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diff --git a/third_party/rust/owning_ref/README.md b/third_party/rust/owning_ref/README.md new file mode 100644 index 0000000000..ad32ac24fd --- /dev/null +++ b/third_party/rust/owning_ref/README.md @@ -0,0 +1,64 @@ +[![Build Status](https://travis-ci.org/Kimundi/owning-ref-rs.svg)](https://travis-ci.org/Kimundi/owning-ref-rs) +[![Crate](https://img.shields.io/crates/v/owning_ref.svg)](https://crates.io/crates/owning_ref) +[![Docs](https://docs.rs/owning_ref/badge.svg)](https://docs.rs/owning_ref) + +owning-ref-rs +============== + +A library for creating references that carry their owner with them. + +This can sometimes be useful because Rust borrowing rules normally prevent +moving a type that has been borrowed from. For example, this kind of code gets rejected: + +```rust +fn return_owned_and_referenced<'a>() -> (Vec<u8>, &'a [u8]) { + let v = vec![1, 2, 3, 4]; + let s = &v[1..3]; + (v, s) +} +``` + +This library enables this safe usage by keeping the owner and the reference +bundled together in a wrapper type that ensure that lifetime constraint: + +```rust +fn return_owned_and_referenced() -> OwningRef<Vec<u8>, [u8]> { + let v = vec![1, 2, 3, 4]; + let or = OwningRef::new(v); + let or = or.map(|v| &v[1..3]); + or +} +``` + +## Getting Started + +To get started, add the following to `Cargo.toml`. + +```toml +owning_ref = "0.4.1" +``` + +...and see the [docs](http://kimundi.github.io/owning-ref-rs/owning_ref/index.html) for how to use it. + + +## Example + +```rust +extern crate owning_ref; +use owning_ref::BoxRef; + +fn main() { + // Create an array owned by a Box. + let arr = Box::new([1, 2, 3, 4]) as Box<[i32]>; + + // Transfer into a BoxRef. + let arr: BoxRef<[i32]> = BoxRef::new(arr); + assert_eq!(&*arr, &[1, 2, 3, 4]); + + // We can slice the array without losing ownership or changing type. + let arr: BoxRef<[i32]> = arr.map(|arr| &arr[1..3]); + assert_eq!(&*arr, &[2, 3]); + + // Also works for Arc, Rc, String and Vec! +} +``` |