Bug: 156526402

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  1. 4052a3c Upgrade pin-project to 1.1.3 am: 774e92dc74 am: ccd6cbd505 am: 95bf428424 by Andrew Walbran · 5 months ago main master
  2. 7f63cf6 Upgrade pin-project to 1.1.3 am: 774e92dc74 am: 9c36a6641d am: 2c6be45e7b by Andrew Walbran · 5 months ago
  3. 95bf428 Upgrade pin-project to 1.1.3 am: 774e92dc74 am: ccd6cbd505 by Andrew Walbran · 5 months ago
  4. 2c6be45 Upgrade pin-project to 1.1.3 am: 774e92dc74 am: 9c36a6641d by Andrew Walbran · 5 months ago
  5. 9c36a66 Upgrade pin-project to 1.1.3 am: 774e92dc74 by Andrew Walbran · 5 months ago

pin-project

crates.io docs.rs license rustc build status

A crate for safe and ergonomic pin-projection.

Usage

Add this to your Cargo.toml:

[dependencies]
pin-project = "1"

Compiler support: requires rustc 1.56+

Examples

#[pin_project] attribute creates projection types covering all the fields of struct or enum.

use std::pin::Pin;

use pin_project::pin_project;

#[pin_project]
struct Struct<T, U> {
    #[pin]
    pinned: T,
    unpinned: U,
}

impl<T, U> Struct<T, U> {
    fn method(self: Pin<&mut Self>) {
        let this = self.project();
        let _: Pin<&mut T> = this.pinned; // Pinned reference to the field
        let _: &mut U = this.unpinned; // Normal reference to the field
    }
}

code like this will be generated

To use #[pin_project] on enums, you need to name the projection type returned from the method.

use std::pin::Pin;

use pin_project::pin_project;

#[pin_project(project = EnumProj)]
enum Enum<T, U> {
    Pinned(#[pin] T),
    Unpinned(U),
}

impl<T, U> Enum<T, U> {
    fn method(self: Pin<&mut Self>) {
        match self.project() {
            EnumProj::Pinned(x) => {
                let _: Pin<&mut T> = x;
            }
            EnumProj::Unpinned(y) => {
                let _: &mut U = y;
            }
        }
    }
}

code like this will be generated

See #[pin_project] attribute for more details, and see examples directory for more examples and generated code.

Related Projects

  • pin-project-lite: A lightweight version of pin-project written with declarative macros.

License

Licensed under either of Apache License, Version 2.0 or MIT license 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.