mcs/class/Commons.Xml.Relaxng/Commons.Xml.Relaxng/RelaxngValidatingReader.cs

   1 //
   2 // Commons.Xml.Relaxng.RelaxngValidatingReader
   3 //
   4 // Author:
   5 //      Atsushi Enomoto <ginga@kit.hi-ho.ne.jp>
   6 //      Alexandre Alapetite <http://alexandre.alapetite.fr/cv/>
   7 //
   8 // 2003 Atsushi Enomoto. "No rights reserved."
   9 //
  10 // Copyright (c) 2004 Novell Inc.
  11 // All rights reserved
  12 //
  13
  14 //
  15 // Permission is hereby granted, free of charge, to any person obtaining
  16 // a copy of this software and associated documentation files (the
  17 // "Software"), to deal in the Software without restriction, including
  18 // without limitation the rights to use, copy, modify, merge, publish,
  19 // distribute, sublicense, and/or sell copies of the Software, and to
  20 // permit persons to whom the Software is furnished to do so, subject to
  21 // the following conditions:
  22 //
  23 // The above copyright notice and this permission notice shall be
  24 // included in all copies or substantial portions of the Software.
  25 //
  26 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  27 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  28 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  29 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  30 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  31 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  32 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  33 //
  34 using System;
  35 using System.Collections;
  36 using System.Text;
  37 using System.Xml;
  38 using Commons.Xml.Relaxng.Derivative;
  39
  40 namespace Commons.Xml.Relaxng
  41 {
  42         public class RelaxngValidatingReader : XmlDefaultReader
  43         {
  44                 public RelaxngValidatingReader (XmlReader reader)
  45                         : this (reader, (RelaxngPattern) null)
  46                 {
  47                 }
  48
  49                 public RelaxngValidatingReader (XmlReader reader, XmlReader grammarXml)
  50                         : this (reader, grammarXml, null)
  51                 {
  52                 }
  53
  54                 public RelaxngValidatingReader (XmlReader reader, XmlReader grammarXml, RelaxngDatatypeProvider provider)
  55                         : this (reader, RelaxngGrammar.Read (grammarXml, provider))
  56                 {
  57                 }
  58
  59                 public RelaxngValidatingReader (XmlReader reader, RelaxngPattern pattern)
  60                         : base (reader)
  61                 {
  62                         if (pattern == null)
  63                                 throw new ArgumentNullException ("pattern");
  64
  65                         if (reader.NodeType == XmlNodeType.Attribute)
  66                                 throw new RelaxngException ("RELAX NG does not support standalone attribute validation (it is prohibited due to the specification section 7.1.5");
  67                         this.reader = reader;
  68                         this.pattern = pattern;
  69                 }
  70
  71                 XmlReader reader;
  72                 RelaxngPattern pattern;
  73                 RdpPattern vState;
  74                 RdpPattern prevState;   // Mainly for debugging.
  75                 bool roughLabelCheck;
  76                 ArrayList strictCheckCache;
  77                 bool reportDetails;
  78                 string cachedValue;
  79                 int startElementDepth = -1;
  80                 bool inContent;
  81                 bool firstRead = true;
  82
  83                 public delegate bool RelaxngValidationEventHandler (XmlReader source, string message);
  84
  85                 public static readonly RelaxngValidationEventHandler IgnoreError = delegate { return true; };
  86
  87                 public event RelaxngValidationEventHandler InvalidNodeFound;
  88
  89                 delegate RdpPattern RecoveryHandler (RdpPattern source);
  90
  91                 RdpPattern HandleError (string error, bool elements, RdpPattern source, RecoveryHandler recover)
  92                 {
  93                         if (InvalidNodeFound != null && InvalidNodeFound (this, error))
  94                                 return recover (source);
  95                         else
  96                                 throw CreateValidationError (error, true);
  97                 }
  98
  99                 internal string CurrentStateXml {
 100                         get { return RdpUtil.DebugRdpPattern (vState, new Hashtable ()); }
 101                 }
 102
 103                 internal string PreviousStateXml {
 104                         get { return RdpUtil.DebugRdpPattern (prevState, new Hashtable ()); }
 105                 }
 106
 107                 #region Validation State support
 108
 109                 public bool ReportDetails {
 110                         get { return reportDetails; }
 111                         set { reportDetails = value; }
 112                 }
 113
 114                 public bool RoughLabelCheck {
 115                         get { return roughLabelCheck; }
 116                         set { roughLabelCheck = value; }
 117                 }
 118
 119                 // It is used to disclose its validation feature to public
 120                 class ValidationState
 121                 {
 122                         RdpPattern state;
 123
 124                         internal ValidationState (RdpPattern startState)
 125                         {
 126                                 this.state = startState;
 127                         }
 128
 129                         public RdpPattern Pattern {
 130                                 get { return state; }
 131                         }
 132
 133                         public ValidationState AfterOpenStartTag (
 134                                 string localName, string ns)
 135                         {
 136                                 RdpPattern p = state.StartTagOpenDeriv (
 137                                         localName, ns);
 138                                 return p is RdpNotAllowed ?
