mcs/class/referencesource/System.Xml/System/Xml/XPath/Internal/XPathAncestorQuery.cs

   1 //------------------------------------------------------------------------------
   2 // <copyright file="XPathAncestorQuery.cs" company="Microsoft">
   3 //     Copyright (c) Microsoft Corporation.  All rights reserved.
   4 // </copyright>
   5 // <owner current="true" primary="true">[....]</owner>
   6 //------------------------------------------------------------------------------
   7
   8 namespace MS.Internal.Xml.XPath {
   9     using System;
  10     using System.Xml;
  11     using System.Xml.XPath;
  12     using System.Diagnostics;
  13     using System.Collections.Generic;
  14
  15     internal sealed class XPathAncestorQuery : CacheAxisQuery {
  16         private bool matchSelf;
  17
  18         public XPathAncestorQuery(Query qyInput, string name, string prefix, XPathNodeType typeTest, bool matchSelf) : base(qyInput, name, prefix, typeTest)  {
  19             this.matchSelf = matchSelf;
  20         }
  21         private XPathAncestorQuery(XPathAncestorQuery other) : base(other) {
  22             this.matchSelf = other.matchSelf;
  23         }
  24
  25         public override object Evaluate(XPathNodeIterator context) {
  26             base.Evaluate(context);
  27
  28             XPathNavigator ancestor = null;
  29             XPathNavigator input;
  30             while ((input = qyInput.Advance()) != null) {
  31                 if (matchSelf) {
  32                     if (matches(input)) {
  33                         if (!Insert(outputBuffer, input)) {
  34                             // If input is already in output buffer all its ancestors are in a buffer as well.
  35                             continue;
  36                         }
  37                     }
  38                 }
  39                 if (ancestor == null || ! ancestor.MoveTo(input)) {
  40                     ancestor = input.Clone();
  41                 }
  42                 while (ancestor.MoveToParent()) {
  43                     if (matches(ancestor)) {
  44                         if (!Insert(outputBuffer, ancestor)) {
  45                             // If input is already in output buffer all its ancestors are in a buffer as well.
  46                             break;
  47                         }
  48                     }
  49                 }
  50             }
  51             return this;
  52         }
  53
  54         public override XPathNodeIterator Clone() { return new XPathAncestorQuery(this); }
  55         public override int CurrentPosition { get { return outputBuffer.Count - count + 1; } }
  56         public override QueryProps Properties { get { return base.Properties | QueryProps.Reverse; } }
  57
  58         public override void PrintQuery(XmlWriter w) {
  59             w.WriteStartElement(this.GetType().Name);
  60             if (matchSelf) {
  61                 w.WriteAttributeString("self", "yes");
  62             }
  63             if (NameTest) {
  64                 w.WriteAttributeString("name", Prefix.Length != 0 ? Prefix + ':' + Name : Name);
  65             }
  66             if (TypeTest != XPathNodeType.Element) {
  67                 w.WriteAttributeString("nodeType", TypeTest.ToString());
  68             }
  69             qyInput.PrintQuery(w);
  70             w.WriteEndElement();
  71         }
  72     }
  73 }