mcs/class/System.XML/System.Xml/XmlNamespaceManager.cs

   1 //
   2 // XmlNamespaceManager.cs
   3 //
   4 // Authors:
   5 //   Jason Diamond (jason@injektilo.org)
   6 //   Ben Maurer (bmaurer@users.sourceforge.net)
   7 //
   8 // (C) 2001 Jason Diamond  http://injektilo.org/
   9 // (C) 2003 Ben Maurer
  10 //
  11
  12 using System.Collections;
  13
  14 namespace System.Xml
  15 {
  16         public class XmlNamespaceManager : IEnumerable
  17         {
  18                 #region Data
  19                 struct NsDecl {
  20                         public string Prefix, Uri;
  21                 }
  22
  23                 struct NsScope {
  24                         public int DeclCount;
  25                         public string DefaultNamespace;
  26                 }
  27
  28                 NsDecl [] decls;
  29                 int declPos = -1;
  30
  31                 NsScope [] scopes;
  32                 int scopePos = -1;
  33
  34                 string defaultNamespace;
  35                 int count;
  36
  37                 void InitData ()
  38                 {
  39                         decls = new NsDecl [10];
  40                         scopes = new NsScope [40];
  41                 }
  42
  43                 // precondition declPos == nsDecl.Length
  44                 void GrowDecls ()
  45                 {
  46                         NsDecl [] old = decls;
  47                         decls = new NsDecl [declPos * 2 + 1];
  48                         if (declPos > 0)
  49                                 Array.Copy (old, 0, decls, 0, declPos);
  50                 }
  51
  52                 // precondition scopePos == scopes.Length
  53                 void GrowScopes ()
  54                 {
  55                         NsScope [] old = scopes;
  56                         scopes = new NsScope [scopePos * 2 + 1];
  57                         if (scopePos > 0)
  58                                 Array.Copy (old, 0, scopes, 0, scopePos);
  59                 }
  60
  61                 #endregion
  62
  63                 #region Fields
  64
  65                 private XmlNameTable nameTable;
  66                 internal const string XmlnsXml = "http://www.w3.org/XML/1998/namespace";
  67                 internal const string XmlnsXmlns = "http://www.w3.org/2000/xmlns/";
  68
  69                 #endregion
  70
  71                 #region Constructor
  72
  73                 internal XmlNamespaceManager () {}
  74                 public XmlNamespaceManager (XmlNameTable nameTable)
  75                 {
  76                         this.nameTable = nameTable;
  77
  78                         nameTable.Add ("xmlns");
  79                         nameTable.Add ("xml");
  80                         nameTable.Add (String.Empty);
  81                         nameTable.Add (XmlnsXmlns);
  82                         nameTable.Add (XmlnsXml);
  83
  84                         InitData ();
  85                 }
  86
  87                 #endregion
  88
  89                 #region Properties
  90
  91                 public virtual string DefaultNamespace {
  92                         get { return defaultNamespace == null ? string.Empty : defaultNamespace; }
  93                 }
  94
  95                 public XmlNameTable NameTable {
  96                         get { return nameTable; }
  97                 }
  98
  99                 #endregion
 100
 101                 #region Methods
 102
 103                 public virtual void AddNamespace (string prefix, string uri)
 104                 {
 105                         if (prefix == null)
 106                                 throw new ArgumentNullException ("prefix", "Value cannot be null.");
 107
 108                         if (uri == null)
 109                                 throw new ArgumentNullException ("uri", "Value cannot be null.");
 110
 111                         prefix = nameTable.Add (prefix);
 112                         uri = nameTable.Add (uri);
 113
 114                         IsValidDeclaration (prefix, uri, true);
 115
 116                         if (prefix == string.Empty)
 117                                 defaultNamespace = uri;
 118
 119                         for (int i = declPos; i > declPos - count; i--) {
 120                                 if (decls [i].Prefix == prefix) {
 121                                         decls [i].Uri = uri;
 122                                         return;
 123                                 }
 124                         }
 125
 126                         declPos ++;
 127                         count ++;
 128
 129                         if (declPos == decls.Length)
 130                                 GrowDecls ();
 131                         decls [declPos].Prefix = prefix;
 132                         decls [declPos].Uri = uri;
 133                 }
 134
 135                 internal static string IsValidDeclaration (string prefix, string uri, bool throwException)
 136                 {
 137                         string message = null;
 138                         if (prefix == "xml" && uri != XmlnsXml)
 139                                 message = String.Format ("Prefix \"xml\" is only allowed to the fixed uri \"{0}\"", XmlnsXml);
 140                         else if (uri == XmlnsXml)
 141                                 message = String.Format ("Namespace URI \"{0}\" can only be declared with the fixed prefix \"xml\"", XmlnsXml);
 142                         if (message == null && prefix == "xmlns")
 143                                 message = "Declaring prefix named \"xmlns\" is not allowed to any namespace.";
 144                         if (message == null && uri == XmlnsXmlns)
 145                                 message = String.Format ("Namespace URI \"{0}\" cannot be declared with any namespace.", XmlnsXmlns);
 146                         if (message != null && throwException)
 147                                 throw new ArgumentException (message);
 148                         else
 149                                 return message;
 150                 }
 151
 152                 public virtual IEnumerator GetEnumerator ()
 153                 {
 154                         // In fact it returns such table's enumerator that contains all the namespaces.
