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# `atomicow`
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A [`Cow`](https://doc.rust-lang.org/std/borrow/enum.Cow.html)-like data structure where owned data is stored inside an [`Arc`](https://doc.rust-lang.org/std/sync/struct.Arc.html).
Here's what it looks like:
```rust, ignore
pub enum CowArc<'a, T: ?Sized + 'static> {
Borrowed(&'a T),
Static(&'static T),
Owned(Arc<T>),
}
```
As implied by the `Cow` name, this type allows for cheap immutable reference, but can be converted into an owned form via cloning when mutation or ownership is required.
This data structure is particularly useful for `str` or other values with a static lifetime,
as might be used in structures such as asset paths.
A `'static str` stored in a `CowArc` can be cloned without allocations or bookkeeping,
while owned values are shared by reference-counting in a thread-safe fashion.
## Comparison to the `cow_arc` crate
The similar [`cow_arc`](https://docs.rs/cow_arc/latest/cow_arc/) crate already exists.
How does `atomicow` differ?
Put simply: `cow_arc`'s data structure is just a wrapper over an `Arc`.
While this is exactly what you need in some use cases,
the enum structure used in `atomicow` is both more transparent and more flexible.
## Contributing
This crate is maintained by the Bevy organization, and is intended to be tiny, stable, zero-dependency, and broadly useful.
[Issues](https://github.com/bevyengine/atomicow/issues) and [pull requests](https://github.com/bevyengine/atomicow/pulls) are genuinely welcome!