SEBWIN-220: Replaced guid with abstact InstanceIdentifier for application instances and started to implement logging for browser component.

SafeExamBrowser.Browser/BrowserApplicationController.cs

@@ -24,6 +24,8 @@ namespace SafeExamBrowser.Browser
 {
 	public class BrowserApplicationController : IBrowserApplicationController
 	{
+		private int instanceIdCounter = default(int);
+
 		private AppConfig appConfig;
 		private IApplicationButton button;
 		private IList<IApplicationInstance> instances;
@@ -57,6 +59,8 @@ namespace SafeExamBrowser.Browser
 			var cefSettings = InitializeCefSettings();
 			var success = Cef.Initialize(cefSettings, true, null);
 
+			logger.Info("Initialized CEF.");
+
 			if (!success)
 			{
 				throw new Exception("Failed to initialize the browser engine!");
@@ -75,14 +79,20 @@ namespace SafeExamBrowser.Browser
 			{
 				instance.Terminated -= Instance_Terminated;
 				instance.Window.Close();
+
+				logger.Info($"Terminated browser instance {instance.Id}.");
 			}
 
 			Cef.Shutdown();
+
+			logger.Info("Terminated CEF.");
 		}
 
 		private void CreateNewInstance()
 		{
-			var instance = new BrowserApplicationInstance(appConfig, settings, text, uiFactory, instances.Count == 0);
+			var id = new BrowserInstanceIdentifier(++instanceIdCounter);
+			var isMainInstance = instances.Count == 0;
+			var instance = new BrowserApplicationInstance(appConfig, settings, id, isMainInstance, text, uiFactory);
 
 			instance.Initialize();
 			instance.ConfigurationDownloadRequested += (fileName, args) => ConfigurationDownloadRequested?.Invoke(fileName, args);
@@ -91,36 +101,44 @@ namespace SafeExamBrowser.Browser
 			button.RegisterInstance(instance);
 			instances.Add(instance);
 			instance.Window.Show();
+
+			logger.Info($"Created browser instance {instance.Id}.");
 		}
 
 		private CefSettings InitializeCefSettings()
 		{
+			var warning = appConfig.LogLevel == LogLevel.Warning;
+			var error = appConfig.LogLevel == LogLevel.Error;
 			var cefSettings = new CefSettings
 			{
 				CachePath = appConfig.BrowserCachePath,
 				LogFile = appConfig.BrowserLogFile,
-				// TODO: Set according to current application LogLevel, but avoid verbose!
+				LogSeverity = error ? LogSeverity.Error : (warning ? LogSeverity.Warning : LogSeverity.Info)
-				LogSeverity = LogSeverity.Info
 			};
 
+			logger.Debug($"CEF cache path is '{cefSettings.CachePath}'.");
+			logger.Debug($"CEF log file is '{cefSettings.LogFile}'.");
+			logger.Debug($"CEF log severity is '{cefSettings.LogSeverity}'.");
+
 			return cefSettings;
 		}
 
-		private void Button_OnClick(Guid? instanceId = null)
+		private void Button_OnClick(InstanceIdentifier id = null)
 		{
-			if (instanceId.HasValue)
+			if (id is null)
-			{
-				instances.FirstOrDefault(i => i.Id == instanceId)?.Window?.BringToForeground();
-			}
-			else
 			{
 				CreateNewInstance();
 			}
+			else
+			{
+				instances.FirstOrDefault(i => i.Id == id)?.Window?.BringToForeground();
+			}
 		}
 
-		private void Instance_Terminated(Guid id)
+		private void Instance_Terminated(InstanceIdentifier id)
 		{
 			instances.Remove(instances.FirstOrDefault(i => i.Id == id));
+			logger.Info($"Browser instance {id} was terminated.");
 		}
 	}
 }

SafeExamBrowser.Browser/BrowserApplicationInstance.cs

@@ -6,7 +6,6 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
-using System;
 using SafeExamBrowser.Browser.Handlers;
 using SafeExamBrowser.Contracts.Behaviour;
 using SafeExamBrowser.Contracts.Behaviour.Events;
@@ -30,7 +29,7 @@ namespace SafeExamBrowser.Browser
 		private IText text;
 		private IUserInterfaceFactory uiFactory;
 
-		public Guid Id { get; private set; }
+		public InstanceIdentifier Id { get; private set; }
 		public string Name { get; private set; }
 		public IWindow Window { get { return window; } }
 
