use std::{thread, time::Duration};
use happylock::{LockCollection, Mutex, ThreadKey};
static PHILOSOPHERS: [Philosopher; 5] = [
Philosopher {
name: "Socrates",
left: 0,
right: 1,
},
Philosopher {
name: "John Rawls",
left: 1,
right: 2,
},
Philosopher {
name: "Jeremy Bentham",
left: 2,
right: 3,
},
Philosopher {
name: "John Stuart Mill",
left: 3,
right: 4,
},
Philosopher {
name: "Judith Butler",
left: 4,
right: 0,
},
];
static FORKS: [Mutex<()>; 5] = [
Mutex::new(()),
Mutex::new(()),
Mutex::new(()),
Mutex::new(()),
Mutex::new(()),
];
struct Philosopher {
name: &'static str,
left: usize,
right: usize,
}
impl Philosopher {
fn cycle(&self) {
let key = ThreadKey::lock().unwrap();
thread::sleep(Duration::from_secs(1));
// safety: no philosopher asks for the same fork twice
let forks =
unsafe { LockCollection::new_unchecked([&FORKS[self.left], &FORKS[self.right]]) };
let forks = forks.lock(key);
println!("{} is eating...", self.name);
thread::sleep(Duration::from_secs(1));
println!("{} is done eating", self.name);
drop(forks);
}
}
fn main() {
let handles = PHILOSOPHERS
.iter()
.map(|philosopher| thread::spawn(move || philosopher.cycle()));
for handle in handles {
_ = handle.join();
}
}
|