 139                                         null : new ValidationState (p);
 140                         }
 141
 142                         public bool OpenStartTag (string localName, string ns)
 143                         {
 144                                 RdpPattern p = state.StartTagOpenDeriv (
 145                                         localName, ns);
 146                                 if (p is RdpNotAllowed)
 147                                         return false;
 148                                 state = p;
 149                                 return true;
 150                         }
 151
 152                         public ValidationState AfterCloseStartTag ()
 153                         {
 154                                 RdpPattern p = state.StartTagCloseDeriv ();
 155                                 return p is RdpNotAllowed ?
 156                                         null : new ValidationState (p);
 157                         }
 158
 159                         public bool CloseStartTag ()
 160                         {
 161                                 RdpPattern p = state.StartTagCloseDeriv ();
 162                                 if (p is RdpNotAllowed)
 163                                         return false;
 164                                 state = p;
 165                                 return true;
 166                         }
 167
 168                         public ValidationState AfterEndTag ()
 169                         {
 170                                 RdpPattern p = state.EndTagDeriv ();
 171                                 if (p is RdpNotAllowed)
 172                                         return null;
 173                                 return new ValidationState (p);
 174                         }
 175
 176                         public bool EndTag ()
 177                         {
 178                                 RdpPattern p = state.EndTagDeriv ();
 179                                 if (p is RdpNotAllowed)
 180                                         return false;
 181                                 state = p;
 182                                 return true;
 183                         }
 184
 185                         public ValidationState AfterAttribute (
 186                                 string localName, string ns, XmlReader reader)
 187                         {
 188                                 RdpPattern p = state.AttDeriv (
 189                                         localName, ns, null, reader);
 190                                 if (p is RdpNotAllowed)
 191                                         return null;
 192                                 return new ValidationState (p);
 193                         }
 194
 195                         public bool Attribute (
 196                                 string localName, string ns, XmlReader reader)
 197                         {
 198                                 RdpPattern p = state.AttDeriv (
 199                                         localName, ns, null, reader);
 200                                 if (p is RdpNotAllowed)
 201                                         return false;
 202                                 state = p;
 203                                 return true;
 204                         }
 205                 }
 206
 207                 public object GetCurrentState ()
 208                 {
 209                         PrepareState ();
 210                         return new ValidationState (vState);
 211                 }
 212
 213                 private ValidationState ToState (object stateObject)
 214                 {
 215                         if (stateObject == null)
 216                                 throw new ArgumentNullException ("stateObject");
 217                         ValidationState state = stateObject as ValidationState;
 218                         if (state == null)
 219                                 throw new ArgumentException ("Argument stateObject is not of expected type.");
 220                         return state;
 221                 }
 222
 223                 public object AfterOpenStartTag (object stateObject,
 224                         string localName, string ns)
 225                 {
 226                         ValidationState state = ToState (stateObject);
 227                         return state.AfterOpenStartTag (localName, ns);
 228                 }
 229
 230                 public bool OpenStartTag (object stateObject,
 231                         string localName, string ns)
 232                 {
 233                         ValidationState state = ToState (stateObject);
 234                         return state.OpenStartTag (localName, ns);
 235                 }
 236
 237                 public object AfterAttribute (object stateObject,
 238                         string localName, string ns)
 239                 {
 240                         ValidationState state = ToState (stateObject);
 241                         return state.AfterAttribute (localName, ns, this);
 242                 }
 243
 244                 public bool Attribute (object stateObject,
 245                         string localName, string ns)
 246                 {
 247                         ValidationState state = ToState (stateObject);
 248                         return state.Attribute (localName, ns, this);
 249                 }
 250
 251                 public object AfterCloseStartTag (object stateObject)
 252                 {
 253                         ValidationState state = ToState (stateObject);
 254                         return state.AfterCloseStartTag ();
 255                 }
 256
 257                 public bool CloseStartTag (object stateObject)
