Java API By Example, From Geeks To Geeks.

1 /* 2  * Copyright 1999-2004 The Apache Software Foundation. 3  * 4  * Licensed under the Apache License, Version 2.0 (the "License"); 5  * you may not use this file except in compliance with the License. 6  * You may obtain a copy of the License at 7  * 8  * http://www.apache.org/licenses/LICENSE-2.0 9  * 10  * Unless required by applicable law or agreed to in writing, software 11  * distributed under the License is distributed on an "AS IS" BASIS, 12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13  * See the License for the specific language governing permissions and 14  * limitations under the License. 15  */ 16 /* 17  * $Id: XPathParser.java,v 1.28 2004/02/17 04:32:49 minchau Exp $ 18  */ 19 package org.apache.xpath.compiler; 20 21 import javax.xml.transform.ErrorListener ; 22 import javax.xml.transform.TransformerException ; 23 24 import org.apache.xalan.res.XSLMessages; 25 import org.apache.xml.utils.PrefixResolver; 26 import org.apache.xpath.XPathProcessorException; 27 import org.apache.xpath.objects.XNumber; 28 import org.apache.xpath.objects.XString; 29 import org.apache.xpath.res.XPATHErrorResources; 30 31 /** 32  * Tokenizes and parses XPath expressions. This should really be named 33  * XPathParserImpl, and may be renamed in the future. 34  * @xsl.usage general 35  */ 36 public class XPathParser 37 { 38     // %REVIEW% Is there a better way of doing this? 39 // Upside is minimum object churn. Downside is that we don't have a useful 40 // backtrace in the exception itself -- but we don't expect to need one. 41 static public final String CONTINUE_AFTER_FATAL_ERROR="CONTINUE_AFTER_FATAL_ERROR"; 42 43   /** 44    * The XPath to be processed. 45    */ 46   private OpMap m_ops; 47 48   /** 49    * The next token in the pattern. 50    */ 51   transient String m_token; 52 53   /** 54    * The first char in m_token, the theory being that this 55    * is an optimization because we won't have to do charAt(0) as 56    * often. 57    */ 58   transient char m_tokenChar = 0; 59 60   /** 61    * The position in the token queue is tracked by m_queueMark. 62    */ 63   int m_queueMark = 0; 64 65   /** 66    * Results from checking FilterExpr syntax 67    */ 68   protected final static int FILTER_MATCH_FAILED = 0; 69   protected final static int FILTER_MATCH_PRIMARY = 1; 70   protected final static int FILTER_MATCH_PREDICATES = 2; 71 72   /** 73    * The parser constructor. 74    */ 75   public XPathParser(ErrorListener errorListener, javax.xml.transform.SourceLocator sourceLocator) 76   { 77     m_errorListener = errorListener; 78     m_sourceLocator = sourceLocator; 79   } 80 81   /** 82    * The prefix resolver to map prefixes to namespaces in the OpMap. 83    */ 84   PrefixResolver m_namespaceContext; 85 86   /** 87    * Given an string, init an XPath object for selections, 88    * in order that a parse doesn't 89    * have to be done each time the expression is evaluated. 90    * 91    * @param compiler The compiler object. 92    * @param expression A string conforming to the XPath grammar. 93    * @param namespaceContext An object that is able to resolve prefixes in 94    * the XPath to namespaces. 95    * 96    * @throws javax.xml.transform.TransformerException 97    */ 98   public void initXPath( 99           Compiler compiler, String expression, PrefixResolver namespaceContext) 100             throws javax.xml.transform.TransformerException 101   { 102 103     m_ops = compiler; 104     m_namespaceContext = namespaceContext; 105 106     Lexer lexer = new Lexer(compiler, namespaceContext, this); 107 108     lexer.tokenize(expression); 109 110     m_ops.setOp(0,OpCodes.OP_XPATH); 111     m_ops.setOp(OpMap.MAPINDEX_LENGTH,2); 112      113      114     // Patch for Christine's gripe. She wants her errorHandler to return from 115 // a fatal error and continue trying to parse, rather than throwing an exception. 116 // Without the patch, that put us into an endless loop. 117 // 118 // %REVIEW% Is there a better way of doing this? 119 // %REVIEW% Are there any other cases which need the safety net? 120 // (and if so do we care right now, or should we rewrite the XPath 121 // grammar engine and can fix it at that time?) 122 try { 123 124       nextToken(); 125       Expr(); 126 127       if (null != m_token) 128       { 129         String extraTokens = ""; 130 131         while (null != m_token) 132         { 133           extraTokens += "'" + m_token + "'"; 134 135           nextToken(); 136 137           if (null != m_token) 138             extraTokens += ", "; 139         } 140 141         error(XPATHErrorResources.ER_EXTRA_ILLEGAL_TOKENS, 142               new Object []{ extraTokens }); //"Extra illegal tokens: "+extraTokens); 143 } 144 145     } 146     catch (org.apache.xpath.XPathProcessorException e) 147     { 148       if(CONTINUE_AFTER_FATAL_ERROR.equals(e.getMessage())) 149       { 150         // What I _want_ to do is null out this XPath. 151 // I doubt this has the desired effect, but I'm not sure what else to do. 152 // %REVIEW%!!! 153 initXPath(compiler, "/..", namespaceContext); 154       } 155       else 156         throw e; 157     } 158 159     compiler.shrink(); 160   } 161 162   /** 163    * Given an string, init an XPath object for pattern matches, 164    * in order that a parse doesn't 165    * have to be done each time the expression is evaluated. 166    * @param compiler The XPath object to be initialized. 167    * @param expression A String representing the XPath. 168    * @param namespaceContext An object that is able to resolve prefixes in 169    * the XPath to namespaces. 170    * 171    * @throws javax.xml.transform.TransformerException 172    */ 173   public void initMatchPattern( 174           Compiler compiler, String expression, PrefixResolver namespaceContext) 175             throws javax.xml.transform.TransformerException 176   { 177 178     m_ops = compiler; 179     m_namespaceContext = namespaceContext; 180 181     Lexer lexer = new Lexer(compiler, namespaceContext, this); 182 183     lexer.tokenize(expression); 184 185     m_ops.setOp(0, OpCodes.OP_MATCHPATTERN); 186     m_ops.setOp(OpMap.MAPINDEX_LENGTH, 2); 187 188     nextToken(); 189     Pattern(); 190 191     if (null != m_token) 192     { 193       String extraTokens = ""; 194 195       while (null != m_token) 196       { 197         extraTokens += "'" + m_token + "'"; 198 199         nextToken(); 200 201         if (null != m_token) 202           extraTokens += ", "; 203       } 204 205       error(XPATHErrorResources.ER_EXTRA_ILLEGAL_TOKENS, 206             new Object []{ extraTokens }); //"Extra illegal tokens: "+extraTokens); 207 } 208 209     // Terminate for safety. 210 m_ops.setOp(m_ops.getOp(OpMap.MAPINDEX_LENGTH), OpCodes.ENDOP); 211     m_ops.setOp(OpMap.MAPINDEX_LENGTH, m_ops.getOp(OpMap.MAPINDEX_LENGTH)+1); 212 213     m_ops.shrink(); 214   } 215 216   /** The error listener where syntax errors are to be sent. 217    */ 218   private ErrorListener m_errorListener; 219    220   /** The source location of the XPath. */ 221   javax.xml.transform.SourceLocator m_sourceLocator; 222 223   /** 224    * Allow an application to register an error event handler, where syntax 225    * errors will be sent. If the error listener is not set, syntax errors 226    * will be sent to System.err. 227    * 228    * @param handler Reference to error listener where syntax errors will be 229    * sent. 230    */ 231   public void setErrorHandler(ErrorListener handler) 232   { 233     m_errorListener = handler; 234   } 235 236   /** 237    * Return the current error listener. 238    * 239    * @return The error listener, which should not normally be null, but may be. 240    */ 241   public ErrorListener getErrorListener() 242   { 243     return m_errorListener; 244   } 245 246   /** 247    * Check whether m_token matches the target string. 248    * 249    * @param s A string reference or null. 250    * 251    * @return If m_token is null, returns false (or true if s is also null), or 252    * return true if the current token matches the string, else false. 253    */ 254   final boolean tokenIs(String s) 255   { 256     return (m_token != null) ? (m_token.equals(s)) : (s == null); 257   } 258 259   /** 260    * Check whether m_tokenChar==c. 261    * 262    * @param c A character to be tested. 263    * 264    * @return If m_token is null, returns false, or return true if c matches 265    * the current token. 266    */ 267   final boolean tokenIs(char c) 268   { 269     return (m_token != null) ? (m_tokenChar == c) : false; 270   } 271 272   /** 273    * Look ahead of the current token in order to 274    * make a branching decision. 