 155                         // while HasNamespace() ignores pushed namespaces.
 156
 157                         Hashtable ht = new Hashtable ();
 158                         for (int i = 0; i <= declPos; i++) {
 159                                 if (decls [i].Prefix != string.Empty && decls [i].Uri != null) {
 160                                         ht [decls [i].Prefix] = decls [i].Uri;
 161                                 }
 162                         }
 163
 164                         ht [string.Empty] = DefaultNamespace;
 165                         ht ["xml"] = XmlnsXml;
 166                         ht ["xmlns"] = XmlnsXmlns;
 167
 168                         return ht.Keys.GetEnumerator ();
 169                 }
 170
 171                 public virtual bool HasNamespace (string prefix)
 172                 {
 173                         if (prefix == null || count == 0)
 174                                 return false;
 175
 176                         for (int i = declPos; i > declPos - count; i--) {
 177                                 if (decls [i].Prefix == prefix)
 178                                         return true;
 179                         }
 180
 181                         return false;
 182                 }
 183
 184                 public virtual string LookupNamespace (string prefix)
 185                 {
 186                         switch (prefix) {
 187                         case "xmlns":
 188                                 return nameTable.Get (XmlnsXmlns);
 189                         case "xml":
 190                                 return nameTable.Get (XmlnsXml);
 191                         case "":
 192                                 return DefaultNamespace;
 193                         }
 194
 195                         for (int i = declPos; i >= 0; i--) {
 196                                 if (decls [i].Prefix == prefix && decls [i].Uri != null /* null == flag for removed */)
 197                                         return decls [i].Uri;
 198                         }
 199
 200                         return null;
 201                 }
 202
 203                 public virtual string LookupPrefix (string uri)
 204                 {
 205                         if (uri == null)
 206                                 return null;
 207
 208                         if (uri == DefaultNamespace)
 209                                 return string.Empty;
 210
 211                         if (uri == XmlnsXml)
 212                                 return nameTable.Add ("xml");
 213
 214                         if (uri == XmlnsXmlns)
 215                                 return nameTable.Add ("xmlns");
 216
 217
 218                         for (int i = declPos; i >= 0; i--) {
 219                                 if (decls [i].Uri == uri && decls [i].Prefix != string.Empty) // we already looked for ""
 220                                         return decls [i].Prefix;
 221                         }
 222
 223                         // ECMA specifies that this method returns String.Empty
 224                         // in case of no match. But actually MS.NET returns null.
 225                         // For more information,see
 226                         //  http://lists.ximian.com/archives/public/mono-list/2003-January/005071.html
 227                         //return String.Empty;
 228                         return null;
 229                 }
 230
 231                 public virtual bool PopScope ()
 232                 {
 233                         if (scopePos == -1)
 234                                 return false;
 235
 236                         declPos -= count;
 237                         defaultNamespace = scopes [scopePos].DefaultNamespace;
 238                         count = scopes [scopePos].DeclCount;
 239                         scopePos --;
 240                         return true;
 241                 }
 242
 243                 public virtual void PushScope ()
 244                 {
 245                         scopePos ++;
 246                         if (scopePos == scopes.Length)
 247                                 GrowScopes ();
 248
 249                         scopes [scopePos].DefaultNamespace = defaultNamespace;
 250                         scopes [scopePos].DeclCount = count;
 251                         count = 0;
 252                 }
 253
 254                 public virtual void RemoveNamespace (string prefix, string uri)
 255                 {
 256                         if (prefix == null)
 257                                 throw new ArgumentNullException ("prefix");
 258
 259                         if (uri == null)
 260                                 throw new ArgumentNullException ("uri");
 261
 262                         if (count == 0)
 263                                 return;
 264
 265                         for (int i = declPos; i > declPos - count; i--) {
 266                                 if (decls [i].Prefix == prefix && decls [i].Uri == uri)
 267                                         decls [i].Uri = null;
 268                         }
 269                 }
 270
 271                 #endregion
 272         }
 273 }