SEBWIN-821: Implemented always on configuration for display and system.

SafeExamBrowser.Client.UnitTests/Operations/DisplayMonitorOperationTests.cs

@@ -45,13 +45,11 @@ namespace SafeExamBrowser.Client.UnitTests.Operations
 			context.Settings = new AppSettings();
 			context.Settings.Taskbar.EnableTaskbar = true;
 
-			displayMonitor.Setup(d => d.PreventSleepMode()).Callback(() => Assert.AreEqual(++order, 1));
+			displayMonitor.Setup(d => d.InitializePrimaryDisplay(It.IsAny<int>())).Callback(() => Assert.AreEqual(++order, 1));
-			displayMonitor.Setup(d => d.InitializePrimaryDisplay(It.IsAny<int>())).Callback(() => Assert.AreEqual(++order, 2));
+			displayMonitor.Setup(d => d.StartMonitoringDisplayChanges()).Callback(() => Assert.AreEqual(++order, 2));
-			displayMonitor.Setup(d => d.StartMonitoringDisplayChanges()).Callback(() => Assert.AreEqual(++order, 3));
 
 			sut.Perform();
 
-			displayMonitor.Verify(d => d.PreventSleepMode(), Times.Once);
 			displayMonitor.Verify(d => d.InitializePrimaryDisplay(It.IsAny<int>()), Times.Once);
 			displayMonitor.Verify(d => d.StartMonitoringDisplayChanges(), Times.Once);
 		}
@@ -59,7 +57,7 @@ namespace SafeExamBrowser.Client.UnitTests.Operations
 		[TestMethod]
 		public void Perform_MustCorrectlyInitializeDisplayWithTaskbar()
 		{
-			int height = 25;
+			var height = 25;
 
 			context.Settings = new AppSettings();
 			context.Settings.Taskbar.EnableTaskbar = true;
@@ -74,7 +72,7 @@ namespace SafeExamBrowser.Client.UnitTests.Operations
 		[TestMethod]
 		public void Perform_MustCorrectlyInitializeDisplayWithoutTaskbar()
 		{
-			int height = 25;
+			var height = 25;
 
 			context.Settings = new AppSettings();
 			context.Settings.Taskbar.EnableTaskbar = false;

SafeExamBrowser.Client.UnitTests/Operations/ShellOperationTests.cs

@@ -22,6 +22,7 @@ using SafeExamBrowser.SystemComponents.Contracts.Network;
 using SafeExamBrowser.SystemComponents.Contracts.PowerSupply;
 using SafeExamBrowser.UserInterface.Contracts;
 using SafeExamBrowser.UserInterface.Contracts.Shell;
+using SafeExamBrowser.WindowsApi.Contracts;
 
 namespace SafeExamBrowser.Client.UnitTests.Operations
 {
@@ -35,6 +36,7 @@ namespace SafeExamBrowser.Client.UnitTests.Operations
 		private Mock<INotification> aboutNotification;
 		private Mock<IKeyboard> keyboard;
 		private Mock<INotification> logNotification;
+		private Mock<INativeMethods> nativeMethods;
 		private Mock<IPowerSupply> powerSupply;
 		private Mock<ISystemInfo> systemInfo;
 		private Mock<ITaskbar> taskbar;
@@ -55,6 +57,7 @@ namespace SafeExamBrowser.Client.UnitTests.Operations
 			aboutNotification = new Mock<INotification>();
 			keyboard = new Mock<IKeyboard>();
 			logNotification = new Mock<INotification>();
+			nativeMethods = new Mock<INativeMethods>();
 			networkAdapter = new Mock<INetworkAdapter>();
 			powerSupply = new Mock<IPowerSupply>();
 			systemInfo = new Mock<ISystemInfo>();
@@ -77,6 +80,7 @@ namespace SafeExamBrowser.Client.UnitTests.Operations
 				keyboard.Object,
 				logger.Object,
 				logNotification.Object,
+				nativeMethods.Object,
 				networkAdapter.Object,
 				powerSupply.Object,
 				systemInfo.Object,
@@ -185,6 +189,25 @@ namespace SafeExamBrowser.Client.UnitTests.Operations
 			uiFactory.Verify(f => f.CreateApplicationControl(It.Is<IApplication>(a => a == application3.Object), Location.Taskbar), Times.Never);
 		}
 
+		[TestMethod]
+		public void Perform_MustInitializeAlwaysOnState()
+		{
+			context.Settings.Display.AlwaysOn = true;
+			context.Settings.System.AlwaysOn = false;
+
+			sut.Perform();
+
+			nativeMethods.Verify(n => n.SetAlwaysOnState(true, false), Times.Once);
+			nativeMethods.Reset();
+
+			context.Settings.Display.AlwaysOn = false;
+			context.Settings.System.AlwaysOn = true;
+
+			sut.Perform();
+
+			nativeMethods.Verify(n => n.SetAlwaysOnState(false, true), Times.Once);
+		}
+
 		[TestMethod]
 		public void Perform_MustInitializeClock()
 		{

