Improve Privacy List code

notably add a cache for the active and default privacy list to avoid
IQ get/response round-trips.

Also add a few methods to PrivacyListManager to get the privacy list
names. The already existing methods always returned the whole list
together with the name, which caused two round-trips.

Simplified some code.

Properly escape Privacy XML.

smack-core/src/main/java/org/jivesoftware/smack/AbstractXMPPConnection.java

@@ -1371,6 +1371,27 @@ public abstract class AbstractXMPPConnection implements XMPPConnection {
         sendStanzaWithResponseCallback(iqRequest, replyFilter, callback, exceptionCallback, timeout);
     }
 
+    @Override
+    public void addOneTimeSyncCallback(final PacketListener callback, final PacketFilter packetFilter) {
+        final PacketListener packetListener = new PacketListener() {
+            @Override
+            public void processPacket(Packet packet) throws NotConnectedException {
+                try {
+                    callback.processPacket(packet);
+                } finally {
+                    removeSyncPacketListener(this);
+                }
+            }
+        };
+        addSyncPacketListener(packetListener, packetFilter);
+        removeCallbacksService.schedule(new Runnable() {
+            @Override
+            public void run() {
+                removeSyncPacketListener(packetListener);
+            }
+        }, getPacketReplyTimeout(), TimeUnit.MILLISECONDS);
+    }
+
     private long lastStanzaReceived;
 
     public long getLastStanzaReceived() {

smack-core/src/main/java/org/jivesoftware/smack/XMPPConnection.java

@@ -556,6 +556,15 @@ public interface XMPPConnection {
                     final ExceptionCallback exceptionCallback, long timeout)
                     throws NotConnectedException;
 
+    /**
+     * Add a callback that is called exactly once and synchronously with the incoming stanza that matches the given
+     * packet filter.
+     * 
+     * @param callback the callback invoked once the packet filter matches a stanza.
+     * @param packetFilter the filter to match stanzas or null to match all.
+     */
+    public void addOneTimeSyncCallback(PacketListener callback, PacketFilter packetFilter);
+
     /**
      * Returns the timestamp in milliseconds when the last stanza was received.
      * 

smack-core/src/main/java/org/jivesoftware/smack/filter/IQResultReplyFilter.java

@@ -0,0 +1,41 @@
+/**
+ *
+ * Copyright 2015 Florian Schmaus
+ *
+ * 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 org.jivesoftware.smack.filter;
+
+import org.jivesoftware.smack.XMPPConnection;
+import org.jivesoftware.smack.packet.IQ;
+import org.jivesoftware.smack.packet.Packet;
+
+/**
+ *
+ */
+public class IQResultReplyFilter extends IQReplyFilter {
+
+
+    public IQResultReplyFilter(IQ iqPacket, XMPPConnection conn) {
+        super(iqPacket, conn);
+    }
+
+    @Override
+    public boolean accept(Packet packet) {
+        if (!super.accept(packet)) {
+            return false;
+        }
+        return IQTypeFilter.RESULT.accept(packet);
+    }
+
+}