@@ -41,11 +40,13 @@ namespace SafeExamBrowser.Browser
 		public BrowserApplicationInstance(
 			AppConfig appConfig,
 			BrowserSettings settings,
+			InstanceIdentifier id,
+			bool isMainInstance,
 			IText text,
-			IUserInterfaceFactory uiFactory,
+			IUserInterfaceFactory uiFactory)
-			bool isMainInstance)
 		{
 			this.appConfig = appConfig;
+			this.Id = id;
 			this.isMainInstance = isMainInstance;
 			this.settings = settings;
 			this.text = text;
@@ -56,7 +57,6 @@ namespace SafeExamBrowser.Browser
 		{
 			var downloadHandler = new DownloadHandler(appConfig, settings);
 
-			Id = Guid.NewGuid();
 			downloadHandler.ConfigurationDownloadRequested += (fileName, args) => ConfigurationDownloadRequested?.Invoke(fileName, args);
 
 			control = new BrowserControl(appConfig, settings, text);

SafeExamBrowser.Browser/BrowserInstanceIdentifier.cs

@@ -0,0 +1,42 @@
+/*
+ * Copyright (c) 2018 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 SafeExamBrowser.Contracts.Behaviour;
+
+namespace SafeExamBrowser.Browser
+{
+	internal class BrowserInstanceIdentifier : InstanceIdentifier
+	{
+		public int Value { get; private set; }
+
+		public BrowserInstanceIdentifier(int id)
+		{
+			Value = id;
+		}
+
+		public override bool Equals(object other)
+		{
+			if (other is BrowserInstanceIdentifier id)
+			{
+				return Value == id.Value;
+			}
+
+			return false;
+		}
+
+		public override int GetHashCode()
+		{
+			return Value.GetHashCode();
+		}
+
+		public override string ToString()
+		{
+			return $"#{Value}";
+		}
+	}
+}

SafeExamBrowser.Browser/SafeExamBrowser.Browser.csproj

@@ -65,6 +65,7 @@
     <Compile Include="BrowserApplicationController.cs" />
     <Compile Include="BrowserApplicationInfo.cs" />
     <Compile Include="BrowserApplicationInstance.cs" />
+    <Compile Include="BrowserInstanceIdentifier.cs" />
     <Compile Include="Handlers\ContextMenuHandler.cs" />
     <Compile Include="BrowserControl.cs">
       <SubType>Component</SubType>

SafeExamBrowser.Client/CompositionRoot.cs

@@ -155,7 +155,7 @@ namespace SafeExamBrowser.Client
 
 		private IOperation BuildBrowserOperation()
 		{
-			var moduleLogger = new ModuleLogger(logger, typeof(BrowserApplicationController));
+			var moduleLogger = new ModuleLogger(logger, "BrowserController");
 			var browserController = new BrowserApplicationController(configuration.AppConfig, configuration.Settings.Browser, moduleLogger, messageBox, text, uiFactory);
 			var browserInfo = new BrowserApplicationInfo();
 			var operation = new BrowserOperation(browserController, browserInfo, logger, Taskbar, uiFactory);

SafeExamBrowser.Configuration/ConfigurationRepository.cs

@@ -11,6 +11,7 @@ using System.IO;
 using System.Reflection;
 using SafeExamBrowser.Contracts.Configuration;
 using SafeExamBrowser.Contracts.Configuration.Settings;
+using SafeExamBrowser.Contracts.Logging;
 
 namespace SafeExamBrowser.Configuration
 {
@@ -81,7 +82,7 @@ namespace SafeExamBrowser.Configuration
 
 			CurrentSettings = new Settings();
 
-			CurrentSettings.KioskMode = KioskMode.DisableExplorerShell;
+			CurrentSettings.KioskMode = KioskMode.None;
 			CurrentSettings.ServicePolicy = ServicePolicy.Optional;
 
 			CurrentSettings.Browser.StartUrl = "https://www.safeexambrowser.org/testing";
@@ -117,6 +118,7 @@ namespace SafeExamBrowser.Configuration
 			appConfig.ConfigurationFileExtension = ".seb";
 			appConfig.DefaultSettingsFileName = "SebClientSettings.seb";
 			appConfig.DownloadDirectory = Path.Combine(appDataFolder, "Downloads");
+			appConfig.LogLevel = LogLevel.Debug;
 			appConfig.ProgramCopyright = executable.GetCustomAttribute<AssemblyCopyrightAttribute>().Copyright;
 			appConfig.ProgramDataFolder = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.CommonApplicationData), nameof(SafeExamBrowser));
 			appConfig.ProgramTitle = executable.GetCustomAttribute<AssemblyTitleAttribute>().Title;