 258                 {
 259                         ValidationState state = ToState (stateObject);
 260                         return state.CloseStartTag ();
 261                 }
 262
 263                 public object AfterEndTag (object stateObject)
 264                 {
 265                         ValidationState state = ToState (stateObject);
 266                         return state.AfterEndTag ();
 267                 }
 268
 269                 public bool EndTag (object stateObject)
 270                 {
 271                         ValidationState state = ToState (stateObject);
 272                         return state.EndTag ();
 273                 }
 274
 275                 public ICollection GetElementLabels (object stateObject)
 276                 {
 277                         ValidationState state = ToState (stateObject);
 278                         RdpPattern p = state.Pattern;
 279                         Hashtable elements = new Hashtable ();
 280                         Hashtable attributes = new Hashtable ();
 281                         p.GetLabels (elements, attributes);
 282
 283                         if (roughLabelCheck)
 284                                 return elements.Values;
 285
 286                         // Strict check that tries actual validation that will
 287                         // cover rejection by notAllowed.
 288                         if (strictCheckCache == null)
 289                                 strictCheckCache = new ArrayList ();
 290                         else
 291                                 strictCheckCache.Clear ();
 292                         foreach (XmlQualifiedName qname in elements.Values)
 293                                 if (p.StartTagOpenDeriv (qname.Name, qname.Namespace) is RdpNotAllowed)
 294                                         strictCheckCache.Add (qname);
 295                         foreach (XmlQualifiedName qname in strictCheckCache)
 296                                 elements.Remove (qname);
 297                         strictCheckCache.Clear ();
 298
 299                         return elements.Values;
 300                 }
 301
 302                 public ICollection GetAttributeLabels (object stateObject)
 303                 {
 304                         ValidationState state = ToState (stateObject);
 305                         RdpPattern p = state.Pattern;
 306                         Hashtable elements = new Hashtable ();
 307                         Hashtable attributes = new Hashtable ();
 308                         p.GetLabels (elements, attributes);
 309
 310                         if (roughLabelCheck)
 311                                 return attributes.Values;
 312
 313                         // Strict check that tries actual validation that will
 314                         // cover rejection by notAllowed.
 315                         if (strictCheckCache == null)
 316                                 strictCheckCache = new ArrayList ();
 317                         else
 318                                 strictCheckCache.Clear ();
 319                         foreach (XmlQualifiedName qname in attributes.Values)
 320                                 if (p.AttDeriv (qname.Name, qname.Namespace,null, this) is RdpNotAllowed)
 321                                         strictCheckCache.Add (qname);
 322                         foreach (XmlQualifiedName qname in strictCheckCache)
 323                                 attributes.Remove (qname);
 324                         strictCheckCache.Clear ();
 325
 326                         return attributes.Values;
 327                 }
 328
 329                 public bool Emptiable (object stateObject)
 330                 {
 331                         ValidationState state = ToState (stateObject);
 332                         RdpPattern p = state.Pattern;
 333                         return !(p.EndTagDeriv () is RdpNotAllowed);
 334                 }
 335                 #endregion
 336
 337                 private RelaxngException CreateValidationError (string message,
 338                         bool elements)
 339                 {
 340                         if (ReportDetails)
 341                                 return CreateValidationError (String.Concat (message,
 342                                         " Expected ",
 343                                         elements ? "elements are: " : "attributes are: ",
 344                                         BuildLabels (elements),
 345                                         "."));
 346                         return CreateValidationError (message);
 347                 }
 348
 349                 private RelaxngException CreateValidationError (string message)
 350                 {
 351                         IXmlLineInfo li = reader as IXmlLineInfo;
 352                         string lineInfo = reader.BaseURI;
 353                         if (li != null)
 354                                 lineInfo += String.Format (" line {0}, column {1}",
 355                                         li.LineNumber, li.LinePosition);
 356                         return new RelaxngException (message + lineInfo, prevState);
 357                 }
 358
 359                 private void PrepareState ()
 360                 {
 361                         if (vState != null)
 362                                 return;
 363                         if (!pattern.IsCompiled) {
 364                                 pattern.Compile ();
 365                         }
 366                         if (vState == null)
 367                                 vState = pattern.StartPattern;
 368                 }
 369
 370                 private string BuildLabels (bool elements)
