Delete draft changes and patchsets

Adds ability to delete draft changes and patchsets that are not meant
or fit for code review. Deleting a draft patchset also deletes the
corresponding ref from the repository and decrements the next patch
set number for the change if necessary. Deleting a draft change
deletes all of its (draft) patchsets.

Change-Id: I04abeb67b64dd2366514e74d23f83066d409904e

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

@@ -28,11 +28,15 @@ import com.google.gerrit.reviewdb.RevId;
 import com.google.gerrit.reviewdb.ReviewDb;
 import com.google.gerrit.server.ChangeUtil;
 import com.google.gerrit.server.IdentifiedUser;
+import com.google.gerrit.server.git.GitRepositoryManager;
 import com.google.gerrit.server.git.MergeOp;
 import com.google.gerrit.server.git.MergeQueue;
+import com.google.gerrit.server.git.ReplicationQueue;
 import com.google.gerrit.server.mail.AbandonedSender;
 import com.google.gerrit.server.mail.EmailException;
 import com.google.gerrit.server.mail.RestoredSender;
+import com.google.gerrit.server.patch.PatchSetInfoFactory;
+import com.google.gerrit.server.patch.PatchSetInfoNotAvailableException;
 import com.google.gerrit.server.patch.PublishComments;
 import com.google.gerrit.server.project.ChangeControl;
 import com.google.gerrit.server.project.InvalidChangeOperationException;
@@ -107,6 +111,9 @@ public class ReviewCommand extends BaseCommand {
   @Option(name = "--publish", usage = "publish a draft patch set")
   private boolean publishPatchSet;
 
+  @Option(name = "--delete", usage = "delete a draft patch set")
+  private boolean deleteDraftPatchSet;
+
   @Inject
   private ReviewDb db;
 
@@ -140,6 +147,15 @@ public class ReviewCommand extends BaseCommand {
   @Inject
   private ChangeHookRunner hooks;
 
+  @Inject
+  private GitRepositoryManager gitManager;
+
+  @Inject
+  private ReplicationQueue replication;
+
+  @Inject
+  private PatchSetInfoFactory patchSetInfoFactory;
+
   private List<ApproveOption> optionList;
 
   private Set<PatchSet.Id> toSubmit = new HashSet<PatchSet.Id>();
@@ -161,6 +177,9 @@ public class ReviewCommand extends BaseCommand {
           if (publishPatchSet) {
             throw error("abandon and publish actions are mutually exclusive");
           }
+          if (deleteDraftPatchSet) {
+            throw error("abandon and delete actions are mutually exclusive");
+          }
         }
         if (publishPatchSet) {
           if (restoreChange) {
@@ -169,6 +188,9 @@ public class ReviewCommand extends BaseCommand {
           if (submitChange) {
             throw error("publish and submit actions are mutually exclusive");
           }
+          if (deleteDraftPatchSet) {
+            throw error("publish and delete actions are mutually exclusive");
+          }
         }
 
         boolean ok = true;
@@ -336,6 +358,19 @@ public class ReviewCommand extends BaseCommand {
         throw error("Not permitted to publish draft patchset");
       }
     }
+    if (deleteDraftPatchSet) {
+      if (changeControl.isOwner() && changeControl.isVisible(db)) {
+        try {
+          ChangeUtil.deleteDraftPatchSet(patchSetId, gitManager, replication, patchSetInfoFactory, db);
+        } catch (PatchSetInfoNotAvailableException e) {
+          throw error("Error retrieving draft patchset: " + patchSetId);
+        } catch (IOException e) {
+          throw error("Error deleting draft patchset: " + patchSetId);
+        }
+      } else {
+        throw error("Not permitted to delete draft patchset");
+      }
+    }
   }
 
   private Set<PatchSet.Id> parsePatchSetId(final String patchIdentity)