зеркало из https://github.com/mozilla/gecko-dev.git
68 строки
1.9 KiB
Markdown
68 строки
1.9 KiB
Markdown
owning-ref-rs
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==============
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A library for creating references that carry their owner with them.
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This can sometimes be useful because Rust borrowing rules normally prevent
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moving a type that has been moved from. For example, this kind of code gets rejected:
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```rust
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fn return_owned_and_referenced<'a>() -> (Vec<u8>, &'a [u8]) {
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let v = vec![1, 2, 3, 4];
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let s = &v[1..3];
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(v, s)
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}
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```
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This library enables this safe usage by keeping the owner and the reference
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bundled together in a wrapper type that ensure that lifetime constraint:
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```rust
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fn return_owned_and_referenced() -> OwningRef<Vec<u8>, [u8]> {
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let v = vec![1, 2, 3, 4];
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let or = OwningRef::new(v);
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let or = or.map(|v| &v[1..3]);
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or
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}
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```
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[](https://travis-ci.org/Kimundi/owning-ref-rs)
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# Getting Started
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[owning-ref-rs is available on crates.io](https://crates.io/crates/owning_ref).
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It is recommended to look there for the newest released version, as well as links to the newest builds of the docs.
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At the point of the last update of this README, the latest published version could be used like this:
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Add the following dependency to your Cargo manifest...
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```toml
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[dependencies]
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owning_ref = "0.3"
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```
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...and see the [docs](http://kimundi.github.io/owning-ref-rs/owning_ref/index.html) for how to use it.
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# Example
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```rust
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extern crate owning_ref;
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use owning_ref::BoxRef;
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fn main() {
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// Create an array owned by a Box.
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let arr = Box::new([1, 2, 3, 4]) as Box<[i32]>;
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// Transfer into a BoxRef.
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let arr: BoxRef<[i32]> = BoxRef::new(arr);
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assert_eq!(&*arr, &[1, 2, 3, 4]);
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// We can slice the array without losing ownership or changing type.
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let arr: BoxRef<[i32]> = arr.map(|arr| &arr[1..3]);
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assert_eq!(&*arr, &[2, 3]);
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// Also works for Arc, Rc, String and Vec!
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}
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```
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