From 105192d7e70a63cba3074084ba14ac042edec10a Mon Sep 17 00:00:00 2001
From: Florian Schmaus <flo@geekplace.eu>
Date: Thu, 6 Sep 2018 19:13:50 +0200
Subject: [PATCH] Only announce support for ChatMarkers if there is a listener

---
 .../chat_markers/ChatMarkersManager.java      | 28 ++++++++++++++-----
 1 file changed, 21 insertions(+), 7 deletions(-)

diff --git a/smack-experimental/src/main/java/org/jivesoftware/smackx/chat_markers/ChatMarkersManager.java b/smack-experimental/src/main/java/org/jivesoftware/smackx/chat_markers/ChatMarkersManager.java
index 8c00c5d39..e203edcc7 100644
--- a/smack-experimental/src/main/java/org/jivesoftware/smackx/chat_markers/ChatMarkersManager.java
+++ b/smack-experimental/src/main/java/org/jivesoftware/smackx/chat_markers/ChatMarkersManager.java
@@ -16,10 +16,10 @@
  */
 package org.jivesoftware.smackx.chat_markers;
 
+import java.util.HashSet;
 import java.util.Map;
 import java.util.Set;
 import java.util.WeakHashMap;
-import java.util.concurrent.CopyOnWriteArraySet;
 
 import org.jivesoftware.smack.AsyncButOrdered;
 import org.jivesoftware.smack.ConnectionCreationListener;
@@ -87,12 +87,16 @@ public final class ChatMarkersManager extends Manager {
     );
     // @FORMATTER:ON
 
-    private final Set<ChatMarkersListener> incomingListeners = new CopyOnWriteArraySet<>();
+    private final Set<ChatMarkersListener> incomingListeners = new HashSet<>();
 
     private final AsyncButOrdered<Chat> asyncButOrdered = new AsyncButOrdered<>();
 
     private final ChatManager chatManager;
 
+    private final ServiceDiscoveryManager serviceDiscoveryManager;
+
+    private boolean enabled;
+
     /**
      * Get the singleton instance of ChatMarkersManager.
      *
@@ -166,7 +170,7 @@ public final class ChatMarkersManager extends Manager {
             }
         }, INCOMING_MESSAGE_FILTER);
 
-        ServiceDiscoveryManager.getInstanceFor(connection).addFeature(ChatMarkersElements.NAMESPACE);
+        serviceDiscoveryManager = ServiceDiscoveryManager.getInstanceFor(connection);
     }
 
     /**
@@ -191,8 +195,13 @@ public final class ChatMarkersManager extends Manager {
      * @param listener ChatMarkersListener
      * @return true, if the listener was not registered before
      */
-    public boolean addIncomingChatMarkerMessageListener(ChatMarkersListener listener) {
-        return incomingListeners.add(listener);
+    public synchronized boolean addIncomingChatMarkerMessageListener(ChatMarkersListener listener) {
+        boolean res = incomingListeners.add(listener);
+        if (!enabled) {
+            serviceDiscoveryManager.addFeature(ChatMarkersElements.NAMESPACE);
+            enabled = true;
+        }
+        return res;
     }
 
     /**
@@ -201,7 +210,12 @@ public final class ChatMarkersManager extends Manager {
      * @param listener ChatMarkersListener
      * @return true, if the listener was registered before
      */
-    public boolean removeIncomingChatMarkerMessageListener(ChatMarkersListener listener) {
-        return incomingListeners.remove(listener);
+    public synchronized boolean removeIncomingChatMarkerMessageListener(ChatMarkersListener listener) {
+        boolean res = incomingListeners.remove(listener);
+        if (incomingListeners.isEmpty() && enabled) {
+            serviceDiscoveryManager.removeFeature(ChatMarkersElements.NAMESPACE);
+            enabled = false;
+        }
+        return res;
     }
 }