Improved window handling and replaced whitespaces in log file names with underscores.

SafeExamBrowser.Configuration/Settings.cs

@@ -16,16 +16,16 @@ namespace SafeExamBrowser.Configuration
 	public class Settings : ISettings
 	{
 		private const string AppDataFolder = "SafeExamBrowser";
-		private static readonly string LogFileDate = DateTime.Now.ToString("yyyy-MM-dd HH\\hmm\\mss\\s");
+		private static readonly string LogFileDate = DateTime.Now.ToString("yyyy-MM-dd\\_HH\\hmm\\mss\\s");
 
 		public string ApplicationLogFile
 		{
-			get { return Path.Combine(LogFolderPath, $"{LogFileDate} Application.txt"); }
+			get { return Path.Combine(LogFolderPath, $"{LogFileDate}_Application.txt"); }
 		}
 
 		public string BrowserLogFile
 		{
-			get { return Path.Combine(LogFolderPath, $"{LogFileDate} Browser.txt"); }
+			get { return Path.Combine(LogFolderPath, $"{LogFileDate}_Browser.txt"); }
 		}
 
 		public string BrowserCachePath

SafeExamBrowser.Contracts/Monitoring/IProcessMonitor.cs

@@ -20,17 +20,16 @@ namespace SafeExamBrowser.Contracts.Monitoring
 		/// </summary>
 		event ExplorerStartedHandler ExplorerStarted;
 
+		/// <summary>
+		/// Performs a check whether the process associated to the given window is allowed.
+		/// </summary>
+		bool BelongsToAllowedProcess(IntPtr window);
+
 		/// <summary>
 		/// Terminates the Windows explorer shell, i.e. the taskbar.
 		/// </summary>
 		void CloseExplorerShell();
 
-		/// <summary>
-		/// Performs a check whether the process associated to the given window is allowed,
-		/// i.e. whether the specified window should be hidden.
-		/// </summary>
-		void OnWindowChanged(IntPtr window, out bool hide);
-
 		/// <summary>
 		/// Starts a new instance of the Windows explorer shell.
 		/// </summary>

SafeExamBrowser.Contracts/Monitoring/IWindowMonitor.cs

@@ -10,7 +10,7 @@ using System;
 
 namespace SafeExamBrowser.Contracts.Monitoring
 {
-	public delegate void WindowChangedHandler(IntPtr window, out bool hide);
+	public delegate void WindowChangedHandler(IntPtr window);
 
 	public interface IWindowMonitor
 	{
@@ -19,6 +19,16 @@ namespace SafeExamBrowser.Contracts.Monitoring
 		/// </summary>
 		event WindowChangedHandler WindowChanged;
 
+		/// <summary>
+		/// Forcefully closes the specified window.
+		/// </summary>
+		void Close(IntPtr window);
+
+		/// <summary>
+		/// Hides the specified window. Returns <c>true</c> if the window was successfully hidden, otherwise <c>false</c>.
+		/// </summary>
+		bool Hide(IntPtr window);
+
 		/// <summary>
 		/// Hides all currently opened windows.
 		/// </summary>

SafeExamBrowser.Contracts/WindowsApi/INativeMethods.cs

@@ -54,9 +54,9 @@ namespace SafeExamBrowser.Contracts.WindowsApi
 		RECT GetWorkingArea();
 
 		/// <summary>
-		/// Hides the given window.
+		/// Hides the given window. Returns <c>true</c> if successful, otherwise <c>false</c>.
 		/// </summary>
-		void HideWindow(IntPtr window);
+		bool HideWindow(IntPtr window);
 
 		/// <summary>
 		/// Minimizes all open windows.
@@ -88,6 +88,11 @@ namespace SafeExamBrowser.Contracts.WindowsApi
 		/// </summary>
 		void RestoreWindow(IntPtr window);
 
+		/// <summary>
+		/// Sends a close message to the given window.
+		/// </summary>
+		void SendCloseMessageTo(IntPtr window);
+
 		/// <summary>
 		/// Sets the working area of the primary screen according to the given dimensions.
 		/// </summary>

