public static object Extract([Implict] Executive engine, object arg, string xpath)
{
QueryNode.LispProcessingContext owner = (QueryNode.LispProcessingContext)engine.Owner;
XmlDataAccessor xmlacc = new XmlDataAccessor();
if (arg == null)
return null;
else if (arg is Resultset)
{
Resultset rs = (Resultset)arg;
Resultset dest = new Resultset(RowType.CreateContainerType(typeof(System.Object)), null);
if (!dest.RowType.RowTypeEquals(rs.RowType))
throw new InvalidOperationException();
while (rs.Begin != null)
{
Row row = rs.Dequeue();
XmlNode node = (XmlNode)row.GetObject(0);
object name = row.GetValue(1);
row = dest.NewRow();
if (node != null)
{
XmlNodeList nodes = node.SelectNodes(xpath,
owner.QueryContext.GetNsManager(node.OwnerDocument));
if (nodes.Count > 0)
row.SetObject(0, nodes);
}
row.SetValue(1, name);
dest.Enqueue(row);
}
return dest;
}
else if (arg is XmlNode)
{
XmlNode node = (XmlNode)arg;
XmlNodeList nodes = node.SelectNodes(xpath,
owner.QueryContext.GetNsManager(node.OwnerDocument));
if (nodes.Count == 0)
return null;
else
return nodes;
}
else if (arg is XmlNodeList)
{
XmlDataAccessor.NodeList nodeList = new XmlDataAccessor.NodeList();
foreach (XmlNode node in (XmlNodeList)arg)
{
XmlNodeList nodes = node.SelectNodes(xpath,
owner.QueryContext.GetNsManager(node.OwnerDocument));
nodeList.AddRange(nodes);
}
if (nodeList.Count > 0)
return nodeList;
else
return null;
}
else
throw new InvalidOperationException();
}