macos_game_mode

game

#!/usr/bin/env swift

import Foundation
import AppKit

let handle = dlopen("/System/Library/Frameworks/CoreGraphics.framework/CoreGraphics", RTLD_NOW)

guard let symConnection = dlsym(handle, "_CGSDefaultConnection"), 
    let symSetProp = dlsym(handle, "CGSSetConnectionProperty") else {
    print("Failed to load CGS symbols")
    exit(1)
}

func hideDock() {
    let _ = try? runShell("defaults write com.apple.dock autohide -bool true")
    let _ = try? runShell("killall Dock")
    let _ = try? runShell("defaults write com.apple.dock autohide-delay -float 1000")
    let _ = try? runShell("killall Dock")
    let _ = try? runShell("defaults write com.apple.dock no-bouncing -bool TRUE")
    let _ = try? runShell("killall Dock")
}

func showDock() {
    let _ = try? runShell("defaults write com.apple.dock autohide -bool false")
    let _ = try? runShell("killall Dock")
    let _ = try? runShell("defaults delete com.apple.dock autohide-delay")
    let _ = try? runShell("killall Dock")
    let _ = try? runShell("defaults write com.apple.dock no-bouncing -bool FALSE")
    let _ = try? runShell("killall Dock")
}

@discardableResult
func runShell(_ command: String) throws -> String {
    let task = Process()
    task.launchPath = "/bin/bash"
    task.arguments = ["-c", command]

    let pipe = Pipe()
    task.standardOutput = pipe
    task.standardError = pipe

    try task.run()
    task.waitUntilExit()

    let data = pipe.fileHandleForReading.readDataToEndOfFile()
    return String(data: data, encoding: .utf8) ?? ""
}

func GlobalHideCursor() {
    typealias CGSConnectionID = Int32
    typealias CGError = Int32
    typealias CGSDefaultConnectionFunc = @convention(c) () -> CGSConnectionID
    typealias CGSSetConnectionPropertyFunc = @convention(c) (CGSConnectionID, CGSConnectionID, CFString, CFTypeRef) -> CGError

    let getDefaultConnection = unsafeBitCast(symConnection, to: CGSDefaultConnectionFunc.self)
    let setProperty = unsafeBitCast(symSetProp, to: CGSSetConnectionPropertyFunc.self)

    let conn = getDefaultConnection()
    let kProperty = "SetsCursorInBackground" as CFString
    let result = setProperty(conn, conn, kProperty, kCFBooleanTrue)
    if result != 0 {
        print("failed to activate SetsCursorInBackground")
        exit(1)
    }

    if CGDisplayHideCursor(CGMainDisplayID()) != .success {
        print("failed to hide cursor")
        exit(1)
    }
}

// even with the dock hidden, when the mouse is near on the dock location, it reappears again
// registering global mouse events didn't work either in this "script" mode, so a timer needs to do the job
// CPU time with and without timer was equal, so it doesn't seem to cause too much runtime impact
let interval: TimeInterval = 0.07
let timer = Timer.scheduledTimer(withTimeInterval: interval, repeats: true) { _ in
    GlobalHideCursor()
}

func signalHandler(signal: Int32) -> Void {
    showDock()
    exit(0)
}

signal(SIGINT, signalHandler)
signal(SIGTERM, signalHandler)

hideDock()
print("Running. Press CTRL+C to stop.")
RunLoop.main.run()