Implement 'Restore Change' feature.

Now it is possible to restore status of abandoned changes to 'NEW'.
It helps in a situation when a change has been abandoned accidently.

Bug: issue 312
Change-Id: Iba61dcf82a9b5ee5b78cd529b041f92a042a9611
[cherry-picked from 32002457744e9e0c17b258fcfea5dd6d30732950]
Change-Id: Icc6dddb63689250c869189639af0d72ed8837336

15 files changed, 399 insertions, 1 deletions

diff --git a/Documentation/cmd-stream-events.txt b/Documentation/cmd-stream-events.txt
index 0b536fc476..aae908a2f7 100644
--- a/Documentation/cmd-stream-events.txt
+++ b/Documentation/cmd-stream-events.txt
@@ -70,6 +70,16 @@ patchset:: link:json.html#patchset[patchset attribute]
 
 abandoner:: link:json.html#account[account attribute]
 
+Change Restored
+^^^^^^^^^^^^^^^^
+type:: "change-restored"
+
+change:: link:json.html#change[change attribute]
+
+patchset:: link:json.html#patchset[patchset attribute]
+
+restorer:: link:json.html#account[account attribute]
+
 Change Merged
 ^^^^^^^^^^^^^
 type:: "change-merged"
diff --git a/Documentation/config-hooks.txt b/Documentation/config-hooks.txt
index 4dd7531c51..95fc7bf0bb 100644
--- a/Documentation/config-hooks.txt
+++ b/Documentation/config-hooks.txt
@@ -57,6 +57,15 @@ Called whenever a change has been abandoned.
   change-abandoned --change <change id> --change-url <change url> --project <project name> --branch <branch> --abandoner <abandoner> --reason <reason>
 ====
 
+change-restored
+~~~~~~~~~~~~~~~~
+
+Called whenever a change has been restored.
+
+====
+  change-restored --change <change id> --change-url <change url> --project <project name> --branch <branch> --restorer <restorer> --reason <reason>
+====
+
 
 Configuration Settings
 ----------------------
diff --git a/gerrit-common/src/main/java/com/google/gerrit/common/data/ChangeDetail.java b/gerrit-common/src/main/java/com/google/gerrit/common/data/ChangeDetail.java
index 80c1c31f28..cd992fdfe8 100644
--- a/gerrit-common/src/main/java/com/google/gerrit/common/data/ChangeDetail.java
+++ b/gerrit-common/src/main/java/com/google/gerrit/common/data/ChangeDetail.java
@@ -30,6 +30,7 @@ public class ChangeDetail {
   protected AccountInfoCache accounts;
   protected boolean allowsAnonymous;
   protected boolean canAbandon;
+  protected boolean canRestore;
   protected Change change;
   protected boolean starred;
   protected List<ChangeInfo> dependsOn;
@@ -69,6 +70,14 @@ public class ChangeDetail {
     canAbandon = a;
   }
 
+  public boolean canRestore() {
+    return canRestore;
+  }
+
+  public void setCanRestore(final boolean a) {
+    canRestore = a;
+  }
+
   public Change getChange() {
     return change;
   }
diff --git a/gerrit-common/src/main/java/com/google/gerrit/common/data/ChangeManageService.java b/gerrit-common/src/main/java/com/google/gerrit/common/data/ChangeManageService.java
index 53946f2230..b61c35c1e4 100644
--- a/gerrit-common/src/main/java/com/google/gerrit/common/data/ChangeManageService.java
+++ b/gerrit-common/src/main/java/com/google/gerrit/common/data/ChangeManageService.java
@@ -29,4 +29,8 @@ public interface ChangeManageService extends RemoteJsonService {
   @SignInRequired
   void abandonChange(PatchSet.Id patchSetId, String message,
       AsyncCallback<ChangeDetail> callback);
+
+  @SignInRequired
+  void restoreChange(PatchSet.Id patchSetId, String message,
+      AsyncCallback<ChangeDetail> callback);
 }
diff --git a/gerrit-gwtui/src/main/java/com/google/gerrit/client/changes/ChangeConstants.java b/gerrit-gwtui/src/main/java/com/google/gerrit/client/changes/ChangeConstants.java
index c5901d6a15..e339d26af2 100644
--- a/gerrit-gwtui/src/main/java/com/google/gerrit/client/changes/ChangeConstants.java
+++ b/gerrit-gwtui/src/main/java/com/google/gerrit/client/changes/ChangeConstants.java
@@ -112,6 +112,12 @@ public interface ChangeConstants extends Constants {
   String headingCoverMessage();
   String headingPatchComments();
 
