mcs/class/System.Xml.Linq/System.Xml.Linq/XNodeEqualityComparer.cs

   1 //
   2 // Authors:
   3 //   Atsushi Enomoto
   4 //
   5 // Copyright 2007 Novell (http://www.novell.com)
   6 //
   7 // Permission is hereby granted, free of charge, to any person obtaining
   8 // a copy of this software and associated documentation files (the
   9 // "Software"), to deal in the Software without restriction, including
  10 // without limitation the rights to use, copy, modify, merge, publish,
  11 // distribute, sublicense, and/or sell copies of the Software, and to
  12 // permit persons to whom the Software is furnished to do so, subject to
  13 // the following conditions:
  14 //
  15 // The above copyright notice and this permission notice shall be
  16 // included in all copies or substantial portions of the Software.
  17 //
  18 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  19 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  20 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  21 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  22 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  23 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  24 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  25 //
  26
  27 using System;
  28 using System.Collections;
  29 using System.Collections.Generic;
  30
  31 using XPI = System.Xml.Linq.XProcessingInstruction;
  32
  33 namespace System.Xml.Linq
  34 {
  35         public sealed class XNodeEqualityComparer : IEqualityComparer, IEqualityComparer<XNode>
  36         {
  37                 public XNodeEqualityComparer ()
  38                 {
  39                 }
  40
  41                 public bool Equals (XNode x, XNode y)
  42                 {
  43                         if (x == null)
  44                                 return y == null;
  45                         else if (y == null)
  46                                 return false;
  47                         //throw new NotImplementedException ();
  48                         if (x.NodeType != y.NodeType)
  49                                 return false;
  50                         switch (x.NodeType) {
  51                         case XmlNodeType.Document:
  52                                 XDocument doc1 = (XDocument) x;
  53                                 XDocument doc2 = (XDocument) y;
  54                                 if (!Equals (doc1.Declaration, doc2.Declaration))
  55                                         return false;
  56                                 IEnumerator<XNode> id2 = doc2.Nodes ().GetEnumerator ();
  57                                 foreach (XNode n in doc1.Nodes ()) {
  58                                         if (!id2.MoveNext ())
  59                                                 return false;
  60                                         if (!Equals (n, id2.Current))
  61                                                 return false;
  62                                 }
  63                                 return !id2.MoveNext ();
  64                         case XmlNodeType.Element:
  65                                 XElement e1 = (XElement) x;
  66                                 XElement e2 = (XElement) y;
  67                                 if (e1.Name != e2.Name)
  68                                         return false;
  69                                 IEnumerator<XAttribute> ia2 = e2.Attributes ().GetEnumerator ();
  70                                 foreach (XAttribute n in e1.Attributes ()) {
  71                                         if (!ia2.MoveNext ())
  72                                                 return false;
  73                                         if (!Equals (n, ia2.Current))
  74                                                 return false;
  75                                 }
  76                                 if (ia2.MoveNext ())
  77                                         return false;
  78                                 IEnumerator<XNode> ie2 = e2.Nodes ().GetEnumerator ();
  79                                 foreach (XNode n in e1.Nodes ()) {
  80                                         if (!ie2.MoveNext ())
  81                                                 return false;
  82                                         if (!Equals (n, ie2.Current))
  83                                                 return false;
  84                                 }
  85                                 return !ie2.MoveNext ();
  86                         case XmlNodeType.Comment:
  87                                 XComment c1 = (XComment) x;
  88                                 XComment c2 = (XComment) y;
  89                                 return c1.Value == c2.Value;
  90                         case XmlNodeType.ProcessingInstruction:
  91                                 XPI p1 = (XPI) x;
  92                                 XPI p2 = (XPI) y;
  93                                 return p1.Target == p2.Target && p1.Data == p2.Data;
