Restore SEBPatch

SafeExamBrowser.Monitoring/System/Components/StickyKeys.cs

@@ -0,0 +1,124 @@
+/*
+ * 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.Threading.Tasks;
+using System.Timers;
+using SafeExamBrowser.Logging.Contracts;
+using SafeExamBrowser.Monitoring.Contracts.System.Events;
+using SafeExamBrowser.WindowsApi.Contracts;
+
+namespace SafeExamBrowser.Monitoring.System.Components
+{
+	internal class StickyKeys
+	{
+		private readonly ILogger logger;
+		private readonly INativeMethods nativeMethods;
+		private readonly Timer timer;
+
+		private IStickyKeysState original;
+
+		internal event SentinelEventHandler Changed;
+
+		internal StickyKeys(ILogger logger, INativeMethods nativeMethods)
+		{
+			this.logger = logger;
+			this.nativeMethods = nativeMethods;
+			this.timer = new Timer();
+		}
+
+		internal bool Disable()
+		{
+
+			return true;
+		}
+
+		internal bool Enable()
+		{
+			return true;
+		}
+
+		internal bool Revert()
+		{
+			var success = true;
+
+			if (original != default)
+			{
+				success = nativeMethods.TrySetStickyKeys(original);
+
+				if (success)
+				{
+					logger.Info($"Successfully reverted sticky keys (original state: {ToString(original)}).");
+				}
+				else
+				{
+					logger.Error($"Failed to revert sticky keys (original state: {ToString(original)})!");
+				}
+			}
+
+			original = default;
+
+			return success;
+		}
+
+		internal void StartMonitoring()
+		{
+			timer.AutoReset = true;
+			timer.Elapsed += Timer_Elapsed;
+			timer.Interval = 1000;
+			timer.Start();
+
+			logger.Info("Started monitoring sticky keys.");
+		}
+
+		internal void StopMonitoring()
+		{
+			timer.Elapsed -= Timer_Elapsed;
+			timer.Stop();
+
+			logger.Info("Stopped monitoring sticky keys.");
+		}
+
+		private void Timer_Elapsed(object sender, ElapsedEventArgs e)
+		{
+			
+		}
+
+		private void HandleStickyKeysChange(IStickyKeysState state)
+		{
+			var args = new SentinelEventArgs();
+
+			logger.Warn($"The sticky keys state has changed: {ToString(state)}.");
+
+			Task.Run(() => Changed?.Invoke(args)).ContinueWith((_) =>
+			{
+				if (args.Allow)
+				{
+					StopMonitoring();
+				}
+			});
+
+			if (nativeMethods.DisableStickyKeys())
+			{
+				logger.Info($"Disabled sticky keys.");
+			}
+			else
+			{
+				logger.Error($"Failed to disable sticky keys!");
+			}
+		}
+
+		private string ToString(IStickyKeysState state)
+		{
+			var availability = state.IsAvailable ? "available" : "unavailable";
+			var status = state.IsEnabled ? "enabled" : "disabled";
+			var hotkey = state.IsHotkeyActive ? "active" : "inactive";
+
+			return $"functionality {availability} and {status}, hotkey {hotkey}";
+		}
+	}
+}