dock.rs

#![allow(non_snake_case, non_upper_case_globals)]

use std::{
  sync::Mutex,
  time::{Duration, Instant},
};

use cocoa::base::{id, NO};

#[link(name = "ApplicationServices", kind = "framework")]
extern "C" {
  fn TransformProcessType(psn: *const ProcessSerialNumber, transformState: i32) -> i32;
}

#[repr(C)]
struct ProcessSerialNumber {
  highLongOfPSN: u32,
  lowLongOfPSN: u32,
}

/// https://developer.apple.com/documentation/applicationservices/1501096-anonymous/kcurrentprocess?language=objc
pub const kCurrentProcess: u32 = 2;
/// https://developer.apple.com/documentation/applicationservices/1501117-anonymous/kprocesstransformtouielementapplication?language=objc
pub const kProcessTransformToUIElementApplication: i32 = 4;
/// https://developer.apple.com/documentation/applicationservices/1501117-anonymous/kprocesstransformtoforegroundapplication?language=objc
pub const kProcessTransformToForegroundApplication: i32 = 1;

lazy_static! {
  static ref LAST_DOCK_SHOW: Mutex<Option<Instant>> = Mutex::new(None);
}

pub fn set_dock_visibility(visible: bool) {
  if visible {
    set_dock_show();
  } else {
    set_dock_hide();
  }
}

fn set_dock_hide() {
  // Transforming application state from UIElement to Foreground is an
  // asynchronous operation, and unfortunately there is currently no way to know
  // when it is finished.
  // So if we call DockHide => DockShow => DockHide => DockShow in a very short
  // time, we would trigger a bug of macOS that, there would be multiple dock
  // icons of the app left in system.
  // To work around this, we make sure DockHide does nothing if it is called
  // immediately after DockShow. After some experiments, 1 second seems to be
  // a proper interval.
  let now = Instant::now();
  let last_dock_show = LAST_DOCK_SHOW.lock().unwrap();
  if let Some(last_dock_show_time) = *last_dock_show {
    if now.duration_since(last_dock_show_time) < Duration::new(1, 0) {
      return;
    }
  }

  unsafe {
    let app: id = msg_send![class!(NSApplication), sharedApplication];
    let windows: id = msg_send![app, windows];

    // Assuming windows is an NSArray, and calling setCanHide on each window
    let selector = sel!(setCanHide:);
    let _: () = msg_send![windows, makeObjectsPerformSelector:selector withObject:NO];

    let psn = ProcessSerialNumber {
      highLongOfPSN: 0,
      lowLongOfPSN: kCurrentProcess,
    };
    TransformProcessType(&psn, kProcessTransformToUIElementApplication);
  }
}

fn set_dock_show() {
  let now = Instant::now();
  let mut last_dock_show = LAST_DOCK_SHOW.lock().unwrap();
  *last_dock_show = Some(now);

  unsafe {
    let psn = ProcessSerialNumber {
      highLongOfPSN: 0,
      lowLongOfPSN: kCurrentProcess,
    };

    TransformProcessType(&psn, kProcessTransformToForegroundApplication);
  }
}