From 314fca3f899685f532df92e857c15b0eb6f7615c Mon Sep 17 00:00:00 2001
From: Christian Kratky <christian.kratky@googlemail.com>
Date: Thu, 8 Jun 2017 14:25:52 +0200
Subject: [PATCH] Optimize task management

---
 MQTTnet.Core/Client/MqttClient.cs | 42 +++++++++++++++----------------
 MQTTnet.nuspec                    |  5 ++--
 2 files changed, 24 insertions(+), 23 deletions(-)

diff --git a/MQTTnet.Core/Client/MqttClient.cs b/MQTTnet.Core/Client/MqttClient.cs
index 72b718e..cc3ebee 100644
--- a/MQTTnet.Core/Client/MqttClient.cs
+++ b/MQTTnet.Core/Client/MqttClient.cs
@@ -191,34 +191,30 @@ namespace MQTTnet.Core.Client
             }
         }
 
-        private async void ProcessReceivedPacketAsync(MqttBasePacket mqttPacket)
+        private Task ProcessReceivedPacketAsync(MqttBasePacket mqttPacket)
         {
             try
             {
                 if (mqttPacket is MqttPingReqPacket)
                 {
-                    await SendAsync(new MqttPingRespPacket());
-                    return;
+                    return SendAsync(new MqttPingRespPacket());
                 }
 
                 if (mqttPacket is MqttDisconnectPacket)
                 {
-                    await DisconnectAsync();
-                    return;
+                    return DisconnectAsync();
                 }
 
                 var publishPacket = mqttPacket as MqttPublishPacket;
                 if (publishPacket != null)
                 {
-                    await ProcessReceivedPublishPacket(publishPacket);
-                    return;
+                    return ProcessReceivedPublishPacket(publishPacket);
                 }
 
                 var pubRelPacket = mqttPacket as MqttPubRelPacket;
                 if (pubRelPacket != null)
                 {
-                    await ProcessReceivedPubRelPacket(pubRelPacket);
-                    return;
+                    return ProcessReceivedPubRelPacket(pubRelPacket);
                 }
 
                 _packetDispatcher.Dispatch(mqttPacket);
@@ -227,6 +223,8 @@ namespace MQTTnet.Core.Client
             {
                 MqttTrace.Error(nameof(MqttClient), exception, "Error while processing received packet.");
             }
+
+            return Task.FromResult(0);
         }
 
         private void FireApplicationMessageReceivedEvent(MqttPublishPacket publishPacket)
@@ -246,25 +244,27 @@ namespace MQTTnet.Core.Client
             ApplicationMessageReceived?.Invoke(this, new MqttApplicationMessageReceivedEventArgs(applicationMessage));
         }
 
-        private async Task ProcessReceivedPublishPacket(MqttPublishPacket publishPacket)
+        private Task ProcessReceivedPublishPacket(MqttPublishPacket publishPacket)
         {
             if (publishPacket.QualityOfServiceLevel == MqttQualityOfServiceLevel.AtMostOnce)
             {
                 FireApplicationMessageReceivedEvent(publishPacket);
+                return Task.FromResult(0);
             }
-            else
+
+            if (publishPacket.QualityOfServiceLevel == MqttQualityOfServiceLevel.AtLeastOnce)
             {
-                if (publishPacket.QualityOfServiceLevel == MqttQualityOfServiceLevel.AtLeastOnce)
-                {
-                    FireApplicationMessageReceivedEvent(publishPacket);
-                    await SendAsync(new MqttPubAckPacket { PacketIdentifier = publishPacket.PacketIdentifier });
-                }
-                else if (publishPacket.QualityOfServiceLevel == MqttQualityOfServiceLevel.ExactlyOnce)
-                {
-                    _pendingExactlyOncePublishPackets[publishPacket.PacketIdentifier] = publishPacket;
-                    await SendAsync(new MqttPubRecPacket { PacketIdentifier = publishPacket.PacketIdentifier });
-                }
+                FireApplicationMessageReceivedEvent(publishPacket);
+                return SendAsync(new MqttPubAckPacket { PacketIdentifier = publishPacket.PacketIdentifier });
             }
+
+            if (publishPacket.QualityOfServiceLevel == MqttQualityOfServiceLevel.ExactlyOnce)
+            {
+                _pendingExactlyOncePublishPackets[publishPacket.PacketIdentifier] = publishPacket;
+                return SendAsync(new MqttPubRecPacket { PacketIdentifier = publishPacket.PacketIdentifier });
+            }
+
+            throw new InvalidOperationException();
         }
 
         private async Task ProcessReceivedPubRelPacket(MqttPubRelPacket pubRelPacket)
diff --git a/MQTTnet.nuspec b/MQTTnet.nuspec
index 2ff14f0..5acb5b5 100644
--- a/MQTTnet.nuspec
+++ b/MQTTnet.nuspec
@@ -12,8 +12,9 @@
     <description>MQTTnet is a .NET library for MQTT based communication. It provides a MQTT client and a MQTT server (broker).</description>
     <releaseNotes>* [Core] Any exception while accessing the underlying data source is now rethrown as "MqttCommunicationException".
 * [Core] Extended exception information when an invalid packet type is received.
-* [Server] Added TLS 1.2 support (thanks to Zazzmatazz)
-* [Client] Added TLS 1.2 support (thanks to Zazzmatazz)</releaseNotes>
+* [Server] Added TLS 1.2 support (but not for UWP) (thanks to Zazzmatazz)
+* [Client] Added TLS 1.2 support (thanks to Zazzmatazz)
+* [Core] Optimized async task management</releaseNotes>
     <copyright>Copyright Christian Kratky 2016-2017</copyright>
     <tags>MQTT MQTTClient MQTTServer MQTTBroker Broker</tags>
   </metadata>