Add ILifetimeService interface and AppTokenLifetimeService implementation

Author: mikasoukhov

ComponentModel/ILifetimeService.cs

@@ -0,0 +1,48 @@
+namespace Ecng.ComponentModel;
+
+using System;
+using System.Threading;
+
+/// <summary>
+/// Interface for application lifecycle management.
+/// Provides abstraction over shutdown and restart operations.
+/// </summary>
+public interface ILifetimeService
+{
+	/// <summary>
+	/// Gets the cancellation token that is triggered when the application is shutting down.
+	/// </summary>
+	CancellationToken Token { get; }
+
+	/// <summary>
+	/// Initiates application shutdown.
+	/// </summary>
+	void Shutdown();
+
+	/// <summary>
+	/// Initiates application restart.
+	/// </summary>
+	void Restart();
+}
+
+/// <summary>
+/// Default implementation of <see cref="ILifetimeService"/> using <see cref="AppToken"/>.
+/// </summary>
+/// <param name="restart">Delegate to handle restart logic.</param>
+public class AppTokenLifetimeService(Action restart) : ILifetimeService
+{
+	private readonly Action _restart = restart ?? throw new ArgumentNullException(nameof(restart));
+
+	/// <inheritdoc />
+	public CancellationToken Token => AppToken.Value;
+
+	/// <inheritdoc />
+	public void Shutdown() => AppToken.Shutdown();
+
+	/// <inheritdoc />
+	public void Restart()
+	{
+		_restart();
+		Shutdown();
+	}
+}

Tests/ComponentModel/LifetimeServiceTests.cs

@@ -0,0 +1,107 @@
+namespace Ecng.Tests.ComponentModel;
+
+using Ecng.ComponentModel;
+
+[TestClass]
+public class LifetimeServiceTests : BaseTestClass
+{
+	private class MockLifetimeService : ILifetimeService
+	{
+		private readonly CancellationTokenSource _cts = new();
+
+		public CancellationToken Token => _cts.Token;
+
+		public bool ShutdownCalled { get; private set; }
+		public bool RestartCalled { get; private set; }
+
+		public void Shutdown()
+		{
+			ShutdownCalled = true;
+			_cts.Cancel();
+		}
+
+		public void Restart()
+		{
+			RestartCalled = true;
+			_cts.Cancel();
+		}
+	}
+
+	[TestMethod]
+	public void Token_InitiallyNotCancelled()
+	{
+		var service = new MockLifetimeService();
+		service.Token.IsCancellationRequested.AssertFalse();
+	}
+
+	[TestMethod]
+	public void Shutdown_CancelsToken()
+	{
+		var service = new MockLifetimeService();
+
+		service.Shutdown();
+
+		service.ShutdownCalled.AssertTrue();
+		service.Token.IsCancellationRequested.AssertTrue();
+	}
+
+	[TestMethod]
+	public void Restart_CancelsToken()
+	{
+		var service = new MockLifetimeService();
+
+		service.Restart();
+
+		service.RestartCalled.AssertTrue();
+		service.Token.IsCancellationRequested.AssertTrue();
+	}
+
+	[TestMethod]
+	public void Token_CanBeUsedWithTaskDelay()
+	{
+		var service = new MockLifetimeService();
+
+		var task = Task.Delay(10000, service.Token);
+
+		service.Shutdown();
+
+		ThrowsExactly<TaskCanceledException>(() => task.GetAwaiter().GetResult());
+	}
+
+	[TestMethod]
+	public void MultipleShutdownCalls_DoNotThrow()
+	{
+		var service = new MockLifetimeService();
+
+		service.Shutdown();
+		// Second call should not throw
+		service.Shutdown();
+
+		service.Token.IsCancellationRequested.AssertTrue();
+	}
+
+	[TestMethod]
+	public void AppTokenLifetimeService_TokenReturnsAppToken()
+	{
+		var service = new AppTokenLifetimeService(() => { });
+
+		service.Token.AssertEqual(AppToken.Value);
+	}
+
+	[TestMethod]
+	public void AppTokenLifetimeService_RestartCallsDelegate()
+	{
+		var restartCalled = false;
+		var service = new AppTokenLifetimeService(() => restartCalled = true);
+
+		service.Restart();
+
+		restartCalled.AssertTrue();
+	}
+
+	[TestMethod]
+	public void AppTokenLifetimeService_NullRestartThrows()
+	{
+		ThrowsExactly<ArgumentNullException>(() => new AppTokenLifetimeService(null));
+	}
+}