275    * 276    * @param c the character to be tested for. 277    * @param n number of tokens to look ahead. Must be 278    * greater than 1. 279    * 280    * @return true if the next token matches the character argument. 281    */ 282   final boolean lookahead(char c, int n) 283   { 284 285     int pos = (m_queueMark + n); 286     boolean b; 287 288     if ((pos <= m_ops.getTokenQueueSize()) && (pos > 0) 289             && (m_ops.getTokenQueueSize() != 0)) 290     { 291       String tok = ((String ) m_ops.m_tokenQueue.elementAt(pos - 1)); 292 293       b = (tok.length() == 1) ? (tok.charAt(0) == c) : false; 294     } 295     else 296     { 297       b = false; 298     } 299 300     return b; 301   } 302 303   /** 304    * Look behind the first character of the current token in order to 305    * make a branching decision. 306    * 307    * @param c the character to compare it to. 308    * @param n number of tokens to look behind. Must be 309    * greater than 1. Note that the look behind terminates 310    * at either the beginning of the string or on a '|' 311    * character. Because of this, this method should only 312    * be used for pattern matching. 313    * 314    * @return true if the token behind the current token matches the character 315    * argument. 316    */ 317   private final boolean lookbehind(char c, int n) 318   { 319 320     boolean isToken; 321     int lookBehindPos = m_queueMark - (n + 1); 322 323     if (lookBehindPos >= 0) 324     { 325       String lookbehind = (String ) m_ops.m_tokenQueue.elementAt(lookBehindPos); 326 327       if (lookbehind.length() == 1) 328       { 329         char c0 = (lookbehind == null) ? '|' : lookbehind.charAt(0); 330 331         isToken = (c0 == '|') ? false : (c0 == c); 332       } 333       else 334       { 335         isToken = false; 336       } 337     } 338     else 339     { 340       isToken = false; 341     } 342 343     return isToken; 344   } 345 346   /** 347    * look behind the current token in order to 348    * see if there is a useable token. 349    * 350    * @param n number of tokens to look behind. Must be 351    * greater than 1. Note that the look behind terminates 352    * at either the beginning of the string or on a '|' 353    * character. Because of this, this method should only 354    * be used for pattern matching. 355    * 356    * @return true if look behind has a token, false otherwise. 357    */ 358   private final boolean lookbehindHasToken(int n) 359   { 360 361     boolean hasToken; 362 363     if ((m_queueMark - n) > 0) 364     { 365       String lookbehind = (String ) m_ops.m_tokenQueue.elementAt(m_queueMark - (n - 1)); 366       char c0 = (lookbehind == null) ? '|' : lookbehind.charAt(0); 367 368       hasToken = (c0 == '|') ? false : true; 369     } 370     else 371     { 372       hasToken = false; 373     } 374 375     return hasToken; 376   } 377 378   /** 379    * Look ahead of the current token in order to 380    * make a branching decision. 381    * 382    * @param s the string to compare it to. 383    * @param n number of tokens to lookahead. Must be 384    * greater than 1. 385    * 386    * @return true if the token behind the current token matches the string 387    * argument. 388    */ 389   private final boolean lookahead(String s, int n) 390   { 391 392     boolean isToken; 393 394     if ((m_queueMark + n) <= m_ops.getTokenQueueSize()) 395     { 396       String lookahead = (String ) m_ops.m_tokenQueue.elementAt(m_queueMark + (n - 1)); 397 398       isToken = (lookahead != null) ? lookahead.equals(s) : (s == null); 399     } 400     else 401     { 402       isToken = (null == s); 403     } 404 405     return isToken; 406   } 407 408   /** 409    * Retrieve the next token from the command and 410    * store it in m_token string. 411    */ 412   private final void nextToken() 413   { 414 415     if (m_queueMark < m_ops.getTokenQueueSize()) 416     { 417       m_token = (String ) m_ops.m_tokenQueue.elementAt(m_queueMark++); 418       m_tokenChar = m_token.charAt(0); 419     } 420     else 421     { 422       m_token = null; 423       m_tokenChar = 0; 424     } 425   } 426 427   /** 428    * Retrieve a token relative to the current token. 429    * 430    * @param i Position relative to current token. 431    * 432    * @return The string at the given index, or null if the index is out 433    * of range. 434    */ 435   private final String getTokenRelative(int i) 436   { 437 438     String tok; 439     int relative = m_queueMark + i; 440 441     if ((relative > 0) && (relative < m_ops.getTokenQueueSize())) 442     { 443       tok = (String ) m_ops.m_tokenQueue.elementAt(relative); 444     } 445     else 446     { 447       tok = null; 448     } 449 450     return tok; 451   } 452 453   /** 454    * Retrieve the previous token from the command and 455    * store it in m_token string. 456    */ 457   private final void prevToken() 458   { 459 460     if (m_queueMark > 0) 461     { 462       m_queueMark--; 463 464       m_token = (String ) m_ops.m_tokenQueue.elementAt(m_queueMark); 465       m_tokenChar = m_token.charAt(0); 466     } 467     else 468     { 469       m_token = null; 470       m_tokenChar = 0; 471     } 472   } 473 474   /** 475    * Consume an expected token, throwing an exception if it 476    * isn't there. 477    * 478    * @param expected The string to be expected. 479    * 480    * @throws javax.xml.transform.TransformerException 481    */ 482   private final void consumeExpected(String expected) 483           throws javax.xml.transform.TransformerException 484   { 485 486     if (tokenIs(expected)) 487     { 488       nextToken(); 489     } 490     else 491     { 492       error(XPATHErrorResources.ER_EXPECTED_BUT_FOUND, new Object []{ expected, 493                                                                      m_token }); //"Expected "+expected+", but found: "+m_token); 494 495       // Patch for Christina's gripe. She wants her errorHandler to return from 496 // this error and continue trying to parse, rather than throwing an exception. 497 // Without the patch, that put us into an endless loop. 498 throw new XPathProcessorException(CONTINUE_AFTER_FATAL_ERROR); 499     } 500   } 501 502   /** 503    * Consume an expected token, throwing an exception if it 504    * isn't there. 505    * 506    * @param expected the character to be expected. 507    * 508    * @throws javax.xml.transform.TransformerException 509    */ 510   private final void consumeExpected(char expected) 511           throws javax.xml.transform.TransformerException 512   { 513 514     if (tokenIs(expected)) 515     { 516       nextToken(); 517     } 518     else 519     { 520       error(XPATHErrorResources.ER_EXPECTED_BUT_FOUND, 521             new Object []{ String.valueOf(expected), 522                           m_token }); //"Expected "+expected+", but found: "+m_token); 523 524       // Patch for Christina's gripe. She wants her errorHandler to return from 525 // this error and continue trying to parse, rather than throwing an exception. 526 // Without the patch, that put us into an endless loop. 527 throw new XPathProcessorException(CONTINUE_AFTER_FATAL_ERROR); 528     } 529   } 530 531   /** 532    * Warn the user of a problem. 533    * 534    * @param msg An error msgkey that corresponds to one of the constants found 535    * in {@link org.apache.xpath.res.XPATHErrorResources}, which is 536    * a key for a format string. 537    * @param args An array of arguments represented in the format string, which 538    * may be null. 539    * 540    * @throws TransformerException if the current ErrorListoner determines to 541    * throw an exception. 542    */ 543   void warn(String msg, Object [] args) throws TransformerException 544   { 545 546     String fmsg = XSLMessages.createXPATHWarning(msg, args); 547     ErrorListener ehandler = this.getErrorListener(); 548 549     if (null != ehandler) 550     { 551       // TO DO: Need to get stylesheet Locator from here. 552 ehandler.warning(new TransformerException (fmsg, m_sourceLocator)); 553     } 554     else 555     { 556       // Should never happen. 557 System.err.println(fmsg); 558     } 559   } 560 561   /** 562    * Notify the user of an assertion error, and probably throw an 563    * exception. 564    * 565    * @param b If false, a runtime exception will be thrown. 566    * @param msg The assertion message, which should be informative. 567    * 568    * @throws RuntimeException if the b argument is false. 