Use a semaphore instead of a cancellation token to halt the main thread

project-fika · Dec 19, 2024 · 7994ecf · 7994ecf
1 parent 81da2dd
commit 7994ecf
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Showing 2 changed files with 14 additions and 38 deletions.
diff --git a/Fuyu.Backend/Program.cs b/Fuyu.Backend/Program.cs
@@ -33,13 +33,12 @@ static async Task Main()
 
 			await ModManager.Instance.Load(container);
 
-			using (var cts = new CancellationTokenSource())
-			{
-				Terminal.WaitForInput(cts);
-				Terminal.WriteLine("WaitOne start");
-				cts.Token.WaitHandle.WaitOne();
-				Terminal.WriteLine("WaitOne finished");
-			}
+			var semaphore = new SemaphoreSlim(0);
+
+			Terminal.WaitForInput(semaphore);
+			Terminal.WriteLine("WaitOne start");
+			await semaphore.WaitAsync();
+            Terminal.WriteLine("WaitOne finished");
 
 			Terminal.WriteLine("Unloading");
 			await ModManager.Instance.UnloadAll();

diff --git a/Fuyu.Common/IO/Terminal.cs b/Fuyu.Common/IO/Terminal.cs
@@ -8,11 +8,6 @@ public static class Terminal
     {
         private static object _lock = new object();
 
-		// NOTE: this exists because ProcessExit gets called after CancelKeyPress
-		// when Main disposes of CancellationTokenSource so this is my fix
-        // -- nexus4880, 2024-12-12
-		private static bool _closing;
-
 		public static void WriteLine(string text)
         {
             var line = $"{text}\n";
@@ -34,7 +29,7 @@ public static void WriteLine(object o)
             WriteLine(o.ToString());
         }
 
-        public static void WaitForInput(CancellationTokenSource cts)
+        public static void WaitForInput(SemaphoreSlim semaphore)
         {
             if (Environment.GetEnvironmentVariable(EnvironmentVariables.Docker) == null)
             {
@@ -44,41 +39,23 @@ public static void WaitForInput(CancellationTokenSource cts)
                 Console.In.ReadLine();
 
 				lock (_lock)
-				{
-					if (!_closing)
-					{
-						cts.Cancel();
-						_closing = true;
-					}
-				}
+                {
+                    semaphore.Release(1);
+                }
 			}
             else
 			{
 				WriteLine("(WaitForInput) Docker");
 				AppDomain.CurrentDomain.ProcessExit += (_, __) =>
-				{
-					lock (_lock)
-					{
-						if (!_closing)
-						{
-							cts.Cancel();
-                            _closing = true;
-						}
-					}
+                {
+                    semaphore.Release(1);
                 };
 
                 Console.CancelKeyPress += (_, e) =>
 				{
 					e.Cancel = true;
-                    lock (_lock)
-                    {
-                        if (!_closing)
-						{
-							cts.Cancel();
-							_closing = true;
-						}
-                    }
-				};
+                    semaphore.Release(1);
+                };
 			}
 		}