Enable termination of transform process

Author: MaggieKimani1

src/Microsoft.OpenApi.Hidi/Program.cs

@@ -1,15 +1,13 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT license.
 
+using System;
 using System.CommandLine;
-using System.CommandLine.Builder;
-using System.CommandLine.Hosting;
 using System.CommandLine.Parsing;
-
+using System.Diagnostics;
 using System.IO;
+using System.Threading;
 using System.Threading.Tasks;
-using Microsoft.Extensions.Configuration;
-using Microsoft.Extensions.Hosting;
 using Microsoft.Extensions.Logging;
 using Microsoft.OpenApi.Hidi.Handlers;
 
@@ -19,6 +17,9 @@ static class Program
     {
         static async Task Main(string[] args)
         {
+            // subscribe to CancelKeyPress event to listen for termination requests from users through Ctrl+C or Ctrl+Break keys
+            Console.CancelKeyPress += new ConsoleCancelEventHandler(Console_CancelKeyPressEvent);
+
             var rootCommand = new RootCommand() {
             };
 
@@ -127,5 +128,29 @@ static async Task Main(string[] args)
             //// Wait for logger to write messages to the console before exiting
             await Task.Delay(10);
         }
+
+        /// <summary>
+        /// This event is raised when the user presses either of the two breaking key combinations: Ctrl+C or Ctrl+Break keys.
+        /// </summary>
+        /// <param name="sender"></param>
+        /// <param name="eventArgs"></param>
+        private static void Console_CancelKeyPressEvent(object sender, ConsoleCancelEventArgs eventArgs)
+        {
+            if ((eventArgs.SpecialKey == ConsoleSpecialKey.ControlC) || (eventArgs.SpecialKey == ConsoleSpecialKey.ControlBreak))
+            {
+                Console.WriteLine("CTRL+C pressed, aborting current process...");
+                Thread.Sleep(5000);
+                
+                if (Process.GetCurrentProcess().HasExited)
+                {
+                    Console.WriteLine("Process has already exited.");
+                }
+                else
+                {
+                    Console.WriteLine("Process has not exited, attempting to kill process...");
+                    Process.GetCurrentProcess().Kill();                    
+                }
+            }
+        }        
     }
 }