SafeExamBrowser.Contracts/Behaviour/Events/InstanceTerminatedEventHandler.cs

@@ -6,12 +6,11 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
-using System;
 
 namespace SafeExamBrowser.Contracts.Behaviour.Events
 {
 	/// <summary>
 	/// Event handler used to indicate that an application instance with a particular ID has terminated.
 	/// </summary>
-	public delegate void InstanceTerminatedEventHandler(Guid id);
+	public delegate void InstanceTerminatedEventHandler(InstanceIdentifier id);
 }

SafeExamBrowser.Contracts/Behaviour/IApplicationInstance.cs

@@ -6,7 +6,6 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
-using System;
 using SafeExamBrowser.Contracts.Behaviour.Events;
 using SafeExamBrowser.Contracts.UserInterface.Windows;
 
@@ -20,7 +19,7 @@ namespace SafeExamBrowser.Contracts.Behaviour
 		/// <summary>
 		/// The unique identifier for the application instance.
 		/// </summary>
-		Guid Id { get; }
+		InstanceIdentifier Id { get; }
 
 		/// <summary>
 		/// The name or (document) title of the application instance.

SafeExamBrowser.Contracts/Behaviour/InstanceIdentifier.cs

@@ -0,0 +1,41 @@
+/*
+ * Copyright (c) 2018 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.Contracts.Behaviour
+{
+	/// <summary>
+	/// Defines an identifier which uniquely identifies an <see cref="IApplicationInstance"/> in the context of a (third-party) application.
+	/// </summary>
+	public abstract class InstanceIdentifier
+	{
+		/// <summary>
+		/// Determines whether two identifiers are equal (i.e. whether they identify the same <see cref="IApplicationInstance"/>).
+		/// </summary>
+		public static bool operator ==(InstanceIdentifier a, InstanceIdentifier b) => Equals(a, b);
+
+		/// <summary>
+		/// Determines whether two identifiers are different (i.e. whether they identify different <see cref="IApplicationInstance"/>s).
+		/// </summary>
+		public static bool operator !=(InstanceIdentifier a, InstanceIdentifier b) => !Equals(a, b);
+
+		/// <summary>
+		/// Indicates whether the given object is an <see cref="InstanceIdentifier"/> for the same <see cref="IApplicationInstance"/>.
+		/// </summary>
+		public abstract override bool Equals(object other);
+
+		/// <summary>
+		/// Returns a hash code for the identifier.
+		/// </summary>
+		public abstract override int GetHashCode();
+
+		/// <summary>
+		/// Returns a human-readable string representation of the identifier.
+		/// </summary>
+		public abstract override string ToString();
+	}
+}

SafeExamBrowser.Contracts/Configuration/AppConfig.cs

@@ -7,6 +7,7 @@
  */
 
 using System;
+using SafeExamBrowser.Contracts.Logging;
 
 namespace SafeExamBrowser.Contracts.Configuration
 {
@@ -71,6 +72,11 @@ namespace SafeExamBrowser.Contracts.Configuration
 		/// </summary>
 		public string DownloadDirectory { get; set; }
 
+		/// <summary>
+		/// The currently active, global log severity threshold.
+		/// </summary>
+		public LogLevel LogLevel { get; set; }
+
 		/// <summary>
 		/// The copyright information for the application (i.e. the executing assembly).
 		/// </summary>

SafeExamBrowser.Contracts/Logging/ILogger.cs

@@ -17,32 +17,32 @@ namespace SafeExamBrowser.Contracts.Logging
 	public interface ILogger
 	{
 		/// <summary>
-		/// Logs the given message with severity <b>DEBUG</b>.
+		/// Logs the given message with severity <see cref="LogLevel.Debug"/>.
 		/// </summary>
 		/// <exception cref="ArgumentNullException" />
 		void Debug(string message);
 
 		/// <summary>
-		/// Logs the given message with severity <b>INFO</b>.
+		/// Logs the given message with severity <see cref="LogLevel.Info"/>.
 		/// </summary>
 		/// <exception cref="ArgumentNullException" />
 		void Info(string message);
 
