Assorted smart pointers for Rust.
Features:
Strong / Weak / Ref / RefMut
This is like Rc<RefCell<T>>, but with slightly different trade-offs:
-
Configurable overhead (compared to a fixed 24 or 12 for
Rc<RefCell<T>>) -
The default of 4 bytes overhead gives you max 64 immutable references, 4096 strong references and 4096 weak references, but this can easily be tweaked with just a few lines of code.
-
Poisoning support - after a panic with an active mutable reference, trying to get mutable or immutable references will return an error. This can be reverted by calling unpoison().
Maybe something for your next tree with parent pointers?
ARef
ARef takes over where OwningRef ends, by abstracting the owner even further.
This makes it possible to return, say, an ARef<str> and have the caller drop the owner
when done looking at it, without having to bother about whether the owner is a String, Rc<String>, a
Ref<String>, a simple &'static str or something else.
It's also repr(C), so it can be transferred over an FFI boundary (if its target is repr(C), too).
RMBA
The RMBA wraps either a &T, &mut T, Box<T> or Arc<T> within the size of a single pointer.
There are two gotchas here:
-
It will panic if you try to store a struct that's not 32 bit aligned.
-
Drop flags were removed in 1.13-nightly. If you run an earlier version, size might be larger than a single pointer due to the drop flag.
Bx, Bxm
These are just simple wrappers around Box that lets you get rid of DerefMove.
This way you can return a Bx in your API and still be sure the inner struct does not move in memory. (This might be helpful if you're dealing with FFI or unsafe code.)
License
Apache 2.0 or MIT, at your preference.