SafeExamBrowser.Client/CompositionRoot.cs

@@ -314,6 +314,7 @@ namespace SafeExamBrowser.Client
 				keyboard,
 				logger,
 				logNotification,
+				nativeMethods,
 				networkAdapter,
 				powerSupply,
 				systemInfo,

SafeExamBrowser.Client/Operations/DisplayMonitorOperation.cs

@@ -17,9 +17,9 @@ namespace SafeExamBrowser.Client.Operations
 {
 	internal class DisplayMonitorOperation : ClientOperation
 	{
-		private IDisplayMonitor displayMonitor;
+		private readonly IDisplayMonitor displayMonitor;
-		private ILogger logger;
+		private readonly ILogger logger;
-		private ITaskbar taskbar;
+		private readonly ITaskbar taskbar;
 
 		public override event ActionRequiredEventHandler ActionRequired { add { } remove { } }
 		public override event StatusChangedEventHandler StatusChanged;
@@ -36,7 +36,6 @@ namespace SafeExamBrowser.Client.Operations
 			logger.Info("Initializing working area...");
 			StatusChanged?.Invoke(TextKey.OperationStatus_InitializeWorkingArea);
 
-			displayMonitor.PreventSleepMode();
 			displayMonitor.InitializePrimaryDisplay(Context.Settings.Taskbar.EnableTaskbar ? taskbar.GetAbsoluteHeight() : 0);
 			displayMonitor.StartMonitoringDisplayChanges();
 

SafeExamBrowser.Client/Operations/ShellOperation.cs

@@ -19,6 +19,7 @@ using SafeExamBrowser.SystemComponents.Contracts.Network;
 using SafeExamBrowser.SystemComponents.Contracts.PowerSupply;
 using SafeExamBrowser.UserInterface.Contracts;
 using SafeExamBrowser.UserInterface.Contracts.Shell;
+using SafeExamBrowser.WindowsApi.Contracts;
 
 namespace SafeExamBrowser.Client.Operations
 {
@@ -30,6 +31,7 @@ namespace SafeExamBrowser.Client.Operations
 		private readonly IKeyboard keyboard;
 		private readonly ILogger logger;
 		private readonly INotification logNotification;
+		private readonly INativeMethods nativeMethods;
 		private readonly INetworkAdapter networkAdapter;
 		private readonly IPowerSupply powerSupply;
 		private readonly ISystemInfo systemInfo;
@@ -49,6 +51,7 @@ namespace SafeExamBrowser.Client.Operations
 			IKeyboard keyboard,
 			ILogger logger,
 			INotification logNotification,
+			INativeMethods nativeMethods,
 			INetworkAdapter networkAdapter,
 			IPowerSupply powerSupply,
 			ISystemInfo systemInfo,
@@ -63,6 +66,7 @@ namespace SafeExamBrowser.Client.Operations
 			this.keyboard = keyboard;
 			this.logger = logger;
 			this.logNotification = logNotification;
+			this.nativeMethods = nativeMethods;
 			this.networkAdapter = networkAdapter;
 			this.powerSupply = powerSupply;
 			this.systemInfo = systemInfo;
@@ -82,6 +86,7 @@ namespace SafeExamBrowser.Client.Operations
 			InitializeTaskbar();
 			InitializeTaskview();
 			InitializeActivators();
+			InitializeAlwaysOnState();
 
 			return OperationResult.Success;
 		}
@@ -150,6 +155,17 @@ namespace SafeExamBrowser.Client.Operations
 			}
 		}
 
+		private void InitializeAlwaysOnState()
+		{
+			var display = Context.Settings.Display.AlwaysOn;
+			var system = Context.Settings.System.AlwaysOn;
+
+			nativeMethods.SetAlwaysOnState(display, system);
+
+			logger.Info($"Display(s) will {(display ? "be always on" : "use the operating system configuration and may turn off")}.");
+			logger.Info($"System will {(system ? "be always on" : "use the operating system configuration and may enter sleep mode or standby")}.");
+		}
+
 		private void InitializeTaskbar()
 		{
 			if (Context.Settings.Taskbar.EnableTaskbar)

SafeExamBrowser.Configuration/ConfigurationData/DataValues.cs

@@ -206,6 +206,7 @@ namespace SafeExamBrowser.Configuration.ConfigurationData
 			settings.ConfigurationMode = ConfigurationMode.Exam;
 
 			settings.Display.AllowedDisplays = 1;
+			settings.Display.AlwaysOn = true;
 			settings.Display.IgnoreError = false;
 			settings.Display.InternalDisplayOnly = false;
 
