83 lines
3.7 KiB
C#
83 lines
3.7 KiB
C#
//------------------------------------------------------------------------------
|
|
// <copyright file="precedingsibling.cs" company="Microsoft">
|
|
// Copyright (c) Microsoft Corporation. All rights reserved.
|
|
// </copyright>
|
|
// <owner current="true" primary="true">Microsoft</owner>
|
|
//------------------------------------------------------------------------------
|
|
|
|
namespace MS.Internal.Xml.XPath {
|
|
using System;
|
|
using System.Xml;
|
|
using System.Xml.XPath;
|
|
using System.Diagnostics;
|
|
using System.Collections.Generic;
|
|
|
|
// This class can be rewritten much more efficient.
|
|
// Algorithm could be like one for FollowingSibling:
|
|
// - Build InputArrays: pares (first, sentinel)
|
|
// -- Cash all input nodes as sentinel
|
|
// -- Add firts node of its parent for each input node.
|
|
// -- Sort these pares by first nodes.
|
|
// - Advance algorithm will look like:
|
|
// -- For each row in InputArays we will output first node + all its following nodes which are < sentinel
|
|
// -- Before outputing each node in row #I we will check that it is < first node in row #I+1
|
|
// --- if true we actualy output it
|
|
// --- if false, we hold with row #I and apply this algorith starting for row #I+1
|
|
// --- when we done with #I+1 we continue with row #I
|
|
|
|
internal class PreSiblingQuery : CacheAxisQuery {
|
|
|
|
public PreSiblingQuery(Query qyInput, string name, string prefix, XPathNodeType typeTest) : base (qyInput, name, prefix, typeTest) {}
|
|
protected PreSiblingQuery(PreSiblingQuery other) : base(other) {}
|
|
|
|
private bool NotVisited(XPathNavigator nav, List<XPathNavigator> parentStk){
|
|
XPathNavigator nav1 = nav.Clone();
|
|
nav1.MoveToParent();
|
|
for (int i = 0; i < parentStk.Count; i++) {
|
|
if (nav1.IsSamePosition(parentStk[i])) {
|
|
return false;
|
|
}
|
|
}
|
|
parentStk.Add(nav1);
|
|
return true;
|
|
}
|
|
|
|
public override object Evaluate(XPathNodeIterator context) {
|
|
base.Evaluate(context);
|
|
|
|
// Fill up base.outputBuffer
|
|
List<XPathNavigator> parentStk = new List<XPathNavigator>();
|
|
Stack<XPathNavigator> inputStk = new Stack<XPathNavigator>();
|
|
while ((currentNode = qyInput.Advance()) != null) {
|
|
inputStk.Push(currentNode.Clone());
|
|
}
|
|
while (inputStk.Count != 0) {
|
|
XPathNavigator input = inputStk.Pop();
|
|
if (input.NodeType == XPathNodeType.Attribute || input.NodeType == XPathNodeType.Namespace) {
|
|
continue;
|
|
}
|
|
if (NotVisited(input, parentStk)) {
|
|
XPathNavigator prev = input.Clone();
|
|
if (prev.MoveToParent()) {
|
|
bool test = prev.MoveToFirstChild();
|
|
Debug.Assert(test, "We just moved to parent, how we can not have first child?");
|
|
while (!prev.IsSamePosition(input)) {
|
|
if (matches(prev)) {
|
|
Insert(outputBuffer, prev);
|
|
}
|
|
if (!prev.MoveToNext()) {
|
|
Debug.Fail("We managed to miss sentinel node (input)");
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
return this;
|
|
}
|
|
|
|
public override XPathNodeIterator Clone() { return new PreSiblingQuery(this); }
|
|
public override QueryProps Properties { get { return base.Properties | QueryProps.Reverse; } }
|
|
}
|
|
}
|