+  String buttonRestoreChangeBegin();
+  String restoreChangeTitle();
+  String buttonRestoreChangeCancel();
+  String headingRestoreMessage();
+  String buttonRestoreChangeSend();
+
   String pagedChangeListPrev();
   String pagedChangeListNext();
 
diff --git a/gerrit-gwtui/src/main/java/com/google/gerrit/client/changes/ChangeConstants.properties b/gerrit-gwtui/src/main/java/com/google/gerrit/client/changes/ChangeConstants.properties
index 75f3ae28b1..ed6be476bb 100644
--- a/gerrit-gwtui/src/main/java/com/google/gerrit/client/changes/ChangeConstants.properties
+++ b/gerrit-gwtui/src/main/java/com/google/gerrit/client/changes/ChangeConstants.properties
@@ -82,6 +82,12 @@ buttonAbandonChangeCancel = Cancel
 headingAbandonMessage = Abandon Message:
 abandonChangeTitle = Code Review - Abandon Change
 
+buttonRestoreChangeBegin = Restore Change
+restoreChangeTitle = Code Review - Restore Change
+buttonRestoreChangeCancel = Cancel
+headingRestoreMessage = Restore Message:
+buttonRestoreChangeSend = Restore Change
+
 buttonReview = Review
 buttonPublishCommentsSend = Publish Comments
 buttonPublishSubmitSend = Publish and Submit
diff --git a/gerrit-gwtui/src/main/java/com/google/gerrit/client/changes/PatchSetComplexDisclosurePanel.java b/gerrit-gwtui/src/main/java/com/google/gerrit/client/changes/PatchSetComplexDisclosurePanel.java
index e004f00d3c..6a57feb165 100644
--- a/gerrit-gwtui/src/main/java/com/google/gerrit/client/changes/PatchSetComplexDisclosurePanel.java
+++ b/gerrit-gwtui/src/main/java/com/google/gerrit/client/changes/PatchSetComplexDisclosurePanel.java
@@ -416,6 +416,26 @@ class PatchSetComplexDisclosurePanel extends ComplexDisclosurePanel implements O
       });
       actionsPanel.add(b);
     }
+
+    if (changeDetail.canRestore()) {
+      final Button b = new Button(Util.C.buttonRestoreChangeBegin());
+      b.addClickHandler(new ClickHandler() {
+        @Override
+        public void onClick(final ClickEvent event) {
+          new RestoreChangeDialog(patchSet.getId(),
+              new AsyncCallback<ChangeDetail>() {
+                public void onSuccess(ChangeDetail result) {
+                  changeScreen.display(result);
+                }
+
+                public void onFailure(Throwable caught) {
+                  b.setEnabled(true);
+                }
+              }).center();
+        }
+      });
+      actionsPanel.add(b);
+    }
   }
 
