xarc

xarc provides atomically swappable atomically refcounted smart pointers as a safer building block for lockfree algorithms than raw atomic pointers.

Xarc is comparable to Arc but with the additional ability to atomically be swapped into and out of AtomicXarc. Xarc is dereferenceable but cannot have its contents atomically swapped. AtomicXarc can have its contents atomically swapped but is not dereferenceable.

Here's a fairly minimal example.

use core::sync::atomic::Ordering;
use xarc::{AtomicXarc, Xarc};

let atomic = AtomicXarc::new(42);

let current = atomic.load(Ordering::Acquire);
let loaded = atomic.compare_exchange(&current, &Xarc::null(), Ordering::AcqRel, Ordering::Acquire).unwrap();
assert_eq!(*loaded.maybe_deref().unwrap(), 42);