Bug: 156526402

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  1. dd72f94 Merge "Refresh Android.bp, cargo2android.json, TEST_MAPPING." by Joel Galenson · 6 weeks ago master
  2. a8e7371 Refresh Android.bp, cargo2android.json, TEST_MAPPING. by Joel Galenson · 8 weeks ago
  3. 5ca8486 Upgrade rust/crates/pin-project to 1.0.8 am: c1569cc62c am: 02a74e9451 am: 854e9fcb8c by Joel Galenson · 6 months ago
  4. 854e9fc Upgrade rust/crates/pin-project to 1.0.8 am: c1569cc62c am: 02a74e9451 by Joel Galenson · 6 months ago android-s-v2-preview-1 android-s-v2-beta-2 android-s-v2-preview-2
  5. 02a74e9 Upgrade rust/crates/pin-project to 1.0.8 am: c1569cc62c by Joel Galenson · 6 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 1.37+

Examples

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

use pin_project::pin_project;
use std::pin::Pin;

#[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 pin_project::pin_project;
use std::pin::Pin;

#[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 documentation 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.