org.sonar.javascript.checks.CommaOperatorUseCheck.java Source code

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Here is the source code for org.sonar.javascript.checks.CommaOperatorUseCheck.java

Source

/*
 * SonarQube JavaScript Plugin
 * Copyright (C) 2011-2016 SonarSource SA
 * mailto:contact AT sonarsource DOT com
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 3 of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */
package org.sonar.javascript.checks;

import com.google.common.collect.Lists;
import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;
import javax.annotation.Nullable;
import org.sonar.check.Rule;
import org.sonar.plugins.javascript.api.tree.Tree;
import org.sonar.plugins.javascript.api.tree.Tree.Kind;
import org.sonar.plugins.javascript.api.tree.expression.BinaryExpressionTree;
import org.sonar.plugins.javascript.api.tree.expression.ExpressionTree;
import org.sonar.plugins.javascript.api.tree.lexical.SyntaxToken;
import org.sonar.plugins.javascript.api.tree.statement.ForStatementTree;
import org.sonar.plugins.javascript.api.visitors.DoubleDispatchVisitorCheck;
import org.sonar.plugins.javascript.api.visitors.PreciseIssue;

@Rule(key = "S878")
public class CommaOperatorUseCheck extends DoubleDispatchVisitorCheck {

    private static final String MESSAGE_ONE_COMMA = "Remove use of this comma operator.";
    private static final String MESSAGE_MANY_COMMAS = "Remove use of all comma operators in this expression.";

    @Override
    public void visitBinaryExpression(BinaryExpressionTree tree) {

        if (!tree.is(Kind.COMMA_OPERATOR)) {
            super.visitBinaryExpression(tree);
            return;
        }

        raiseIssue(tree);

        getAllSubExpressions(tree).forEach(expression -> super.scan(expression));
    }

    private void raiseIssue(BinaryExpressionTree tree) {
        List<SyntaxToken> commas = getCommas(tree);
        String message = commas.size() > 1 ? MESSAGE_MANY_COMMAS : MESSAGE_ONE_COMMA;
        PreciseIssue issue = addIssue(commas.get(0), message);
        commas.subList(1, commas.size()).forEach(issue::secondary);
    }

    @Override
    public void visitForStatement(ForStatementTree tree) {
        visitPossibleException(tree.init());
        super.scan(tree.condition());
        visitPossibleException(tree.update());
        super.scan(tree.statement());
    }

    private void visitPossibleException(@Nullable Tree tree) {
        if (tree != null && tree.is(Kind.COMMA_OPERATOR)) {
            List<ExpressionTree> expressions = getAllSubExpressions((BinaryExpressionTree) tree);
            for (ExpressionTree expression : expressions) {
                super.scan(expression);
            }
        } else {
            super.scan(tree);
        }
    }

    private static List<ExpressionTree> getAllSubExpressions(BinaryExpressionTree tree) {
        List<ExpressionTree> result = new LinkedList<>();
        result.add(tree.rightOperand());
        ExpressionTree currentExpression = tree.leftOperand();
        while (currentExpression.is(Kind.COMMA_OPERATOR)) {
            result.add(((BinaryExpressionTree) currentExpression).rightOperand());
            currentExpression = ((BinaryExpressionTree) currentExpression).leftOperand();
        }
        result.add(currentExpression);
        return result;
    }

    private static List<SyntaxToken> getCommas(BinaryExpressionTree tree) {
        List<SyntaxToken> commas = new ArrayList<>();
        commas.add(tree.operator());
        ExpressionTree currentExpression = tree.leftOperand();
        while (currentExpression.is(Kind.COMMA_OPERATOR)) {
            commas.add(((BinaryExpressionTree) currentExpression).operator());
            currentExpression = ((BinaryExpressionTree) currentExpression).leftOperand();
        }
        return Lists.reverse(commas);
    }

}