Display progress while checking connectivity on push

Verifying 100 new objects are fully connected to the existing DAG
is usually very cheap. Checking the entire Linux kernel history is
fully connected when pushing it to a new repository can take 30-60
seconds. Display a progress counter during this time so the client
knows the server is still working.

Change-Id: Iababe3ee1d35cb82f2bef2f12da7a2ecd03282b0

org.eclipse.jgit/src/org/eclipse/jgit/transport/BaseReceivePack.java

@@ -1036,6 +1036,12 @@ public abstract class BaseReceivePack {
 	private void checkConnectivity() throws IOException {
 		ObjectIdSubclassMap<ObjectId> baseObjects = null;
 		ObjectIdSubclassMap<ObjectId> providedObjects = null;
+		ProgressMonitor checking = NullProgressMonitor.INSTANCE;
+		if (sideBand) {
+			SideBandProgressMonitor m = new SideBandProgressMonitor(msgOut);
+			m.setDelayStart(750, TimeUnit.MILLISECONDS);
+			checking = m;
+		}
 
 		if (checkReferencedIsReachable) {
 			baseObjects = parser.getBaseObjectIds();
@@ -1071,8 +1077,10 @@ public abstract class BaseReceivePack {
 			}
 		}
 
+		checking.beginTask(JGitText.get().countingObjects, ProgressMonitor.UNKNOWN);
 		RevCommit c;
 		while ((c = ow.next()) != null) {
+			checking.update(1);
 			if (providedObjects != null //
 					&& !c.has(RevFlag.UNINTERESTING) //
 					&& !providedObjects.contains(c))
@@ -1081,6 +1089,7 @@ public abstract class BaseReceivePack {
 
 		RevObject o;
 		while ((o = ow.nextObject()) != null) {
+			checking.update(1);
 			if (o.has(RevFlag.UNINTERESTING))
 				continue;
 
@@ -1094,6 +1103,7 @@ public abstract class BaseReceivePack {
 			if (o instanceof RevBlob && !db.hasObject(o))
 				throw new MissingObjectException(o, Constants.TYPE_BLOB);
 		}
+		checking.endTask();
 
 		if (baseObjects != null) {
 			for (ObjectId id : baseObjects) {