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      1 /*
      2  * [The "BSD license"]
      3  *  Copyright (c) 2010 Terence Parr
      4  *  All rights reserved.
      5  *
      6  *  Redistribution and use in source and binary forms, with or without
      7  *  modification, are permitted provided that the following conditions
      8  *  are met:
      9  *  1. Redistributions of source code must retain the above copyright
     10  *      notice, this list of conditions and the following disclaimer.
     11  *  2. Redistributions in binary form must reproduce the above copyright
     12  *      notice, this list of conditions and the following disclaimer in the
     13  *      documentation and/or other materials provided with the distribution.
     14  *  3. The name of the author may not be used to endorse or promote products
     15  *      derived from this software without specific prior written permission.
     16  *
     17  *  THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     18  *  IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     19  *  OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     20  *  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     21  *  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     22  *  NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     23  *  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     24  *  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     25  *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     26  *  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     27  */
     28 package org.antlr.tool;
     29 
     30 import org.antlr.analysis.DFAState;
     31 import org.antlr.analysis.DecisionProbe;
     32 import org.antlr.analysis.NFAState;
     33 import org.antlr.misc.Utils;
     34 import org.stringtemplate.v4.ST;
     35 
     36 import java.util.Iterator;
     37 import java.util.List;
     38 import java.util.Set;
     39 
     40 /** Reports a potential parsing issue with a decision; the decision is
     41  *  nondeterministic in some way.
     42  */
     43 public class GrammarNonDeterminismMessage extends Message {
     44 	public DecisionProbe probe;
     45     public DFAState problemState;
     46 
     47 	public GrammarNonDeterminismMessage(DecisionProbe probe,
     48 										DFAState problemState)
     49 	{
     50 		super(ErrorManager.MSG_GRAMMAR_NONDETERMINISM);
     51 		this.probe = probe;
     52 		this.problemState = problemState;
     53 		// flip msg ID if alts are actually token refs in Tokens rule
     54 		if ( probe.dfa.isTokensRuleDecision() ) {
     55 			setMessageID(ErrorManager.MSG_TOKEN_NONDETERMINISM);
     56 		}
     57 	}
     58 
     59 	public String toString() {
     60 		GrammarAST decisionASTNode = probe.dfa.getDecisionASTNode();
     61 		line = decisionASTNode.getLine();
     62 		column = decisionASTNode.getCharPositionInLine();
     63 		String fileName = probe.dfa.nfa.grammar.getFileName();
     64 		if ( fileName!=null ) {
     65 			file = fileName;
     66 		}
     67 
     68 		ST st = getMessageTemplate();
     69 		// Now fill template with information about problemState
     70 		List labels = probe.getSampleNonDeterministicInputSequence(problemState);
     71 		String input = probe.getInputSequenceDisplay(labels);
     72 		st.add("input", input);
     73 
     74 		if ( probe.dfa.isTokensRuleDecision() ) {
     75 			Set disabledAlts = probe.getDisabledAlternatives(problemState);
     76 			for (Iterator it = disabledAlts.iterator(); it.hasNext();) {
     77 				Integer altI = (Integer) it.next();
     78 				String tokenName =
     79 					probe.getTokenNameForTokensRuleAlt(altI.intValue());
     80 				// reset the line/col to the token definition (pick last one)
     81 				NFAState ruleStart =
     82 					probe.dfa.nfa.grammar.getRuleStartState(tokenName);
     83 				line = ruleStart.associatedASTNode.getLine();
     84 				column = ruleStart.associatedASTNode.getCharPositionInLine();
     85 				st.add("disabled", tokenName);
     86 			}
     87 		}
     88 		else {
     89 			st.add("disabled", probe.getDisabledAlternatives(problemState));
     90 		}
     91 
     92 		List nondetAlts = probe.getNonDeterministicAltsForState(problemState);
     93 		NFAState nfaStart = probe.dfa.getNFADecisionStartState();
     94 		// all state paths have to begin with same NFA state
     95 		int firstAlt = 0;
     96 		if ( nondetAlts!=null ) {
     97 			for (Iterator iter = nondetAlts.iterator(); iter.hasNext();) {
     98 				Integer displayAltI = (Integer) iter.next();
     99 				if ( DecisionProbe.verbose ) {
    100 					int tracePathAlt =
    101 						nfaStart.translateDisplayAltToWalkAlt(displayAltI.intValue());
    102 					if ( firstAlt == 0 ) {
    103 						firstAlt = tracePathAlt;
    104 					}
    105 					List path =
    106 						probe.getNFAPathStatesForAlt(firstAlt,
    107 													 tracePathAlt,
    108 													 labels);
    109 					st.addAggr("paths.{alt, states}", displayAltI, path);
    110 				}
    111 				else {
    112 					if ( probe.dfa.isTokensRuleDecision() ) {
    113 						// alts are token rules, convert to the names instead of numbers
    114 						String tokenName =
    115 							probe.getTokenNameForTokensRuleAlt(displayAltI.intValue());
    116 						st.add("conflictingTokens", tokenName);
    117 					}
    118 					else {
    119 						st.add("conflictingAlts", displayAltI);
    120 					}
    121 				}
    122 			}
    123 		}
    124 		st.add("hasPredicateBlockedByAction", problemState.dfa.hasPredicateBlockedByAction);
    125 		return super.toString(st);
    126 	}
    127 
    128 }
    129