fix: do not cache lastReceived in release

When building release mode, the compiler could theoretically catch the lastReceived value. By using VolatileRead, we can ensure this is not the case and make sure we get an up to date value for it
MirageNet · Nov 3, 2020 · 9a15863 · 9a15863
1 parent b25a1f6
commit 9a15863
Showing 1 changed file with 7 additions and 4 deletions.
diff --git a/Assets/Mirror/Runtime/Transport/Kcp/KcpConnection.cs b/Assets/Mirror/Runtime/Transport/Kcp/KcpConnection.cs
@@ -3,6 +3,7 @@
 using System.IO;
 using System.Net;
 using System.Net.Sockets;
+using System.Threading;
 using Cysharp.Threading.Tasks;
 using Debug = UnityEngine.Debug;
 
@@ -62,7 +63,6 @@ protected void SetupKcp()
 
             kcp.SetNoDelay(delayMode);
             open = true;
-            lastReceived = stopWatch.ElapsedMilliseconds;
 
             Tick().Forget();
         }
@@ -71,10 +71,13 @@ async UniTaskVoid Tick()
         {
             try
             {
+                Thread.VolatileWrite(ref lastReceived, stopWatch.ElapsedMilliseconds);
+
                 while (open )
                 {
                     long now = stopWatch.ElapsedMilliseconds;
-                    if (now > lastReceived + Timeout)
+                    long received = Thread.VolatileRead(ref lastReceived);
+                    if (now > received + Timeout)
                         break;
 
                     kcp.Update((uint)now);
@@ -132,7 +135,7 @@ internal void RawInput(byte[] buffer, int msgLength)
         private void InputUnreliable(byte[] buffer, int msgLength)
         {
             unreliable.Input(buffer, msgLength);
-            lastReceived = stopWatch.ElapsedMilliseconds;
+            Thread.VolatileWrite(ref lastReceived, stopWatch.ElapsedMilliseconds);
 
             if (isWaiting && unreliable.PeekSize() > 0)
             {
@@ -144,7 +147,7 @@ private void InputReliable(byte[] buffer, int msgLength)
         {
             kcp.Input(buffer, msgLength);
 
-            lastReceived = stopWatch.ElapsedMilliseconds;
+            Thread.VolatileWrite(ref lastReceived, stopWatch.ElapsedMilliseconds);
 
             if (isWaiting && kcp.PeekSize() > 0)
             {