public XmlQueryType DescendantsOf(XmlQueryType source, XmlQueryType filter) {
Debug.Assert(filter.IsNode && filter.Count == 1 && filter.IsSingleton);
List<XmlQueryType> list = new List<XmlQueryType>();
XmlQueryCardinality card = XmlQueryCardinality.None;
foreach (XmlQueryType sourceItem in source) {
switch (sourceItem.TypeCode) {
case XmlTypeCode.Node:
case XmlTypeCode.Document:
case XmlTypeCode.Element:
XmlQueryCardinality itemCard = XmlQueryCardinality.None;
if ((filter.NodeKinds & (XmlNodeKindFlags.Element | XmlNodeKindFlags.Text)) != 0) {
Dictionary<XmlQualifiedName, XmlQueryCardinality> allTypes = new Dictionary<XmlQualifiedName, XmlQueryCardinality>();
XmlSchemaType sourceSchemaType = sourceItem.SchemaType;
if (sourceSchemaType == null) {
Debug.Assert(sourceItem.TypeCode == XmlTypeCode.Node);
sourceSchemaType = XmlSchemaComplexType.AnyType;
}
itemCard = AddElementOrTextDescendants(list, allTypes, sourceSchemaType, filter);
}
itemCard += AddFilteredPrime(list, PI, filter);
itemCard += AddFilteredPrime(list, Comment, filter);
card |= itemCard;
break;
case XmlTypeCode.Attribute:
case XmlTypeCode.ProcessingInstruction:
case XmlTypeCode.Comment:
case XmlTypeCode.Namespace:
case XmlTypeCode.Text:
card |= XmlQueryCardinality.Zero;
break;
default:
Debug.Assert(sourceItem.IsAtomicValue, "missed case for a node");
break;
}
}
// Make sure that cardinality is at least Zero
return PrimeProduct(ChoiceType.Create(list), source.Cardinality * card);
}