 371                 {
 372                         StringBuilder sb = new StringBuilder ();
 373                         ValidationState s = new ValidationState (prevState);
 374                         ICollection col = elements ?
 375                                 GetElementLabels (s) : GetAttributeLabels (s);
 376                         foreach (XmlQualifiedName qname in col) {
 377                                 sb.Append (qname.ToString ());
 378                                 sb.Append (' ');
 379                         }
 380                         return sb.ToString ();
 381                 }
 382
 383                 public override bool Read ()
 384                 {
 385                         PrepareState ();
 386
 387                         // If the input XmlReader is already positioned on
 388                         // the first node to validate, skip Read() here
 389                         // (idea by Alex).
 390                         bool ret;
 391                         if (firstRead) {
 392                                 firstRead = false;
 393                                 if (reader.ReadState == ReadState.Initial)
 394                                         ret = reader.Read ();
 395                                 else
 396                                         ret = !((reader.ReadState == ReadState.Closed) || (reader.ReadState == ReadState.EndOfFile));
 397                         }
 398                         else
 399                                 ret = reader.Read ();
 400
 401                         // Process pending text node validation if required.
 402                         if (cachedValue != null)
 403                                 ValidateText (ret);
 404                         else if (cachedValue == null &&
 405                                 reader.NodeType == XmlNodeType.EndElement &&
 406                                 startElementDepth == reader.Depth)
 407                                 ValidateWeakMatch3 ();
 408
 409                         switch (reader.NodeType) {
 410                         case XmlNodeType.Element:
 411                                 inContent = true;
 412                                 // StartTagOpenDeriv
 413                                 prevState = vState;
 414                                 vState = memo.StartTagOpenDeriv (vState,
 415                                         reader.LocalName, reader.NamespaceURI);
 416                                 if (vState.PatternType == RelaxngPatternType.NotAllowed) {
 417                                         if (InvalidNodeFound != null)
 418                                                 vState = HandleError (String.Format ("Invalid start tag found. LocalName = {0}, NS = {1}.", reader.LocalName, reader.NamespaceURI), true, prevState, RecoverFromInvalidStartTag);
 419                                 }
 420
 421                                 // AttsDeriv equals to for each AttDeriv
 422                                 string elementNS = reader.NamespaceURI;
 423                                 if (reader.MoveToFirstAttribute ()) {
 424                                         do {
 425                                                 if (reader.NamespaceURI == "http://www.w3.org/2000/xmlns/")
 426                                                         continue;
 427
 428                                                 RdpPattern savedState = vState;
 429                                                 prevState = vState;
 430                                                 string attrNS = reader.NamespaceURI;
 431
 432                                                 vState = memo.StartAttDeriv (vState, reader.LocalName, attrNS);
 433                                                 if (vState == RdpNotAllowed.Instance) {
 434                                                         vState = HandleError (String.Format ("Invalid attribute occurence found. LocalName = {0}, NS = {1}.", reader.LocalName, reader.NamespaceURI), false, savedState, p => p);
 435                                                         continue; // the following steps are ignored.
