Structure* Structure::addPropertyTransition(JSGlobalData& globalData, Structure* structure, PropertyName propertyName, unsigned attributes, JSCell* specificValue, PropertyOffset& offset)
{
// If we have a specific function, we may have got to this point if there is
// already a transition with the correct property name and attributes, but
// specialized to a different function. In this case we just want to give up
// and despecialize the transition.
// In this case we clear the value of specificFunction which will result
// in us adding a non-specific transition, and any subsequent lookup in
// Structure::addPropertyTransitionToExistingStructure will just use that.
if (specificValue && structure->m_transitionTable.contains(propertyName.uid(), attributes))
specificValue = 0;
ASSERT(!structure->isDictionary());
ASSERT(structure->isObject());
ASSERT(!Structure::addPropertyTransitionToExistingStructure(structure, propertyName, attributes, specificValue, offset));
if (structure->m_specificFunctionThrashCount == maxSpecificFunctionThrashCount)
specificValue = 0;
if (structure->transitionCount() > s_maxTransitionLength) {
Structure* transition = toCacheableDictionaryTransition(globalData, structure);
ASSERT(structure != transition);
offset = transition->putSpecificValue(globalData, propertyName, attributes, specificValue);
if (transition->outOfLineSize() > transition->outOfLineCapacity())
transition->growOutOfLineCapacity();
return transition;
}
Structure* transition = create(globalData, structure);
transition->m_cachedPrototypeChain.setMayBeNull(globalData, transition, structure->m_cachedPrototypeChain.get());
transition->m_previous.set(globalData, transition, structure);
transition->m_nameInPrevious = propertyName.uid();
transition->m_attributesInPrevious = attributes;
transition->m_specificValueInPrevious.setMayBeNull(globalData, transition, specificValue);
if (structure->m_propertyTable) {
if (structure->m_isPinnedPropertyTable)
transition->m_propertyTable = structure->m_propertyTable->copy(globalData, transition, structure->m_propertyTable->size() + 1);
else
transition->m_propertyTable = structure->m_propertyTable.release();
} else {
if (structure->m_previous)
transition->materializePropertyMap(globalData);
else
transition->createPropertyMap();
}
offset = transition->putSpecificValue(globalData, propertyName, attributes, specificValue);
if (transition->outOfLineSize() > transition->outOfLineCapacity())
transition->growOutOfLineCapacity();
transition->m_offset = offset;
checkOffset(transition->m_offset, transition->inlineCapacity());
structure->m_transitionTable.add(globalData, transition);
return transition;
}
Structure* Structure::nonPropertyTransition(JSGlobalData& globalData, Structure* structure, NonPropertyTransition transitionKind)
{
unsigned attributes = toAttributes(transitionKind);
IndexingType indexingType = newIndexingType(structure->indexingTypeIncludingHistory(), transitionKind);
if (JSGlobalObject* globalObject = structure->m_globalObject.get()) {
if (globalObject->isOriginalArrayStructure(structure)) {
Structure* result = globalObject->originalArrayStructureForIndexingType(indexingType);
if (result->indexingTypeIncludingHistory() == indexingType) {
structure->notifyTransitionFromThisStructure();
return result;
}
}
}
if (Structure* existingTransition = structure->m_transitionTable.get(0, attributes)) {
ASSERT(existingTransition->m_attributesInPrevious == attributes);
ASSERT(existingTransition->indexingTypeIncludingHistory() == indexingType);
return existingTransition;
}
Structure* transition = create(globalData, structure);
transition->m_previous.set(globalData, transition, structure);
transition->m_attributesInPrevious = attributes;
transition->m_indexingType = indexingType;
transition->m_offset = structure->m_offset;
checkOffset(transition->m_offset, transition->inlineCapacity());
if (structure->m_propertyTable) {
if (structure->m_isPinnedPropertyTable)
transition->m_propertyTable = structure->m_propertyTable->copy(globalData, transition, structure->m_propertyTable->size() + 1);
else
transition->m_propertyTable = structure->m_propertyTable.release();
} else {
if (structure->m_previous)
transition->materializePropertyMap(globalData);
else
transition->createPropertyMap();
}
structure->m_transitionTable.add(globalData, transition);
return transition;
}