RecyclableObject* ForInObjectEnumerator::GetFirstPrototypeWithEnumerableProperties(RecyclableObject* object)
{
RecyclableObject* firstPrototype = nullptr;
if (JavascriptOperators::GetTypeId(object) != TypeIds_HostDispatch)
{
firstPrototype = object;
while (true)
{
firstPrototype = firstPrototype->GetPrototype();
if (JavascriptOperators::GetTypeId(firstPrototype) == TypeIds_Null)
{
firstPrototype = nullptr;
break;
}
if (!DynamicType::Is(firstPrototype->GetTypeId())
|| !DynamicObject::FromVar(firstPrototype)->GetHasNoEnumerableProperties())
{
break;
}
}
}
return firstPrototype;
}
JavascriptString * ForInObjectEnumerator::MoveAndGetNext(PropertyId& propertyId)
{
PropertyRecord const * propRecord;
PropertyAttributes attributes = PropertyNone;
while (true)
{
propertyId = Constants::NoProperty;
JavascriptString * currentIndex = enumerator.MoveAndGetNext(propertyId, &attributes);
// The object type may have changed and we may not be able to use Jit fast path anymore.
// canUseJitFastPath is determined in ForInObjectEnumerator::Initialize, once we decide we can't use
// Jit fast path we will never go back to use fast path so && with current value - if it's already
// false we don't call CanUseJITFastPath()
this->canUseJitFastPath = this->canUseJitFastPath && enumerator.CanUseJITFastPath();
if (currentIndex)
{
if (this->shadowData == nullptr)
{
// There are no prototype that has enumerable properties,
// don't need to keep track of the propertyIds we visited.
// We have asked for enumerable properties only, so don't need to check the attribute returned.
Assert(attributes & PropertyEnumerable);
return currentIndex;
}
// Property Id does not exist.
if (propertyId == Constants::NoProperty)
{
if (VirtualTableInfo<Js::PropertyString>::HasVirtualTable(currentIndex))
{
// If we have a property string, it is assumed that the propertyId is being
// kept alive with the object
PropertyString * propertyString = (PropertyString *)currentIndex;
propertyId = propertyString->GetPropertyRecord()->GetPropertyId();
}
else
{
ScriptContext* scriptContext = currentIndex->GetScriptContext();
scriptContext->GetOrAddPropertyRecord(currentIndex->GetString(), currentIndex->GetLength(), &propRecord);
propertyId = propRecord->GetPropertyId();
// We keep the track of what is enumerated using a bit vector of propertyID.
// so the propertyId can't be collected until the end of the for in enumerator
// Keep a list of the property string.
this->shadowData->newPropertyStrings.Prepend(GetScriptContext()->GetRecycler(), propRecord);
}
}
if (TestAndSetEnumerated(propertyId) //checks if the property is already enumerated or not
&& (attributes & PropertyEnumerable))
{
return currentIndex;
}
}
else
{
if (this->shadowData == nullptr)
{
Assert(!this->enumeratingPrototype);
return nullptr;
}
RecyclableObject * object;
if (!this->enumeratingPrototype)
{
this->enumeratingPrototype = true;
object = this->shadowData->firstPrototype;
this->shadowData->currentObject = object;
}
else
{
//walk the prototype chain
object = this->shadowData->currentObject->GetPrototype();
this->shadowData->currentObject = object;
if ((object == nullptr) || (JavascriptOperators::GetTypeId(object) == TypeIds_Null))
{
return nullptr;
}
}
do
{
if (!InitializeCurrentEnumerator(object))
{
return nullptr;
}
if (!enumerator.IsNullEnumerator())
{
break;
}
//walk the prototype chain
object = object->GetPrototype();
this->shadowData->currentObject = object;
if ((object == nullptr) || (JavascriptOperators::GetTypeId(object) == TypeIds_Null))
{
return nullptr;
}
}
while (true);
}
}
}