orx-concurrent-option 1.6.0

ConcurrentOption is a lock-free concurrent read and write option type.
Documentation 
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#![cfg(not(miri))]

use orx_concurrent_option::*;
use std::time::Duration;
use test_case::test_matrix;

#[cfg(not(miri))]
const N: usize = 100;
#[cfg(miri)]
const N: usize = 15;

#[test_matrix(
    [2, 4, 8, 16],
    [false, true]
)]
fn concurrent_insert_single_writer(num_readers: usize, do_sleep: bool) {
    let maybe = ConcurrentOption::some(7.to_string());
    let maybe_ref = &maybe;

    std::thread::scope(|s| {
        for _ in 0..(num_readers / 2) {
            s.spawn(move || reader(do_sleep, maybe_ref));
        }

        s.spawn(move || inserter(do_sleep, maybe_ref));

        for _ in 0..(num_readers / 2) {
            s.spawn(move || reader(do_sleep, maybe_ref));
        }
    });
}

#[test_matrix(
    [4, 8],
    [2, 4, 8, 16],
    [false, true]
)]
fn concurrent_insert_multiple_writer(num_writers: usize, num_readers: usize, do_sleep: bool) {
    let maybe = ConcurrentOption::some(9.to_string());
    let maybe_ref = &maybe;

    std::thread::scope(|s| {
        for _ in 0..(num_writers / 2) {
            s.spawn(move || inserter(do_sleep, maybe_ref));
        }

        for _ in 0..num_readers {
            s.spawn(move || reader(do_sleep, maybe_ref));
        }

        for _ in 0..(num_writers / 2) {
            s.spawn(move || inserter(do_sleep, maybe_ref));
        }
    });
}

// helpers
fn reader(do_sleep: bool, maybe: &ConcurrentOption<String>) {
    for _ in 0..N {
        sleep(do_sleep);

        let is_nine_or_seven = maybe
            .map(|x| x == &7.to_string() || x == &9.to_string())
            .unwrap_or(false);
        assert!(is_nine_or_seven);
    }
}

fn inserter(do_sleep: bool, maybe: &ConcurrentOption<String>) {
    for i in 0..N {
        sleep(do_sleep);
        match i % 5 {
            1 => {
                let _ = unsafe { maybe.insert(7.to_string()) };
            }
            3 => {
                let _ = unsafe { maybe.insert(9.to_string()) };
            }
            _ => {}
        }
    }
}

fn sleep(do_sleep: bool) {
    if do_sleep {
        let duration = Duration::from_millis(24);
        std::thread::sleep(duration);
    }
}