569    */ 570   private void assertion(boolean b, String msg) 571   { 572 573     if (!b) 574     { 575       String fMsg = XSLMessages.createXPATHMessage( 576         XPATHErrorResources.ER_INCORRECT_PROGRAMMER_ASSERTION, 577         new Object []{ msg }); 578 579       throw new RuntimeException (fMsg); 580     } 581   } 582 583   /** 584    * Notify the user of an error, and probably throw an 585    * exception. 586    * 587    * @param msg An error msgkey that corresponds to one of the constants found 588    * in {@link org.apache.xpath.res.XPATHErrorResources}, which is 589    * a key for a format string. 590    * @param args An array of arguments represented in the format string, which 591    * may be null. 592    * 593    * @throws TransformerException if the current ErrorListoner determines to 594    * throw an exception. 595    */ 596   void error(String msg, Object [] args) throws TransformerException 597   { 598 599     String fmsg = XSLMessages.createXPATHMessage(msg, args); 600     ErrorListener ehandler = this.getErrorListener(); 601 602     TransformerException te = new TransformerException (fmsg, m_sourceLocator); 603     if (null != ehandler) 604     { 605       // TO DO: Need to get stylesheet Locator from here. 606 ehandler.fatalError(te); 607     } 608     else 609     { 610       // System.err.println(fmsg); 611 throw te; 612     } 613   } 614 615   /** 616    * Dump the remaining token queue. 617    * Thanks to Craig for this. 618    * 619    * @return A dump of the remaining token queue, which may be appended to 620    * an error message. 621    */ 622   protected String dumpRemainingTokenQueue() 623   { 624 625     int q = m_queueMark; 626     String returnMsg; 627 628     if (q < m_ops.getTokenQueueSize()) 629     { 630       String msg = "\n Remaining tokens: ("; 631 632       while (q < m_ops.getTokenQueueSize()) 633       { 634         String t = (String ) m_ops.m_tokenQueue.elementAt(q++); 635 636         msg += (" '" + t + "'"); 637       } 638 639       returnMsg = msg + ")"; 640     } 641     else 642     { 643       returnMsg = ""; 644     } 645 646     return returnMsg; 647   } 648 649   /** 650    * Given a string, return the corresponding function token. 651    * 652    * @param key A local name of a function. 653    * 654    * @return The function ID, which may correspond to one of the FUNC_XXX 655    * values found in {@link org.apache.xpath.compiler.FunctionTable}, but may 656    * be a value installed by an external module. 657    */ 658   final int getFunctionToken(String key) 659   { 660 661     int tok; 662 663     try 664     { 665       tok = ((Integer ) (Keywords.m_functions.get(key))).intValue(); 666     } 667     catch (NullPointerException npe) 668     { 669       tok = -1; 670     } 671     catch (ClassCastException cce) 672     { 673       tok = -1; 674     } 675 676     return tok; 677   } 678 679   /** 680    * Insert room for operation. This will NOT set 681    * the length value of the operation, but will update 682    * the length value for the total expression. 683    * 684    * @param pos The position where the op is to be inserted. 685    * @param length The length of the operation space in the op map. 686    * @param op The op code to the inserted. 687    */ 688   void insertOp(int pos, int length, int op) 689   { 690 691     int totalLen = m_ops.getOp(OpMap.MAPINDEX_LENGTH); 692 693     for (int i = totalLen - 1; i >= pos; i--) 694     { 695       m_ops.setOp(i + length, m_ops.getOp(i)); 696     } 697 698     m_ops.setOp(pos,op); 699     m_ops.setOp(OpMap.MAPINDEX_LENGTH,totalLen + length); 700   } 701 702   /** 703    * Insert room for operation. This WILL set 704    * the length value of the operation, and will update 705    * the length value for the total expression. 706    * 707    * @param length The length of the operation. 708    * @param op The op code to the inserted. 709    */ 710   void appendOp(int length, int op) 711   { 712 713     int totalLen = m_ops.getOp(OpMap.MAPINDEX_LENGTH); 714 715     m_ops.setOp(totalLen, op); 716     m_ops.setOp(totalLen + OpMap.MAPINDEX_LENGTH, length); 717     m_ops.setOp(OpMap.MAPINDEX_LENGTH, totalLen + length); 718   } 719 720   // ============= EXPRESSIONS FUNCTIONS ================= 721 722   /** 723    * 724    * 725    * Expr ::= OrExpr 726    * 727    * 728    * @throws javax.xml.transform.TransformerException 729    */ 730   protected void Expr() throws javax.xml.transform.TransformerException 731   { 732     OrExpr(); 733   } 734 735   /** 736    * 737    * 738    * OrExpr ::= AndExpr 739    * | OrExpr 'or' AndExpr 740    * 741    * 742    * @throws javax.xml.transform.TransformerException 743    */ 744   protected void OrExpr() throws javax.xml.transform.TransformerException 745   { 746 747     int opPos = m_ops.getOp(OpMap.MAPINDEX_LENGTH); 748 749     AndExpr(); 750 751     if ((null != m_token) && tokenIs("or")) 752     { 753       nextToken(); 754       insertOp(opPos, 2, OpCodes.OP_OR); 755       OrExpr(); 756 757       m_ops.setOp(opPos + OpMap.MAPINDEX_LENGTH, 758         m_ops.getOp(OpMap.MAPINDEX_LENGTH) - opPos); 759     } 760   } 761 762   /** 763    * 764    * 765    * AndExpr ::= EqualityExpr 766    * | AndExpr 'and' EqualityExpr 767    * 768    * 769    * @throws javax.xml.transform.TransformerException 770    */ 771   protected void AndExpr() throws javax.xml.transform.TransformerException 772   { 773 774     int opPos = m_ops.getOp(OpMap.MAPINDEX_LENGTH); 775 776     EqualityExpr(-1); 777 778     if ((null != m_token) && tokenIs("and")) 779     { 780       nextToken(); 781       insertOp(opPos, 2, OpCodes.OP_AND); 782       AndExpr(); 783 784       m_ops.setOp(opPos + OpMap.MAPINDEX_LENGTH, 785         m_ops.getOp(OpMap.MAPINDEX_LENGTH) - opPos); 786     } 787   } 788 789   /** 790    * 791    * @returns an Object which is either a String, a Number, a Boolean, or a vector 792    * of nodes. 793    * 794    * EqualityExpr ::= RelationalExpr 795    * | EqualityExpr '=' RelationalExpr 796    * 797    * 798    * @param addPos Position where expression is to be added, or -1 for append. 799    * 800    * @return the position at the end of the equality expression. 801    * 802    * @throws javax.xml.transform.TransformerException 803    */ 804   protected int EqualityExpr(int addPos) throws javax.xml.transform.TransformerException 805   { 806 807     int opPos = m_ops.getOp(OpMap.MAPINDEX_LENGTH); 808 809     if (-1 == addPos) 810       addPos = opPos; 811 812     RelationalExpr(-1); 813 814     if (null != m_token) 815     { 816       if (tokenIs('!') && lookahead('=', 1)) 817       { 818         nextToken(); 819         nextToken(); 820         insertOp(addPos, 2, OpCodes.OP_NOTEQUALS); 821 822         int opPlusLeftHandLen = m_ops.getOp(OpMap.MAPINDEX_LENGTH) - addPos; 823 824         addPos = EqualityExpr(addPos); 825         m_ops.setOp(addPos + OpMap.MAPINDEX_LENGTH, 826           m_ops.getOp(addPos + opPlusLeftHandLen + 1) + opPlusLeftHandLen); 827         addPos += 2; 828       } 829       else if (tokenIs('=')) 830       { 831         nextToken(); 832         insertOp(addPos, 2, OpCodes.OP_EQUALS); 833 834         int opPlusLeftHandLen = m_ops.getOp(OpMap.MAPINDEX_LENGTH) - addPos; 835 836         addPos = EqualityExpr(addPos); 837         m_ops.setOp(addPos + OpMap.MAPINDEX_LENGTH, 838           m_ops.getOp(addPos + opPlusLeftHandLen + 1) + opPlusLeftHandLen); 839         addPos += 2; 840       } 841     } 842 843     return addPos; 844   } 845 846   /** 847    * . 848    * @returns an Object which is either a String, a Number, a Boolean, or a vector 849    * of nodes. 850    * 851    * RelationalExpr ::= AdditiveExpr 852    * | RelationalExpr '<' AdditiveExpr 853    * | RelationalExpr '>' AdditiveExpr 854    * | RelationalExpr '<=' AdditiveExpr 855    * | RelationalExpr '>=' AdditiveExpr 856    * 857    * 858    * @param addPos Position where expression is to be added, or -1 for append. 859    * 860    * @return the position at the end of the relational expression. 