# maybe-owned [](https://travis-ci.org/rustonaut/maybe-owned) [](https://crates.io/crates/maybe-owned) [](https://docs.rs/maybe-owned) [](https://img.shields.io/badge/maintenance-passively--maintained-blue.svg) [](https://opensource.org/licenses/MIT) [](https://opensource.org/licenses/Apache-2.0)
**provides a `MaybeOwned<'a,T>` type different to std's `Cow` it implements `From<T>` and `From<&'a T>` and does not require `ToOwned`**
---
This crate provides a `MaybeOwned<'a,T>` enum. Different to `std::borrow::Cow` it
implements `From<T>` and `From<&'a T>` and does not require a `ToOwned` implementation.
While this can be nice for API's mainly consuming T's not implementing `ToOwned` or implementing
`ToOwned` through `Clone` it also means it's borrowed version of `String` is
`&String` and not `&str` making it less performant for cases like `String` or `Vec`.
Documentation can be [viewed on docs.rs](https://docs.rs/maybe-owned).
## Example
Take a look at the [examples dir](./examples) and the documentation
for more complete examples.
The main benefit of `MaybeOwned` over `Cow` is for API design,
allowing API consumer to pass in both `T` and `&'a T`:
```rust
//... in a trait implementation
fn register<D>(&mut self, key: SomeId, data: D)
where D: Into<MaybeOwned<'a, Data>>
{
self.map.entry(key).or_insert_with(||data.into());
}
//...
//... in usage
// use owned data
registry.register(id1, data_owned);
// use a reference to the data
registry.register(id2, &data_ref);
// it ok to use the same reference again
registry.register(id3, &data_ref);
//...
```
## License
Licensed under either of
* Apache License, Version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or http://www.apache.org/licenses/LICENSE-2.0)
* MIT license ([LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT)
at your option.
### Contribution
Unless you explicitly state otherwise, any contribution intentionally submitted
for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any
additional terms or conditions.
## Change Log
- `v0.3.3`:
- added MaybeOwnedMut
- `v0.3.2`:
- added transitive `std::ops` implementations
- `v0.3.1`:
- added `serde` support