1 files changed, 213 insertions, 0 deletions
diff --git a/sonar-scanner-engine/src/main/java/org/sonar/scm/git/NativeGitBlameCommand.java b/sonar-scanner-engine/src/main/java/org/sonar/scm/git/NativeGitBlameCommand.java
new file mode 100644
index 00000000000..0dd2e1620ef
--- /dev/null
+++ b/sonar-scanner-engine/src/main/java/org/sonar/scm/git/NativeGitBlameCommand.java
@@ -0,0 +1,213 @@
+/*
+ * SonarQube
+ * Copyright (C) 2009-2023 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.scm.git;
+
+import java.io.IOException;
+import java.nio.file.Path;
+import java.time.Instant;
+import java.util.Date;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+import java.util.stream.Collectors;
+import org.apache.commons.lang.math.NumberUtils;
+import org.sonar.api.batch.scm.BlameLine;
+import org.sonar.api.utils.System2;
+import org.sonar.api.utils.Version;
+import org.sonar.api.utils.log.Logger;
+import org.sonar.api.utils.log.Loggers;
+import org.springframework.beans.factory.annotation.Autowired;
+
+import static java.util.Collections.emptyList;
+import static org.sonar.api.utils.Preconditions.checkState;
+
+public class NativeGitBlameCommand {
+  protected static final String BLAME_COMMAND = "blame";
+  protected static final String GIT_DIR_FLAG = "--git-dir";
+  protected static final String GIT_DIR_ARGUMENT = "%s/.git";
+  protected static final String GIT_DIR_FORCE_FLAG = "-C";
+
+  private static final Logger LOG = Loggers.get(NativeGitBlameCommand.class);
+  private static final Pattern EMAIL_PATTERN = Pattern.compile("<(.*?)>");
+  private static final String COMMITTER_TIME = "committer-time ";
+  private static final String AUTHOR_MAIL = "author-mail ";
+
+  private static final String MINIMUM_REQUIRED_GIT_VERSION = "2.24.0";
+  private static final String DEFAULT_GIT_COMMAND = "git";
+  private static final String BLAME_LINE_PORCELAIN_FLAG = "--line-porcelain";
+  private static final String END_OF_OPTIONS_FLAG = "--end-of-options";
+  private static final String IGNORE_WHITESPACES = "-w";
+
+  private static final Pattern whitespaceRegex = Pattern.compile("\\s+");
+  private static final Pattern semanticVersionDelimiter = Pattern.compile("\\.");
+
+  private final System2 system;
+  private final ProcessWrapperFactory processWrapperFactory;
+  private String gitCommand;
+
+  @Autowired
+  public NativeGitBlameCommand(System2 system, ProcessWrapperFactory processWrapperFactory) {
+    this.system = system;
+    this.processWrapperFactory = processWrapperFactory;
+  }
+
+  NativeGitBlameCommand(String gitCommand, System2 system, ProcessWrapperFactory processWrapperFactory) {
+    this.gitCommand = gitCommand;
+    this.system = system;
+    this.processWrapperFactory = processWrapperFactory;
+  }
+
+  /**
+   * This method must be executed before org.sonar.scm.git.GitBlameCommand#blame
+   *
+   * @return true, if native git is installed
+   */
+  public boolean checkIfEnabled() {
+    try {
+      this.gitCommand = locateDefaultGit();
+      MutableString stdOut = new MutableString();
+      this.processWrapperFactory.create(null, l -> stdOut.string = l, gitCommand, "--version").execute();
+      return stdOut.string != null && stdOut.string.startsWith("git version") && isCompatibleGitVersion(stdOut.string);
+    } catch (Exception e) {
+      LOG.debug("Failed to find git native client", e);
+      return false;
+    }
+  }
+
+  private String locateDefaultGit() throws IOException {
+    if (this.gitCommand != null) {
+      return this.gitCommand;
+    }
+    // if not set fall back to defaults
+    if (system.isOsWindows()) {
+      return locateGitOnWindows();
+    }
+    return DEFAULT_GIT_COMMAND;
+  }
+
+  private String locateGitOnWindows() throws IOException {
+    // Windows will search current directory in addition to the PATH variable, which is unsecure.
+    // To avoid it we use where.exe to find git binary only in PATH.
