Merging upstream version 1.67.1+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 27 insertions, 0 deletions

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+# yoke [![crates.io](https://img.shields.io/crates/v/yoke)](https://crates.io/crates/yoke)
+
+This crate provides [`Yoke<Y, C>`][Yoke], which allows one to "yoke" (attach) a zero-copy deserialized
+object (say, a [`Cow<'a, str>`](alloc::borrow::Cow)) to the source it was deserialized from, (say, an [`Rc<[u8]>`](alloc::rc::Rc)),
+known in this crate as a "cart", producing a type that looks like `Yoke<Cow<'static, str>, Rc<[u8]>>`
+and can be moved around with impunity.
+
+Succinctly, this allows one to "erase" static lifetimes and turn them into dynamic ones, similarly
+to how `dyn` allows one to "erase" static types and turn them into dynamic ones.
+
+Most of the time the yokeable `Y` type will be some kind of zero-copy deserializable
+abstraction, potentially with an owned variant (like [`Cow`](alloc::borrow::Cow),
+[`ZeroVec`](https://docs.rs/zerovec), or an aggregate containing such types), and the cart `C` will be some smart pointer like
+  [`Box<T>`](alloc::boxed::Box), [`Rc<T>`](alloc::rc::Rc), or [`Arc<T>`](std::sync::Arc), potentially wrapped in an [`Option<T>`](Option).
+
+The key behind this crate is [`Yoke::get()`], where calling [`.get()`][Yoke::get] on a type like
+`Yoke<Cow<'static, str>, _>` will get you a short-lived `&'a Cow<'a, str>`, restricted to the
+lifetime of the borrow used during [`.get()`](Yoke::get). This is entirely safe since the `Cow` borrows from
+the cart type `C`, which cannot be interfered with as long as the `Yoke` is borrowed by [`.get()`](Yoke::get).
+[`.get()`](Yoke::get) protects access by essentially reifying the erased lifetime to a safe local one
+when necessary.
+
+See the documentation of [`Yoke`] for more details.
+
+## More Information
+
+For more information on development, authorship, contributing etc. please visit [`ICU4X home page`](https://github.com/unicode-org/icu4x).