Restore SEBPatch

SafeExamBrowser.Core.Contracts/OperationModel/IOperationSequence.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 SafeExamBrowser.Core.Contracts.OperationModel.Events;
+
+namespace SafeExamBrowser.Core.Contracts.OperationModel
+{
+	/// <summary>
+	/// A sequence of <see cref="IOperation"/> which can be used for sequential procedures, e.g. the initialization &amp; finalization of
+	/// an application component. Each operation will be executed failsafe, i.e. the return value will indicate whether a procedure
+	/// completed successfully or not.
+	/// 
+	/// Exemplary execution order for a sequence initialized with operations A, B, C, D:
+	/// 
+	/// <see cref="TryPerform"/>: A -> B -> C -> D.
+	/// <see cref="TryRevert"/>: D -> C -> B -> A.
+	/// </summary>
+	public interface IOperationSequence
+	{
+		/// <summary>
+		/// Event fired when an operation requires user interaction.
+		/// </summary>
+		event ActionRequiredEventHandler ActionRequired;
+
+		/// <summary>
+		/// Event fired when the progress of the sequence has changed.
+		/// </summary>
+		event ProgressChangedEventHandler ProgressChanged;
+
+		/// <summary>
+		/// Event fired when the status of an operation has changed.
+		/// </summary>
+		event StatusChangedEventHandler StatusChanged;
+
+		/// <summary>
+		/// Tries to perform the operations of this sequence according to their initialized order. If any operation fails, the already
+		/// performed operations will be reverted.
+		/// </summary>
+		OperationResult TryPerform();
+
+		/// <summary>
+		/// Tries to revert the operations of this sequence in reversion of their initialized order. The reversion of all operations will
+		/// continue, even if one or multiple operations fail to revert successfully.
+		/// </summary>
+		OperationResult TryRevert();
+	}
+}