Expand description
A type-branded cell for aliasing checked at compile-time.
It’s based on the prior work of GhostCell, but trades lifetime brands for type brands.
§Usage
The interface of this crate is very similar to that of GhostCell. The main
difference is that “tokens” are type brands from
type-factory instead of lifetime brands.
use toast_cell::{type_factory, Cell};
// Create a unique token.
type_factory::with(|mut token| {
let cell = Cell::new(0);
// These are all references to the same cell, but we can still mutate it safely!
let references = [&cell, &cell, &cell];
for cell in references {
*cell.borrow_mut(&mut token) += 1;
}
assert_eq!(cell.into_inner(), 3);
});As impl Unique brand types cannot be copied and are
exclusively borrowed for mutation, Cells of the same brand are
guaranteed to never alias.
type_factory::with(|mut token| {
let cell = Cell::new("Ghost");
let borrow1 = cell.borrow_mut(&mut token);
let borrow2 = cell.borrow_mut(&mut token);
// error: cannot borrow `token` as mutable more than once at a time
*borrow1 = "Toast";
});It is also guaranteed that cells used with one brand are incompatible with other brands.
type_factory::with(|token| {
let (mut token, mut other_token) = type_factory::split(token);
let cell = Cell::new(41);
*cell.borrow_mut(&mut token) += 1; // ✅
*cell.borrow_mut(&mut other_token) -= 1; // ❌
});§How does it work?
The documentation of this crate is currently rather sparse. I recommend
reading the documentation of
ghost-cell for more information on
the exact properties of GhostCell.
§Safety
Unlike GhostCell, this crate has not been formally proven. Use at your own risk.
§Minimum supported Rust version
The MSRV is currently 1.83.
This may change between minor releases.
§License
This crate is licensed under the Blue Oak Model License 1.0.0.
Re-exports§
pub use type_factory;