org.sonar.javascript.checks.CommaOperatorUseCheck Maven / Gradle / Ivy

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/*
 * SonarQube JavaScript Plugin
 * Copyright (C) 2011 SonarSource and Eriks Nukis
 * [email protected]
 *
 * 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  02
 */
package org.sonar.javascript.checks;

import org.sonar.api.server.rule.RulesDefinition;
import org.sonar.check.Priority;
import org.sonar.check.Rule;
import org.sonar.plugins.javascript.api.visitors.BaseTreeVisitor;
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.squidbridge.annotations.SqaleConstantRemediation;
import org.sonar.squidbridge.annotations.SqaleSubCharacteristic;

import javax.annotation.Nullable;
import java.util.LinkedList;
import java.util.List;

@Rule(
    key = "S878",
    name = "Comma operator should not be used",
    priority = Priority.MAJOR,
    tags = {Tags.MISRA})
@SqaleSubCharacteristic(RulesDefinition.SubCharacteristics.UNDERSTANDABILITY)
@SqaleConstantRemediation("5min")
public class CommaOperatorUseCheck extends BaseTreeVisitor {

  @Override
  public void visitBinaryExpression(BinaryExpressionTree tree) {

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

    List expressions = getAllSubExpressions(tree);

    String message;
    if (expressions.size() > 2) {
      message = "Remove use of all comma operators in this expression.";
    } else {
      message = "Remove use of this comma operator.";
    }

    getContext().addIssue(this, getFirstComma(tree), message);
    for (ExpressionTree expression : expressions) {
      super.scan(expression);
    }
  }

  @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 expressions = getAllSubExpressions((BinaryExpressionTree) tree);
      for (ExpressionTree expression : expressions) {
        super.scan(expression);
      }
    } else {
      super.scan(tree);
    }
  }

  private List getAllSubExpressions(BinaryExpressionTree tree) {
    List 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 SyntaxToken getFirstComma(BinaryExpressionTree tree) {
    SyntaxToken result = tree.operator();
    ExpressionTree currentExpression = tree.leftOperand();
    while (currentExpression.is(Kind.COMMA_OPERATOR)) {
      result = ((BinaryExpressionTree)currentExpression).operator();
      currentExpression = ((BinaryExpressionTree) currentExpression).leftOperand();
    }
    return result;
  }

}