861    * 862    * @throws javax.xml.transform.TransformerException 863    */ 864   protected int RelationalExpr(int addPos) throws javax.xml.transform.TransformerException 865   { 866 867     int opPos = m_ops.getOp(OpMap.MAPINDEX_LENGTH); 868 869     if (-1 == addPos) 870       addPos = opPos; 871 872     AdditiveExpr(-1); 873 874     if (null != m_token) 875     { 876       if (tokenIs('<')) 877       { 878         nextToken(); 879 880         if (tokenIs('=')) 881         { 882           nextToken(); 883           insertOp(addPos, 2, OpCodes.OP_LTE); 884         } 885         else 886         { 887           insertOp(addPos, 2, OpCodes.OP_LT); 888         } 889 890         int opPlusLeftHandLen = m_ops.getOp(OpMap.MAPINDEX_LENGTH) - addPos; 891 892         addPos = RelationalExpr(addPos); 893         m_ops.setOp(addPos + OpMap.MAPINDEX_LENGTH, 894           m_ops.getOp(addPos + opPlusLeftHandLen + 1) + opPlusLeftHandLen); 895         addPos += 2; 896       } 897       else if (tokenIs('>')) 898       { 899         nextToken(); 900 901         if (tokenIs('=')) 902         { 903           nextToken(); 904           insertOp(addPos, 2, OpCodes.OP_GTE); 905         } 906         else 907         { 908           insertOp(addPos, 2, OpCodes.OP_GT); 909         } 910 911         int opPlusLeftHandLen = m_ops.getOp(OpMap.MAPINDEX_LENGTH) - addPos; 912 913         addPos = RelationalExpr(addPos); 914         m_ops.setOp(addPos + OpMap.MAPINDEX_LENGTH, 915           m_ops.getOp(addPos + opPlusLeftHandLen + 1) + opPlusLeftHandLen); 916         addPos += 2; 917       } 918     } 919 920     return addPos; 921   } 922 923   /** 924    * This has to handle construction of the operations so that they are evaluated 925    * in pre-fix order. So, for 9+7-6, instead of |+|9|-|7|6|, this needs to be 926    * evaluated as |-|+|9|7|6|. 927    * 928    * AdditiveExpr ::= MultiplicativeExpr 929    * | AdditiveExpr '+' MultiplicativeExpr 930    * | AdditiveExpr '-' MultiplicativeExpr 931    * 932    * 933    * @param addPos Position where expression is to be added, or -1 for append. 934    * 935    * @return the position at the end of the equality expression. 936    * 937    * @throws javax.xml.transform.TransformerException 938    */ 939   protected int AdditiveExpr(int addPos) throws javax.xml.transform.TransformerException 940   { 941 942     int opPos = m_ops.getOp(OpMap.MAPINDEX_LENGTH); 943 944     if (-1 == addPos) 945       addPos = opPos; 946 947     MultiplicativeExpr(-1); 948 949     if (null != m_token) 950     { 951       if (tokenIs('+')) 952       { 953         nextToken(); 954         insertOp(addPos, 2, OpCodes.OP_PLUS); 955 956         int opPlusLeftHandLen = m_ops.getOp(OpMap.MAPINDEX_LENGTH) - addPos; 957 958         addPos = AdditiveExpr(addPos); 959         m_ops.setOp(addPos + OpMap.MAPINDEX_LENGTH, 960           m_ops.getOp(addPos + opPlusLeftHandLen + 1) + opPlusLeftHandLen); 961         addPos += 2; 962       } 963       else if (tokenIs('-')) 964       { 965         nextToken(); 966         insertOp(addPos, 2, OpCodes.OP_MINUS); 967 968         int opPlusLeftHandLen = m_ops.getOp(OpMap.MAPINDEX_LENGTH) - addPos; 969 970         addPos = AdditiveExpr(addPos); 971         m_ops.setOp(addPos + OpMap.MAPINDEX_LENGTH, 972           m_ops.getOp(addPos + opPlusLeftHandLen + 1) + opPlusLeftHandLen); 973         addPos += 2; 974       } 975     } 976 977     return addPos; 978   } 979 980   /** 981    * This has to handle construction of the operations so that they are evaluated 982    * in pre-fix order. So, for 9+7-6, instead of |+|9|-|7|6|, this needs to be 983    * evaluated as |-|+|9|7|6|. 984    * 985    * MultiplicativeExpr ::= UnaryExpr 986    * | MultiplicativeExpr MultiplyOperator UnaryExpr 987    * | MultiplicativeExpr 'div' UnaryExpr 988    * | MultiplicativeExpr 'mod' UnaryExpr 989    * | MultiplicativeExpr 'quo' UnaryExpr 990    * 991    * @param addPos Position where expression is to be added, or -1 for append. 992    * 993    * @return the position at the end of the equality expression. 994    * 995    * @throws javax.xml.transform.TransformerException 996    */ 997   protected int MultiplicativeExpr(int addPos) throws javax.xml.transform.TransformerException 998   { 999 1000    int opPos = m_ops.getOp(OpMap.MAPINDEX_LENGTH); 1001 1002    if (-1 == addPos) 1003      addPos = opPos; 1004 1005    UnaryExpr(); 1006 1007    if (null != m_token) 1008    { 1009      if (tokenIs('*')) 1010      { 1011        nextToken(); 1012        insertOp(addPos, 2, OpCodes.OP_MULT); 1013 1014        int opPlusLeftHandLen = m_ops.getOp(OpMap.MAPINDEX_LENGTH) - addPos; 1015 1016        addPos = MultiplicativeExpr(addPos); 1017        m_ops.setOp(addPos + OpMap.MAPINDEX_LENGTH, 1018          m_ops.getOp(addPos + opPlusLeftHandLen + 1) + opPlusLeftHandLen); 1019        addPos += 2; 1020      } 1021      else if (tokenIs("div")) 1022      { 1023        nextToken(); 1024        insertOp(addPos, 2, OpCodes.OP_DIV); 1025 1026        int opPlusLeftHandLen = m_ops.getOp(OpMap.MAPINDEX_LENGTH) - addPos; 1027 1028        addPos = MultiplicativeExpr(addPos); 1029        m_ops.setOp(addPos + OpMap.MAPINDEX_LENGTH, 1030          m_ops.getOp(addPos + opPlusLeftHandLen + 1) + opPlusLeftHandLen); 1031        addPos += 2; 1032      } 1033      else if (tokenIs("mod")) 1034      { 1035        nextToken(); 1036        insertOp(addPos, 2, OpCodes.OP_MOD); 1037 1038        int opPlusLeftHandLen = m_ops.getOp(OpMap.MAPINDEX_LENGTH) - addPos; 1039 1040        addPos = MultiplicativeExpr(addPos); 1041        m_ops.setOp(addPos + OpMap.MAPINDEX_LENGTH, 1042          m_ops.getOp(addPos + opPlusLeftHandLen + 1) + opPlusLeftHandLen); 1043        addPos += 2; 1044      } 1045      else if (tokenIs("quo")) 1046      { 1047        nextToken(); 1048        insertOp(addPos, 2, OpCodes.OP_QUO); 1049 1050        int opPlusLeftHandLen = m_ops.getOp(OpMap.MAPINDEX_LENGTH) - addPos; 1051 1052        addPos = MultiplicativeExpr(addPos); 1053        m_ops.setOp(addPos + OpMap.MAPINDEX_LENGTH, 1054          m_ops.getOp(addPos + opPlusLeftHandLen + 1) + opPlusLeftHandLen); 1055        addPos += 2; 1056      } 1057    } 1058 1059    return addPos; 1060  } 1061 1062  /** 1063   * 1064   * UnaryExpr ::= UnionExpr 1065   * | '-' UnaryExpr 1066   * 1067   * 1068   * @throws javax.xml.transform.TransformerException 1069   */ 1070  protected void UnaryExpr() throws javax.xml.transform.TransformerException 1071  { 1072 1073    int opPos = m_ops.getOp(OpMap.MAPINDEX_LENGTH); 1074    boolean isNeg = false; 1075 1076    if (m_tokenChar == '-') 1077    { 1078      nextToken(); 1079      appendOp(2, OpCodes.OP_NEG); 1080 1081      isNeg = true; 1082    } 1083 1084    UnionExpr(); 1085 1086    if (isNeg) 1087      m_ops.setOp(opPos + OpMap.MAPINDEX_LENGTH, 1088        m_ops.getOp(OpMap.MAPINDEX_LENGTH) - opPos); 1089  } 1090 1091  /** 1092   * 1093   * StringExpr ::= Expr 1094   * 1095   * 1096   * @throws javax.xml.transform.TransformerException 1097   */ 1098  protected void StringExpr() throws javax.xml.transform.TransformerException 1099  { 1100 1101    int opPos = m_ops.getOp(OpMap.MAPINDEX_LENGTH); 1102 1103    appendOp(2, OpCodes.OP_STRING); 1104    Expr(); 1105 1106    m_ops.setOp(opPos + OpMap.MAPINDEX_LENGTH, 1107      m_ops.getOp(OpMap.MAPINDEX_LENGTH) - opPos); 1108  } 1109 1110  /** 1111   * 1112   * 1113   * StringExpr ::= Expr 1114   * 1115   * 1116   * @throws javax.xml.transform.TransformerException 1117   */ 1118  protected void BooleanExpr() throws javax.xml.transform.TransformerException 1119  { 1120 1121    int opPos = m_ops.getOp(OpMap.MAPINDEX_LENGTH); 1122 1123    appendOp(2, OpCodes.OP_BOOL); 1124    Expr(); 1125 1126    int opLen = m_ops.getOp(OpMap.MAPINDEX_LENGTH) - opPos; 1127 1128    if (opLen == 2) 1129    { 1130      error(XPATHErrorResources.ER_BOOLEAN_ARG_NO_LONGER_OPTIONAL, null); //"boolean(...) argument is no longer optional with 19990709 XPath draft."); 1131 } 1132 1133    m_ops.setOp(opPos + OpMap.MAPINDEX_LENGTH, opLen); 1134  } 1135 1136  /** 1137   * 1138   * 1139   * NumberExpr ::= Expr 1140   * 1141   * 1142   * @throws javax.xml.transform.TransformerException 1143   */ 1144  protected void NumberExpr() throws javax.xml.transform.TransformerException 1145  { 1146 1147    int opPos = m_ops.getOp(OpMap.MAPINDEX_LENGTH); 1148 1149    appendOp(2, OpCodes.OP_NUMBER); 1150    Expr(); 1151 1152    m_ops.setOp(opPos + OpMap.MAPINDEX_LENGTH, 1153      m_ops.getOp(OpMap.MAPINDEX_LENGTH) - opPos); 1154  } 1155 1156  /** 1157   * The context of the right hand side expressions is the context of the 1158   * left hand side expression. The results of the right hand side expressions 1159   * are node sets. The result of the left hand side UnionExpr is the union 1160   * of the results of the right hand side expressions. 1161   * 1162   * 1163   * UnionExpr ::= PathExpr 1164   * | UnionExpr '|' PathExpr 1165   * 1166   * 1167   * @throws javax.xml.transform.TransformerException 1168   */ 1169  protected void UnionExpr() throws javax.xml.transform.TransformerException 1170  { 1171 1172    int opPos = m_ops.getOp(OpMap.MAPINDEX_LENGTH); 1173    boolean continueOrLoop = true; 1174    boolean foundUnion = false; 1175 1176    do 1177    { 1178      PathExpr(); 1179 1180      if (tokenIs('|')) 1181      { 1182        if (false == foundUnion) 1183        { 1184          foundUnion = true; 1185 1186          insertOp(opPos, 2, OpCodes.OP_UNION); 1187        } 1188 1189        nextToken(); 1190      } 1191      else 1192      { 1193        break; 1194      } 1195 1196      // this.m_testForDocOrder = true; 1197 } 1198    while (continueOrLoop); 1199 1200    m_ops.setOp(opPos + OpMap.MAPINDEX_LENGTH, 1201          m_ops.getOp(OpMap.MAPINDEX_LENGTH) - opPos); 1202  } 1203 1204  /** 1205   * PathExpr ::= LocationPath 1206   * | FilterExpr 1207   * | FilterExpr '/' RelativeLocationPath 1208   * | FilterExpr '//' RelativeLocationPath 1209   * 1210   * @throws XSLProcessorException thrown if the active ProblemListener and XPathContext decide 1211   * the error condition is severe enough to halt processing. 