@@ -296,6 +297,8 @@ namespace SafeExamBrowser.Configuration.ConfigurationData
 
 			settings.SessionMode = SessionMode.Normal;
 
+			settings.System.AlwaysOn = true;
+
 			settings.Taskbar.EnableTaskbar = true;
 			settings.Taskbar.ShowApplicationInfo = false;
 			settings.Taskbar.ShowApplicationLog = false;

SafeExamBrowser.Monitoring.Contracts/Display/IDisplayMonitor.cs

@@ -20,17 +20,12 @@ namespace SafeExamBrowser.Monitoring.Contracts.Display
 		/// Event fired when the primary display or its settings have changed.
 		/// </summary>
 		event DisplayChangedEventHandler DisplayChanged;
-		
+
 		/// <summary>
 		/// Sets the desktop working area to accommodate to the taskbar's height and removes the configured wallpaper (if possible).
 		/// </summary>
 		void InitializePrimaryDisplay(int taskbarHeight);
 
-		/// <summary>
-		/// Prevents the computer from entering sleep mode and turning its display(s) off.
-		/// </summary>
-		void PreventSleepMode();
-
 		/// <summary>
 		/// Resets the desktop working area and wallpaper to their previous (initial) state.
 		/// </summary>

SafeExamBrowser.Monitoring/Display/DisplayMonitor.cs

@@ -26,9 +26,9 @@ namespace SafeExamBrowser.Monitoring.Display
 	public class DisplayMonitor : IDisplayMonitor
 	{
 		private IBounds originalWorkingArea;
-		private ILogger logger;
+		private readonly ILogger logger;
-		private INativeMethods nativeMethods;
+		private readonly INativeMethods nativeMethods;
-		private ISystemInfo systemInfo;
+		private readonly ISystemInfo systemInfo;
 		private string wallpaper;
 
 		public event DisplayChangedEventHandler DisplayChanged;
@@ -46,12 +46,6 @@ namespace SafeExamBrowser.Monitoring.Display
 			InitializeWallpaper();
 		}
 
-		public void PreventSleepMode()
-		{
-			nativeMethods.PreventSleepMode();
-			logger.Info("Disabled sleep mode and display timeout.");
-		}
-
 		public void ResetPrimaryDisplay()
 		{
 			ResetWorkingArea();

SafeExamBrowser.Settings/AppSettings.cs

@@ -15,6 +15,7 @@ using SafeExamBrowser.Settings.Proctoring;
 using SafeExamBrowser.Settings.Security;
 using SafeExamBrowser.Settings.Server;
 using SafeExamBrowser.Settings.Service;
+using SafeExamBrowser.Settings.System;
 using SafeExamBrowser.Settings.SystemComponents;
 using SafeExamBrowser.Settings.UserInterface;
 
@@ -96,6 +97,11 @@ namespace SafeExamBrowser.Settings
 		/// </summary>
 		public SessionMode SessionMode { get; set; }
 
+		/// <summary>
+		/// All system-related settings.
+		/// </summary>
+		public SystemSettings System { get; set; }
+
 		/// <summary>
 		/// All taskbar-related settings.
 		/// </summary>
@@ -119,6 +125,7 @@ namespace SafeExamBrowser.Settings
 			Security = new SecuritySettings();
 			Server = new ServerSettings();
 			Service = new ServiceSettings();
+			System = new SystemSettings();
 			Taskbar = new TaskbarSettings();
 		}
 	}

SafeExamBrowser.Settings/Monitoring/DisplaySettings.cs

@@ -21,6 +21,12 @@ namespace SafeExamBrowser.Settings.Monitoring
 		/// </summary>
 		public int AllowedDisplays { get; set; }
 
+		/// <summary>
+		/// Determines whether the display(s) will remain always on or not. This does not prevent the operating system from entering sleep mode or
+		/// standby, see <see cref="System.SystemSettings.AlwaysOn"/>.
+		/// </summary>
+		public bool AlwaysOn { get; set; }
+
 		/// <summary>
 		/// Determines whether any display configuration may be allowed when the configuration can't be verified due to an error.
 		/// </summary>

SafeExamBrowser.Settings/SafeExamBrowser.Settings.csproj

@@ -92,6 +92,7 @@
     <Compile Include="Service\ServiceSettings.cs" />
     <Compile Include="AppSettings.cs" />
     <Compile Include="SystemComponents\AudioSettings.cs" />
+    <Compile Include="System\SystemSettings.cs" />
     <Compile Include="UserInterface\ActionCenterSettings.cs" />
     <Compile Include="UserInterface\TaskbarSettings.cs" />
     <Compile Include="UserInterface\UserInterfaceMode.cs" />

