LaxCow

Clone-on-write smart pointer similar to Cow, but with relaxed trait constraints. Crate is totally no_std.

Examples

Simple usage

use laxcow::LaxCow;

let lc = LaxCow::Borrowed("foobar");

let lc2 = lc.clone();
assert_eq!(lc2, LaxCow::Borrowed("foobar"));

let owned = lc.into_owned();
assert_eq!(owned, "foobar".to_owned());

Usage not possible with `Cow`

Storing a borrowed struct which doesn't implement Clone. This is possible because LaxCow::Owned variant is not restricted by the LaxCow::Borrowed variant via ToOwned trait.

use laxcow::LaxCow;

struct Foo;

// We don't care about the owned type as it is not used.
let laxcow = LaxCow::<_, ()>::Borrowed(&Foo);

`Cow` definition by wrapping `LaxCow`

This example shows the difference between LaxCow and Cow. It makes Cow a struct, but only works here as an example.

use laxcow::LaxCow;

struct Cow<'a, T: ?Sized + ToOwned>(LaxCow::<'a, T, <T as ToOwned>::Owned>);

Usability without `alloc`

LaxCow can be used without alloc but this restricts the usage quite a bit as ToOwned is defined in alloc. Interaction with Cow also is not possible. It is also debatable if clone-on-write functionality is useful in no_std environment, but this crate tries not to make any assumptions about the usage.

License

Licensed under either of

Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.

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.

kauppie/laxcow