Added "version" command for Gerrit sshd.

Change-Id: I04ebc93940e18d933fe3186d771cccb1672f054e

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

@@ -41,6 +41,7 @@ public class DefaultCommandModule extends CommandModule {
     command(gerrit, "show-connections").to(AdminShowConnections.class);
     command(gerrit, "show-queue").to(ShowQueue.class);
     command(gerrit, "stream-events").to(StreamEvents.class);
+    command(gerrit, "version").to(VersionCommand.class);
 
     command(git).toProvider(new DispatchCommandProvider(git));
     command(git, "receive-pack").to(Commands.key(gerrit, "receive-pack"));

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

@@ -0,0 +1,43 @@
+// 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.sshd.commands;
+
+import com.google.gerrit.common.Version;
+import com.google.gerrit.sshd.BaseCommand;
+
+import org.apache.sshd.server.Environment;
+
+import java.io.PrintWriter;
+
+final class VersionCommand extends BaseCommand {
+  @Override
+  public void start(final Environment env) {
+    startThread(new CommandRunnable() {
+      @Override
+      public void run() throws Failure {
+        parseCommandLine();
+
+        String v = Version.getVersion();
+        if (v == null) {
+          throw new Failure(1, "fatal: version unavailable");
+        }
+
+        final PrintWriter stdout = toPrintWriter(out);
+        stdout.println("gerrit version " + v);
+        stdout.flush();
+      }
+    });
+  }
+}