 436                                                 }
 437                                                 prevState = vState;
 438                                                 vState = memo.TextOnlyDeriv (vState);
 439                                                 vState = TextDeriv (vState, reader.Value, reader);
 440                                                 if (Util.IsWhitespace (reader.Value))
 441                                                         vState = vState.Choice (prevState);
 442                                                 if (vState == RdpNotAllowed.Instance)
 443                                                         vState = HandleError (String.Format ("Invalid attribute value is found. Value = '{0}'", reader.Value), false, prevState, RecoverFromInvalidText);
 444                                                 prevState = vState;
 445                                                 vState = memo.EndAttDeriv (vState);
 446                                                 if (vState == RdpNotAllowed.Instance)
 447                                                         vState = HandleError (String.Format ("Invalid attribute value is found. Value = '{0}'", reader.Value), false, prevState, RecoverFromInvalidEnd);
 448                                         } while (reader.MoveToNextAttribute ());
 449                                         MoveToElement ();
 450                                 }
 451
 452                                 // StarTagCloseDeriv
 453                                 prevState = vState;
 454                                 vState = memo.StartTagCloseDeriv (vState);
 455                                 if (vState.PatternType == RelaxngPatternType.NotAllowed)
 456                                         vState = HandleError (String.Format ("Invalid start tag closing found. LocalName = {0}, NS = {1}.", reader.LocalName, reader.NamespaceURI), false, prevState, RecoverFromInvalidStartTagClose);
 457
 458                                 // if it is empty, then redirect to EndElement
 459                                 if (reader.IsEmptyElement) {
 460                                         ValidateWeakMatch3 ();
 461                                         goto case XmlNodeType.EndElement;
 462                                 }
 463                                 break;
 464                         case XmlNodeType.EndElement:
 465                                 if (reader.Depth == 0)
 466                                         inContent = false;
 467                                 // EndTagDeriv
 468                                 prevState = vState;
 469                                 vState = memo.EndTagDeriv (vState);
 470                                 if (vState.PatternType == RelaxngPatternType.NotAllowed)
 471                                         vState = HandleError (String.Format ("Invalid end tag found. LocalName = {0}, NS = {1}.", reader.LocalName, reader.NamespaceURI), true, prevState, RecoverFromInvalidEnd);
 472                                 break;
 473                         case XmlNodeType.Whitespace:
 474                                 if (inContent)
 475                                         goto case XmlNodeType.Text;
 476                                 break;
 477                         case XmlNodeType.CDATA:
 478                         case XmlNodeType.Text:
 479                         case XmlNodeType.SignificantWhitespace:
 480                                 // Whitespace cannot be skipped because data and
 481                                 // value types are required to validate whitespaces.
 482                                 cachedValue += Value;
 483                                 break;
 484                         }
 485
 486                         if (reader.NodeType == XmlNodeType.Element && !reader.IsEmptyElement)
 487                                 startElementDepth = reader.Depth;
 488                         else if (reader.NodeType == XmlNodeType.EndElement)
 489                                 startElementDepth = -1;
 490
 491                         return ret;
 492                 }
 493
 494                 #region error recovery
 495                 // Error recovery feature can be enabled by using
 496                 // InvalidNodeFound event of type RelaxngValidationEventHandler.
 497                 //
 498                 // Other than startTagOpenDeriv, it is (again) based on
 499                 // James Clark's derivative algorithm.
 500                 // http://www.thaiopensource.com/relaxng/derivative.html
 501                 // For invalid start tag, we just recover from it by using
 502                 // xs:any-like pattern for unexpected node occurence.
 503
 504                 RdpPattern MakeGroupHeadOptional (RdpPattern p)
 505                 {
 506                         if (p is RdpAbstractSingleContent)
 507                                 return new RdpChoice (RdpEmpty.Instance, p);
 508                         RdpAbstractBinary ab = p as RdpAbstractBinary;
 509                         if (ab == null)
 510                                 return p;
 511                         if (ab is RdpGroup)
 512                                 return new RdpGroup (new RdpChoice (RdpEmpty.Instance, ab.LValue), ab.RValue);
 513                         else if (ab is RdpChoice)
 514                                 return new RdpChoice (MakeGroupHeadOptional (ab.LValue), MakeGroupHeadOptional (ab.RValue));
 515                         else if (ab is RdpInterleave)
 516                                 return new RdpInterleave (MakeGroupHeadOptional (ab.LValue), MakeGroupHeadOptional (ab.RValue));
 517                         else if (ab is RdpAfter) // FIXME: is it correct?
