Restore SEBPatch

SafeExamBrowser.Client/Coordinator.cs

@@ -0,0 +1,78 @@
+/*
+ * 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.Concurrent;
+using SafeExamBrowser.Client.Contracts;
+
+namespace SafeExamBrowser.Client
+{
+	internal class Coordinator : ICoordinator
+	{
+		private readonly ConcurrentBag<Guid> reconfiguration;
+		private readonly ConcurrentBag<Guid> session;
+
+		internal Coordinator()
+		{
+			reconfiguration = new ConcurrentBag<Guid>();
+			session = new ConcurrentBag<Guid>();
+		}
+
+		public bool IsReconfigurationLocked()
+		{
+			return !reconfiguration.IsEmpty;
+		}
+
+		public bool IsSessionLocked()
+		{
+			return !session.IsEmpty;
+		}
+
+		public void ReleaseReconfigurationLock()
+		{
+			reconfiguration.TryTake(out _);
+		}
+
+		public void ReleaseSessionLock()
+		{
+			session.TryTake(out _);
+		}
+
+		public bool RequestReconfigurationLock()
+		{
+			var acquired = false;
+
+			lock (reconfiguration)
+			{
+				if (reconfiguration.IsEmpty)
+				{
+					reconfiguration.Add(Guid.NewGuid());
+					acquired = true;
+				}
+			}
+
+			return acquired;
+		}
+
+		public bool RequestSessionLock()
+		{
+			var acquired = false;
+
+			lock (session)
+			{
+				if (session.IsEmpty)
+				{
+					session.Add(Guid.NewGuid());
+					acquired = true;
+				}
+			}
+
+			return acquired;
+		}
+	}
+}