ahrightos-process 0.1.0

use core::fmt;
use core::sync::atomic::{AtomicUsize, Ordering};

#[derive(Debug, Clone, Copy, Default, PartialEq, Eq, PartialOrd, Ord)]
pub struct ProcessId(usize);

impl ProcessId {
    pub fn new() -> Self {
        static NEXT_PID: AtomicUsize = AtomicUsize::new(1);
        Self(NEXT_PID.fetch_add(1, Ordering::Relaxed))
    }

    pub fn as_usize(self) -> usize {
        self.0
    }

    pub const fn from_usize(pid: usize) -> Self {
        Self(pid)
    }

    pub fn is_init(self) -> bool {
        self.0 == 1
    }
}

impl fmt::Display for ProcessId {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "{}", self.0)
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn pid_from_usize_preserves_value() {
        assert_eq!(ProcessId::from_usize(42).as_usize(), 42);
    }
}