   private void populateDiffAllActions(final PatchSetDetail detail) {
diff --git a/gerrit-gwtui/src/main/java/com/google/gerrit/client/changes/RestoreChangeDialog.java b/gerrit-gwtui/src/main/java/com/google/gerrit/client/changes/RestoreChangeDialog.java
new file mode 100644
index 0000000000..e05c42afc6
--- /dev/null
+++ b/gerrit-gwtui/src/main/java/com/google/gerrit/client/changes/RestoreChangeDialog.java
@@ -0,0 +1,133 @@
+// Copyright (C) 2009 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.client.changes;
+
+import com.google.gerrit.client.Gerrit;
+import com.google.gerrit.client.rpc.GerritCallback;
+import com.google.gerrit.client.ui.SmallHeading;
+import com.google.gerrit.common.data.ChangeDetail;
+import com.google.gerrit.reviewdb.PatchSet;
+import com.google.gwt.event.dom.client.ClickEvent;
+import com.google.gwt.event.dom.client.ClickHandler;
+import com.google.gwt.event.logical.shared.CloseEvent;
+import com.google.gwt.event.logical.shared.CloseHandler;
+import com.google.gwt.user.client.DOM;
+import com.google.gwt.user.client.rpc.AsyncCallback;
+import com.google.gwt.user.client.ui.Button;
+import com.google.gwt.user.client.ui.FlowPanel;
+import com.google.gwt.user.client.ui.PopupPanel;
+import com.google.gwtexpui.globalkey.client.GlobalKey;
+import com.google.gwtexpui.globalkey.client.NpTextArea;
+import com.google.gwtexpui.user.client.AutoCenterDialogBox;
+
+public class RestoreChangeDialog extends AutoCenterDialogBox implements CloseHandler<PopupPanel>{
+  private final FlowPanel panel;
+  private final NpTextArea message;
+  private final Button sendButton;
+  private final Button cancelButton;
+  private final PatchSet.Id psid;
+  private final AsyncCallback<ChangeDetail> callback;
+
+  private boolean buttonClicked = false;
+
+  public RestoreChangeDialog(final PatchSet.Id psi,
+      final AsyncCallback<ChangeDetail> callback) {
+    super(/* auto hide */false, /* modal */true);
+    setGlassEnabled(true);
+
+    psid = psi;
+    this.callback = callback;
+    addStyleName(Gerrit.RESOURCES.css().abandonChangeDialog());
+    setText(Util.C.restoreChangeTitle());
+
+    panel = new FlowPanel();
+    add(panel);
+
+    panel.add(new SmallHeading(Util.C.headingRestoreMessage()));
+
+    final FlowPanel mwrap = new FlowPanel();
+    mwrap.setStyleName(Gerrit.RESOURCES.css().abandonMessage());
+    panel.add(mwrap);
+
+    message = new NpTextArea();
+    message.setCharacterWidth(60);
+    message.setVisibleLines(10);
+    DOM.setElementPropertyBoolean(message.getElement(), "spellcheck", true);
+    mwrap.add(message);
+
+    final FlowPanel buttonPanel = new FlowPanel();
+    panel.add(buttonPanel);
+
+    sendButton = new Button(Util.C.buttonRestoreChangeSend());
+    sendButton.addClickHandler(new ClickHandler() {
+      @Override
+      public void onClick(final ClickEvent event) {
+        sendButton.setEnabled(false);
+        Util.MANAGE_SVC.restoreChange(psid, message.getText().trim(),
+            new GerritCallback<ChangeDetail>() {
+              @Override
+              public void onSuccess(ChangeDetail result) {
+                buttonClicked = true;
+                if (callback != null) {
+                  callback.onSuccess(result);
+                }
+                hide();
+              }
+
+              @Override
+              public void onFailure(Throwable caught) {
+                sendButton.setEnabled(true);
+                super.onFailure(caught);
+              }
+            });
+      }
+    });
+    buttonPanel.add(sendButton);
+
+    cancelButton = new Button(Util.C.buttonRestoreChangeCancel());
+    DOM.setStyleAttribute(cancelButton.getElement(), "marginLeft", "300px");
+    cancelButton.addClickHandler(new ClickHandler() {
+      @Override
+      public void onClick(final ClickEvent event) {
+        buttonClicked = true;
+        if (callback != null) {
+          callback.onFailure(null);
+        }
+        hide();
+      }
+    });
+    buttonPanel.add(cancelButton);
+
+    addCloseHandler(this);
+  }
+
+  @Override
+  public void center() {
+    super.center();
+    GlobalKey.dialog(this);
+    message.setFocus(true);
+  }
+
+  @Override
+  public void onClose(CloseEvent<PopupPanel> event) {
+    if (!buttonClicked) {
+      // the dialog was closed without one of the buttons being pressed
+      // e.g. the user pressed ESC to close the dialog
+      if (callback != null) {
+        callback.onFailure(null);
+      }
+    }
+  }
+}
diff --git a/gerrit-httpd/src/main/java/com/google/gerrit/httpd/rpc/changedetail/ChangeDetailFactory.java b/gerrit-httpd/src/main/java/com/google/gerrit/httpd/rpc/changedetail/ChangeDetailFactory.java
index bcea11d992..954f0a233b 100644
--- a/gerrit-httpd/src/main/java/com/google/gerrit/httpd/rpc/changedetail/ChangeDetailFactory.java
+++ b/gerrit-httpd/src/main/java/com/google/gerrit/httpd/rpc/changedetail/ChangeDetailFactory.java
@@ -101,6 +101,7 @@ public class ChangeDetailFactory extends Handler<ChangeDetail> {
     detail.setChange(change);
     detail.setAllowsAnonymous(control.forAnonymousUser().isVisible());
     detail.setCanAbandon(change.getStatus().isOpen() && control.canAbandon());
+    detail.setCanRestore(change.getStatus() == Change.Status.ABANDONED && control.canRestore());
     detail.setStarred(control.getCurrentUser().getStarredChanges().contains(
         changeId));
     loadPatchSets();
diff --git a/gerrit-httpd/src/main/java/com/google/gerrit/httpd/rpc/changedetail/ChangeManageServiceImpl.java b/gerrit-httpd/src/main/java/com/google/gerrit/httpd/rpc/changedetail/ChangeManageServiceImpl.java
index 196d400de6..0eccc2c3fd 100644
--- a/gerrit-httpd/src/main/java/com/google/gerrit/httpd/rpc/changedetail/ChangeManageServiceImpl.java
+++ b/gerrit-httpd/src/main/java/com/google/gerrit/httpd/rpc/changedetail/ChangeManageServiceImpl.java
@@ -23,12 +23,15 @@ import com.google.inject.Inject;
 class ChangeManageServiceImpl implements ChangeManageService {
   private final SubmitAction.Factory submitAction;
   private final AbandonChange.Factory abandonChangeFactory;
+  private final RestoreChange.Factory restoreChangeFactory;
 
