フォークの奪い合いの様子を可視化

Dining_philosophers.rs

// Dining Philosophers
use std::thread;
use std::time::Duration;
use std::sync::{Arc, Mutex};

struct Table {
    forks: Vec<Mutex<()>>,
}

struct Philosopher {
    name: String,
    left: usize,
    right: usize,
}

impl Philosopher {
    fn new(name: &str, left: usize, right: usize) -> Philosopher {
        Philosopher {
            name: name.to_string(),
            left: left,
            right: right,
        }
    }

    fn eat(&self, table: &Table) {
        let l = table.forks[self.left].lock().unwrap();
        println!("Fork {} is in the left hand of {}.", self.left, self.name);

        thread::sleep(Duration::from_millis(150));

        let r = table.forks[self.right].lock().unwrap();
        println!("Fork {} is in the right hand of {}.", self.right, self.name);

        println!("{} is eating.", self.name);
        thread::sleep(Duration::from_millis(1000));
        println!("{} is done eating.", self.name);
    }
}

fn main() {

    let table = Arc::new(Table { forks: vec![
        Mutex::new(()),
        Mutex::new(()),
        Mutex::new(()),
        Mutex::new(()),
        Mutex::new(()),
    ]});

    let philosophers = vec![
        Philosopher::new("Judith Butler", 0, 1),
        Philosopher::new("Gilles Deleuze", 1, 2),
        Philosopher::new("Karl Marx", 2, 3),
        Philosopher::new("Emma Goldman", 3, 4),
        Philosopher::new("Michel Foucault", 0, 4),
    ];

    let handles: Vec<_> = philosophers.into_iter().map(|p| {
        let table = table.clone();

        thread::spawn(move || {
            p.eat(&table);
        })
    }).collect();

    for h in handles {
        h.join().unwrap();
    }
}

Output

Fork 0 is in the left hand of Judith Butler.
Fork 2 is in the left hand of Karl Marx.
Fork 1 is in the left hand of Gilles Deleuze.
Fork 3 is in the left hand of Emma Goldman.
Fork 4 is in the right hand of Emma Goldman.
Emma Goldman is eating.
Emma Goldman is done eating.
Fork 3 is in the right hand of Karl Marx.
Karl Marx is eating.
Karl Marx is done eating.
Fork 2 is in the right hand of Gilles Deleuze.
Gilles Deleuze is eating.
Gilles Deleuze is done eating.
Fork 1 is in the right hand of Judith Butler.
Judith Butler is eating.
Judith Butler is done eating.
Fork 0 is in the left hand of Michel Foucault.
Fork 4 is in the right hand of Michel Foucault.
Michel Foucault is eating.
Michel Foucault is done eating.