Add SSH command "gerrit ls-projects" to show all visible projects

This command evaluates through all known projects and outputs their
name, one per line, if the current user account has Read access to
that project.  Its mostly useful for scripting applications such as
mirroring what you can see:

  for p in $(ssh -p 29418 host gerrit ls-projects)
  do
    git clone git://mirror/$p.git
  done

Signed-off-by: Shawn O. Pearce <sop@google.com>

appjar/src/main/java/com/google/gerrit/server/ssh/GerritCommandFactory.java

@@ -40,6 +40,11 @@ class GerritCommandFactory implements CommandFactory {
         return new AdminFlushCaches();
       }
     });
+    commands.put("gerrit-ls-projects", new Factory() {
+      public AbstractCommand create() {
+        return new ListProjects();
+      }
+    });
 
     alias("gerrit-upload-pack", "git-upload-pack");
     alias("gerrit-receive-pack", "git-receive-pack");

appjar/src/main/java/com/google/gerrit/server/ssh/ListProjects.java

@@ -0,0 +1,62 @@
+// Copyright 2009 Google Inc.
+//
+// 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.ssh;
+
+import com.google.gerrit.client.data.ProjectCache;
+import com.google.gerrit.client.reviewdb.Project;
+import com.google.gerrit.client.reviewdb.ProjectRight;
+import com.google.gerrit.client.reviewdb.ReviewDb;
+import com.google.gerrit.client.rpc.Common;
+import com.google.gwtorm.client.OrmException;
+
+import java.io.BufferedWriter;
+import java.io.IOException;
+import java.io.OutputStreamWriter;
+import java.io.PrintWriter;
+
+class ListProjects extends AbstractCommand {
+  @Override
+  protected void run(final String[] args) throws IOException, Failure {
+    if (args.length != 0) {
+      throw new Failure(1, "usage: " + getName());
+    }
+
+    final PrintWriter stdout =
+        new PrintWriter(
+            new BufferedWriter(new OutputStreamWriter(out, "UTF-8")));
+    final ReviewDb db = openReviewDb();
+    try {
+      final ProjectCache cache = Common.getProjectCache();
+      for (final Project p : db.projects().all()) {
+        if (ProjectRight.WILD_PROJECT.equals(p.getId())) {
+          // This project "doesn't exist". At least not as a repository.
+          //
+          continue;
+        }
+
+        final ProjectCache.Entry e = cache.get(p.getId());
+        if (e != null && canRead(e)) {
+          stdout.print(p.getName());
+          stdout.println();
+        }
+      }
+    } catch (OrmException e) {
+      throw new Failure(1, "fatal: database error", e);
+    } finally {
+      db.close();
+    }
+    stdout.flush();
+  }
+}