From adc04d3038e6ef308551ce09d7b3f2364b62abae Mon Sep 17 00:00:00 2001
From: Matt Tucker <tuck@whistlingfish.net>
Date: Tue, 26 Aug 2014 20:30:43 -0700
Subject: [PATCH] Fix an issue with message timeouts when retrieving the
 current activity during a start activity operation

---
 .../net/whistlingfish/harmony/HarmonyClient.java  | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/src/main/java/net/whistlingfish/harmony/HarmonyClient.java b/src/main/java/net/whistlingfish/harmony/HarmonyClient.java
index 85def03..d0e60cc 100644
--- a/src/main/java/net/whistlingfish/harmony/HarmonyClient.java
+++ b/src/main/java/net/whistlingfish/harmony/HarmonyClient.java
@@ -8,6 +8,7 @@
 import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.ScheduledFuture;
 import java.util.concurrent.TimeUnit;
+import java.util.concurrent.locks.ReentrantLock;
 
 import javax.inject.Inject;
 
@@ -69,6 +70,12 @@ public class HarmonyClient {
     private final ScheduledExecutorService scheduler = Executors.newScheduledThreadPool(1);
     private ScheduledFuture<?> heartbeat;
 
+    /*
+     * To prevent timeouts when different threads send a message and expect a response, create a lock that only allows a
+     * single thread at a time to perform a send/receive action.
+     */
+    private ReentrantLock messageLock = new ReentrantLock();
+
     @Inject
     private AuthService authService;
 
@@ -189,12 +196,14 @@ private Packet sendOAPacket(XMPPTCPConnection authConnection, OAPacket packet) {
     private Packet sendOAPacket(XMPPTCPConnection authConnection, OAPacket packet, long replyTimeout) {
         PacketCollector collector = authConnection.createPacketCollector(new EmptyIncrementedIdReplyFilter(packet,
                 authConnection));
+        messageLock.lock();
         try {
             authConnection.sendPacket(packet);
             return getNextPacketSkipContinues(collector, replyTimeout);
         } catch (SmackException | XMPPErrorException e) {
             throw new RuntimeException("Failed communicating with Harmony Hub", e);
         } finally {
+            messageLock.unlock();
             collector.cancel();
         }
     }
@@ -206,18 +215,20 @@ private <R extends OAPacket> R sendOAPacket(XMPPTCPConnection authConnection, OA
     private <R extends OAPacket> R sendOAPacket(XMPPTCPConnection authConnection, OAPacket packet, Class<R> replyClass,
             long replyTimeout) {
         PacketCollector collector = authConnection.createPacketCollector(new OAReplyFilter(packet, authConnection));
+        messageLock.lock();
         try {
             authConnection.sendPacket(packet);
             return replyClass.cast(getNextPacketSkipContinues(collector, replyTimeout));
         } catch (SmackException | XMPPErrorException e) {
             throw new RuntimeException("Failed communicating with Harmony Hub", e);
         } finally {
+            messageLock.unlock();
             collector.cancel();
         }
     }
 
-    private Packet getNextPacketSkipContinues(PacketCollector collector, long replyTimeout)
-            throws NoResponseException, XMPPErrorException {
+    private Packet getNextPacketSkipContinues(PacketCollector collector, long replyTimeout) throws NoResponseException,
+            XMPPErrorException {
         while (true) {
             Packet reply = collector.nextResult(replyTimeout);
             if (reply == null) {