+    LOG.debug("Looking for git command in the PATH using where.exe (Windows)");
+    List<String> whereCommandResult = new LinkedList<>();
+    this.processWrapperFactory.create(null, whereCommandResult::add, "C:\\Windows\\System32\\where.exe", "$PATH:git.exe")
+      .execute();
+
+    if (!whereCommandResult.isEmpty()) {
+      String out = whereCommandResult.get(0).trim();
+      LOG.debug("Found git.exe at {}", out);
+      return out;
+    }
+    throw new IllegalStateException("git.exe not found in PATH. PATH value was: " + system.property("PATH"));
+  }
+
+  public List<BlameLine> blame(Path baseDir, String fileName) throws Exception {
+    BlameOutputProcessor outputProcessor = new BlameOutputProcessor();
+    try {
+      this.processWrapperFactory.create(
+          baseDir,
+          outputProcessor::process,
+          gitCommand,
+          GIT_DIR_FLAG, String.format(GIT_DIR_ARGUMENT, baseDir), GIT_DIR_FORCE_FLAG, baseDir.toString(),
+          BLAME_COMMAND,
+          BLAME_LINE_PORCELAIN_FLAG, IGNORE_WHITESPACES, END_OF_OPTIONS_FLAG, fileName)
+        .execute();
+    } catch (UncommittedLineException e) {
+      LOG.debug("Unable to blame file '{}' - it has uncommitted changes", fileName);
+      return emptyList();
+    }
+    return outputProcessor.getBlameLines();
+  }
+
+  private static class BlameOutputProcessor {
+    private final List<BlameLine> blameLines = new LinkedList<>();
+    private String sha1 = null;
+    private String committerTime = null;
+    private String authorMail = null;
+
+    public List<BlameLine> getBlameLines() {
+      return blameLines;
+    }
+
+    public void process(String line) {
+      if (sha1 == null) {
+        sha1 = line.split(" ")[0];
+      } else if (line.startsWith("\t")) {
+        saveEntry();
+      } else if (line.startsWith(COMMITTER_TIME)) {
+        committerTime = line.substring(COMMITTER_TIME.length());
+      } else if (line.startsWith(AUTHOR_MAIL)) {
+        Matcher matcher = EMAIL_PATTERN.matcher(line);
+        if (matcher.find(AUTHOR_MAIL.length())) {
+          authorMail = matcher.group(1);
+        }
+        if (authorMail.equals("not.committed.yet")) {
+          throw new UncommittedLineException();
+        }
+      }
+    }
+
+    private void saveEntry() {
+      checkState(authorMail != null, "Did not find an author email for an entry");
+      checkState(committerTime != null, "Did not find a committer time for an entry");
+      checkState(sha1 != null, "Did not find a commit sha1 for an entry");
+      try {
+        blameLines.add(new BlameLine()
+          .revision(sha1)
+          .author(authorMail)
+          .date(Date.from(Instant.ofEpochSecond(Long.parseLong(committerTime)))));
+      } catch (NumberFormatException e) {
+        throw new IllegalStateException("Invalid committer time found: " + committerTime);
+      }
+      authorMail = null;
+      sha1 = null;
+      committerTime = null;
+    }
+  }
+
+  private static boolean isCompatibleGitVersion(String gitVersionCommandOutput) {
+    // Due to the danger of argument injection on git blame the use of `--end-of-options` flag is necessary
+    // The flag is available only on git versions >= 2.24.0
+    String gitVersion = whitespaceRegex
+      .splitAsStream(gitVersionCommandOutput)
+      .skip(2)
+      .findFirst()
+      .orElse("");
+
+    String formattedGitVersion = formatGitSemanticVersion(gitVersion);
+    return Version.parse(formattedGitVersion).isGreaterThanOrEqual(Version.parse(MINIMUM_REQUIRED_GIT_VERSION));
+  }
+
+  private static String formatGitSemanticVersion(String version) {
+    return semanticVersionDelimiter
+      .splitAsStream(version)
+      .takeWhile(NumberUtils::isNumber)
+      .collect(Collectors.joining("."));
+  }
+
+  private static class MutableString {
+    String string;
+  }
+
+  private static class UncommittedLineException extends RuntimeException {
+
+  }
+}