SafeExamBrowser.Settings/System/SystemSettings.cs

@@ -0,0 +1,25 @@
+/*
+ * Copyright (c) 2023 ETH Zürich, Educational Development and Technology (LET)
+ * 
+ * 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;
+
+namespace SafeExamBrowser.Settings.System
+{
+	/// <summary>
+	/// Defines all settings related to functionality of the operating system.
+	/// </summary>
+	[Serializable]
+	public class SystemSettings
+	{
+		/// <summary>
+		/// Determines whether the system will remain always on or not (i.e. potentially entering sleep mode or standby). This does not prevent the
+		/// display(s) from turning off, see <see cref="Monitoring.DisplaySettings.AlwaysOn"/>.
+		/// </summary>
+		public bool AlwaysOn { get; set; }
+	}
+}

SafeExamBrowser.WindowsApi.Contracts/INativeMethods.cs

@@ -131,11 +131,6 @@ namespace SafeExamBrowser.WindowsApi.Contracts
 		/// </exception>
 		void PostCloseMessageToShell();
 
-		/// <summary>
-		/// Prevents Windows from entering sleep mode and keeps all displays powered on.
-		/// </summary>
-		void PreventSleepMode();
-
 		/// <summary>
 		/// Registers a keyboard hook for the given callback. Returns the identifier of the newly registered hook.
 		/// </summary>
@@ -182,6 +177,12 @@ namespace SafeExamBrowser.WindowsApi.Contracts
 		/// </summary>
 		void SendCloseMessageTo(IntPtr window);
 
+		/// <summary>
+		/// Sets the always on state for the display and the operating system according to the given parameters, i.e. keeps all displays powered on
+		/// and/or prevents Windows from entering sleep mode or standby when set to <c>true</c> respectively.
+		/// </summary>
+		void SetAlwaysOnState(bool display = true, bool system = true);
+
 		/// <summary>
 		/// Sets the wallpaper to the image located at the specified file path.
 		/// </summary>

SafeExamBrowser.WindowsApi/Desktops/DesktopMonitor.cs

@@ -68,6 +68,8 @@ namespace SafeExamBrowser.WindowsApi.Desktops
 					if (name?.Equals(desktop.Name, StringComparison.OrdinalIgnoreCase) != true)
 					{
 						logger.Warn($"Detected desktop switch to '{name}' [{handle}], trying to reactivate {desktop}...");
+
+						// TODO: SEBWIN-827
 						desktop.Activate();
 					}
 				}

SafeExamBrowser.WindowsApi/NativeMethods.cs

@@ -165,7 +165,7 @@ namespace SafeExamBrowser.WindowsApi
 
 		public uint GetProcessIdFor(IntPtr window)
 		{
-			User32.GetWindowThreadProcessId(window, out uint processId);
+			User32.GetWindowThreadProcessId(window, out var processId);
 
 			return processId;
 		}
@@ -178,7 +178,7 @@ namespace SafeExamBrowser.WindowsApi
 		public uint GetShellProcessId()
 		{
 			var handle = GetShellWindowHandle();
-			var threadId = User32.GetWindowThreadProcessId(handle, out uint processId);
+			var threadId = User32.GetWindowThreadProcessId(handle, out var processId);
 
 			return processId;
 		}
@@ -276,11 +276,6 @@ namespace SafeExamBrowser.WindowsApi
 			}
 		}
 
-		public void PreventSleepMode()
-		{
-			Kernel32.SetThreadExecutionState(EXECUTION_STATE.CONTINUOUS | EXECUTION_STATE.DISPLAY_REQUIRED | EXECUTION_STATE.SYSTEM_REQUIRED);
-		}
-
 		public Guid RegisterKeyboardHook(KeyboardHookCallback callback)
 		{
 			var hookId = default(Guid);
@@ -411,6 +406,19 @@ namespace SafeExamBrowser.WindowsApi
 			User32.SendMessage(window, Constant.WM_SYSCOMMAND, (IntPtr) SystemCommand.CLOSE, IntPtr.Zero);
 		}
 
+		public void SetAlwaysOnState(bool display = true, bool system = true)
+		{
+			if (display || system)
+			{
+				var state = EXECUTION_STATE.CONTINUOUS;
+
+				state |= display ? EXECUTION_STATE.DISPLAY_REQUIRED : 0x0;
+				state |= system ? EXECUTION_STATE.SYSTEM_REQUIRED : 0x0;
+
+				Kernel32.SetThreadExecutionState(state);
+			}
+		}
+
 		public void SetWallpaper(string filePath)
 		{
 			var success = User32.SystemParametersInfo(SPI.SETDESKWALLPAPER, 0, filePath, SPIF.NONE);