OF-1028: Avoid potential concurrency issue.

Do not expose the collection of packets that our implementation
modifies only under a mutex (alternatively, we could return a
defensive copy instead, but there does not seem to be a need
to expose the collection in the first place).

src/java/org/jivesoftware/openfire/streammanagement/StreamManager.java

@@ -138,9 +138,8 @@ public class StreamManager {
 				if (ack.attribute("h") != null) {
 					long count = Long.valueOf(ack.attributeValue("h"));
 					// Remove stanzas from temporary storage as now acknowledged
-					Deque<UnackedPacket> unacknowledgedStanzas = getUnacknowledgedServerStanzas();
 					long i = getClientProcessedStanzas();
-					Log.debug("Ack: h={} mine={} length={}", count, i, unacknowledgedStanzas.size());
+					Log.debug("Ack: h={} mine={} length={}", count, i, unacknowledgedServerStanzas.size());
 					if (count < i) {
                                     /* Consider rollover? */
 						Log.debug("Maybe rollover");
@@ -152,9 +151,9 @@ public class StreamManager {
 						}
 					}
 					while (i < count) {
-						unacknowledgedStanzas.removeFirst();
+						unacknowledgedServerStanzas.removeFirst();
 						i++;
-						Log.debug("In Ack: h={} mine={} length={}", count, i, unacknowledgedStanzas.size());
+						Log.debug("In Ack: h={} mine={} length={}", count, i, unacknowledgedServerStanzas.size());
 					}
 
 					setClientProcessedStanzas(count);
@@ -169,8 +168,8 @@ public class StreamManager {
 			synchronized (this) {
 				incrementServerSentStanzas();
 				// Temporarily store packet until delivery confirmed
-				getUnacknowledgedServerStanzas().addLast(new StreamManager.UnackedPacket(new Date(), packet.createCopy()));
-				Log.debug("Added stanza of type {}, now {} / {}", packet.getClass().getName(), getServerSentStanzas(), getUnacknowledgedServerStanzas().size());
+				unacknowledgedServerStanzas.addLast( new StreamManager.UnackedPacket( new Date(), packet.createCopy() ) );
+				Log.debug("Added stanza of type {}, now {} / {}", packet.getClass().getName(), getServerSentStanzas(), unacknowledgedServerStanzas.size());
 			}
 			if(getServerSentStanzas() % JiveGlobals.getLongProperty("stream.management.requestFrequency", 5) == 0) {
 				sendServerRequest();
@@ -184,9 +183,8 @@ public class StreamManager {
 		if(isEnabled()) {
 			setEnabled(false); // Avoid concurrent usage.
 			synchronized (this) {
-				Deque<StreamManager.UnackedPacket> unacknowledgedStanzas = getUnacknowledgedServerStanzas();
-				if (!unacknowledgedStanzas.isEmpty()) {
-					for (StreamManager.UnackedPacket unacked : unacknowledgedStanzas) {
+				if (!unacknowledgedServerStanzas.isEmpty()) {
+					for (StreamManager.UnackedPacket unacked : unacknowledgedServerStanzas) {
 						if (unacked.packet instanceof Message) {
 							Message m = (Message) unacked.packet;
 							if (m.getExtension("delay", "urn:xmpp:delay") == null) {
@@ -302,13 +300,4 @@ public class StreamManager {
 			clientProcessedStanzas = count;
 		}
 	}
-
-	/**
-	 * Retrieves all unacknowledged stanzas sent to client from server.
-	 * @return  all unacknowledged stanzas sent to client from server.
-	 */
-	public Deque<UnackedPacket> getUnacknowledgedServerStanzas() {
-		return unacknowledgedServerStanzas;
-	}
-
 }