 		/// <summary>
-		/// Logs the given message with severity <b>WARNING</b>.
+		/// Logs the given message with severity <see cref="LogLevel.Warning"/>.
 		/// </summary>
 		/// <exception cref="ArgumentNullException" />
 		void Warn(string message);
 
 		/// <summary>
-		/// Logs the given message with severity <b>ERROR</b>.
+		/// Logs the given message with severity <see cref="LogLevel.Error"/>.
 		/// </summary>
 		/// <exception cref="ArgumentNullException" />
 		void Error(string message);
 
 		/// <summary>
-		/// Logs the given message with severity <b>ERROR</b> and includes information about
+		/// Logs the given message with severity <see cref="LogLevel.Error"/> and includes
-		/// the specified exception (i.e. type, message and stacktrace).
+		/// information about the specified exception (i.e. type, message and stacktrace).
 		/// </summary>
 		/// <exception cref="ArgumentNullException" />
 		void Error(string message, Exception exception);
@@ -60,7 +60,7 @@ namespace SafeExamBrowser.Contracts.Logging
 		void Log(ILogContent content);
 
 		/// <summary>
-		/// Suscribes an observer to the application log.
+		/// Subscribes an observer to the application log.
 		/// </summary>
 		/// <exception cref="ArgumentNullException" />
 		void Subscribe(ILogObserver observer);

SafeExamBrowser.Contracts/SafeExamBrowser.Contracts.csproj

@@ -55,6 +55,7 @@
     <Compile Include="Behaviour\Events\InstanceTerminatedEventHandler.cs" />
     <Compile Include="Behaviour\Events\NameChangedEventHandler.cs" />
     <Compile Include="Behaviour\IApplicationController.cs" />
+    <Compile Include="Behaviour\InstanceIdentifier.cs" />
     <Compile Include="Behaviour\IRuntimeController.cs" />
     <Compile Include="Behaviour\OperationModel\IOperationSequence.cs" />
     <Compile Include="Behaviour\OperationModel\OperationResult.cs" />

SafeExamBrowser.Contracts/UserInterface/Taskbar/Events/ApplicationButtonClickedEventHandler.cs

@@ -6,7 +6,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
-using System;
+using SafeExamBrowser.Contracts.Behaviour;
 
 namespace SafeExamBrowser.Contracts.UserInterface.Taskbar.Events
 {
@@ -14,5 +14,5 @@ namespace SafeExamBrowser.Contracts.UserInterface.Taskbar.Events
 	/// Indicates that an <see cref="IApplicationButton"/> has been clicked, optionally specifying the ID of the selected instance (if
 	/// multiple instances of the same application are running).
 	/// </summary>
-	public delegate void ApplicationButtonClickedEventHandler(Guid? instanceId = null);
+	public delegate void ApplicationButtonClickedEventHandler(InstanceIdentifier id = null);
 }

SafeExamBrowser.Contracts/WindowsApi/IExplorerShell.cs

@@ -8,6 +8,9 @@
 
 namespace SafeExamBrowser.Contracts.WindowsApi
 {
+	/// <summary>
+	/// Defines an abstraction of the Windows explorer shell (i.e. the process controlling the GUI of the operating system).
+	/// </summary>
 	public interface IExplorerShell
 	{
 		/// <summary>

SafeExamBrowser.Core/Communication/Proxies/BaseProxy.cs

@@ -23,7 +23,7 @@ namespace SafeExamBrowser.Core.Communication.Proxies
 	public abstract class BaseProxy : ICommunicationProxy
 	{
 		private const int ONE_MINUTE = 60000;
-		private static readonly object @lock = new object();
+		private readonly object @lock = new object();
 
 		private string address;
 		private IProxyObject proxy;

SafeExamBrowser.Core/Logging/LogFileWriter.cs

@@ -17,7 +17,7 @@ namespace SafeExamBrowser.Core.Logging
 	/// </summary>
 	public class LogFileWriter : ILogObserver
 	{
-		private static readonly object @lock = new object();
+		private readonly object @lock = new object();
 		private readonly string filePath;
 		private readonly ILogContentFormatter formatter;
 

SafeExamBrowser.Core/Logging/Logger.cs

@@ -20,7 +20,7 @@ namespace SafeExamBrowser.Core.Logging
 	/// </summary>
 	public class Logger : ILogger
 	{
-		private static readonly object @lock = new object();
+		private readonly object @lock = new object();
 		private readonly IList<ILogContent> log = new List<ILogContent>();
 		private readonly IList<ILogObserver> observers = new List<ILogObserver>();
 

