offset);
  63
  64         return existingTransition;
  65     }
  66
  67     if (structureID->m_transitionCount > s_maxTransitionLength) {
  68         RefPtr<StructureID> transition = toDictionaryTransition(structureID);
  69         transition->m_propertyMap.put(propertyName, value, attributes, false, slotBase, slot, propertyStorage);
  70         return transition.release();
  71     }
  72
  73     RefPtr<StructureID> transition = create(structureID->m_prototype);
  74     transition->m_cachedPrototypeChain = structureID->m_cachedPrototypeChain;
  75     transition->m_previous = structureID;
  76     transition->m_nameInPrevious = propertyName.ustring().rep();
  77     transition->m_attributesInPrevious = attributes;
  78     transition->m_transitionCount = structureID->m_transitionCount + 1;
  79     transition->m_propertyMap = structureID->m_propertyMap;
  80
  81     transition->m_propertyMap.put(propertyName, value, attributes, false, slotBase, slot, propertyStorage);
  82
  83     structureID->m_transitionTable.add(make_pair(propertyName.ustring().rep(), attributes), transition.get());
  84     return transition.release();
  85 }
  86
  87 PassRefPtr<StructureID> StructureID::toDictionaryTransition(StructureID* structureID)
  88 {
  89     ASSERT(!structureID->m_isDictionary);
  90
  91     RefPtr<StructureID> transition = create(structureID->m_prototype);
  92     transition->m_isDictionary = true;
  93     transition->m_propertyMap = structureID->m_propertyMap;
  94     return transition.release();
  95 }
  96
  97 PassRefPtr<StructureID> StructureID::fromDictionaryTransition(StructureID* structureID)
  98 {
  99     ASSERT(structureID->m_isDictionary);
 100
 101     // Since dictionary StructureIDs are not shared, and no opcodes specialize
 102     // for them, we don't need to allocate a new StructureID when transitioning
 103     // to non-dictionary status.
 104     structureID->m_isDictionary = false;
 105     return structureID;
 106 }
 107
 108 PassRefPtr<StructureID> StructureID::changePrototypeTransition(StructureID* structureID, JSValue* prototype)
 109 {
 110     RefPtr<StructureID> transition = create(prototype);
 111     transition->m_transitionCount = structureID->m_transitionCount + 1;
 112     transition->m_propertyMap = structureID->m_propertyMap;
 113     return transition.release();
 114 }
 115
 116 PassRefPtr<StructureID> StructureID::getterSetterTransition(StructureID* structureID)
 117 {
 118     RefPtr<StructureID> transition = create(structureID->storedPrototype());
 119     transition->m_transitionCount = structureID->m_transitionCount + 1;
 120     transition->m_propertyMap = structureID->m_propertyMap;
 121     return transition.release();
 122 }
 123
 124 StructureID::~StructureID()
 125 {
 126     if (m_previous) {
 127         ASSERT(m_previous->m_transitionTable.contains(make_pair(m_nameInPrevious, m_attributesInPrevious)));
 128         m_previous->m_transitionTable.remove(make_pair(m_nameInPrevious, m_attributesInPrevious));
 129     }
 130 }
 131
 132 StructureIDChain::StructureIDChain(StructureID* structureID)
 133 {
 134     size_t size = 1;
 135
 136     StructureID* tmp = structureID;
 137     while (!tmp->storedPrototype()->isNull()) {
 138         ++size;
 139         tmp = static_cast<JSCell*>(tmp->storedPrototype())->structureID();
 140     }
 141
 142     m_vector.set(new RefPtr<StructureID>[size]);
 143
 144     size_t i;
 145     for (i = 0; i < size - 1; ++i) {
 146         m_vector[i] = structureID;
 147         structureID = static_cast<JSObject*>(structureID->storedPrototype())->structureID();
 148     }
 149     m_vector[i] = structureID;
 150 }
 151
 152 } // namespace JSC