 518                                 return new RdpAfter (MakeGroupHeadOptional (ab.LValue), MakeGroupHeadOptional (ab.RValue));
 519                         throw new SystemException ("INTERNAL ERROR: unexpected pattern: " + p.GetType ());
 520                 }
 521
 522                 RdpPattern ReplaceAfterHeadWithEmpty (RdpPattern p)
 523                 {
 524                         if (p is RdpAbstractSingleContent)
 525                                 return new RdpChoice (RdpEmpty.Instance, p);
 526                         RdpAbstractBinary ab = p as RdpAbstractBinary;
 527                         if (ab == null)
 528                                 return p;
 529                         if (ab is RdpGroup)
 530                                 return new RdpGroup (ReplaceAfterHeadWithEmpty (ab.LValue), ReplaceAfterHeadWithEmpty (ab.RValue));
 531                         else if (ab is RdpChoice)
 532                                 return new RdpChoice (ReplaceAfterHeadWithEmpty (ab.LValue), ReplaceAfterHeadWithEmpty (ab.RValue));
 533                         else if (ab is RdpInterleave)
 534                                 return new RdpInterleave (ReplaceAfterHeadWithEmpty (ab.LValue), ReplaceAfterHeadWithEmpty (ab.RValue));
 535                         else if (ab is RdpAfter)
 536                                 return new RdpAfter (RdpEmpty.Instance, ab.RValue);
 537                         throw new SystemException ("INTERNAL ERROR: unexpected pattern: " + p.GetType ());
 538                 }
 539
 540                 RdpPattern CollectAfterTailAsChoice (RdpPattern p)
 541                 {
 542                         RdpAbstractBinary ab = p as RdpAbstractBinary;
 543                         if (ab == null)
 544                                 return RdpEmpty.Instance;
 545                         if (ab is RdpAfter)
 546                                 return ab.RValue;
 547                         RdpPattern l = CollectAfterTailAsChoice (ab.LValue);
 548                         if (l == RdpEmpty.Instance)
 549                                 return CollectAfterTailAsChoice (ab.RValue);
 550                         RdpPattern r = CollectAfterTailAsChoice (ab.RValue);
 551                         if (r == RdpEmpty.Instance)
 552                                 return l;
 553                         return new RdpChoice (l, r);
 554                 }
 555
 556                 RdpPattern ReplaceAttributesWithEmpty (RdpPattern p)
 557                 {
 558                         if (p is RdpAttribute)
 559                                 return RdpEmpty.Instance;
 560
 561                         RdpAbstractSingleContent asc = p as RdpAbstractSingleContent;
 562                         if (asc is RdpList)
 563                                 return new RdpList (ReplaceAttributesWithEmpty (asc.Child));
 564                         if (asc is RdpOneOrMore)
 565                                 return new RdpOneOrMore (ReplaceAttributesWithEmpty (asc.Child));
 566                         else if (asc is RdpElement)
 567                                 return asc; // should not be expected to contain any attribute as RdpElement.
 568
 569                         RdpAbstractBinary ab = p as RdpAbstractBinary;
 570                         if (ab == null)
 571                                 return p;
 572                         if (ab is RdpGroup)
 573                                 return new RdpGroup (ReplaceAttributesWithEmpty (ab.LValue), ReplaceAttributesWithEmpty (ab.RValue));
 574                         else if (ab is RdpChoice)
 575                                 return new RdpChoice (ReplaceAttributesWithEmpty (ab.LValue), ReplaceAttributesWithEmpty (ab.RValue));
 576                         else if (ab is RdpInterleave)
 577                                 return new RdpInterleave (ReplaceAttributesWithEmpty (ab.LValue), ReplaceAttributesWithEmpty (ab.RValue));
 578                         else if (ab is RdpAfter) // FIXME: is it correct?
 579                                 return new RdpAfter (ReplaceAttributesWithEmpty (ab.LValue), ReplaceAttributesWithEmpty (ab.RValue));
 580                         throw new SystemException ("INTERNAL ERROR: unexpected pattern: " + p.GetType ());
 581                 }
 582
 583                 RdpPattern RecoverFromInvalidStartTag (RdpPattern p)
 584                 {
 585                         RdpPattern test1 = MakeGroupHeadOptional (p);
 586                         test1 = memo.StartTagOpenDeriv (test1, reader.LocalName, reader.NamespaceURI);
 587                         if (test1 != null)
 588                                 return test1;
 589                         // FIXME: JJC derivative algorithm suggests more complicated recovery. We simply treats current "extra" node as "anything".