1212   * 1213   * @throws javax.xml.transform.TransformerException 1214   */ 1215  protected void PathExpr() throws javax.xml.transform.TransformerException 1216  { 1217 1218    int opPos = m_ops.getOp(OpMap.MAPINDEX_LENGTH); 1219 1220    int filterExprMatch = FilterExpr(); 1221 1222    if (filterExprMatch != FILTER_MATCH_FAILED) 1223    { 1224      // If FilterExpr had Predicates, a OP_LOCATIONPATH opcode would already 1225 // have been inserted. 1226 boolean locationPathStarted = (filterExprMatch==FILTER_MATCH_PREDICATES); 1227 1228      if (tokenIs('/')) 1229      { 1230        nextToken(); 1231 1232        if (!locationPathStarted) 1233        { 1234          // int locationPathOpPos = opPos; 1235 insertOp(opPos, 2, OpCodes.OP_LOCATIONPATH); 1236 1237          locationPathStarted = true; 1238        } 1239 1240        if (!RelativeLocationPath()) 1241        { 1242          // "Relative location path expected following '/' or '//'" 1243 error(XPATHErrorResources.ER_EXPECTED_REL_LOC_PATH, null); 1244        } 1245 1246      } 1247 1248      // Terminate for safety. 1249 if (locationPathStarted) 1250      { 1251        m_ops.setOp(m_ops.getOp(OpMap.MAPINDEX_LENGTH), OpCodes.ENDOP); 1252        m_ops.setOp(OpMap.MAPINDEX_LENGTH, m_ops.getOp(OpMap.MAPINDEX_LENGTH) + 1); 1253        m_ops.setOp(opPos + OpMap.MAPINDEX_LENGTH, 1254          m_ops.getOp(OpMap.MAPINDEX_LENGTH) - opPos); 1255      } 1256    } 1257    else 1258    { 1259      LocationPath(); 1260    } 1261  } 1262 1263  /** 1264   * 1265   * 1266   * FilterExpr ::= PrimaryExpr 1267   * | FilterExpr Predicate 1268   * 1269   * @throws XSLProcessorException thrown if the active ProblemListener and XPathContext decide 1270   * the error condition is severe enough to halt processing. 1271   * 1272   * @return FILTER_MATCH_PREDICATES, if this method successfully matched a 1273   * FilterExpr with one or more Predicates; 1274   * FILTER_MATCH_PRIMARY, if this method successfully matched a 1275   * FilterExpr that was just a PrimaryExpr; or 1276   * FILTER_MATCH_FAILED, if this method did not match a FilterExpr 1277   * 1278   * @throws javax.xml.transform.TransformerException 1279   */ 1280  protected int FilterExpr() throws javax.xml.transform.TransformerException 1281  { 1282 1283    int opPos = m_ops.getOp(OpMap.MAPINDEX_LENGTH); 1284 1285    int filterMatch; 1286 1287    if (PrimaryExpr()) 1288    { 1289      if (tokenIs('[')) 1290      { 1291 1292        // int locationPathOpPos = opPos; 1293 insertOp(opPos, 2, OpCodes.OP_LOCATIONPATH); 1294 1295        while (tokenIs('[')) 1296        { 1297          Predicate(); 1298        } 1299 1300        filterMatch = FILTER_MATCH_PREDICATES; 1301      } 1302      else 1303      { 1304        filterMatch = FILTER_MATCH_PRIMARY; 1305      } 1306    } 1307    else 1308    { 1309      filterMatch = FILTER_MATCH_FAILED; 1310    } 1311 1312    return filterMatch; 1313 1314    /* 1315     * if(tokenIs('[')) 1316     * { 1317     * Predicate(); 1318     * m_ops.m_opMap[opPos + OpMap.MAPINDEX_LENGTH] = m_ops.m_opMap[OpMap.MAPINDEX_LENGTH] - opPos; 1319     * } 1320     */ 1321  } 1322 1323  /** 1324   * 1325   * PrimaryExpr ::= VariableReference 1326   * | '(' Expr ')' 1327   * | Literal 1328   * | Number 1329   * | FunctionCall 1330   * 1331   * @return true if this method successfully matched a PrimaryExpr 1332   * 1333   * @throws javax.xml.transform.TransformerException 1334   * 1335   */ 1336  protected boolean PrimaryExpr() throws javax.xml.transform.TransformerException 1337  { 1338 1339    boolean matchFound; 1340    int opPos = m_ops.getOp(OpMap.MAPINDEX_LENGTH); 1341 1342    if ((m_tokenChar == '\'') || (m_tokenChar == '"')) 1343    { 1344      appendOp(2, OpCodes.OP_LITERAL); 1345      Literal(); 1346 1347      m_ops.setOp(opPos + OpMap.MAPINDEX_LENGTH, 1348        m_ops.getOp(OpMap.MAPINDEX_LENGTH) - opPos); 1349 1350      matchFound = true; 1351    } 1352    else if (m_tokenChar == '$') 1353    { 1354      nextToken(); // consume '$' 1355 appendOp(2, OpCodes.OP_VARIABLE); 1356      QName(); 1357       1358      m_ops.setOp(opPos + OpMap.MAPINDEX_LENGTH, 1359        m_ops.getOp(OpMap.MAPINDEX_LENGTH) - opPos); 1360 1361      matchFound = true; 1362    } 1363    else if (m_tokenChar == '(') 1364    { 1365      nextToken(); 1366      appendOp(2, OpCodes.OP_GROUP); 1367      Expr(); 1368      consumeExpected(')'); 1369 1370      m_ops.setOp(opPos + OpMap.MAPINDEX_LENGTH, 1371        m_ops.getOp(OpMap.MAPINDEX_LENGTH) - opPos); 1372 1373      matchFound = true; 1374    } 1375    else if ((null != m_token) && ((('.' == m_tokenChar) && (m_token.length() > 1) && Character.isDigit( 1376            m_token.charAt(1))) || Character.isDigit(m_tokenChar))) 1377    { 1378      appendOp(2, OpCodes.OP_NUMBERLIT); 1379      Number(); 1380 1381      m_ops.setOp(opPos + OpMap.MAPINDEX_LENGTH, 1382        m_ops.getOp(OpMap.MAPINDEX_LENGTH) - opPos); 1383 1384      matchFound = true; 1385    } 1386    else if (lookahead('(', 1) || (lookahead(':', 1) && lookahead('(', 3))) 1387    { 1388      matchFound = FunctionCall(); 1389    } 1390    else 1391    { 1392      matchFound = false; 1393    } 1394 1395    return matchFound; 1396  } 1397 1398  /** 1399   * 1400   * Argument ::= Expr 1401   * 1402   * 1403   * @throws javax.xml.transform.TransformerException 1404   */ 1405  protected void Argument() throws javax.xml.transform.TransformerException 1406  { 1407 1408    int opPos = m_ops.getOp(OpMap.MAPINDEX_LENGTH); 1409 1410    appendOp(2, OpCodes.OP_ARGUMENT); 1411    Expr(); 1412 1413    m_ops.setOp(opPos + OpMap.MAPINDEX_LENGTH, 1414      m_ops.getOp(OpMap.MAPINDEX_LENGTH) - opPos); 1415  } 1416 1417  /** 1418   * 1419   * FunctionCall ::= FunctionName '(' ( Argument ( ',' Argument)*)? ')' 1420   * 1421   * @return true if, and only if, a FunctionCall was matched 1422   * 1423   * @throws javax.xml.transform.TransformerException 1424   */ 1425  protected boolean FunctionCall() throws javax.xml.transform.TransformerException 1426  { 1427 1428    int opPos = m_ops.getOp(OpMap.MAPINDEX_LENGTH); 1429 1430    if (lookahead(':', 1)) 1431    { 1432      appendOp(4, OpCodes.OP_EXTFUNCTION); 1433 1434      m_ops.setOp(opPos + OpMap.MAPINDEX_LENGTH + 1, m_queueMark - 1); 1435 1436      nextToken(); 1437      consumeExpected(':'); 1438 1439      m_ops.setOp(opPos + OpMap.MAPINDEX_LENGTH + 2, m_queueMark - 1); 1440 1441      nextToken(); 1442    } 1443    else 1444    { 1445      int funcTok = getFunctionToken(m_token); 1446 1447      if (-1 == funcTok) 1448      { 1449        error(XPATHErrorResources.ER_COULDNOT_FIND_FUNCTION, 1450              new Object []{ m_token }); //"Could not find function: "+m_token+"()"); 1451 } 1452 1453      switch (funcTok) 1454      { 1455      case OpCodes.NODETYPE_PI : 1456      case OpCodes.NODETYPE_COMMENT : 1457      case OpCodes.NODETYPE_TEXT : 1458      case OpCodes.NODETYPE_NODE : 1459        // Node type tests look like function calls, but they're not 1460 return false; 1461      default : 1462        appendOp(3, OpCodes.OP_FUNCTION); 1463 1464        m_ops.setOp(opPos + OpMap.MAPINDEX_LENGTH + 1, funcTok); 1465      } 1466 1467      nextToken(); 1468    } 1469 1470    consumeExpected('('); 1471 1472    while (!tokenIs(')') && m_token != null) 1473    { 1474      if (tokenIs(',')) 1475      { 1476        error(XPATHErrorResources.ER_FOUND_COMMA_BUT_NO_PRECEDING_ARG, null); //"Found ',' but no preceding argument!"); 1477 } 1478 1479      Argument(); 1480 1481      if (!tokenIs(')')) 1482      { 1483        consumeExpected(','); 1484 1485        if (tokenIs(')')) 1486        { 1487          error(XPATHErrorResources.ER_FOUND_COMMA_BUT_NO_FOLLOWING_ARG, 1488                null); //"Found ',' but no following argument!"); 1489 } 1490      } 1491    } 1492 1493    consumeExpected(')'); 1494 1495    // Terminate for safety. 