   @Inject
   ChangeManageServiceImpl(final SubmitAction.Factory patchSetAction,
-      final AbandonChange.Factory abandonChangeFactory) {
+      final AbandonChange.Factory abandonChangeFactory,
+      final RestoreChange.Factory restoreChangeFactory) {
     this.submitAction = patchSetAction;
     this.abandonChangeFactory = abandonChangeFactory;
+    this.restoreChangeFactory = restoreChangeFactory;
   }
 
   public void submit(final PatchSet.Id patchSetId,
@@ -40,4 +43,9 @@ class ChangeManageServiceImpl implements ChangeManageService {
       final AsyncCallback<ChangeDetail> callback) {
     abandonChangeFactory.create(patchSetId, message).to(callback);
   }
+
+  public void restoreChange(final PatchSet.Id patchSetId, final String message,
+      final AsyncCallback<ChangeDetail> callback) {
+    restoreChangeFactory.create(patchSetId, message).to(callback);
+  }
 }
diff --git a/gerrit-httpd/src/main/java/com/google/gerrit/httpd/rpc/changedetail/ChangeModule.java b/gerrit-httpd/src/main/java/com/google/gerrit/httpd/rpc/changedetail/ChangeModule.java
index 8605de398c..85e2aef018 100644
--- a/gerrit-httpd/src/main/java/com/google/gerrit/httpd/rpc/changedetail/ChangeModule.java
+++ b/gerrit-httpd/src/main/java/com/google/gerrit/httpd/rpc/changedetail/ChangeModule.java
@@ -29,6 +29,7 @@ public class ChangeModule extends RpcServletModule {
       @Override
       protected void configure() {
         factory(AbandonChange.Factory.class);
+        factory(RestoreChange.Factory.class);
         factory(ChangeDetailFactory.Factory.class);
         factory(IncludedInDetailFactory.Factory.class);
         factory(PatchSetDetailFactory.Factory.class);
diff --git a/gerrit-httpd/src/main/java/com/google/gerrit/httpd/rpc/changedetail/RestoreChange.java b/gerrit-httpd/src/main/java/com/google/gerrit/httpd/rpc/changedetail/RestoreChange.java
new file mode 100644
index 0000000000..9639f1a2bb
--- /dev/null
+++ b/gerrit-httpd/src/main/java/com/google/gerrit/httpd/rpc/changedetail/RestoreChange.java
@@ -0,0 +1,132 @@
+// Copyright (C) 2009 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.httpd.rpc.changedetail;
+
+import com.google.gerrit.common.ChangeHookRunner;
+import com.google.gerrit.common.data.ChangeDetail;
+import com.google.gerrit.common.errors.NoSuchEntityException;
+import com.google.gerrit.httpd.rpc.Handler;
+import com.google.gerrit.reviewdb.*;
+import com.google.gerrit.server.ChangeUtil;
+import com.google.gerrit.server.IdentifiedUser;
+import com.google.gerrit.server.mail.AbandonedSender;
+import com.google.gerrit.server.mail.EmailException;
+import com.google.gerrit.server.patch.PatchSetInfoNotAvailableException;
+import com.google.gerrit.server.project.ChangeControl;
+import com.google.gerrit.server.project.NoSuchChangeException;
+import com.google.gwtorm.client.AtomicUpdate;
+import com.google.gwtorm.client.OrmException;
+import com.google.inject.Inject;
+import com.google.inject.assistedinject.Assisted;
+
+import javax.annotation.Nullable;
+import java.util.Collections;
+import java.util.List;
+
+class RestoreChange extends Handler<ChangeDetail> {
+  interface Factory {
+    RestoreChange create(PatchSet.Id patchSetId, String message);
+  }
+
+  private final ChangeControl.Factory changeControlFactory;
+  private final ReviewDb db;
+  private final IdentifiedUser currentUser;
+  private final AbandonedSender.Factory abandonedSenderFactory;
+  private final ChangeDetailFactory.Factory changeDetailFactory;
+
+  private final PatchSet.Id patchSetId;
+  @Nullable
+  private final String message;
+
+  private final ChangeHookRunner hooks;
+
+  @Inject
