Helps disable Mac keyboards by eating up key presses

AppDelegate.swift

import Cocoa

@main
class AppDelegate: NSObject, NSApplicationDelegate {
    var eventTap: CFMachPort?
    

    func applicationDidFinishLaunching(_ aNotification: Notification) {
        let eventMask = (1 << CGEventType.keyDown.rawValue) | (1 << CGEventType.keyUp.rawValue)

        guard let tap = CGEvent.tapCreate(
            tap: .cgSessionEventTap,
            place: .headInsertEventTap,
            options: .defaultTap,
            eventsOfInterest: CGEventMask(eventMask),
            callback: { _, _, _, _ in
                return nil
            },
            userInfo: nil
        ) else {
            print("Failed to create event tap.")
            NSApp.terminate(nil)
            return
        }

        eventTap = tap
        
        let runLoopSource = CFMachPortCreateRunLoopSource(kCFAllocatorDefault, tap, 0)
        CFRunLoopAddSource(CFRunLoopGetCurrent(), runLoopSource, .commonModes)
        CGEvent.tapEnable(tap: tap, enable: true)
    }

    func applicationWillTerminate(_ aNotification: Notification) {
        if let tap = eventTap {
            CGEvent.tapEnable(tap: tap, enable: false)
        }
    }

    func applicationSupportsSecureRestorableState(_ app: NSApplication) -> Bool {
        return true
    }


}