Modify git HEAD on default branch change

scm-plugins/scm-git-plugin/src/main/java/sonia/scm/repository/GitHeadModifier.java

@@ -0,0 +1,101 @@
+/**
+ * Copyright (c) 2014, Sebastian Sdorra
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. Neither the name of SCM-Manager; nor the names of its
+ *    contributors may be used to endorse or promote products derived from this
+ *    software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * http://bitbucket.org/sdorra/scm-manager
+ *
+ */
+package sonia.scm.repository;
+
+import org.eclipse.jgit.lib.Constants;
+import org.eclipse.jgit.lib.Ref;
+import org.eclipse.jgit.lib.RefUpdate;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import javax.inject.Inject;
+import java.io.File;
+import java.io.IOException;
+import java.util.Objects;
+
+/**
+ * The GitHeadModifier is able to modify the head of a git repository.
+ *
+ * @author Sebastian Sdorra
+ * @since 1.61
+ */
+public class GitHeadModifier {
+
+  private static final Logger LOG = LoggerFactory.getLogger(GitHeadModifier.class);
+
+  private final GitRepositoryHandler repositoryHandler;
+
+  @Inject
+  public GitHeadModifier(GitRepositoryHandler repositoryHandler) {
+    this.repositoryHandler = repositoryHandler;
+  }
+
+  /**
+   * Ensures that the repositories head points to the given branch. The method will return {@code false} if the
+   * repositories head points already to the given branch.
+   *
+   * @param repository repository to modify
+   * @param newHead branch which should be the new head of the repository
+   *
+   * @return {@code true} if the head has changed
+   */
+  public boolean ensure(Repository repository, String newHead)  {
+    try (org.eclipse.jgit.lib.Repository gitRepository = open(repository)) {
+      String currentHead = resolve(gitRepository);
+      if (!Objects.equals(currentHead, newHead)) {
+        return modify(gitRepository, newHead);
+      }
+    } catch (IOException ex) {
+      LOG.warn("failed to change head of repository", ex);
+    }
+    return false;
+  }
+
+  private String resolve(org.eclipse.jgit.lib.Repository gitRepository) throws IOException {
+    Ref ref = gitRepository.getRefDatabase().getRef(Constants.HEAD);
+    if ( ref.isSymbolic() ) {
+      ref = ref.getTarget();
+    }
+    return GitUtil.getBranch(ref);
+  }
+
+  private boolean modify(org.eclipse.jgit.lib.Repository gitRepository, String newHead) throws IOException {
+    RefUpdate refUpdate = gitRepository.getRefDatabase().newUpdate(Constants.HEAD, true);
+    refUpdate.setForceUpdate(true);
+    RefUpdate.Result result = refUpdate.link(Constants.R_HEADS + newHead);
+    return result == RefUpdate.Result.FORCED;
+  }
+
+  private org.eclipse.jgit.lib.Repository open(Repository repository) throws IOException {
+    File directory = repositoryHandler.getDirectory(repository.getId());
+    return GitUtil.open(directory);
+  }
+}

scm-plugins/scm-git-plugin/src/main/java/sonia/scm/repository/GitRepositoryModifyListener.java

@@ -0,0 +1,75 @@
+/**
+ * Copyright (c) 2014, Sebastian Sdorra
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. Neither the name of SCM-Manager; nor the names of its
+ *    contributors may be used to endorse or promote products derived from this
+ *    software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * http://bitbucket.org/sdorra/scm-manager
+ *
+ */
+package sonia.scm.repository;
+
+import com.github.legman.Subscribe;
+import sonia.scm.EagerSingleton;
+import sonia.scm.api.v2.resources.GitRepositoryConfigChangedEvent;
+import sonia.scm.api.v2.resources.GitRepositoryConfigStoreProvider;
+import sonia.scm.plugin.Extension;
+
+import javax.inject.Inject;
+
+/**
+ * Repository listener which handles git related repository events.
+ *
+ * @author Sebastian Sdorra
+ * @since 1.50
+ */
+@Extension
+@EagerSingleton
+public class GitRepositoryModifyListener {
+
+  private final GitHeadModifier headModifier;
+  private final GitRepositoryConfigStoreProvider storeProvider;
+
+  @Inject
+  public GitRepositoryModifyListener(GitHeadModifier headModifier, GitRepositoryConfigStoreProvider storeProvider) {
+    this.headModifier = headModifier;
+    this.storeProvider = storeProvider;
+  }
+
+  /**
+   * Receives {@link RepositoryModificationEvent} and fires a {@link ClearRepositoryCacheEvent} if
+   * the default branch of a git repository was modified.
+   *
+   * @param event repository modification event
+   */
+  @Subscribe
+  public void handleEvent(GitRepositoryConfigChangedEvent event){
+    Repository repository = event.getRepository();
+
+    String defaultBranch = storeProvider.get(repository).get().getDefaultBranch();
+    if (defaultBranch != null) {
+      headModifier.ensure(repository, defaultBranch);
+    }
+  }
+}