+  RestoreChange(final ChangeControl.Factory changeControlFactory,
+      final ReviewDb db, final IdentifiedUser currentUser,
+      final AbandonedSender.Factory abandonedSenderFactory,
+      final ChangeDetailFactory.Factory changeDetailFactory,
+      @Assisted final PatchSet.Id patchSetId,
+      @Assisted @Nullable final String message, final ChangeHookRunner hooks) {
+    this.changeControlFactory = changeControlFactory;
+    this.db = db;
+    this.currentUser = currentUser;
+    this.abandonedSenderFactory = abandonedSenderFactory;
+    this.changeDetailFactory = changeDetailFactory;
+
+    this.patchSetId = patchSetId;
+    this.message = message;
+    this.hooks = hooks;
+  }
+
+  @Override
+  public ChangeDetail call() throws NoSuchChangeException, OrmException,
+      EmailException, NoSuchEntityException, PatchSetInfoNotAvailableException {
+    final Change.Id changeId = patchSetId.getParentKey();
+    final ChangeControl control = changeControlFactory.validateFor(changeId);
+    if (!control.canRestore()) {
+      throw new NoSuchChangeException(changeId);
+    }
+    final PatchSet patch = db.patchSets().get(patchSetId);
+    if (patch == null) {
+      throw new NoSuchChangeException(changeId);
+    }
+
+    final ChangeMessage cmsg =
+        new ChangeMessage(new ChangeMessage.Key(changeId, ChangeUtil
+            .messageUUID(db)), currentUser.getAccountId());
+    final StringBuilder msgBuf =
+        new StringBuilder("Patch Set " + patchSetId.get() + ": Restored");
+    if (message != null && message.length() > 0) {
+      msgBuf.append("\n\n");
+      msgBuf.append(message);
+    }
+    cmsg.setMessage(msgBuf.toString());
+
+    Change change = db.changes().atomicUpdate(changeId, new AtomicUpdate<Change>() {
+      @Override
+      public Change update(Change change) {
+        if (change.getStatus() == Change.Status.ABANDONED
+            && change.currentPatchSetId().equals(patchSetId)) {
+          change.setStatus(Change.Status.NEW);
+          ChangeUtil.updated(change);
+          return change;
+        } else {
+          return null;
+        }
+      }
+    });
+
+    if (change != null) {
+      db.changeMessages().insert(Collections.singleton(cmsg));
+
+      final List<PatchSetApproval> approvals =
+          db.patchSetApprovals().byChange(changeId).toList();
+      for (PatchSetApproval a : approvals) {
+        a.cache(change);
+      }
+      db.patchSetApprovals().update(approvals);
+
+      // Email the reviewers
+      final AbandonedSender cm = abandonedSenderFactory.create(change);
+      cm.setFrom(currentUser.getAccountId());
+      cm.setChangeMessage(cmsg);
+      cm.send();
+    }
+
+    hooks.doChangeRestoreHook(change, currentUser.getAccount(), message);
+
+    return changeDetailFactory.create(changeId).call();
+  }
+}
diff --git a/gerrit-server/src/main/java/com/google/gerrit/common/ChangeHookRunner.java b/gerrit-server/src/main/java/com/google/gerrit/common/ChangeHookRunner.java
index 05bd28b9df..d29bc23964 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/common/ChangeHookRunner.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/common/ChangeHookRunner.java
@@ -31,6 +31,7 @@ import com.google.gerrit.server.events.ApprovalAttribute;
 import com.google.gerrit.server.events.ChangeAbandonedEvent;
 import com.google.gerrit.server.events.ChangeEvent;
 import com.google.gerrit.server.events.ChangeMergedEvent;
+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;
@@ -92,6 +93,9 @@ public class ChangeHookRunner {
     /** Filename of the change abandoned hook. */
     private final File changeAbandonedHook;
 
