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

   1 //------------------------------------------------------------------------------
   2 // <copyright file="XPathSelectionIterator.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     // We need this wrapper object to:
  16     //      1. Calculate position
  17     //      2. Protect internal query.Current from user who may call MoveNext().
  18     internal class XPathSelectionIterator : ResetableIterator {
  19         private XPathNavigator nav;
  20         private Query          query;
  21         private int            position;
  22
  23         internal XPathSelectionIterator(XPathNavigator nav, Query query) {
  24             this.nav = nav.Clone();
  25             this.query = query;
  26         }
  27
  28         protected XPathSelectionIterator(XPathSelectionIterator it) {
  29             this.nav   = it.nav.Clone();
  30             this.query = (Query) it.query.Clone();
  31             this.position = it.position;
  32         }
  33
  34         public override void Reset() {
  35             this.query.Reset();
  36         }
  37
  38         public override bool MoveNext() {
  39             XPathNavigator n = query.Advance();
  40                 if( n != null ) {
  41                 position++;
  42                 if (!nav.MoveTo(n)) {
  43                             nav = n.Clone();
  44                 }
  45                 return true;
  46             }
  47             return false;
  48         }
  49
  50         public override int            Count      { get { return query.Count; } }
  51         public override XPathNavigator Current    { get { return nav; } }
  52         public override int CurrentPosition       { get { return position;  } }
  53         public override XPathNodeIterator Clone() { return new XPathSelectionIterator(this); }
  54     }
  55 }