org.sonar.java.checks.CommentedOutCodeLineCheck Maven / Gradle / Ivy

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/*
 * SonarQube Java
 * Copyright (C) 2012-2024 SonarSource SA
 * mailto:info 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.java.checks;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import javax.annotation.Nullable;
import org.apache.commons.lang3.StringUtils;
import org.sonar.check.Rule;
import org.sonar.java.model.DefaultJavaFileScannerContext;
import org.sonar.java.model.LineUtils;
import org.sonar.java.reporting.AnalyzerMessage;
import org.sonar.plugins.java.api.IssuableSubscriptionVisitor;
import org.sonar.plugins.java.api.location.Position;
import org.sonar.plugins.java.api.tree.SyntaxToken;
import org.sonar.plugins.java.api.tree.SyntaxTrivia;
import org.sonar.plugins.java.api.tree.Tree;
import org.sonarsource.analyzer.commons.annotations.DeprecatedRuleKey;
import org.sonarsource.analyzer.commons.recognizers.CodeRecognizer;

@DeprecatedRuleKey(ruleKey = "CommentedOutCodeLine", repositoryKey = "squid")
@Rule(key = "S125")
public class CommentedOutCodeLineCheck extends IssuableSubscriptionVisitor {

  private static final double THRESHOLD = 0.9;
  private static final String START_JSNI = "/*-{";
  private static final String END_JSNI = "}-*/";
  private static final String MESSAGE = "This block of commented-out lines of code should be removed.";

  private final CodeRecognizer codeRecognizer;

  public CommentedOutCodeLineCheck() {
    codeRecognizer = new CodeRecognizer(THRESHOLD, new JavaFootprint());
  }

  @Override
  public List nodesToVisit() {
    return Collections.singletonList(Tree.Kind.TOKEN);
  }

  @Override
  public void visitToken(SyntaxToken syntaxToken) {
    List issues = new ArrayList<>();
    AnalyzerMessage previousRelatedIssue = null;
    int previousCommentLine = -1;
    for (SyntaxTrivia syntaxTrivia : syntaxToken.trivias()) {
      int currentCommentLine = LineUtils.startLine(syntaxTrivia);
      if (currentCommentLine != previousCommentLine + 1 &&
        currentCommentLine != previousCommentLine) {
        previousRelatedIssue = null;
      }
      if (!isHeader(syntaxTrivia) && !isJavadoc(syntaxTrivia.comment()) && !isJSNI(syntaxTrivia.comment())) {
        previousRelatedIssue = collectIssues(issues, syntaxTrivia, previousRelatedIssue);
        previousCommentLine = currentCommentLine;
      }
    }
    DefaultJavaFileScannerContext scannerContext = (DefaultJavaFileScannerContext) this.context;
    issues.forEach(scannerContext::reportIssue);
  }

  public AnalyzerMessage collectIssues(List issues, SyntaxTrivia syntaxTrivia, @Nullable AnalyzerMessage previousRelatedIssue) {
    String[] lines = syntaxTrivia.comment().split("\r\n?|\n");
    AnalyzerMessage issue = previousRelatedIssue;
    for (int lineOffset = 0; lineOffset < lines.length; lineOffset++) {
      String line = lines[lineOffset];
      if (!isJavadocLink(line) && codeRecognizer.isLineOfCode(line)) {
        int startLine = LineUtils.startLine(syntaxTrivia) + lineOffset;
        int startColumnOffset = (lineOffset == 0 ? Position.startOf(syntaxTrivia).columnOffset() : 0);
        if (issue != null) {
          issue.flows.add(Collections.singletonList(createAnalyzerMessage(startLine, startColumnOffset, line, "Code")));
        } else {
          issue = createAnalyzerMessage(startLine, startColumnOffset, line, MESSAGE);
          issues.add(issue);
        }
      }
    }
    return issue;
  }

  private AnalyzerMessage createAnalyzerMessage(int startLine, int startColumn, String line, String message) {
    String lineWithoutCommentPrefix = line.replaceFirst("^(//|/\\*\\*?|[ \t]*\\*)?[ \t]*+", "");
    int prefixSize = line.length() - lineWithoutCommentPrefix.length();
    String lineWithoutCommentPrefixAndSuffix = removeCommentSuffix(lineWithoutCommentPrefix);

    AnalyzerMessage.TextSpan textSpan = new AnalyzerMessage.TextSpan(
      startLine,
      startColumn + prefixSize,
      startLine,
      startColumn + prefixSize + lineWithoutCommentPrefixAndSuffix.length());

    return new AnalyzerMessage(this, context.getInputFile(), textSpan, message, 0);
  }

  private static String removeCommentSuffix(String line) {
    // We do not use a regex for this task, to avoid ReDoS.
    if (line.endsWith("*/")) {
      line = line.substring(0, line.length() - 2);
    }
    return line.stripTrailing();
  }

  /**
   * We assume that comment on a first line - is a header with license.
   * However possible to imagine corner case: file may contain commented-out code starting from first line.
   * But we assume that probability of this is really low.
   */
  private static boolean isHeader(SyntaxTrivia syntaxTrivia) {
    return LineUtils.startLine(syntaxTrivia) == 1;
  }

  private static boolean isJavadocLink(String line) {
    return line.contains("{@link");
  }

  /**
   * From documentation for Javadoc-tool:
   * Documentation comments should be recognized only when placed
   * immediately before class, interface, constructor, method, or field declarations.
   */
  private static boolean isJavadoc(String comment) {
    return StringUtils.startsWith(comment, "/**");
  }

  /**
   * From GWT documentation:
   * JSNI methods are declared native and contain JavaScript code in a specially formatted comment block
   * between the end of the parameter list and the trailing semicolon.
   * A JSNI comment block begins with the exact token {@link #START_JSNI} and ends with the exact token {@link #END_JSNI}.
   */
  private static boolean isJSNI(String comment) {
    return StringUtils.startsWith(comment, START_JSNI) && StringUtils.endsWith(comment, END_JSNI);
  }

}