 590                         return new RdpChoice (RdpPattern.Anything, p);
 591                 }
 592
 593                 RdpPattern RecoverFromInvalidText (RdpPattern p)
 594                 {
 595                         return ReplaceAfterHeadWithEmpty (p);
 596                 }
 597
 598                 RdpPattern RecoverFromInvalidEnd (RdpPattern p)
 599                 {
 600                         return CollectAfterTailAsChoice (p);
 601                 }
 602
 603                 RdpPattern RecoverFromInvalidStartTagClose (RdpPattern p)
 604                 {
 605                         return ReplaceAttributesWithEmpty (p);
 606                 }
 607
 608                 #endregion
 609
 610                 RdpPattern TextDeriv (RdpPattern p, string value, XmlReader context)
 611                 {
 612                         if (value.Length > 0 && p.IsTextValueDependent)
 613                                 return memo.TextDeriv (p, value, context);
 614                         else
 615                                 return memo.EmptyTextDeriv (p);
 616                 }
 617
 618                 void ValidateText (bool remain)
 619                 {
 620                         RdpPattern ts = vState;
 621                         switch (reader.NodeType) {
 622                         case XmlNodeType.EndElement:
 623                                 if (startElementDepth != reader.Depth)
 624                                         goto case XmlNodeType.Element;
 625                                 ts = ValidateTextOnlyCore ();
 626                                 break;
 627                         case XmlNodeType.Element:
 628                                 startElementDepth = -1;
 629                                 if (!Util.IsWhitespace (cachedValue)) {
 630                                         // HandleError() is not really useful here since it involves else condition...
 631                                         ts = memo.MixedTextDeriv (ts);
 632                                         /*if (InvalidNodeFound != null) {
 633                                                 InvalidNodeFound (reader, "Not allowed text node was found.");
 634                                                 ts = vState;
 635                                                 cachedValue = null;
 636                                         }
 637                                         else*/
 638                                                 ts = TextDeriv (ts, cachedValue, reader);
 639                                 }
 640                                 break;
 641                         default:
 642                                 if (!remain)
 643                                         goto case XmlNodeType.Element;
 644                                 return;
 645                         }
 646
 647                         prevState = vState;
 648                         vState = ts;
 649
 650                         if (vState.PatternType == RelaxngPatternType.NotAllowed)
 651                                 vState = HandleError (String.Format ("Invalid text found. Text value = {0} ", cachedValue), true, prevState, RecoverFromInvalidText);
 652                         cachedValue = null;
 653                         return;
 654                 }
 655
 656                 // section 6.2.7 weak match 3
 657                 // childrenDeriv cx p [] = childrenDeriv cx p [(TextNode "")]
 658                 void ValidateWeakMatch3 ()
 659                 {
 660                         cachedValue = String.Empty;
 661                         RdpPattern ts = ValidateTextOnlyCore ();
 662
 663                         prevState = vState;
 664                         vState = ts;
 665
 666                         if (vState.PatternType == RelaxngPatternType.NotAllowed)
 667                                 vState = HandleError (String.Format ("Invalid text found. Text value = {0} ", cachedValue), true, prevState, RecoverFromInvalidText);
 668                         cachedValue = null;
 669                         startElementDepth = -1;
 670                 }
 671
 672                 RdpPattern ValidateTextOnlyCore ()
 673                 {
 674                         RdpPattern ts = memo.TextOnlyDeriv (vState);
 675                         ts = TextDeriv (ts, cachedValue, reader);
 676                         if (Util.IsWhitespace (cachedValue))
 677                                 ts = vState.Choice (ts);
 678                         return ts;
 679                 }
 680
 681                 MemoizationStore memo = new MemoizationStore ();
 682         }
 683
 684         #region Memoization support
 685         internal class MemoizationStore
 686         {
 687                 Hashtable startOpen = new Hashtable ();
 688                 Hashtable startClose = new Hashtable ();
 689                 Hashtable startAtt = new Hashtable ();
 690                 Hashtable endTag = new Hashtable ();
 691                 Hashtable endAtt = new Hashtable ();
 692                 Hashtable textOnly = new Hashtable ();
 693                 Hashtable mixedText = new Hashtable ();
 694                 Hashtable emptyText = new Hashtable ();
 695                 Hashtable text = new Hashtable ();
 696                 Hashtable text_value = new Hashtable ();
 697                 Hashtable qnames = new Hashtable ();
 698
 699                 enum DerivativeType {
 700                         StartTagOpen,
 701                         StartAtt,
 702                         StartTagClose,
 703                         EndTag,
 704                         EndAtt,
