gistfile1.rs

//////////////////////////////////
// in rgtk
//////////////////////////////////

impl Window {
    /* ... */

    pub fn connect_destroy_signal(&self, handler: ~WidgetDestroyHandler) {
        let data = unsafe { cast::transmute::<~~WidgetDestroyHandler, ffi::gpointer>(~handler) };
        "destroy".with_c_str(|cstr| {
            unsafe {
                ffi::g_signal_connect_data(self.pointer as ffi::gpointer,
                    cstr,
                    Some(cast::transmute(widget_destroy_callback)),
                    data,
                    Some(drop_widget_destroy_handler),
                    0);
            }
        });
    }
}

pub trait WidgetDestroyHandler {
    fn callback(&mut self, window: &Window);
}

extern "C" fn widget_destroy_callback(object: *ffi::C_GtkWidget, user_data: ffi::gpointer) {
    let mut handler = unsafe { cast::transmute::<ffi::gpointer, ~~WidgetDestroyHandler>(user_data) };

    let mut window = check_pointer!(object, Window).unwrap();
    window.can_drop = false;
    handler.callback(&window);

    unsafe {
        cast::forget(handler);
    }
}

extern "C" fn drop_widget_destroy_handler(data: ffi::gpointer, _closure: *ffi::C_GClosure) {
    unsafe {
        let handler = cast::transmute::<ffi::gpointer, ~~WidgetDestroyHandler>(data);
        drop(handler);
    }
}



//////////////////////////
// Usage
//////////////////////////

#[pkgid="window"];

#[feature(globs)];

extern mod rgtk;

use rgtk::gtk::Window;
use rgtk::gtk::window::WidgetDestroyHandler;
use rgtk::traits::*;

struct Quitter;
impl WidgetDestroyHandler for Quitter {
    fn callback(&mut self, _window: &Window) {
        rgtk::rt::_main_quit();
    }
}

struct Printer;
impl WidgetDestroyHandler for Printer {
    fn callback(&mut self, _window: &Window) {
        println("hellooooo");
    }
}

fn main() {
    rgtk::rt::init();
    let mut w = Window::new(rgtk::GtkWindowTopLevel).unwrap();
    w.connect_destroy_signal(~Quitter as ~WidgetDestroyHandler);
    for _ in range(0, 1000) {
        w.connect_destroy_signal(~Printer as ~WidgetDestroyHandler);
    }
    w.show_all();
    rgtk::rt::_main();
}