Restore SEBPatch

SafeExamBrowser.Logging/Logger.cs

@@ -0,0 +1,190 @@
+/*
+ * 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.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading;
+using SafeExamBrowser.Logging.Contracts;
+using SafeExamBrowser.Settings.Logging;
+
+namespace SafeExamBrowser.Logging
+{
+	/// <summary>
+	/// Default, thread-safe implementation of <see cref="ILogger"/>.
+	/// </summary>
+	public class Logger : ILogger
+	{
+		private readonly object @lock = new object();
+		private readonly IList<ILogContent> log = new List<ILogContent>();
+		private readonly IList<ILogObserver> observers = new List<ILogObserver>();
+
+		public LogLevel LogLevel { get; set; }
+
+		public void Debug(string message)
+		{
+			if (message == null)
+			{
+				throw new ArgumentNullException(nameof(message));
+			}
+
+			if (LogLevel <= LogLevel.Debug)
+			{
+				Add(LogLevel.Debug, message);
+			}
+		}
+
+		public void Info(string message)
+		{
+			if (message == null)
+			{
+				throw new ArgumentNullException(nameof(message));
+			}
+
+			if (LogLevel <= LogLevel.Info)
+			{
+				Add(LogLevel.Info, message);
+			}
+		}
+
+		public void Warn(string message)
+		{
+			if (message == null)
+			{
+				throw new ArgumentNullException(nameof(message));
+			}
+
+			if (LogLevel <= LogLevel.Warning)
+			{
+				Add(LogLevel.Warning, message);
+			}
+		}
+
+		public void Error(string message)
+		{
+			if (message == null)
+			{
+				throw new ArgumentNullException(nameof(message));
+			}
+
+			if (LogLevel <= LogLevel.Error)
+			{
+				Add(LogLevel.Error, message);
+			}
+		}
+
+		public void Error(string message, Exception exception)
+		{
+			if (message == null)
+			{
+				throw new ArgumentNullException(nameof(message));
+			}
+
+			if (exception == null)
+			{
+				throw new ArgumentNullException(nameof(exception));
+			}
+
+			var details = new StringBuilder();
+
+			details.AppendLine();
+			details.AppendLine($"   Exception Message: {exception.Message}");
+			details.AppendLine($"   Exception Type: {exception.GetType()}");
+
+			if (exception.StackTrace != null)
+			{
+				details.AppendLine();
+				details.AppendLine(exception.StackTrace);
+			}
+
+			for (var inner = exception.InnerException; inner != null; inner = inner.InnerException)
+			{
+				details.AppendLine();
+				details.AppendLine($"   Inner Exception Message: {inner.Message}");
+				details.AppendLine($"   Inner Exception Type: {inner.GetType()}");
+
+				if (inner.StackTrace != null)
+				{
+					details.AppendLine();
+					details.AppendLine(inner.StackTrace);
+				}
+			}
+
+			if (LogLevel <= LogLevel.Error)
+			{
+				Add(LogLevel.Error, message);
+				Add(new LogText(details.ToString()));
+			}
+		}
+
+		public void Log(string text)
+		{
+			if (text == null)
+			{
+				throw new ArgumentNullException(nameof(text));
+			}
+
+			Add(new LogText(text));
+		}
+
+		public IList<ILogContent> GetLog()
+		{
+			lock (@lock)
+			{
+				return log.Select(m => m.Clone() as ILogContent).ToList();
+			}
+		}
+
+		public void Subscribe(ILogObserver observer)
+		{
+			if (observer == null)
+			{
+				throw new ArgumentNullException(nameof(observer));
+			}
+
+			lock (@lock)
+			{
+				if (!observers.Contains(observer))
+				{
+					observers.Add(observer);
+				}
+			}
+		}
+
+		public void Unsubscribe(ILogObserver observer)
+		{
+			lock (@lock)
+			{
+				observers.Remove(observer);
+			}
+		}
+
+		private void Add(LogLevel severity, string message)
+		{
+			var threadId = Thread.CurrentThread.ManagedThreadId;
+			var threadName = Thread.CurrentThread.Name;
+			var threadInfo = new ThreadInfo(threadId, threadName);
+
+			Add(new LogMessage(DateTime.Now, severity, message, threadInfo));
+		}
+
+		private void Add(ILogContent content)
+		{
+			lock (@lock)
+			{
+				log.Add(content);
+
+				foreach (var observer in observers)
+				{
+					observer.Notify(content);
+				}
+			}
+		}
+	}
+}