From 6e07a26a6cb351e6abd482b062e7301e80ae2c85 Mon Sep 17 00:00:00 2001
From: Ellpeck <me@ellpeck.de>
Date: Wed, 17 Mar 2021 01:13:57 +0100
Subject: [PATCH] fixed some race conditions with nested coroutines

---
 Coroutine/ActiveCoroutine.cs          |  2 +-
 Coroutine/CoroutineHandlerInstance.cs | 51 +++++++++++++++------------
 2 files changed, 30 insertions(+), 23 deletions(-)

diff --git a/Coroutine/ActiveCoroutine.cs b/Coroutine/ActiveCoroutine.cs
index 17a95a9..5604593 100644
--- a/Coroutine/ActiveCoroutine.cs
+++ b/Coroutine/ActiveCoroutine.cs
@@ -124,7 +124,7 @@ namespace Coroutine {
 
         /// <inheritdoc />
         public int CompareTo(ActiveCoroutine other) {
-            return this.Priority.CompareTo(other.Priority);
+            return other.Priority.CompareTo(this.Priority);
         }
 
     }
diff --git a/Coroutine/CoroutineHandlerInstance.cs b/Coroutine/CoroutineHandlerInstance.cs
index 4aa2f24..5db850c 100644
--- a/Coroutine/CoroutineHandlerInstance.cs
+++ b/Coroutine/CoroutineHandlerInstance.cs
@@ -12,6 +12,7 @@ namespace Coroutine {
 
         private readonly List<ActiveCoroutine> tickingCoroutines = new List<ActiveCoroutine>();
         private readonly List<ActiveCoroutine> eventCoroutines = new List<ActiveCoroutine>();
+        private readonly Queue<ActiveCoroutine> outstandingCoroutines = new Queue<ActiveCoroutine>();
         private readonly Stopwatch stopwatch = new Stopwatch();
 
         /// <summary>
@@ -45,7 +46,7 @@ namespace Coroutine {
         public ActiveCoroutine Start(IEnumerator<Wait> coroutine, string name = "", int priority = 0) {
             var inst = new ActiveCoroutine(coroutine, name, priority, this.stopwatch);
             if (inst.MoveNext())
-                AddSorted(inst.IsWaitingForEvent() ? this.eventCoroutines : this.tickingCoroutines, inst);
+                this.outstandingCoroutines.Enqueue(inst);
             return inst;
         }
 
@@ -67,15 +68,16 @@ namespace Coroutine {
         /// </summary>
         /// <param name="deltaSeconds">The amount of seconds that have passed since the last time this method was invoked</param>
         public void Tick(double deltaSeconds) {
-            for (var i = this.tickingCoroutines.Count - 1; i >= 0; i--) {
-                var coroutine = this.tickingCoroutines[i];
-                if (coroutine.Tick(deltaSeconds)) {
-                    this.tickingCoroutines.RemoveAt(i);
-                } else if (coroutine.IsWaitingForEvent()) {
-                    this.tickingCoroutines.RemoveAt(i);
-                    this.eventCoroutines.Add(coroutine);
+            this.AddOutstandingCoroutines();
+            this.tickingCoroutines.RemoveAll(c => {
+                if (c.Tick(deltaSeconds)) {
+                    return true;
+                } else if (c.IsWaitingForEvent()) {
+                    this.outstandingCoroutines.Enqueue(c);
+                    return true;
                 }
-            }
+                return false;
+            });
         }
 
         /// <summary>
@@ -83,15 +85,16 @@ namespace Coroutine {
         /// </summary>
         /// <param name="evt">The event to raise</param>
         public void RaiseEvent(Event evt) {
-            for (var i = this.eventCoroutines.Count - 1; i >= 0; i--) {
-                var coroutine = this.eventCoroutines[i];
-                if (coroutine.OnEvent(evt)) {
-                    this.eventCoroutines.RemoveAt(i);
-                } else if (!coroutine.IsWaitingForEvent()) {
-                    this.eventCoroutines.RemoveAt(i);
-                    this.tickingCoroutines.Add(coroutine);
+            this.AddOutstandingCoroutines();
+            this.eventCoroutines.RemoveAll(c => {
+                if (c.OnEvent(evt)) {
+                    return true;
+                } else if (!c.IsWaitingForEvent()) {
+                    this.outstandingCoroutines.Enqueue(c);
+                    return true;
                 }
-            }
+                return false;
+            });
         }
 
         /// <summary>
@@ -102,15 +105,19 @@ namespace Coroutine {
             return this.tickingCoroutines.Concat(this.eventCoroutines);
         }
 
+        private void AddOutstandingCoroutines() {
+            while (this.outstandingCoroutines.Count > 0) {
+                var coroutine = this.outstandingCoroutines.Dequeue();
+                var list = coroutine.IsWaitingForEvent() ? this.eventCoroutines : this.tickingCoroutines;
+                var position = list.BinarySearch(coroutine);
+                list.Insert(position < 0 ? ~position : position, coroutine);
+            }
+        }
+
         private static IEnumerator<Wait> InvokeLaterImpl(Wait wait, Action action) {
             yield return wait;
             action();
         }
 
-        private static void AddSorted(List<ActiveCoroutine> list, ActiveCoroutine coroutine) {
-            var position = list.BinarySearch(coroutine);
-            list.Insert(position < 0 ? ~position : position, coroutine);
-        }
-
     }
 }
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