create-project: Bring back --permissions-only flag

If a project is permissions only, assign HEAD to point to
refs/meta/config. This way gitweb view of the project shows the
permissions history by default, and clients that clone the project
are able to get a detached HEAD pointing to the current permission
state, rather than an empty repository.

Change-Id: I194bfef1af9d00268de9c503ea986879f1fbaff9

Documentation/cmd-create-project.txt

@@ -13,6 +13,7 @@ SYNOPSIS
  [--branch <REF>] \
  [\--owner <GROUP> ...] \
  [\--parent <NAME>] \
+ [\--permissions-only] \
  [\--description <DESC>] \
  [\--submit-type <TYPE>] \
  [\--use-content-merge] \
@@ -70,6 +71,11 @@ repository.*.createGroup will be used. If they don't exist,
 	through. If not specified, the parent is set to the default
 	project `\-- All Projects \--`.
 
+\--permissions-only::
+	Create the project only to serve as a parent for other
+	projects.  The new project's Git repository will be
+	initialized to have 'HEAD' point to 'refs/meta/config'.
+
 \--description::
 	Initial description of the project.  If not specified,
 	no description is stored.

gerrit-server/src/main/java/com/google/gerrit/server/schema/SchemaVersion.java

@@ -32,7 +32,7 @@ import java.util.List;
 /** A version of the database schema. */
 public abstract class SchemaVersion {
   /** The current schema version. */
-  private static final Class<? extends SchemaVersion> C = Schema_55.class;
+  private static final Class<? extends SchemaVersion> C = Schema_56.class;
 
   public static class Module extends AbstractModule {
     @Override

gerrit-server/src/main/java/com/google/gerrit/server/schema/Schema_56.java

@@ -0,0 +1,80 @@
+// Copyright (C) 2011 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.schema;
+
+import com.google.gerrit.reviewdb.Project;
+import com.google.gerrit.reviewdb.ReviewDb;
+import com.google.gerrit.server.git.GitRepositoryManager;
+import com.google.gerrit.server.git.LocalDiskRepositoryManager;
+import com.google.inject.Inject;
+import com.google.inject.Provider;
+
+import org.eclipse.jgit.errors.RepositoryNotFoundException;
+import org.eclipse.jgit.lib.Constants;
+import org.eclipse.jgit.lib.Ref;
+import org.eclipse.jgit.lib.RefUpdate;
+import org.eclipse.jgit.lib.Repository;
+
+import java.io.IOException;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+
+public class Schema_56 extends SchemaVersion {
+  private final LocalDiskRepositoryManager mgr;
+  private final Set<String> keysOne;
+  private final Set<String> keysTwo;
+
+  @Inject
+  Schema_56(Provider<Schema_55> prior, LocalDiskRepositoryManager mgr) {
+    super(prior);
+    this.mgr = mgr;
+
+    keysOne = new HashSet<String>();
+    keysTwo = new HashSet<String>();
+
+    keysOne.add(GitRepositoryManager.REF_CONFIG);
+    keysTwo.add(GitRepositoryManager.REF_CONFIG);
+    keysTwo.add(Constants.HEAD);
+  }
+
+  @Override
+  protected void migrateData(ReviewDb db, UpdateUI ui) {
+    for (Project.NameKey name : mgr.list()) {
+      Repository git;
+      try {
+        git = mgr.openRepository(name);
+      } catch (RepositoryNotFoundException e) {
+        ui.message("warning: Cannot open " + name.get());
+        continue;
+      }
+      try {
+        Map<String, Ref> all = git.getAllRefs();
+        if (all.keySet().equals(keysOne) || all.keySet().equals(keysTwo)) {
+          try {
+            RefUpdate update = git.updateRef(Constants.HEAD);
+            update.disableRefLog();
+            update.link(GitRepositoryManager.REF_CONFIG);
+          } catch (IOException err) {
+            ui.message("warning: " + name.get() + ": Cannot update HEAD to "
+                + GitRepositoryManager.REF_CONFIG + ": " + err.getMessage());
+          }
+        }
+      } finally {
+        git.close();
+      }
+    }
+  }
+}

gerrit-sshd/src/main/java/com/google/gerrit/sshd/commands/CreateProject.java

@@ -70,6 +70,9 @@ final class CreateProject extends BaseCommand {
   @Option(name = "--parent", aliases = {"-p"}, metaVar = "NAME", usage = "parent project")
   private ProjectControl newParent;
 
+  @Option(name = "--permissions-only", usage = "create project for use only as parent")
+  private boolean permissionsOnly;
+
   @Option(name = "--description", aliases = {"-d"}, metaVar = "DESC", usage = "description of project")
   private String projectDescription = "";
 
@@ -141,20 +144,21 @@ final class CreateProject extends BaseCommand {
           validateParameters();
           nameKey = new Project.NameKey(projectName);
 
+          String head = permissionsOnly ? GitRepositoryManager.REF_CONFIG : branch;
           final Repository repo = repoManager.createRepository(nameKey);
           try {
             RefUpdate u = repo.updateRef(Constants.HEAD);
             u.disableRefLog();
-            u.link(branch);
+            u.link(head);
 
             createProject();
             repoManager.setProjectDescription(nameKey, projectDescription);
 
-            if (createEmptyCommit) {
+            if (!permissionsOnly && createEmptyCommit) {
               createEmptyCommit(repo, nameKey, branch);
             }
 
-            rq.replicateNewProject(nameKey, branch);
+            rq.replicateNewProject(nameKey, head);
           } finally {
             repo.close();
           }