Added support for ref-update events

Whenever a ref is updated via either a direct push to a branch or a
Gerrit change submission, Gerrit will now send a new "ref-updated"
event to the event stream.  This can be used by external agents for
things like automatic submodule ref updating, replication, build bot
hooks, etc.

Change-Id: Ice9d65db8fd662d53df53ff6b61d811815c9f2f6

gerrit-server/src/main/java/com/google/gerrit/common/ChangeHookRunner.java

@@ -19,6 +19,7 @@ import com.google.gerrit.common.data.ApprovalTypes;
 import com.google.gerrit.reviewdb.Account;
 import com.google.gerrit.reviewdb.ApprovalCategory;
 import com.google.gerrit.reviewdb.ApprovalCategoryValue;
+import com.google.gerrit.reviewdb.Branch;
 import com.google.gerrit.reviewdb.Change;
 import com.google.gerrit.reviewdb.PatchSet;
 import com.google.gerrit.reviewdb.Project;
@@ -35,6 +36,7 @@ import com.google.gerrit.server.events.ChangeRestoreEvent;
 import com.google.gerrit.server.events.CommentAddedEvent;
 import com.google.gerrit.server.events.EventFactory;
 import com.google.gerrit.server.events.PatchSetCreatedEvent;
+import com.google.gerrit.server.events.RefUpdatedEvent;
 import com.google.gerrit.server.git.GitRepositoryManager;
 import com.google.gerrit.server.git.WorkQueue;
 import com.google.gerrit.server.project.ProjectCache;
@@ -45,6 +47,8 @@ import com.google.inject.Singleton;
 
 import org.eclipse.jgit.errors.RepositoryNotFoundException;
 import org.eclipse.jgit.lib.Config;
+import org.eclipse.jgit.lib.ObjectId;
+import org.eclipse.jgit.lib.RefUpdate;
 import org.eclipse.jgit.lib.Repository;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -96,6 +100,9 @@ public class ChangeHookRunner {
     /** Filename of the change abandoned hook. */
     private final File changeRestoredHook;
 
+    /** Filename of the ref updated hook. */
+    private final File refUpdatedHook;
+
     /** Repository Manager. */
     private final GitRepositoryManager repoManager;
 
@@ -141,6 +148,7 @@ public class ChangeHookRunner {
         changeMergedHook = sitePath.resolve(new File(hooksPath, getValue(config, "hooks", "changeMergedHook", "change-merged")).getPath());
         changeAbandonedHook = sitePath.resolve(new File(hooksPath, getValue(config, "hooks", "changeAbandonedHook", "change-abandoned")).getPath());
         changeRestoredHook = sitePath.resolve(new File(hooksPath, getValue(config, "hooks", "changeRestoredHook", "change-restored")).getPath());
+        refUpdatedHook = sitePath.resolve(new File(hooksPath, getValue(config, "hooks", "refUpdatedHook", "ref-updated")).getPath());
     }
 
     public void addChangeListener(ChangeListener listener, IdentifiedUser user) {
@@ -172,7 +180,16 @@ public class ChangeHookRunner {
      * @return Repository or null.
      */
     private Repository openRepository(final Change change) {
-        Project.NameKey name = change.getProject();
+        return openRepository(change.getProject());
+    }
+
+    /**
+     * Get the Repository for the given project name, or null on error.
+     *
+     * @param name Project to get repo for,
+     * @return Repository or null.
+     */
+    private Repository openRepository(final Project.NameKey name) {
         try {
             return repoManager.openRepository(name.get());
         } catch (RepositoryNotFoundException err) {
@@ -335,6 +352,44 @@ public class ChangeHookRunner {
         runHook(openRepository(change), changeRestoredHook, args);
     }
 
+    /**
+     * Fire the Ref Updated Hook
+     * @param project The project the ref update occured on
+     * @param refUpdate An actual RefUpdate object
+     * @param account The gerrit user who moved the ref
+     */
+    public void doRefUpdatedHook(final Branch.NameKey refName, final RefUpdate refUpdate, final Account account) {
+      doRefUpdatedHook(refName, refUpdate.getOldObjectId(), refUpdate.getNewObjectId(), account);
+    }
+
+    /**
+     * Fire the Ref Updated Hook
+     * @param refName The Branch.NameKey of the ref that was updated
+     * @param oldId The ref's old id
+     * @param newId The ref's new id
+     * @param account The gerrit user who moved the ref
+     */
+    public void doRefUpdatedHook(final Branch.NameKey refName, final ObjectId oldId, final ObjectId newId, final Account account) {
+      final RefUpdatedEvent event = new RefUpdatedEvent();
+
+      if (account != null) {
+        event.submitter = eventFactory.asAccountAttribute(account);
+      }
+      event.refUpdate = eventFactory.asRefUpdateAttribute(oldId, newId, refName);
+      fireEvent(refName, event);
+
+      final List<String> args = new ArrayList<String>();
+      addArg(args, "--oldrev", event.refUpdate.oldRev);
+      addArg(args, "--newrev", event.refUpdate.newRev);
+      addArg(args, "--refname", event.refUpdate.refName);
+      addArg(args, "--project", event.refUpdate.project);
+      if (account != null) {
+        addArg(args, "--submitter", getDisplayName(account));
+      }
+
+      runHook(openRepository(refName.getParentKey()), refUpdatedHook, args);
+    }
+
     private void fireEvent(final Change change, final ChangeEvent event) {
       for (ChangeListenerHolder holder : listeners.values()) {
           if (isVisibleTo(change, holder.user)) {
@@ -343,6 +398,14 @@ public class ChangeHookRunner {
       }
     }
 