SafeExamBrowser.Core/Logging/ModuleLogger.cs

@@ -18,12 +18,16 @@ namespace SafeExamBrowser.Core.Logging
 	public class ModuleLogger : ILogger
 	{
 		private ILogger logger;
-		private Type module;
+		private string moduleInfo;
 
-		public ModuleLogger(ILogger logger, Type module)
+		public ModuleLogger(ILogger logger, string moduleInfo)
 		{
 			this.logger = logger;
-			this.module = module;
+			this.moduleInfo = moduleInfo;
+		}
+
+		public ModuleLogger(ILogger logger, Type module) : this(logger, module.Name)
+		{
 		}
 
 		public void Debug(string message)
@@ -78,7 +82,7 @@ namespace SafeExamBrowser.Core.Logging
 
 		private string AppendModuleInfo(string message)
 		{
-			return $"[{module.Name}] {message}";
+			return $"[{moduleInfo}] {message}";
 		}
 	}
 }

SafeExamBrowser.UserInterface.Classic/Controls/ApplicationButton.xaml.cs

@@ -6,7 +6,6 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
-using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Windows;
@@ -90,7 +89,7 @@ namespace SafeExamBrowser.UserInterface.Classic.Controls
 			}
 		}
 
-		private void Instance_OnTerminated(Guid id, ApplicationInstanceButton instanceButton)
+		private void Instance_OnTerminated(InstanceIdentifier id, ApplicationInstanceButton instanceButton)
 		{
 			instances.Remove(instances.FirstOrDefault(i => i.Id == id));
 			InstanceStackPanel.Children.Remove(instanceButton);

SafeExamBrowser.UserInterface.Classic/Controls/ApplicationInstanceButton.xaml.cs

@@ -6,23 +6,21 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
-using System;
 using System.Windows;
 using System.Windows.Controls;
 using SafeExamBrowser.Contracts.Behaviour;
 using SafeExamBrowser.Contracts.Configuration;
+using SafeExamBrowser.Contracts.UserInterface.Taskbar.Events;
 using SafeExamBrowser.UserInterface.Classic.Utilities;
 
 namespace SafeExamBrowser.UserInterface.Classic.Controls
 {
-	internal delegate void InstanceButtonClickedEventHandler(Guid instanceId);
-
 	public partial class ApplicationInstanceButton : UserControl
 	{
 		private IApplicationInfo info;
 		private IApplicationInstance instance;
 
-		internal event InstanceButtonClickedEventHandler Clicked;
+		internal event ApplicationButtonClickedEventHandler Clicked;
 
 		public ApplicationInstanceButton(IApplicationInstance instance, IApplicationInfo info)
 		{

SafeExamBrowser.UserInterface.Windows10/Controls/ApplicationButton.xaml.cs

@@ -91,7 +91,7 @@ namespace SafeExamBrowser.UserInterface.Windows10.Controls
 			}
 		}
 
-		private void Instance_OnTerminated(Guid id, ApplicationInstanceButton instanceButton)
+		private void Instance_OnTerminated(InstanceIdentifier id, ApplicationInstanceButton instanceButton)
 		{
 			instances.Remove(instances.FirstOrDefault(i => i.Id == id));
 			InstanceStackPanel.Children.Remove(instanceButton);

SafeExamBrowser.UserInterface.Windows10/Controls/ApplicationInstanceButton.xaml.cs

@@ -6,23 +6,21 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
-using System;
 using System.Windows;
 using System.Windows.Controls;
 using SafeExamBrowser.Contracts.Behaviour;
 using SafeExamBrowser.Contracts.Configuration;
+using SafeExamBrowser.Contracts.UserInterface.Taskbar.Events;
 using SafeExamBrowser.UserInterface.Windows10.Utilities;
 
 namespace SafeExamBrowser.UserInterface.Windows10.Controls
 {
-	internal delegate void InstanceButtonClickedEventHandler(Guid instanceId);
-
 	public partial class ApplicationInstanceButton : UserControl
 	{
 		private IApplicationInfo info;
 		private IApplicationInstance instance;
 
-		internal event InstanceButtonClickedEventHandler Clicked;
+		internal event ApplicationButtonClickedEventHandler Clicked;
 
 		public ApplicationInstanceButton(IApplicationInstance instance, IApplicationInfo info)
 		{