1496 m_ops.setOp(m_ops.getOp(OpMap.MAPINDEX_LENGTH), OpCodes.ENDOP); 1497    m_ops.setOp(OpMap.MAPINDEX_LENGTH,m_ops.getOp(OpMap.MAPINDEX_LENGTH) + 1); 1498    m_ops.setOp(opPos + OpMap.MAPINDEX_LENGTH, 1499      m_ops.getOp(OpMap.MAPINDEX_LENGTH) - opPos); 1500 1501    return true; 1502  } 1503 1504  // ============= GRAMMAR FUNCTIONS ================= 1505 1506  /** 1507   * 1508   * LocationPath ::= RelativeLocationPath 1509   * | AbsoluteLocationPath 1510   * 1511   * 1512   * @throws javax.xml.transform.TransformerException 1513   */ 1514  protected void LocationPath() throws javax.xml.transform.TransformerException 1515  { 1516 1517    int opPos = m_ops.getOp(OpMap.MAPINDEX_LENGTH); 1518 1519    // int locationPathOpPos = opPos; 1520 appendOp(2, OpCodes.OP_LOCATIONPATH); 1521 1522    boolean seenSlash = tokenIs('/'); 1523 1524    if (seenSlash) 1525    { 1526      appendOp(4, OpCodes.FROM_ROOT); 1527 1528      // Tell how long the step is without the predicate 1529 m_ops.setOp(m_ops.getOp(OpMap.MAPINDEX_LENGTH) - 2, 4); 1530      m_ops.setOp(m_ops.getOp(OpMap.MAPINDEX_LENGTH) - 1, OpCodes.NODETYPE_ROOT); 1531 1532      nextToken(); 1533    } 1534 1535    if (m_token != null) 1536    { 1537      if (!RelativeLocationPath() && !seenSlash) 1538      { 1539        // Neither a '/' nor a RelativeLocationPath - i.e., matched nothing 1540 // "Location path expected, but found "+m_token+" was encountered." 1541 error(XPATHErrorResources.ER_EXPECTED_LOC_PATH, 1542              new Object [] {m_token}); 1543      } 1544    } 1545 1546    // Terminate for safety. 1547 m_ops.setOp(m_ops.getOp(OpMap.MAPINDEX_LENGTH), OpCodes.ENDOP); 1548    m_ops.setOp(OpMap.MAPINDEX_LENGTH,m_ops.getOp(OpMap.MAPINDEX_LENGTH) + 1); 1549    m_ops.setOp(opPos + OpMap.MAPINDEX_LENGTH, 1550      m_ops.getOp(OpMap.MAPINDEX_LENGTH) - opPos); 1551  } 1552 1553  /** 1554   * 1555   * RelativeLocationPath ::= Step 1556   * | RelativeLocationPath '/' Step 1557   * | AbbreviatedRelativeLocationPath 1558   * 1559   * @returns true if, and only if, a RelativeLocationPath was matched 1560   * 1561   * @throws javax.xml.transform.TransformerException 1562   */ 1563  protected boolean RelativeLocationPath() 1564               throws javax.xml.transform.TransformerException 1565  { 1566    if (!Step()) 1567    { 1568      return false; 1569    } 1570 1571    while (tokenIs('/')) 1572    { 1573      nextToken(); 1574 1575      if (!Step()) 1576      { 1577        // RelativeLocationPath can't end with a trailing '/' 1578 // "Location step expected following '/' or '//'" 1579 error(XPATHErrorResources.ER_EXPECTED_LOC_STEP, null); 1580      } 1581    } 1582 1583    return true; 1584  } 1585 1586  /** 1587   * 1588   * Step ::= Basis Predicate 1589   * | AbbreviatedStep 1590   * 1591   * @returns false if step was empty (or only a '/'); true, otherwise 1592   * 1593   * @throws javax.xml.transform.TransformerException 1594   */ 1595  protected boolean Step() throws javax.xml.transform.TransformerException 1596  { 1597    int opPos = m_ops.getOp(OpMap.MAPINDEX_LENGTH); 1598 1599    boolean doubleSlash = tokenIs('/'); 1600 1601    // At most a single '/' before each Step is consumed by caller; if the 1602 // first thing is a '/', that means we had '//' and the Step must not 1603 // be empty. 1604 if (doubleSlash) 1605    { 1606      nextToken(); 1607 1608      appendOp(2, OpCodes.FROM_DESCENDANTS_OR_SELF); 1609 1610      // Have to fix up for patterns such as '//@foo' or '//attribute::foo', 1611 // which translate to 'descendant-or-self::node()/attribute::foo'. 1612 // notice I leave the '/' on the queue, so the next will be processed 1613 // by a regular step pattern. 1614 1615      // Make room for telling how long the step is without the predicate 1616 m_ops.setOp(OpMap.MAPINDEX_LENGTH,m_ops.getOp(OpMap.MAPINDEX_LENGTH) + 1); 1617      m_ops.setOp(m_ops.getOp(OpMap.MAPINDEX_LENGTH), OpCodes.NODETYPE_NODE); 1618      m_ops.setOp(OpMap.MAPINDEX_LENGTH,m_ops.getOp(OpMap.MAPINDEX_LENGTH) + 1); 1619 1620      // Tell how long the step is without the predicate 1621 m_ops.setOp(opPos + OpMap.MAPINDEX_LENGTH + 1, 1622          m_ops.getOp(OpMap.MAPINDEX_LENGTH) - opPos); 1623 1624      // Tell how long the step is with the predicate 1625 m_ops.setOp(opPos + OpMap.MAPINDEX_LENGTH, 1626          m_ops.getOp(OpMap.MAPINDEX_LENGTH) - opPos); 1627 1628      opPos = m_ops.getOp(OpMap.MAPINDEX_LENGTH); 1629    } 1630 1631    if (tokenIs(".")) 1632    { 1633      nextToken(); 1634 1635      if (tokenIs('[')) 1636      { 1637        error(XPATHErrorResources.ER_PREDICATE_ILLEGAL_SYNTAX, null); //"'..[predicate]' or '.[predicate]' is illegal syntax. Use 'self::node()[predicate]' instead."); 1638 } 1639 1640      appendOp(4, OpCodes.FROM_SELF); 1641 1642      // Tell how long the step is without the predicate 1643 m_ops.setOp(m_ops.getOp(OpMap.MAPINDEX_LENGTH) - 2,4); 1644      m_ops.setOp(m_ops.getOp(OpMap.MAPINDEX_LENGTH) - 1, OpCodes.NODETYPE_NODE); 1645    } 1646    else if (tokenIs("..")) 1647    { 1648      nextToken(); 1649      appendOp(4, OpCodes.FROM_PARENT); 1650 1651      // Tell how long the step is without the predicate 1652 m_ops.setOp(m_ops.getOp(OpMap.MAPINDEX_LENGTH) - 2,4); 1653      m_ops.setOp(m_ops.getOp(OpMap.MAPINDEX_LENGTH) - 1, OpCodes.NODETYPE_NODE); 1654    } 1655 1656    // There is probably a better way to test for this 1657 // transition... but it gets real hairy if you try 1658 // to do it in basis(). 1659 else if (tokenIs('*') || tokenIs('@') || tokenIs('_') 1660             || (m_token!= null && Character.isLetter(m_token.charAt(0)))) 1661    { 1662      Basis(); 1663 1664      while (tokenIs('[')) 1665      { 1666        Predicate(); 1667      } 1668 1669      // Tell how long the entire step is. 1670 m_ops.setOp(opPos + OpMap.MAPINDEX_LENGTH, 1671        m_ops.getOp(OpMap.MAPINDEX_LENGTH) - opPos); 1672    } 1673    else 1674    { 1675      // No Step matched - that's an error if previous thing was a '//' 1676 if (doubleSlash) 1677      { 1678        // "Location step expected following '/' or '//'" 1679 error(XPATHErrorResources.ER_EXPECTED_LOC_STEP, null); 1680      } 1681 1682      return false; 1683    } 1684 1685    return true; 1686  } 1687 1688  /** 1689   * 1690   * Basis ::= AxisName '::' NodeTest 1691   * | AbbreviatedBasis 1692   * 1693   * @throws javax.xml.transform.TransformerException 1694   */ 1695  protected void Basis() throws javax.xml.transform.TransformerException 1696  { 1697 1698    int opPos = m_ops.getOp(OpMap.MAPINDEX_LENGTH); 1699    int axesType; 1700 1701    // The next blocks guarantee that a FROM_XXX will be added. 1702 if (lookahead("::", 1)) 1703    { 1704      axesType = AxisName(); 1705 1706      nextToken(); 1707      nextToken(); 1708    } 1709    else if (tokenIs('@')) 1710    { 1711      axesType = OpCodes.FROM_ATTRIBUTES; 1712 1713      appendOp(2, axesType); 1714      nextToken(); 1715    } 1716    else 1717    { 1718      axesType = OpCodes.FROM_CHILDREN; 1719 1720      appendOp(2, axesType); 1721    } 1722 1723    // Make room for telling how long the step is without the predicate 1724 m_ops.setOp(OpMap.MAPINDEX_LENGTH, m_ops.getOp(OpMap.MAPINDEX_LENGTH) + 1); 1725 1726    NodeTest(axesType); 1727 1728    // Tell how long the step is without the predicate 1729 m_ops.setOp(opPos + OpMap.MAPINDEX_LENGTH + 1, 1730      m_ops.getOp(OpMap.MAPINDEX_LENGTH) - opPos); 1731   } 1732 1733  /** 1734   * 1735   * Basis ::= AxisName '::' NodeTest 1736   * | AbbreviatedBasis 1737   * 1738   * @return FROM_XXX axes type, found in {@link org.apache.xpath.compiler.Keywords}. 1739   * 1740   * @throws javax.xml.transform.TransformerException 1741   */ 1742  protected int AxisName() throws javax.xml.transform.TransformerException 1743  { 1744 1745    Object val = Keywords.m_axisnames.get(m_token); 1746 1747    if (null == val) 1748    { 1749      error(XPATHErrorResources.ER_ILLEGAL_AXIS_NAME, 1750            new Object []{ m_token }); //"illegal axis name: "+m_token); 1751 } 1752 1753    int axesType = ((Integer ) val).intValue(); 1754 1755    appendOp(2, axesType); 1756 1757    return axesType; 1758  } 1759 1760  /** 1761   * 1762   * NodeTest ::= WildcardName 1763   * | NodeType '(' ')' 1764   * | 'processing-instruction' '(' Literal ')' 1765   * 1766   * @param axesType FROM_XXX axes type, found in {@link org.apache.xpath.compiler.Keywords}. 1767   * 1768   * @throws javax.xml.transform.TransformerException 1769   */ 1770  protected void NodeTest(int axesType) throws javax.xml.transform.TransformerException 1771  { 1772 1773    if (lookahead('(', 1)) 1774    { 1775      Object nodeTestOp = Keywords.m_nodetypes.get(m_token); 1776 1777      if (null == nodeTestOp) 1778      { 1779        error(XPATHErrorResources.ER_UNKNOWN_NODETYPE, 1780              new Object []{ m_token }); //"Unknown nodetype: "+m_token); 1781 } 1782      else 1783      { 1784        nextToken(); 1785 1786        int nt = ((Integer ) nodeTestOp).intValue(); 1787 1788        m_ops.setOp(m_ops.getOp(OpMap.MAPINDEX_LENGTH), nt); 1789        m_ops.setOp(OpMap.MAPINDEX_LENGTH, m_ops.getOp(OpMap.MAPINDEX_LENGTH) + 1); 1790 1791        consumeExpected('('); 1792 1793        if (OpCodes.NODETYPE_PI == nt) 1794        { 1795          if (!tokenIs(')')) 1796          { 1797            Literal(); 1798          } 1799        } 1800 1801        consumeExpected(')'); 1802      } 1803    } 1804    else 1805    { 1806 1807      // Assume name of attribute or element. 