+    /** Filename of the change abandoned hook. */
+    private final File changeRestoredHook;
+
     /** Repository Manager. */
     private final GitRepositoryManager repoManager;
 
@@ -136,6 +140,7 @@ public class ChangeHookRunner {
         commentAddedHook = sitePath.resolve(new File(hooksPath, getValue(config, "hooks", "commentAddedHook", "comment-added")).getPath());
         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());
     }
 
     public void addChangeListener(ChangeListener listener, IdentifiedUser user) {
@@ -304,6 +309,32 @@ public class ChangeHookRunner {
         runHook(openRepository(change), changeAbandonedHook, args);
     }
 
+    /**
+     * Fire the Change Restored Hook.
+     *
+     * @param change The change itself.
+     * @param account The gerrit user who restored the change.
+     * @param reason Reason for restoring the change.
+     */
+    public void doChangeRestoreHook(final Change change, final Account account, final String reason) {
+        final ChangeRestoreEvent event = new ChangeRestoreEvent();
+
+        event.change = eventFactory.asChangeAttribute(change);
+        event.restorer = eventFactory.asAccountAttribute(account);
+        event.reason = reason;
+        fireEvent(change, event);
+
+        final List<String> args = new ArrayList<String>();
+        addArg(args, "--change", event.change.id);
+        addArg(args, "--change-url", event.change.url);
+        addArg(args, "--project", event.change.project);
+        addArg(args, "--branch", event.change.branch);
+        addArg(args, "--restorer", getDisplayName(account));
+        addArg(args, "--reason", reason == null ? "" : reason);
+
+        runHook(openRepository(change), changeRestoredHook, args);
+    }
+
     private void fireEvent(final Change change, final ChangeEvent event) {
       for (ChangeListenerHolder holder : listeners.values()) {
           if (isVisibleTo(change, holder.user)) {
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/events/ChangeRestoreEvent.java b/gerrit-server/src/main/java/com/google/gerrit/server/events/ChangeRestoreEvent.java
new file mode 100644
index 0000000000..1a2922bb33
--- /dev/null
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/events/ChangeRestoreEvent.java
@@ -0,0 +1,23 @@
+// 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 ChangeRestoreEvent extends ChangeEvent {
+    public final String type = "change-restored";
+    public ChangeAttribute change;
+    public PatchSetAttribute patchSet;
+    public AccountAttribute restorer;
+    public String reason;
+}
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/project/ChangeControl.java b/gerrit-server/src/main/java/com/google/gerrit/server/project/ChangeControl.java
index c9435d3151..3291f1ac3b 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/project/ChangeControl.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/project/ChangeControl.java
@@ -159,6 +159,11 @@ public class ChangeControl {
     ;
   }
 
+  /** Can this user restore this change? */
+  public boolean canRestore() {
+    return canAbandon(); // Anyone who can abandon the change can restore it back
+  }
+
   public short normalize(ApprovalCategory.Id category, short score) {
     return getRefControl().normalize(category, score);
   }