From 469566c0e48c14edd673a2490828245c5feecded Mon Sep 17 00:00:00 2001
From: Skipcast <jonathanjl99@gmail.com>
Date: Sun, 16 Jan 2022 23:38:56 +0100
Subject: [PATCH] Fixed p2p related crash when multiple messages are received
 in a short amount of time

---
 JKMP.Plugin.Multiplayer/Networking/Framed.cs  | 25 ++++++---
 .../Networking/ReusableTCS.cs                 | 52 -------------------
 2 files changed, 19 insertions(+), 58 deletions(-)
 delete mode 100644 JKMP.Plugin.Multiplayer/Networking/ReusableTCS.cs

diff --git a/JKMP.Plugin.Multiplayer/Networking/Framed.cs b/JKMP.Plugin.Multiplayer/Networking/Framed.cs
index 3338b83..5262194 100644
--- a/JKMP.Plugin.Multiplayer/Networking/Framed.cs
+++ b/JKMP.Plugin.Multiplayer/Networking/Framed.cs
@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using System.IO;
 using System.Linq;
 using System.Threading;
@@ -16,7 +17,8 @@ namespace JKMP.Plugin.Multiplayer.Networking
     {
         private bool isRunning = true;
 
-        private readonly ReusableTCS<TData?> tcs = new();
+        private TaskCompletionSource<bool>? tcs = new();
+        private readonly Queue<TData> queuedMessages = new();
         private readonly TCodec codec;
         private readonly byte[] sendBuffer = new byte[4096];
         
@@ -54,8 +56,9 @@ private async Task StartPolling()
                             Logger.Error(ex, "An unhandled exception was raised when decoding message from {steamId}", packet.SteamId);
                             continue;
                         }
-
-                        await tcs.SetResult(message);
+                        
+                        queuedMessages.Enqueue(message);
+                        tcs?.TrySetResult(true);
                     }
 
                     await Task.Delay(33).ConfigureAwait(false); // poll around 30 times per second
@@ -73,9 +76,19 @@ private async Task StartPolling()
             if (!isRunning)
                 return default;
 
-            await tcs;
-            TData? result = tcs.GetResult();
-            tcs.Reset();
+            if (tcs != null)
+            {
+                await tcs.Task;
+                tcs = null;
+            }
+
+            TData result = queuedMessages.Dequeue();
+
+            if (queuedMessages.Count == 0)
+            {
+                tcs = new();
+            }
+            
             return result;
         }
 
diff --git a/JKMP.Plugin.Multiplayer/Networking/ReusableTCS.cs b/JKMP.Plugin.Multiplayer/Networking/ReusableTCS.cs
deleted file mode 100644
index 93ca910..0000000
--- a/JKMP.Plugin.Multiplayer/Networking/ReusableTCS.cs
+++ /dev/null
@@ -1,52 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Runtime.CompilerServices;
-using System.Threading.Tasks;
-
-namespace JKMP.Plugin.Multiplayer.Networking
-{
-    /// <summary>
-    /// A reusable task completion source
-    /// </summary>
-    internal class ReusableTCS<T> : INotifyCompletion
-    {
-        private bool isCompleted;
-        private T? result;
-
-        public bool IsCompleted => isCompleted;
-
-        private Action? onCompleted;
-        
-        public void OnCompleted(Action continuation)
-        {
-            if (onCompleted != null)
-                throw new NotSupportedException("Multiple awaiters is not supported");
-            
-            onCompleted = continuation;
-        }
-
-        public void Reset()
-        {
-            isCompleted = false;
-            result = default;
-            onCompleted = null;
-        }
-
-        public async Task SetResult(T? result)
-        {
-            if (isCompleted)
-                throw new InvalidOperationException("Result is already set. Make sure to call Reset before calling SetResult again.");
-            
-            this.result = result;
-            isCompleted = true;
-
-            if (onCompleted != null)
-                await Task.Run(onCompleted).ConfigureAwait(false);
-        }
-
-        public ReusableTCS<T> GetAwaiter() => this;
-
-        public T? GetResult() => result;
-    }
-}
\ No newline at end of file