1808 m_ops.setOp(m_ops.getOp(OpMap.MAPINDEX_LENGTH), OpCodes.NODENAME); 1809      m_ops.setOp(OpMap.MAPINDEX_LENGTH, m_ops.getOp(OpMap.MAPINDEX_LENGTH) + 1); 1810 1811      if (lookahead(':', 1)) 1812      { 1813        if (tokenIs('*')) 1814        { 1815          m_ops.setOp(m_ops.getOp(OpMap.MAPINDEX_LENGTH), OpCodes.ELEMWILDCARD); 1816        } 1817        else 1818        { 1819          m_ops.setOp(m_ops.getOp(OpMap.MAPINDEX_LENGTH), m_queueMark - 1); 1820 1821          // Minimalist check for an NCName - just check first character 1822 // to distinguish from other possible tokens 1823 if (!Character.isLetter(m_tokenChar) && !tokenIs('_')) 1824          { 1825            // "Node test that matches either NCName:* or QName was expected." 1826 error(XPATHErrorResources.ER_EXPECTED_NODE_TEST, null); 1827          } 1828        } 1829 1830        nextToken(); 1831        consumeExpected(':'); 1832      } 1833      else 1834      { 1835        m_ops.setOp(m_ops.getOp(OpMap.MAPINDEX_LENGTH), OpCodes.EMPTY); 1836      } 1837 1838      m_ops.setOp(OpMap.MAPINDEX_LENGTH, m_ops.getOp(OpMap.MAPINDEX_LENGTH) + 1); 1839 1840      if (tokenIs('*')) 1841      { 1842        m_ops.setOp(m_ops.getOp(OpMap.MAPINDEX_LENGTH), OpCodes.ELEMWILDCARD); 1843      } 1844      else 1845      { 1846        if (OpCodes.FROM_NAMESPACE == axesType) 1847        { 1848          String prefix = (String ) this.m_ops.m_tokenQueue.elementAt(m_queueMark - 1); 1849          String namespace = 1850            ((PrefixResolver) m_namespaceContext).getNamespaceForPrefix( 1851              prefix); 1852 1853          this.m_ops.m_tokenQueue.setElementAt(namespace,m_queueMark - 1); 1854        } 1855 1856        m_ops.setOp(m_ops.getOp(OpMap.MAPINDEX_LENGTH), m_queueMark - 1); 1857 1858        // Minimalist check for an NCName - just check first character 1859 // to distinguish from other possible tokens 1860 if (!Character.isLetter(m_tokenChar) && !tokenIs('_')) 1861        { 1862          // "Node test that matches either NCName:* or QName was expected." 1863 error(XPATHErrorResources.ER_EXPECTED_NODE_TEST, null); 1864        } 1865      } 1866 1867      m_ops.setOp(OpMap.MAPINDEX_LENGTH, m_ops.getOp(OpMap.MAPINDEX_LENGTH) + 1); 1868 1869      nextToken(); 1870    } 1871  } 1872 1873  /** 1874   * 1875   * Predicate ::= '[' PredicateExpr ']' 1876   * 1877   * 1878   * @throws javax.xml.transform.TransformerException 1879   */ 1880  protected void Predicate() throws javax.xml.transform.TransformerException 1881  { 1882 1883    if (tokenIs('[')) 1884    { 1885      nextToken(); 1886      PredicateExpr(); 1887      consumeExpected(']'); 1888    } 1889  } 1890 1891  /** 1892   * 1893   * PredicateExpr ::= Expr 1894   * 1895   * 1896   * @throws javax.xml.transform.TransformerException 1897   */ 1898  protected void PredicateExpr() throws javax.xml.transform.TransformerException 1899  { 1900 1901    int opPos = m_ops.getOp(OpMap.MAPINDEX_LENGTH); 1902 1903    appendOp(2, OpCodes.OP_PREDICATE); 1904    Expr(); 1905 1906    // Terminate for safety. 1907 m_ops.setOp(m_ops.getOp(OpMap.MAPINDEX_LENGTH), OpCodes.ENDOP); 1908    m_ops.setOp(OpMap.MAPINDEX_LENGTH, m_ops.getOp(OpMap.MAPINDEX_LENGTH) + 1); 1909    m_ops.setOp(opPos + OpMap.MAPINDEX_LENGTH, 1910      m_ops.getOp(OpMap.MAPINDEX_LENGTH) - opPos); 1911  } 1912 1913  /** 1914   * QName ::= (Prefix ':')? LocalPart 1915   * Prefix ::= NCName 1916   * LocalPart ::= NCName 1917   * 1918   * @throws javax.xml.transform.TransformerException 1919   */ 1920  protected void QName() throws javax.xml.transform.TransformerException 1921  { 1922    // Namespace 1923 if(lookahead(':', 1)) 1924    { 1925      m_ops.setOp(m_ops.getOp(OpMap.MAPINDEX_LENGTH), m_queueMark - 1); 1926      m_ops.setOp(OpMap.MAPINDEX_LENGTH, m_ops.getOp(OpMap.MAPINDEX_LENGTH) + 1); 1927 1928      nextToken(); 1929      consumeExpected(':'); 1930    } 1931    else 1932    { 1933      m_ops.setOp(m_ops.getOp(OpMap.MAPINDEX_LENGTH), OpCodes.EMPTY); 1934      m_ops.setOp(OpMap.MAPINDEX_LENGTH, m_ops.getOp(OpMap.MAPINDEX_LENGTH) + 1); 1935    } 1936     1937    // Local name 1938 m_ops.setOp(m_ops.getOp(OpMap.MAPINDEX_LENGTH), m_queueMark - 1); 1939    m_ops.setOp(OpMap.MAPINDEX_LENGTH, m_ops.getOp(OpMap.MAPINDEX_LENGTH) + 1); 1940 1941    nextToken(); 1942  } 1943 1944  /** 1945   * NCName ::= (Letter | '_') (NCNameChar) 1946   * NCNameChar ::= Letter | Digit | '.' | '-' | '_' | CombiningChar | Extender 1947   */ 1948  protected void NCName() 1949  { 1950 1951    m_ops.setOp(m_ops.getOp(OpMap.MAPINDEX_LENGTH), m_queueMark - 1); 1952    m_ops.setOp(OpMap.MAPINDEX_LENGTH, m_ops.getOp(OpMap.MAPINDEX_LENGTH) + 1); 1953 1954    nextToken(); 1955  } 1956 1957  /** 1958   * The value of the Literal is the sequence of characters inside 1959   * the " or ' characters>. 1960   * 1961   * Literal ::= '"' [^"]* '"' 1962   * | "'" [^']* "'" 1963   * 1964   * 1965   * @throws javax.xml.transform.TransformerException 1966   */ 1967  protected void Literal() throws javax.xml.transform.TransformerException 1968  { 1969 1970    int last = m_token.length() - 1; 1971    char c0 = m_tokenChar; 1972    char cX = m_token.charAt(last); 1973 1974    if (((c0 == '\"') && (cX == '\"')) || ((c0 == '\'') && (cX == '\''))) 1975    { 1976 1977      // Mutate the token to remove the quotes and have the XString object 1978 // already made. 1979 int tokenQueuePos = m_queueMark - 1; 1980 1981      m_ops.m_tokenQueue.setElementAt(null,tokenQueuePos); 1982 1983      Object obj = new XString(m_token.substring(1, last)); 1984 1985      m_ops.m_tokenQueue.setElementAt(obj,tokenQueuePos); 1986 1987      // lit = m_token.substring(1, last); 1988 m_ops.setOp(m_ops.getOp(OpMap.MAPINDEX_LENGTH), tokenQueuePos); 1989      m_ops.setOp(OpMap.MAPINDEX_LENGTH, m_ops.getOp(OpMap.MAPINDEX_LENGTH) + 1); 1990 1991      nextToken(); 1992    } 1993    else 1994    { 1995      error(XPATHErrorResources.ER_PATTERN_LITERAL_NEEDS_BE_QUOTED, 1996            new Object []{ m_token }); //"Pattern literal ("+m_token+") needs to be quoted!"); 1997 } 1998  } 1999 2000  /** 2001   * 2002   * Number ::= [0-9]+('.'[0-9]+)? | '.'[0-9]+ 2003   * 2004   * 2005   * @throws javax.xml.transform.TransformerException 2006   */ 2007  protected void Number() throws javax.xml.transform.TransformerException 2008  { 2009 2010    if (null != m_token) 2011    { 2012 2013      // Mutate the token to remove the quotes and have the XNumber object 2014 // already made. 2015 double num; 2016 2017      try 2018      { 2019        // XPath 1.0 does not support number in exp notation 2020 if ((m_token.indexOf('e') > -1)||(m_token.indexOf('E') > -1)) 2021            throw new NumberFormatException (); 2022        num = Double.valueOf(m_token).doubleValue(); 2023      } 2024      catch (NumberFormatException nfe) 2025      { 2026        num = 0.0; // to shut up compiler. 2027 2028        error(XPATHErrorResources.ER_COULDNOT_BE_FORMATTED_TO_NUMBER, 2029              new Object []{ m_token }); //m_token+" could not be formatted to a number!"); 2030 } 2031 2032      m_ops.m_tokenQueue.setElementAt(new XNumber(num),m_queueMark - 1); 2033      m_ops.setOp(m_ops.getOp(OpMap.MAPINDEX_LENGTH), m_queueMark - 1); 2034      m_ops.setOp(OpMap.MAPINDEX_LENGTH, m_ops.getOp(OpMap.MAPINDEX_LENGTH) + 1); 2035 2036      nextToken(); 2037    } 2038  } 2039 2040  // ============= PATTERN FUNCTIONS ================= 2041 2042  /** 2043   * 2044   * Pattern ::= LocationPathPattern 2045   * | Pattern '|' LocationPathPattern 2046   * 2047   * 2048   * @throws javax.xml.transform.TransformerException 2049   */ 2050  protected void Pattern() throws javax.xml.transform.TransformerException 2051  { 2052 2053    while (true) 2054    { 2055      LocationPathPattern(); 2056 2057      if (tokenIs('|')) 2058      { 2059        nextToken(); 2060      } 2061      else 2062      { 2063        break; 2064      } 2065    } 2066  } 2067 2068  /** 2069   * 2070   * 2071   * LocationPathPattern ::= '/' RelativePathPattern? 2072   * | IdKeyPattern (('/' | '//') RelativePathPattern)? 