Restore SEBPatch

SafeExamBrowser.Service/Operations/SessionInitializationOperation.cs

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+/*
+ * 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 SafeExamBrowser.Core.Contracts.OperationModel;
+using SafeExamBrowser.Logging.Contracts;
+
+namespace SafeExamBrowser.Service.Operations
+{
+	internal class SessionInitializationOperation : SessionOperation
+	{
+		private ILogger logger;
+		private Func<string, EventWaitHandle> serviceEventFactory;
+
+		public SessionInitializationOperation(ILogger logger, Func<string, EventWaitHandle> serviceEventFactory, SessionContext sessionContext) : base(sessionContext)
+		{
+			this.logger = logger;
+			this.serviceEventFactory = serviceEventFactory;
+		}
+
+		public override OperationResult Perform()
+		{
+			logger.Info("Initializing new session...");
+			logger.Info($" -> Client-ID: {Context.Configuration.AppConfig.ClientId}");
+			logger.Info($" -> Runtime-ID: {Context.Configuration.AppConfig.RuntimeId}");
+			logger.Info($" -> Session-ID: {Context.Configuration.SessionId}");
+
+			logger.Info("Stopping auto-restore mechanism...");
+			Context.AutoRestoreMechanism.Stop();
+
+			InitializeServiceEvent();
+
+			return OperationResult.Success;
+		}
+
+		public override OperationResult Revert()
+		{
+			var success = true;
+			var wasRunning = Context.IsRunning;
+
+			logger.Info("Starting auto-restore mechanism...");
+			Context.AutoRestoreMechanism.Start();
+
+			logger.Info("Clearing session data...");
+			Context.Configuration = null;
+			Context.IsRunning = false;
+
+			if (Context.ServiceEvent != null && wasRunning)
+			{
+				success = Context.ServiceEvent.Set();
+
+				if (success)
+				{
+					logger.Info("Successfully informed runtime about session termination.");
+				}
+				else
+				{
+					logger.Error("Failed to inform runtime about session termination!");
+				}
+			}
+
+			return success ? OperationResult.Success : OperationResult.Failed;
+		}
+
+		private void InitializeServiceEvent()
+		{
+			if (Context.ServiceEvent != null)
+			{
+				logger.Info("Closing service event from previous session...");
+				Context.ServiceEvent.Close();
+				logger.Info("Service event successfully closed.");
+			}
+
+			logger.Info("Attempting to create new service event...");
+			Context.ServiceEvent = serviceEventFactory.Invoke(Context.Configuration.AppConfig.ServiceEventName);
+			logger.Info("Service event successfully created.");
+		}
+	}
+}