NSMachBootstrapServer is deprecated, how can NSXPCConnection be used to register a Mach Service?

I need to write a Mach Service that both my app and a system plugin can talk to, I use the NSMachPort API to create a new port, then register it with NSMachBootstrapServer:

- (void) run
{
    NSMachPort *serverPort = (NSMachPort *)[NSMachPort port];
    [serverPort setDelegate:self];
    [serverPort scheduleInRunLoop:NSRunLoop.currentRunLoop forMode:NSDefaultRunLoopMode];
    [NSMachBootstrapServer.sharedInstance registerPort:serverPort name:@"com.example.MyApp"];

    [NSRunLoop.currentRunLoop run];
}

Clang complains that NSMachBootstrapServer has been deprecated:

warning: 'NSMachBootstrapServer' is deprecated: first deprecated in macOS 10.13 - Use NSXPCConnection instead

How does one use NSXPCConnection to replace the functionality of NSMachBootstrapServer when writing a non-XPC mach service?

That's true: NSMachBootstrapServer class and the majority of its companion classes are deprecated in macOS 10.13 High Sierra.

In macOS 10.14 Mojave and higher you have to use a NSXPCConnection API, that is the Foundation module's part. It's described in the header file NSXPCConnection.h. At the moment it consists of the four main classes:

• NSXPCConnection
• NSXPCInterface
• NSXPCListener
• NSXPCListenerEndpoint

Here's how a XPC Connection process looks like:

And as you can see on a picture, you have to implement a listener.

Here's how a Swift code snippet with listener might look like:

let listener = NSXPCListener(machServiceName: "Name-of-Sample.Helper")
listener.delegate = delegate
listener.resume()
RunLoop.current.run()

Here's how an Obj-C code snippet with listener might look like:

self.listener = [[NSXPCListener alloc] initWithMachServiceName:@"Name-of-Sample.Helper"];
self.listener.delegate = self;
[self.listener resume];
[[NSRunLoop currentRunLoop] run];

If you look at This Post you'll find out how to properly implement all the necessary XPC Connection's objects.

and...

If you look at This Post you'll also find out how it can be used with a Mach Service (there's GitHub link).