2073   * | '//'? RelativePathPattern 2074   * 2075   * 2076   * @throws javax.xml.transform.TransformerException 2077   */ 2078  protected void LocationPathPattern() throws javax.xml.transform.TransformerException 2079  { 2080 2081    int opPos = m_ops.getOp(OpMap.MAPINDEX_LENGTH); 2082 2083    final int RELATIVE_PATH_NOT_PERMITTED = 0; 2084    final int RELATIVE_PATH_PERMITTED = 1; 2085    final int RELATIVE_PATH_REQUIRED = 2; 2086 2087    int relativePathStatus = RELATIVE_PATH_NOT_PERMITTED; 2088 2089    appendOp(2, OpCodes.OP_LOCATIONPATHPATTERN); 2090 2091    if (lookahead('(', 1) 2092            && (tokenIs(Keywords.FUNC_ID_STRING) 2093                || tokenIs(Keywords.FUNC_KEY_STRING))) 2094    { 2095      IdKeyPattern(); 2096 2097      if (tokenIs('/')) 2098      { 2099        nextToken(); 2100 2101        if (tokenIs('/')) 2102        { 2103          appendOp(4, OpCodes.MATCH_ANY_ANCESTOR); 2104 2105          nextToken(); 2106        } 2107        else 2108        { 2109          appendOp(4, OpCodes.MATCH_IMMEDIATE_ANCESTOR); 2110        } 2111 2112        // Tell how long the step is without the predicate 2113 m_ops.setOp(m_ops.getOp(OpMap.MAPINDEX_LENGTH) - 2, 4); 2114        m_ops.setOp(m_ops.getOp(OpMap.MAPINDEX_LENGTH) - 1, OpCodes.NODETYPE_FUNCTEST); 2115 2116        relativePathStatus = RELATIVE_PATH_REQUIRED; 2117      } 2118    } 2119    else if (tokenIs('/')) 2120    { 2121      if (lookahead('/', 1)) 2122      { 2123        appendOp(4, OpCodes.MATCH_ANY_ANCESTOR); 2124         2125        // Added this to fix bug reported by Myriam for match="//x/a" 2126 // patterns. If you don't do this, the 'x' step will think it's part 2127 // of a '//' pattern, and so will cause 'a' to be matched when it has 2128 // any ancestor that is 'x'. 2129 nextToken(); 2130 2131        relativePathStatus = RELATIVE_PATH_REQUIRED; 2132      } 2133      else 2134      { 2135        appendOp(4, OpCodes.FROM_ROOT); 2136 2137        relativePathStatus = RELATIVE_PATH_PERMITTED; 2138      } 2139 2140 2141      // Tell how long the step is without the predicate 2142 m_ops.setOp(m_ops.getOp(OpMap.MAPINDEX_LENGTH) - 2, 4); 2143      m_ops.setOp(m_ops.getOp(OpMap.MAPINDEX_LENGTH) - 1, OpCodes.NODETYPE_ROOT); 2144 2145      nextToken(); 2146    } 2147    else 2148    { 2149      relativePathStatus = RELATIVE_PATH_REQUIRED; 2150    } 2151 2152    if (relativePathStatus != RELATIVE_PATH_NOT_PERMITTED) 2153    { 2154      if (!tokenIs('|') && (null != m_token)) 2155      { 2156        RelativePathPattern(); 2157      } 2158      else if (relativePathStatus == RELATIVE_PATH_REQUIRED) 2159      { 2160        // "A relative path pattern was expected." 2161 error(XPATHErrorResources.ER_EXPECTED_REL_PATH_PATTERN, null); 2162      } 2163    } 2164 2165    // Terminate for safety. 2166 m_ops.setOp(m_ops.getOp(OpMap.MAPINDEX_LENGTH), OpCodes.ENDOP); 2167    m_ops.setOp(OpMap.MAPINDEX_LENGTH, m_ops.getOp(OpMap.MAPINDEX_LENGTH) + 1); 2168    m_ops.setOp(opPos + OpMap.MAPINDEX_LENGTH, 2169      m_ops.getOp(OpMap.MAPINDEX_LENGTH) - opPos); 2170  } 2171 2172  /** 2173   * 2174   * IdKeyPattern ::= 'id' '(' Literal ')' 2175   * | 'key' '(' Literal ',' Literal ')' 2176   * (Also handle doc()) 2177   * 2178   * 2179   * @throws javax.xml.transform.TransformerException 2180   */ 2181  protected void IdKeyPattern() throws javax.xml.transform.TransformerException 2182  { 2183    FunctionCall(); 2184  } 2185 2186  /** 2187   * 2188   * RelativePathPattern ::= StepPattern 2189   * | RelativePathPattern '/' StepPattern 2190   * | RelativePathPattern '//' StepPattern 2191   * 2192   * @throws javax.xml.transform.TransformerException 2193   */ 2194  protected void RelativePathPattern() 2195              throws javax.xml.transform.TransformerException 2196  { 2197 2198    // Caller will have consumed any '/' or '//' preceding the 2199 // RelativePathPattern, so let StepPattern know it can't begin with a '/' 2200 boolean trailingSlashConsumed = StepPattern(false); 2201 2202    while (tokenIs('/')) 2203    { 2204      nextToken(); 2205 2206      // StepPattern() may consume first slash of pair in "a//b" while 2207 // processing StepPattern "a". On next iteration, let StepPattern know 2208 // that happened, so it doesn't match ill-formed patterns like "a///b". 2209 trailingSlashConsumed = StepPattern(!trailingSlashConsumed); 2210    } 2211  } 2212 2213  /** 2214   * 2215   * StepPattern ::= AbbreviatedNodeTestStep 2216   * 2217   * @param isLeadingSlashPermitted a boolean indicating whether a slash can 2218   * appear at the start of this step 2219   * 2220   * @return boolean indicating whether a slash following the step was consumed 2221   * 2222   * @throws javax.xml.transform.TransformerException 2223   */ 2224  protected boolean StepPattern(boolean isLeadingSlashPermitted) 2225            throws javax.xml.transform.TransformerException 2226  { 2227    return AbbreviatedNodeTestStep(isLeadingSlashPermitted); 2228  } 2229 2230  /** 2231   * 2232   * AbbreviatedNodeTestStep ::= '@'? NodeTest Predicate 2233   * 2234   * @param isLeadingSlashPermitted a boolean indicating whether a slash can 2235   * appear at the start of this step 2236   * 2237   * @return boolean indicating whether a slash following the step was consumed 2238   * 2239   * @throws javax.xml.transform.TransformerException 2240   */ 2241  protected boolean AbbreviatedNodeTestStep(boolean isLeadingSlashPermitted) 2242            throws javax.xml.transform.TransformerException 2243  { 2244 2245    int opPos = m_ops.getOp(OpMap.MAPINDEX_LENGTH); 2246    int axesType; 2247 2248    // The next blocks guarantee that a MATCH_XXX will be added. 2249 int matchTypePos = -1; 2250 2251    if (tokenIs('@')) 2252    { 2253      axesType = OpCodes.MATCH_ATTRIBUTE; 2254 2255      appendOp(2, axesType); 2256      nextToken(); 2257    } 2258    else if (this.lookahead("::", 1)) 2259    { 2260      if (tokenIs("attribute")) 2261      { 2262        axesType = OpCodes.MATCH_ATTRIBUTE; 2263 2264        appendOp(2, axesType); 2265      } 2266      else if (tokenIs("child")) 2267      { 2268        matchTypePos = m_ops.getOp(OpMap.MAPINDEX_LENGTH); 2269        axesType = OpCodes.MATCH_IMMEDIATE_ANCESTOR; 2270 2271        appendOp(2, axesType); 2272      } 2273      else 2274      { 2275        axesType = -1; 2276 2277        this.error(XPATHErrorResources.ER_AXES_NOT_ALLOWED, 2278                   new Object []{ this.m_token }); 2279      } 2280 2281      nextToken(); 2282      nextToken(); 2283    } 2284    else if (tokenIs('/')) 2285    { 2286      if (!isLeadingSlashPermitted) 2287      { 2288        // "A step was expected in the pattern, but '/' was encountered." 2289 error(XPATHErrorResources.ER_EXPECTED_STEP_PATTERN, null); 2290      } 2291      axesType = OpCodes.MATCH_ANY_ANCESTOR; 2292 2293      appendOp(2, axesType); 2294      nextToken(); 2295    } 2296    else 2297    { 2298      matchTypePos = m_ops.getOp(OpMap.MAPINDEX_LENGTH); 2299      axesType = OpCodes.MATCH_IMMEDIATE_ANCESTOR; 2300 2301      appendOp(2, axesType); 2302    } 2303 2304    // Make room for telling how long the step is without the predicate 2305 m_ops.setOp(OpMap.MAPINDEX_LENGTH, m_ops.getOp(OpMap.MAPINDEX_LENGTH) + 1); 2306 2307    NodeTest(axesType); 2308 2309    // Tell how long the step is without the predicate 2310 m_ops.setOp(opPos + OpMap.MAPINDEX_LENGTH + 1, 2311      m_ops.getOp(OpMap.MAPINDEX_LENGTH) - opPos); 2312 2313    while (tokenIs('[')) 2314    { 2315      Predicate(); 2316    } 2317 2318    boolean trailingSlashConsumed; 2319 2320    // For "a//b", where "a" is current step, we need to mark operation of 2321 // current step as "MATCH_ANY_ANCESTOR". Then we'll consume the first 2322 // slash and subsequent step will be treated as a MATCH_IMMEDIATE_ANCESTOR 2323 // (unless it too is followed by '//'.) 2324 // 2325 // %REVIEW% Following is what happens today, but I'm not sure that's 2326 // %REVIEW% correct behaviour. Perhaps no valid case could be constructed 2327 // %REVIEW% where it would matter? 2328 // 2329 // If current step is on the attribute axis (e.g., "@x//b"), we won't 2330 // change the current step, and let following step be marked as 2331 // MATCH_ANY_ANCESTOR on next call instead. 2332 if ((matchTypePos > -1) && tokenIs('/') && lookahead('/', 1)) 2333    { 2334      m_ops.setOp(matchTypePos, OpCodes.MATCH_ANY_ANCESTOR); 2335 2336      nextToken(); 2337 2338      trailingSlashConsumed = true; 2339    } 2340    else 2341    { 2342      trailingSlashConsumed = false; 2343    } 2344 2345    // Tell how long the entire step is. 2346 m_ops.setOp(opPos + OpMap.MAPINDEX_LENGTH, 2347      m_ops.getOp(OpMap.MAPINDEX_LENGTH) - opPos); 2348 2349    return trailingSlashConsumed; 2350  } 2351} 2352

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