Restore SEBPatch

SafeExamBrowser.Runtime/App.cs

@@ -0,0 +1,91 @@
+/*
+ * Copyright (c) 2024 ETH Zürich, IT Services
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+using System;
+using System.Threading;
+using System.Threading.Tasks;
+using System.Windows;
+using SafeExamBrowser.Configuration.Contracts;
+
+namespace SafeExamBrowser.Runtime
+{
+	public class App : Application
+	{
+		private static readonly Mutex Mutex = new Mutex(true, AppConfig.RUNTIME_MUTEX_NAME);
+		private readonly CompositionRoot instances = new CompositionRoot();
+
+		[STAThread]
+		public static void Main()
+		{
+			try
+			{
+				StartApplication();
+			}
+			catch (Exception e)
+			{
+				MessageBox.Show(e.Message + "\n\n" + e.StackTrace, "Fatal Error", MessageBoxButton.OK, MessageBoxImage.Error);
+			}
+			finally
+			{
+				Mutex.Close();
+			}
+		}
+
+		private static void StartApplication()
+		{
+			if (NoInstanceRunning())
+			{
+				new App().Run();
+			}
+			else
+			{
+				MessageBox.Show("You can only run one instance of SEB at a time.", "Startup Not Allowed", MessageBoxButton.OK, MessageBoxImage.Information);
+			}
+		}
+
+		private static bool NoInstanceRunning()
+		{
+			return Mutex.WaitOne(TimeSpan.Zero, true);
+		}
+
+		protected override void OnStartup(StartupEventArgs e)
+		{
+			base.OnStartup(e);
+
+			ShutdownMode = ShutdownMode.OnExplicitShutdown;
+
+			instances.BuildObjectGraph(Shutdown);
+			instances.LogStartupInformation();
+
+			Task.Run(new Action(TryStart));
+		}
+
+		private void TryStart()
+		{
+			var success = instances.RuntimeController.TryStart();
+
+			if (!success)
+			{
+				Shutdown();
+			}
+		}
+
+		public new void Shutdown()
+		{
+			Task.Run(new Action(ShutdownInternal));
+		}
+
+		private void ShutdownInternal()
+		{
+			instances.RuntimeController.Terminate();
+			instances.LogShutdownInformation();
+
+			Dispatcher.Invoke(base.Shutdown);
+		}
+	}
+}