Restore SEBPatch

SafeExamBrowser.Logging/LogFileWriter.cs

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+/*
+ * 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.IO;
+using System.Text;
+using SafeExamBrowser.Logging.Contracts;
+
+namespace SafeExamBrowser.Logging
+{
+	/// <summary>
+	/// <see cref="ILogObserver"/> which immediately saves new log content to disk.
+	/// </summary>
+	public class LogFileWriter : ILogObserver
+	{
+		private readonly object @lock = new object();
+		private readonly string filePath;
+		private readonly ILogContentFormatter formatter;
+
+		public LogFileWriter(ILogContentFormatter formatter, string filePath)
+		{
+			this.filePath = filePath;
+			this.formatter = formatter;
+		}
+
+		public void Initialize()
+		{
+			var directory = Path.GetDirectoryName(filePath);
+
+			if (!Directory.Exists(directory))
+			{
+				Directory.CreateDirectory(directory);
+			}
+		}
+
+		public void Notify(ILogContent content)
+		{
+			lock (@lock)
+			{
+				var raw = formatter.Format(content);
+
+				using (var stream = new StreamWriter(filePath, true, Encoding.UTF8))
+				{
+					stream.WriteLine(raw);
+				}
+			}
+		}
+	}
+}