+    private void fireEvent(Branch.NameKey branchName, final ChangeEvent event) {
+      for (ChangeListenerHolder holder : listeners.values()) {
+          if (isVisibleTo(branchName, holder.user)) {
+              holder.listener.onChangeEvent(event);
+          }
+      }
+    }
+
     private boolean isVisibleTo(Change change, IdentifiedUser user) {
         final ProjectState pe = projectCache.get(change.getProject());
         if (pe == null) {
@@ -352,6 +415,15 @@ public class ChangeHookRunner {
         return pc.controlFor(change).isVisible();
     }
 
+    private boolean isVisibleTo(Branch.NameKey branchName, IdentifiedUser user) {
+        final ProjectState pe = projectCache.get(branchName.getParentKey());
+        if (pe == null) {
+          return false;
+        }
+        final ProjectControl pc = pe.controlFor(user);
+        return pc.controlForRef(branchName).isVisible();
+    }
+
     /**
      * Create an ApprovalAttribute for the given approval suitable for serialization to JSON.
      * @param approval

gerrit-server/src/main/java/com/google/gerrit/server/events/EventFactory.java

@@ -17,6 +17,7 @@ package com.google.gerrit.server.events;
 import com.google.gerrit.common.data.ApprovalType;
 import com.google.gerrit.common.data.ApprovalTypes;
 import com.google.gerrit.reviewdb.Account;
+import com.google.gerrit.reviewdb.Branch;
 import com.google.gerrit.reviewdb.Change;
 import com.google.gerrit.reviewdb.PatchSet;
 import com.google.gerrit.reviewdb.PatchSetApproval;
@@ -28,6 +29,8 @@ import com.google.inject.Provider;
 import com.google.inject.Singleton;
 import com.google.inject.internal.Nullable;
 
+import org.eclipse.jgit.lib.ObjectId;
+
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Map;
@@ -67,6 +70,23 @@ public class EventFactory {
     return a;
   }
 
+  /**
+   * Create a RefUpdateAttribute for the given old ObjectId, new ObjectId, and
+   * branch that is suitable for serialization to JSON.
+   *
+   * @param refUpdate
+   * @param refName
+   * @return object suitable for serialization to JSON
+   */
+  public RefUpdateAttribute asRefUpdateAttribute(final ObjectId oldId, final ObjectId newId, final Branch.NameKey refName) {
+    RefUpdateAttribute ru = new RefUpdateAttribute();
+    ru.newRev = newId != null ? newId.getName() : ObjectId.zeroId().getName();
+    ru.oldRev = oldId != null ? oldId.getName() : ObjectId.zeroId().getName();
+    ru.project = refName.getParentKey().get();
+    ru.refName = refName.getShortName();
+    return ru;
+  }
+
   /**
    * Extend the existing ChangeAttribute with additional fields.
    *

gerrit-server/src/main/java/com/google/gerrit/server/events/RefUpdateAttribute.java

@@ -0,0 +1,22 @@
+// Copyright (C) 2010 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.events;
+
+public class RefUpdateAttribute {
+  public String oldRev;
+  public String newRev;
+  public String refName;
+  public String project;
+}

gerrit-server/src/main/java/com/google/gerrit/server/events/RefUpdatedEvent.java

@@ -0,0 +1,21 @@
+// Copyright (C) 2010 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.events;
+
+public class RefUpdatedEvent extends ChangeEvent {
+  public final String type = "ref-updated";
+  public AccountAttribute submitter;
+  public RefUpdateAttribute refUpdate;
+}

gerrit-server/src/main/java/com/google/gerrit/server/git/MergeOp.java

@@ -881,6 +881,13 @@ public class MergeOp {
           case FAST_FORWARD:
             replication.scheduleUpdate(destBranch.getParentKey(), branchUpdate
                 .getName());
+
+            Account account = null;
+            final PatchSetApproval submitter = getSubmitter(mergeTip.patchsetId);
+            if (submitter != null) {
+              account = accountCache.get(submitter.getAccountId()).getAccount();
+            }
+            hooks.doRefUpdatedHook(destBranch, branchUpdate, account);
             break;
 
           default:

gerrit-server/src/main/java/com/google/gerrit/server/git/ReceiveCommits.java

@@ -302,6 +302,8 @@ public class ReceiveCommits implements PreReceiveHook, PostReceiveHook {
           // Change refs are scheduled when they are created.
           //
           replication.scheduleUpdate(project.getNameKey(), c.getRefName());
+          Branch.NameKey destBranch = new Branch.NameKey(project.getNameKey(), c.getRefName());
+          hooks.doRefUpdatedHook(destBranch, c.getOldId(), c.getNewId(), currentUser.getAccount());
         }
       }
     }