1 files changed, 218 insertions, 0 deletions
diff --git a/java/com/google/gerrit/server/submit/MergeOpRepoManager.java b/java/com/google/gerrit/server/submit/MergeOpRepoManager.java
new file mode 100644
index 0000000000..3f07ed7500
--- /dev/null
+++ b/java/com/google/gerrit/server/submit/MergeOpRepoManager.java
@@ -0,0 +1,218 @@
+// Copyright (C) 2016 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.submit;
+
+import static com.google.common.base.Preconditions.checkState;
+
+import com.google.common.collect.Maps;
+import com.google.gerrit.reviewdb.client.Branch;
+import com.google.gerrit.reviewdb.client.Project;
+import com.google.gerrit.reviewdb.client.RefNames;
+import com.google.gerrit.reviewdb.server.ReviewDb;
+import com.google.gerrit.server.IdentifiedUser;
+import com.google.gerrit.server.git.CodeReviewCommit;
+import com.google.gerrit.server.git.CodeReviewCommit.CodeReviewRevWalk;
+import com.google.gerrit.server.git.GitRepositoryManager;
+import com.google.gerrit.server.git.MergeTip;
+import com.google.gerrit.server.git.validators.OnSubmitValidators;
+import com.google.gerrit.server.project.NoSuchProjectException;
+import com.google.gerrit.server.project.ProjectCache;
+import com.google.gerrit.server.project.ProjectState;
+import com.google.gerrit.server.update.BatchUpdate;
+import com.google.inject.Inject;
+import java.io.IOException;
+import java.sql.Timestamp;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+import org.eclipse.jgit.errors.RepositoryNotFoundException;
+import org.eclipse.jgit.lib.ObjectId;
+import org.eclipse.jgit.lib.ObjectInserter;
+import org.eclipse.jgit.lib.ObjectReader;
+import org.eclipse.jgit.lib.RefUpdate;
+import org.eclipse.jgit.lib.Repository;
+import org.eclipse.jgit.revwalk.RevFlag;
+import org.eclipse.jgit.revwalk.RevSort;
+
+/**
+ * This is a helper class for MergeOp and not intended for general use.
+ *
+ * <p>Some database backends require to open a repository just once within a transaction of a
+ * submission, this caches open repositories to satisfy that requirement.
+ */
+public class MergeOpRepoManager implements AutoCloseable {
+  public class OpenRepo {
+    final Repository repo;
+    final CodeReviewRevWalk rw;
+    final RevFlag canMergeFlag;
+    final ObjectInserter ins;
+
+    final ProjectState project;
+    BatchUpdate update;
+
+    private final ObjectReader reader;
+    private final Map<Branch.NameKey, OpenBranch> branches;
+
+    private OpenRepo(Repository repo, ProjectState project) {
+      this.repo = repo;
+      this.project = project;
+      ins = repo.newObjectInserter();
+      reader = ins.newReader();
+      rw = CodeReviewCommit.newRevWalk(reader);
+      rw.sort(RevSort.TOPO);
+      rw.sort(RevSort.COMMIT_TIME_DESC, true);
+      rw.setRetainBody(false);
+      canMergeFlag = rw.newFlag("CAN_MERGE");
+      rw.retainOnReset(canMergeFlag);
+
+      branches = Maps.newHashMapWithExpectedSize(1);
+    }
+
+    OpenBranch getBranch(Branch.NameKey branch) throws IntegrationException {
+      OpenBranch ob = branches.get(branch);
+      if (ob == null) {
+        ob = new OpenBranch(this, branch);
+        branches.put(branch, ob);
+      }
+      return ob;
+    }
+
+    public Repository getRepo() {
+      return repo;
+    }
+
+    Project.NameKey getProjectName() {
+      return project.getNameKey();
+    }
+
+    public CodeReviewRevWalk getCodeReviewRevWalk() {
+      return rw;
+    }
+
+    public BatchUpdate getUpdate() {
+      checkState(db != null, "call setContext before getUpdate");
+      if (update == null) {
+        update =
+            batchUpdateFactory
+                .create(db, getProjectName(), caller, ts)
+                .setRepository(repo, rw, ins)
+                .setOnSubmitValidators(onSubmitValidatorsFactory.create());
+      }
+      return update;
+    }
+
+    private void close() {
+      if (update != null) {
+        update.close();
+      }
+      rw.close();
+      reader.close();
+      ins.close();
+      repo.close();
+    }
+  }
+
+  public static class OpenBranch {
+    final RefUpdate update;
+    final CodeReviewCommit oldTip;
+    MergeTip mergeTip;
+
+    OpenBranch(OpenRepo or, Branch.NameKey name) throws IntegrationException {
+      try {
+        update = or.repo.updateRef(name.get());
+        if (update.getOldObjectId() != null) {
+          oldTip = or.rw.parseCommit(update.getOldObjectId());
+        } else if (Objects.equals(or.repo.getFullBranch(), name.get())
+            || Objects.equals(RefNames.REFS_CONFIG, name.get())) {
+          oldTip = null;
+          update.setExpectedOldObjectId(ObjectId.zeroId());
+        } else {
+          throw new IntegrationException(
+              "The destination branch " + name + " does not exist anymore.");
+        }
+      } catch (IOException e) {
+        throw new IntegrationException("Cannot open branch " + name, e);
+      }
+    }
+  }
+
+  private final Map<Project.NameKey, OpenRepo> openRepos;
+  private final BatchUpdate.Factory batchUpdateFactory;
+  private final OnSubmitValidators.Factory onSubmitValidatorsFactory;
+  private final GitRepositoryManager repoManager;
+  private final ProjectCache projectCache;
+
+  private ReviewDb db;
+  private Timestamp ts;
+  private IdentifiedUser caller;
+
+  @Inject
+  MergeOpRepoManager(
+      GitRepositoryManager repoManager,
+      ProjectCache projectCache,
+      BatchUpdate.Factory batchUpdateFactory,
+      OnSubmitValidators.Factory onSubmitValidatorsFactory) {
+    this.repoManager = repoManager;
+    this.projectCache = projectCache;
+    this.batchUpdateFactory = batchUpdateFactory;
+    this.onSubmitValidatorsFactory = onSubmitValidatorsFactory;
+
+    openRepos = new HashMap<>();
+  }
+
+  public void setContext(ReviewDb db, Timestamp ts, IdentifiedUser caller) {
+    this.db = db;
+    this.ts = ts;
+    this.caller = caller;
+  }
+
+  public OpenRepo getRepo(Project.NameKey project) throws NoSuchProjectException, IOException {
+    if (openRepos.containsKey(project)) {
+      return openRepos.get(project);
+    }
+
+    ProjectState projectState = projectCache.get(project);
+    if (projectState == null) {
+      throw new NoSuchProjectException(project);
+    }
+    try {
+      OpenRepo or = new OpenRepo(repoManager.openRepository(project), projectState);
+      openRepos.put(project, or);
+      return or;
+    } catch (RepositoryNotFoundException e) {
+      throw new NoSuchProjectException(project, e);
+    }
+  }
+
+  public List<BatchUpdate> batchUpdates(Collection<Project.NameKey> projects)
+      throws NoSuchProjectException, IOException {
+    List<BatchUpdate> updates = new ArrayList<>(projects.size());
+    for (Project.NameKey project : projects) {
+      updates.add(getRepo(project).getUpdate().setRefLogMessage("merged"));
+    }
+    return updates;
+  }
+
+  @Override
+  public void close() {
+    for (OpenRepo repo : openRepos.values()) {
+      repo.close();
+    }
+    openRepos.clear();
+  }
+}