Add 'gerrit set-topic' SSH command

Currently the only way to set the topic is through the REST API,
however this is a bit annoying if you don't want to use the REST API.
It's desirable to also have an SSH command that covers this use case.

Change-Id: I6686e64a788365bd252df69ae5b3ec9d65aaf068

Documentation/cmd-index.txt

@@ -94,6 +94,9 @@ link:cmd-set-project-parent.html[gerrit set-project-parent]::
 link:cmd-set-reviewers.html[gerrit set-reviewers]::
 	Add or remove reviewers on a change.
 
+link:cmd-set-topic.html[gerrit set-topic]::
+	Set the topic for a change.
+
 link:cmd-stream-events.html[gerrit stream-events]::
 	Monitor events occurring in real time.
 

Documentation/cmd-set-topic.txt

@@ -0,0 +1,43 @@
+= gerrit set-topic
+
+== NAME
+gerrit set-topic - Set the topic for one or more changes.
+
+== SYNOPSIS
+[verse]
+--
+_ssh_ -p <port> <host> _gerrit set-topic_
+  <CHANGE>
+  [ --topic <TOPIC> | -t <TOPIC> ]
+--
+
+== DESCRIPTION
+Sets the topic for the specified changes.
+
+== ACCESS
+Caller must have the rights to modify the topic of the specified changes.
+
+== SCRIPTING
+This command is intended to be used in scripts.
+
+== OPTIONS
+<CHANGE>::
+	Required; change id.
+
+--topic::
+-topic::
+	Valid topic name to apply to the specified changes.
+
+== EXAMPLES
+Set the topic of the change "I6686e64a788365bd252df69ae5b3ec9d65aaf068" in "MyProject" on branch "master" to "MyTopic".
+
+----
+$ ssh -p 29418 user@review.example.com gerrit set-topic MyProject~master~I6686e64a788365bd252df69ae5b3ec9d65aaf068 --topic MyTopic
+----
+
+GERRIT
+------
+Part of link:index.html[Gerrit Code Review]
+
+SEARCHBOX
+---------

java/com/google/gerrit/sshd/commands/DefaultCommandModule.java

@@ -109,6 +109,7 @@ public class DefaultCommandModule extends CommandModule {
     command(gerrit, ReviewCommand.class);
     command(gerrit, SetProjectCommand.class);
     command(gerrit, SetReviewersCommand.class);
+    command(gerrit, SetTopicCommand.class);
 
     command(gerrit, SetMembersCommand.class);
     command(gerrit, CreateBranchCommand.class);

java/com/google/gerrit/sshd/commands/SetTopicCommand.java

@@ -0,0 +1,104 @@
+// Copyright (C) 2020 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.entities.Change;
+import com.google.gerrit.exceptions.StorageException;
+import com.google.gerrit.extensions.api.changes.TopicInput;
+import com.google.gerrit.extensions.restapi.BadRequestException;
+import com.google.gerrit.server.ChangeMessagesUtil;
+import com.google.gerrit.server.ChangeUtil;
+import com.google.gerrit.server.change.ChangeResource;
+import com.google.gerrit.server.extensions.events.TopicEdited;
+import com.google.gerrit.server.permissions.PermissionBackendException;
+import com.google.gerrit.server.restapi.change.SetTopicOp;
+import com.google.gerrit.server.update.BatchUpdate;
+import com.google.gerrit.server.util.time.TimeUtil;
+import com.google.gerrit.sshd.ChangeArgumentParser;
+import com.google.gerrit.sshd.CommandMetaData;
+import com.google.gerrit.sshd.SshCommand;
+import com.google.inject.Inject;
+import java.util.LinkedHashMap;
+import java.util.Map;
+import org.kohsuke.args4j.Argument;
+import org.kohsuke.args4j.Option;
+
+@CommandMetaData(name = "set-topic", description = "Set the topic for one or more changes")
+public class SetTopicCommand extends SshCommand {
+  private final BatchUpdate.Factory updateFactory;
+  private final ChangeMessagesUtil cmUtil;
+  private final TopicEdited topicEdited;
+  private final ChangeArgumentParser changeArgumentParser;
+  private final SetTopicOp.Factory topicOpFactory;
+
+  private Map<Change.Id, ChangeResource> changes = new LinkedHashMap<>();
+
+  @Argument(
+      index = 0,
+      required = true,
+      multiValued = true,
+      metaVar = "CHANGE",
+      usage = "changes to index")
+  void addChange(String token) {
+    try {
+      changeArgumentParser.addChange(token, changes, null, true);
+    } catch (UnloggedFailure | StorageException | PermissionBackendException e) {
+      writeError("warning", e.getMessage());
+    }
+  }
+
+  @Option(
+      name = "--topic",
+      aliases = "-t",
+      usage = "applies a topic to the given changes",
+      metaVar = "TOPIC")
+  private String topic;
+
+  @Inject
+  SetTopicCommand(
+      BatchUpdate.Factory updateFactory,
+      ChangeMessagesUtil cmUtil,
+      TopicEdited topicEdited,
+      ChangeArgumentParser changeArgumentParser,
+      SetTopicOp.Factory topicOpFactory) {
+    this.updateFactory = updateFactory;
+    this.cmUtil = cmUtil;
+    this.topicEdited = topicEdited;
+    this.changeArgumentParser = changeArgumentParser;
+    this.topicOpFactory = topicOpFactory;
+  }
+
+  @Override
+  public void run() throws Exception {
+    TopicInput input = new TopicInput();
+    if (topic != null) {
+      input.topic = topic.trim();
+    }
+
+    if (input.topic != null && input.topic.length() > ChangeUtil.TOPIC_MAX_LENGTH) {
+      throw new BadRequestException(
+          String.format("topic length exceeds the limit (%s)", ChangeUtil.TOPIC_MAX_LENGTH));
+    }
+
+    for (ChangeResource r : changes.values()) {
+      SetTopicOp op = topicOpFactory.create(input);
+      try (BatchUpdate u =
+          updateFactory.create(r.getChange().getProject(), user, TimeUtil.nowTs())) {
+        u.addOp(r.getId(), op);
+        u.execute();
+      }
+    }
+  }
+}

javatests/com/google/gerrit/acceptance/ssh/SshCommandsIT.java

@@ -74,6 +74,7 @@ public class SshCommandsIT extends AbstractDaemonTest {
           "set-project",
           "set-project-parent",
           "set-reviewers",
+          "set-topic",
           "stream-events",
           "test-submit");