SafeExamBrowser.Core/Behaviour/EventController.cs

@@ -6,6 +6,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
+using System;
 using SafeExamBrowser.Contracts.Behaviour;
 using SafeExamBrowser.Contracts.Configuration;
 using SafeExamBrowser.Contracts.Logging;
@@ -39,13 +40,13 @@ namespace SafeExamBrowser.Core.Behaviour
 		public void Start()
 		{
 			processMonitor.ExplorerStarted += ProcessMonitor_ExplorerStarted;
-			windowMonitor.WindowChanged += processMonitor.OnWindowChanged;
+			windowMonitor.WindowChanged += WindowMonitor_WindowChanged;
 		}
 
 		public void Stop()
 		{
 			processMonitor.ExplorerStarted -= ProcessMonitor_ExplorerStarted;
-			windowMonitor.WindowChanged -= processMonitor.OnWindowChanged;
+			windowMonitor.WindowChanged -= WindowMonitor_WindowChanged;
 		}
 
 		private void ProcessMonitor_ExplorerStarted()
@@ -56,7 +57,22 @@ namespace SafeExamBrowser.Core.Behaviour
 			workingArea.InitializeFor(taskbar);
 			logger.Info("Reinitializing taskbar bounds...");
 			taskbar.InitializeBounds();
-			logger.Info("Desktop successfully restored!");
+			logger.Info("Desktop successfully restored.");
+		}
+
+		private void WindowMonitor_WindowChanged(IntPtr window)
+		{
+			var allowed = processMonitor.BelongsToAllowedProcess(window);
+
+			if (!allowed)
+			{
+				var success = windowMonitor.Hide(window);
+
+				if (!success)
+				{
+					windowMonitor.Close(window);
+				}
+			}
 		}
 	}
 }

SafeExamBrowser.Monitoring/Processes/ProcessMonitor.cs

@@ -32,6 +32,26 @@ namespace SafeExamBrowser.Monitoring.Processes
 			this.nativeMethods = nativeMethods;
 		}
 
+		public bool BelongsToAllowedProcess(IntPtr window)
+		{
+			var processId = nativeMethods.GetProcessIdFor(window);
+			var process = Process.GetProcessById(Convert.ToInt32(processId));
+
+			if (process != null)
+			{
+				var allowed = process.ProcessName == "SafeExamBrowser";
+
+				if (!allowed)
+				{
+					logger.Warn($"Window with handle = {window} belongs to not allowed process '{process.ProcessName}'!");
+				}
+
+				return allowed;
+			}
+
+			return true;
+		}
+
 		public void CloseExplorerShell()
 		{
 			var processId = nativeMethods.GetShellProcessId();
@@ -58,21 +78,6 @@ namespace SafeExamBrowser.Monitoring.Processes
 			}
 		}
 
-		public void OnWindowChanged(IntPtr window, out bool hide)
-		{
-			var processId = nativeMethods.GetProcessIdFor(window);
-			var process = Process.GetProcessById(Convert.ToInt32(processId));
-
-			if (process != null)
-			{
-				hide = process.ProcessName != "SafeExamBrowser";
-			}
-			else
-			{
-				hide = true;
-			}
-		}
-
 		public void StartExplorerShell()
 		{
 			var process = new Process();

SafeExamBrowser.Monitoring/Windows/WindowMonitor.cs

@@ -30,6 +30,31 @@ namespace SafeExamBrowser.Monitoring.Windows
 			this.nativeMethods = nativeMethods;
 		}
 
+		public void Close(IntPtr window)
+		{
+			var title = nativeMethods.GetWindowTitle(window);
+
+			nativeMethods.SendCloseMessageTo(window);
+			logger.Info($"Sent close message to window '{title}' with handle = {window}.");
+		}
+
+		public bool Hide(IntPtr window)
+		{
+			var title = nativeMethods.GetWindowTitle(window);
+			var success = nativeMethods.HideWindow(window);
+
+			if (success)
+			{
+				logger.Info($"Hid window '{title}' with handle = {window}.");
+			}
+			else
+			{
+				logger.Warn($"Failed to hide window '{title}' with handle = {window}!");
+			}
+
+			return success;
+		}
+
 		public void HideAllWindows()
 		{
 			logger.Info("Saving windows to be minimized...");
@@ -90,18 +115,7 @@ namespace SafeExamBrowser.Monitoring.Windows
 
