protected ForwardPositionQuery(ForwardPositionQuery other) : base((CacheOutputQuery)other)
{
}
private Query ProcessFilter(Filter root, Flags flags, out Props props)
{
bool first = ((flags & Flags.Filter) == 0);
Props propsCond;
Query cond = ProcessNode(root.Condition, Flags.None, out propsCond);
if (
CanBeNumber(cond) ||
(propsCond & (Props.HasPosition | Props.HasLast)) != 0
)
{
propsCond |= Props.HasPosition;
flags |= Flags.PosFilter;
}
// We don't want DescendantOverDescendant pattern to be recognized here (in case descendent::foo[expr]/descendant::bar)
// So we clean this flag here:
flags &= ~Flags.SmartDesc;
// ToDo: Instead it would be nice to wrap descendent::foo[expr] into special query that will flatten it -- i.e.
// remove all nodes that are descendant of other nodes. This is very easy becuase for sorted nodesets all children
// follow its parent. One step caching. This can be easyly done by rightmost DescendantQuery itsef.
// Interesting note! Can we garatee that DescendantOverDescendant returns flat nodeset? This defenetely true if it's input is flat.
Query qyInput = ProcessNode(root.Input, flags | Flags.Filter, out props);
if (root.Input.Type != AstNode.AstType.Filter)
{
// Props.PosFilter is for nested filters only.
// We clean it here to avoid cleaning it in all other ast nodes.
props &= ~Props.PosFilter;
}
if ((propsCond & Props.HasPosition) != 0)
{
// this condition is positional rightmost filter should be avare of this.
props |= Props.PosFilter;
}
/*merging predicates*/ {
FilterQuery qyFilter = qyInput as FilterQuery;
if (qyFilter != null && (propsCond & Props.HasPosition) == 0 && qyFilter.Condition.StaticType != XPathResultType.Any)
{
Query prevCond = qyFilter.Condition;
if (prevCond.StaticType == XPathResultType.Number)
{
prevCond = new LogicalExpr(Operator.Op.EQ, new NodeFunctions(FT.FuncPosition, null), prevCond);
}
cond = new BooleanExpr(Operator.Op.AND, prevCond, cond);
qyInput = qyFilter.qyInput;
}
}
if ((props & Props.PosFilter) != 0 && qyInput is DocumentOrderQuery)
{
qyInput = ((DocumentOrderQuery)qyInput).input;
}
if (firstInput == null)
{
firstInput = qyInput as BaseAxisQuery;
}
bool merge = (qyInput.Properties & QueryProps.Merge) != 0;
bool reverse = (qyInput.Properties & QueryProps.Reverse) != 0;
if ((propsCond & Props.HasPosition) != 0)
{
if (reverse)
{
qyInput = new ReversePositionQuery(qyInput);
}
else if ((propsCond & Props.HasLast) != 0)
{
qyInput = new ForwardPositionQuery(qyInput);
}
}
if (first && firstInput != null)
{
if (merge && (props & Props.PosFilter) != 0)
{
qyInput = new FilterQuery(qyInput, cond, /*noPosition:*/ false);
Query parent = firstInput.qyInput;
if (!(parent is ContextQuery)) // we don't need to wrap filter with MergeFilterQuery when cardinality is parent <: ?
{
firstInput.qyInput = new ContextQuery();
firstInput = null;
return(new MergeFilterQuery(parent, qyInput));
}
firstInput = null;
return(qyInput);
}
firstInput = null;
}
return(new FilterQuery(qyInput, cond, /*noPosition:*/ (propsCond & Props.HasPosition) == 0));
}
protected ForwardPositionQuery(ForwardPositionQuery other) : base(other)
{
}