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

   1 //------------------------------------------------------------------------------
   2 // <copyright file="AttributeQuery.cs" company="Microsoft">
   3 //     Copyright (c) Microsoft Corporation.  All rights reserved.
   4 // </copyright>
   5 // <owner current="true" primary="true">Microsoft</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.Globalization;
  14
  15     internal sealed class AttributeQuery : BaseAxisQuery {
  16         private bool onAttribute = false;
  17
  18         public AttributeQuery(Query qyParent, string Name, string Prefix, XPathNodeType Type) : base(qyParent, Name, Prefix, Type) {}
  19         private AttributeQuery(AttributeQuery other) : base(other) {
  20             this.onAttribute = other.onAttribute;
  21         }
  22         public override void Reset() {
  23             onAttribute = false;
  24             base.Reset();
  25         }
  26
  27         public override XPathNavigator Advance() {
  28             while (true) {
  29                 if (! onAttribute) {
  30                     currentNode = qyInput.Advance();
  31                     if (currentNode == null) {
  32                         return null;
  33                     }
  34                     position = 0;
  35                     currentNode = currentNode.Clone();
  36                     onAttribute = currentNode.MoveToFirstAttribute();
  37                 } else {
  38                     onAttribute = currentNode.MoveToNextAttribute();
  39                 }
  40
  41                 if (onAttribute) {
  42                     Debug.Assert(! currentNode.NamespaceURI.Equals(XmlReservedNs.NsXmlNs));
  43                     if (matches(currentNode)) {
  44                         position++;
  45                         return currentNode;
  46                     }
  47                 }
  48             } // while
  49         }
  50
  51         public override XPathNavigator MatchNode(XPathNavigator context) {
  52             if (context != null) {
  53                 if (context.NodeType == XPathNodeType.Attribute && matches(context)) {
  54                     XPathNavigator temp = context.Clone();
  55                     if (temp.MoveToParent()) {
  56                         return qyInput.MatchNode(temp);
  57                     }
  58                 }
  59             }
  60             return null;
  61         }
  62
  63         public override XPathNodeIterator Clone() { return new AttributeQuery(this); }
  64     }
  65 }