Regular Rust Async Example

main.rs

use std::{sync::{mpsc::channel, Arc, Mutex}, thread, time::Duration};

fn main() {
    let result = run();
    assert_eq!(result, 3)
}

struct Counter {
    value: u32,
}

fn run() -> u32 {
    let counter = Arc::new(Mutex::new(Counter { value: 0 }));

    let (snd, rcv) = channel::<()>();
    let snd_arc = Arc::new(snd);

    let counter_1 = Arc::clone(&counter);
    let done_1 = Arc::clone(&snd_arc);
    thread::spawn(move || {
        thread::sleep(Duration::new(1, 0));
        counter_1.lock().unwrap().value += 1;
        done_1.send(())
    });

    let counter_2 = Arc::clone(&counter);
    let done_2 = Arc::clone(&snd_arc);
    thread::spawn(move || {
        thread::sleep(Duration::new(3, 0));
        counter_2.lock().unwrap().value += 1;
        done_2.send(())
    });

    let counter_3 = Arc::clone(&counter);
    let done_3 = Arc::clone(&snd_arc);
    thread::spawn(move || {
        thread::sleep(Duration::new(2, 0));
        counter_3.lock().unwrap().value += 1;
        done_3.send(())
    });

    while Arc::strong_count(&snd_arc) > 1 {
        let _ = rcv.recv();
    };

    let final_value = counter.lock().unwrap().value;
    final_value
}