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