  94                         case XmlNodeType.DocumentType:
  95                                 XDocumentType d1 = (XDocumentType) x;
  96                                 XDocumentType d2 = (XDocumentType) y;
  97                                 return d1.Name == d2.Name &&
  98                                        d1.PublicId == d2.PublicId &&
  99                                        d1.SystemId == d2.SystemId &&
 100                                        d1.InternalSubset == d2.InternalSubset;
 101                         case XmlNodeType.Text:
 102                                 return ((XText) x).Value == ((XText) y).Value;
 103                         }
 104                         throw new Exception ("INTERNAL ERROR: should not happen");
 105                 }
 106
 107                 bool Equals (XAttribute a1, XAttribute a2)
 108                 {
 109                         if (a1 == null)
 110                                 return a2 == null;
 111                         else if (a2 == null)
 112                                 return false;
 113                         return a1.Name == a2.Name && a1.Value == a2.Value;
 114                 }
 115
 116                 bool Equals (XDeclaration d1, XDeclaration d2)
 117                 {
 118                         if (d1 == null)
 119                                 return d2 == null;
 120                         else if (d2 == null)
 121                                 return false;
 122                         return d1.Version == d2.Version &&
 123                                d1.Encoding == d2.Encoding &&
 124                                d1.Standalone == d2.Standalone;
 125                 }
 126
 127                 bool IEqualityComparer.Equals (object n1, object n2)
 128                 {
 129                         return Equals ((XNode) n1, (XNode) n2);
 130                 }
 131
 132                 int GetHashCode (XDeclaration d)
 133                 {
 134                         if (d == null)
 135                                 return 0;
 136                         return (d.Version.GetHashCode () << 7) ^
 137                                (d.Encoding.GetHashCode () << 6) ^
 138                                d.Standalone.GetHashCode ();
 139                 }
 140
 141                 public int GetHashCode (XNode obj)
 142                 {
 143                         if (obj == null)
 144                                 return 0;
 145                         int h = ((int) obj.NodeType << 6);
 146                         switch (obj.NodeType) {
 147                         case XmlNodeType.Document:
 148                                 XDocument doc = (XDocument) obj;
 149                                 h = h ^ GetHashCode (doc.Declaration);
 150                                 foreach (XNode n in doc.Nodes ())
 151                                         h = h ^ (n.GetHashCode () << 5);
 152                                 break;
 153                         case XmlNodeType.Element:
 154                                 XElement el = (XElement) obj;
 155                                 h = h ^ (el.Name.GetHashCode () << 3);
 156                                 foreach (XAttribute a in el.Attributes ())
 157                                         h = h ^ (a.GetHashCode () << 7);
 158                                 foreach (XNode n in el.Nodes ())
 159                                         h = h ^ (n.GetHashCode () << 6);
 160                                 break;
 161                         case XmlNodeType.Comment:
 162                                 h = h ^ ((XComment) obj).Value.GetHashCode ();
 163                                 break;
 164                         case XmlNodeType.ProcessingInstruction:
 165                                 XPI pi = (XPI) obj;
 166                                 h = h ^ ((pi.Target.GetHashCode () << 6) + pi.Data.GetHashCode ());
 167                                 break;
 168                         case XmlNodeType.DocumentType:
 169                                 XDocumentType dtd = (XDocumentType) obj;
 170                                 h = h ^ (dtd.Name.GetHashCode () << 7) ^
 171                                     (dtd.PublicId.GetHashCode () << 6) ^
 172                                     (dtd.SystemId.GetHashCode () << 5) ^
 173                                     (dtd.InternalSubset.GetHashCode () << 4);
 174                                 break;
 175                         case XmlNodeType.Text:
 176                                 h = h ^ (((XText) obj).GetHashCode ());
 177                                 break;
 178                         }
 179                         return h;
 180                 }
 181
 182                 int IEqualityComparer.GetHashCode (object obj)
 183                 {
 184                         return GetHashCode ((XNode) obj);
 185                 }
 186         }
 187 }