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

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/*
 * Sonar JavaScript Plugin
 * Copyright (C) 2011 Eriks Nukis and SonarSource
 * [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 com.sonar.sslr.api.AstNode;
import com.sonar.sslr.squid.checks.SquidCheck;
import org.sonar.check.BelongsToProfile;
import org.sonar.check.Priority;
import org.sonar.check.Rule;
import org.sonar.javascript.api.EcmaScriptGrammar;

@Rule(
  key = "CollapsibleIfStatements",
  priority = Priority.MAJOR)
@BelongsToProfile(title = CheckList.SONAR_WAY_PROFILE, priority = Priority.MAJOR)
public class CollapsibleIfStatementsCheck extends SquidCheck {

  @Override
  public void init() {
    subscribeTo(getContext().getGrammar().ifStatement);
  }

  @Override
  public void visitNode(AstNode node) {
    if (isIfStatementWithoutElse(node)) {
      AstNode innerStatement = node.findFirstDirectChild(getContext().getGrammar().statement).getFirstChild();
      if (isBlockAndContainsOnlyOneIfStatement(innerStatement) || isIfStatementWithoutElse(innerStatement)) {
        getContext().createLineViolation(this, "Those two 'if' statements can be consolidated.", node);
      }
    }
  }

  private boolean isBlockAndContainsOnlyOneIfStatement(AstNode statement) {
    if (!statement.is(getContext().getGrammar().block)) {
      return false;
    }
    AstNode statementList = statement.findFirstDirectChild(getContext().getGrammar().statementList);
    if (statementList == null || statementList.getNumberOfChildren() != 1 || statementList.getFirstChild().isNot(getContext().getGrammar().statement)) {
      return false;
    }
    return isIfStatementWithoutElse(statementList.getFirstChild().getFirstChild());
  }

  private boolean isIfStatementWithoutElse(AstNode statement) {
    if (statement.isNot(getContext().getGrammar().ifStatement) || statement.hasDirectChildren(getContext().getGrammar().elseClause)) {
      return false;
    }
    return true;
  }

}