 705                         Mixed,
 706                         TextOnly
 707                 }
 708
 709                 XmlQualifiedName GetQName (string local, string ns)
 710                 {
 711                         Hashtable nst = qnames [ns] as Hashtable;
 712                         if (nst == null) {
 713                                 nst = new Hashtable ();
 714                                 qnames [ns] = nst;
 715                         }
 716                         XmlQualifiedName qn = nst [local] as XmlQualifiedName;
 717                         if (qn == null) {
 718                                 qn = new XmlQualifiedName (local, ns);
 719                                 nst [local] = qn;
 720                         }
 721                         return qn;
 722                 }
 723
 724                 public RdpPattern StartTagOpenDeriv (RdpPattern p, string local, string ns)
 725                 {
 726                         Hashtable h = startOpen [p] as Hashtable;
 727                         if (h == null) {
 728                                 h = new Hashtable ();
 729                                 startOpen [p] = h;
 730                         }
 731                         XmlQualifiedName qn = GetQName (local, ns);
 732                         RdpPattern m = h [qn] as RdpPattern;
 733                         if (m == null) {
 734                                 m = p.StartTagOpenDeriv (local, ns, this);
 735                                 h [qn] = m;
 736                         }
 737                         return m;
 738                 }
 739
 740                 public RdpPattern StartAttDeriv (RdpPattern p, string local, string ns)
 741                 {
 742                         Hashtable h = startAtt [p] as Hashtable;
 743                         if (h == null) {
 744                                 h = new Hashtable ();
 745                                 startAtt [p] = h;
 746                         }
 747                         XmlQualifiedName qn = GetQName (local, ns);
 748                         RdpPattern m = h [qn] as RdpPattern;
 749                         if (m == null) {
 750                                 m = p.StartAttDeriv (local, ns, this);
 751                                 h [qn] = m;
 752                         }
 753                         return m;
 754                 }
 755
 756                 public RdpPattern StartTagCloseDeriv (RdpPattern p)
 757                 {
 758                         RdpPattern m = startClose [p] as RdpPattern;
 759                         if (m != null)
 760                                 return m;
 761
 762                         m = p.StartTagCloseDeriv (this);
 763                         startClose [p] = m;
 764                         return m;
 765                 }
 766
 767                 public RdpPattern EndTagDeriv (RdpPattern p)
 768                 {
 769                         RdpPattern m = endTag [p] as RdpPattern;
 770                         if (m != null)
 771                                 return m;
 772
 773                         m = p.EndTagDeriv (this);
 774                         endTag [p] = m;
 775                         return m;
 776                 }
 777
 778                 public RdpPattern EndAttDeriv (RdpPattern p)
 779                 {
 780                         RdpPattern m = endAtt [p] as RdpPattern;
 781                         if (m != null)
 782                                 return m;
 783
 784                         m = p.EndAttDeriv (this);
 785                         endAtt [p] = m;
 786                         return m;
 787                 }
 788
 789                 public RdpPattern MixedTextDeriv (RdpPattern p)
 790                 {
 791                         RdpPattern m = mixedText [p] as RdpPattern;
 792                         if (m != null)
 793                                 return m;
 794
 795                         m = p.MixedTextDeriv (this);
 796                         mixedText [p] = m;
 797                         return m;
 798                 }
 799
 800                 public RdpPattern TextOnlyDeriv (RdpPattern p)
 801                 {
 802                         RdpPattern m = textOnly [p] as RdpPattern;
 803                         if (m != null)
 804                                 return m;
 805
 806                         m = p.TextOnlyDeriv (this);
 807                         textOnly [p] = m;
 808                         return m;
 809                 }
 810
 811                 public RdpPattern TextDeriv (RdpPattern p, string value, XmlReader context)
 812                 {
 813                         if (p.IsContextDependent)
 814                                 return p.TextDeriv (value, context);
 815
 816                         if (Object.ReferenceEquals (text_value [p], value))
 817                                 return text [p] as RdpPattern;
 818                         RdpPattern m = p.TextDeriv (value, context, this);
 819                         text_value [p] = value;
 820                         text [p] = m;
 821                         return m;
 822                 }
 823
 824                 public RdpPattern EmptyTextDeriv (RdpPattern p)
 825                 {
 826                         RdpPattern m = emptyText [p] as RdpPattern;
 827                         if (m != null)
 828                                 return m;
 829
 830                         m = p.EmptyTextDeriv (this);
 831                         emptyText [p] = m;
 832                         return m;
 833                 }
 834         }
 835         #endregion
 836 }
 837