 		private void OnWindowChanged(IntPtr window)
 		{
-			if (WindowChanged != null)
+			WindowChanged?.Invoke(window);
-			{
-				WindowChanged.Invoke(window, out bool hide);
-
-				if (hide)
-				{
-					var title = nativeMethods.GetWindowTitle(window);
-
-					nativeMethods.HideWindow(window);
-					logger.Info($"Hid window '{title}' with handle = {window}.");
-				}
-			}
 		}
 
 		private struct Window

SafeExamBrowser.WindowsApi/Constants/Constant.cs

@@ -48,5 +48,13 @@ namespace SafeExamBrowser.WindowsApi.Constants
 		/// See https://msdn.microsoft.com/en-us/library/windows/desktop/ms647591(v=vs.85).aspx.
 		/// </summary>
 		internal const int WM_COMMAND = 0x111;
+
+		/// <summary>
+		/// A window receives this message when the user chooses a command from the Window menu (formerly known as the system or control
+		/// menu) or when the user chooses the maximize button, minimize button, restore button, or close button.
+		/// 
+		/// See https://msdn.microsoft.com/en-us/library/windows/desktop/ms646360(v=vs.85).aspx.
+		/// </summary>
+		internal const int WM_SYSCOMMAND = 0x112;
 	}
 }

SafeExamBrowser.WindowsApi/Constants/SystemCommand.cs

@@ -0,0 +1,21 @@
+/*
+ * Copyright (c) 2017 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/.
+ */
+
+namespace SafeExamBrowser.WindowsApi.Constants
+{
+	/// <summary>
+	/// See https://msdn.microsoft.com/en-us/library/windows/desktop/ms646360(v=vs.85).aspx.
+	/// </summary>
+	internal enum SystemCommand
+	{
+		/// <summary>
+		/// Closes the window.
+		/// </summary>
+		CLOSE = 0xF060
+	}
+}

SafeExamBrowser.WindowsApi/NativeMethods.cs

@@ -1,10 +1,10 @@
 /*
-* Copyright (c) 2017 ETH Zürich, Educational Development and Technology (LET)
+ * Copyright (c) 2017 ETH Zürich, Educational Development and Technology (LET)
-* 
+ * 
-* This Source Code Form is subject to the terms of the Mozilla Public
+ * 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
+ * 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/.
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
-*/
+ */
 
 using System;
 using System.Collections.Concurrent;
@@ -92,9 +92,9 @@ namespace SafeExamBrowser.WindowsApi
 			return workingArea;
 		}
 
-		public void HideWindow(IntPtr window)
+		public bool HideWindow(IntPtr window)
 		{
-			User32.ShowWindow(window, (int)ShowWindowCommand.Hide);
+			return User32.ShowWindow(window, (int) ShowWindowCommand.Hide);
 		}
 
 		public void MinimizeAllOpenWindows()
@@ -157,6 +157,11 @@ namespace SafeExamBrowser.WindowsApi
 			User32.ShowWindow(window, (int)ShowWindowCommand.Restore);
 		}
 
+		public void SendCloseMessageTo(IntPtr window)
+		{
+			User32.SendMessage(window, Constant.WM_SYSCOMMAND, (IntPtr) SystemCommand.CLOSE, IntPtr.Zero);
+		}
+
 		public void SetWorkingArea(RECT bounds)
 		{
 			var success = User32.SystemParametersInfo(SPI.SETWORKAREA, 0, ref bounds, SPIF.UPDATEANDCHANGE);

SafeExamBrowser.WindowsApi/SafeExamBrowser.WindowsApi.csproj

@@ -60,6 +60,7 @@
   <ItemGroup>
     <Compile Include="Constants\Constant.cs" />
     <Compile Include="Constants\ShowWindowCommand.cs" />
+    <Compile Include="Constants\SystemCommand.cs" />
     <Compile Include="NativeMethods.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="Constants\SPI.cs" />