org.sonar.erlang.metrics.ErlangComplexityVisitor Maven / Gradle / Ivy

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/*
 * Sonar Erlang Plugin
 * Copyright (C) 2012 Tamas Kende
 * [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.erlang.metrics;

import com.sonar.sslr.api.AstNode;
import com.sonar.sslr.api.AstNodeType;

import org.sonar.squidbridge.SquidAstVisitor;
import org.sonar.erlang.api.ErlangMetric;
import org.sonar.erlang.parser.ErlangGrammarImpl;
import org.sonar.sslr.parser.LexerlessGrammar;

/**
 * Erlang complexity calculation +1 for every function clause over 1 +1 for
 * every fun expression +1 for every branch expression (if) +1 for every pattern
 * statement (case, try) +1 for every catch pattern statement (catch)
 *
 * @author Tamas Kende
 */
public class ErlangComplexityVisitor extends SquidAstVisitor {

  private AstNodeType[] complexityAstNodeType;

  @Override
  public void init() {
    complexityAstNodeType = new AstNodeType[]{
      // Entry points
      ErlangGrammarImpl.functionClause,

      // Branching nodes
      ErlangGrammarImpl.branchExp, ErlangGrammarImpl.patternStatement, ErlangGrammarImpl.catchPatternStatement,

      // TODO: Expressions? when increase? if there are more than one guard
      // and more than
      // one guard expression?
      // grammar.guardSequence
    };
    subscribeTo(complexityAstNodeType);
  }

  @Override
  public void visitNode(AstNode astNode) {
    increaseComplexity(1);
  }

  private void increaseComplexity(int i) {
    getContext().peekSourceCode().add(ErlangMetric.COMPLEXITY, i);
  }
}