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 */
28package org.antlr.tool;
29
30import org.antlr.analysis.DFAState;
31import org.antlr.analysis.DecisionProbe;
32import org.antlr.analysis.NFAState;
33import org.antlr.misc.Utils;
34import org.stringtemplate.v4.ST;
35
36import java.util.Iterator;
37import java.util.List;
38import java.util.Set;
39
40/** Reports a potential parsing issue with a decision; the decision is
41 *  nondeterministic in some way.
42 */
43public 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