Merge branch '755-group-message-timestamp' into 'master'

Made private group timestamp greater than that of latest message

I did not change `getPreviousMsgId()` to `getPreviousMsgHeader()` because there doesn't seem to be a need for it anymore.

Closes #755

See merge request !409

briar-android/src/org/briarproject/android/privategroup/conversation/GroupControllerImpl.java

@@ -6,6 +6,7 @@ import org.briarproject.android.api.AndroidNotificationManager;
 import org.briarproject.android.controller.handler.ResultExceptionHandler;
 import org.briarproject.android.privategroup.conversation.GroupController.GroupListener;
 import org.briarproject.android.threaded.ThreadListControllerImpl;
+import org.briarproject.api.clients.MessageTracker.GroupCount;
 import org.briarproject.api.crypto.CryptoExecutor;
 import org.briarproject.api.db.DatabaseExecutor;
 import org.briarproject.api.db.DbException;
@@ -130,15 +131,10 @@ public class GroupControllerImpl extends
 					MessageId parentId = null;
 					MessageId previousMsgId =
 							privateGroupManager.getPreviousMsgId(getGroupId());
-					// timestamp must be greater than the timestamps
-					// of the member's previous message...
-					long timestamp = privateGroupManager
-							.getMessageTimestamp(previousMsgId);
-					// ...and the parent post, if any
-					if (parentItem != null) {
-						timestamp = max(parentItem.getTimestamp(), timestamp);
-						parentId = parentItem.getId();
-					}
+					GroupCount count =
+							privateGroupManager.getGroupCount(getGroupId());
+					long timestamp = count.getLatestMsgTime();
+					if (parentItem != null) parentId = parentItem.getId();
 					timestamp = max(clock.currentTimeMillis(), timestamp + 1);
 					createMessage(body, timestamp, parentId, author,
 							previousMsgId, handler);

briar-api/src/org/briarproject/api/privategroup/PrivateGroupManager.java

@@ -51,12 +51,6 @@ public interface PrivateGroupManager extends MessageTracker {
 	 */
 	MessageId getPreviousMsgId(GroupId g) throws DbException;
 
-	/**
-	 * Returns the timestamp of the message with the given ID
-	 */
-	// TODO change to getPreviousMessageHeader()
-	long getMessageTimestamp(MessageId id) throws DbException;
-
 	/**
 	 * Marks the group with GroupId g as resolved
 	 */

briar-core/src/org/briarproject/privategroup/PrivateGroupManagerImpl.java

@@ -192,16 +192,6 @@ public class PrivateGroupManagerImpl extends BdfIncomingMessageHook implements
 		txn.attach(e);
 	}
 
-	@Override
-	public long getMessageTimestamp(MessageId id) throws DbException {
-		try {
-			BdfDictionary d = clientHelper.getMessageMetadataAsDictionary(id);
-			return d.getLong(KEY_TIMESTAMP);
-		} catch (FormatException e) {
-			throw new DbException(e);
-		}
-	}
-
 	@Override
 	public GroupMessageHeader addLocalMessage(GroupMessage m)
 			throws DbException {