Snap for 7110675 from 803535edf46cf1e4d0b092b6b2e52ae776b41711 to sdk-release

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tree: b4a59a0bf295d7cc3837dd372b5068cb95023fc6
  1. .cargo_vcs_info.json
  2. .clippy.toml
  3. .editorconfig
  4. .gitattributes
  5. .gitignore
  6. .rustfmt.toml
  7. Android.bp
  8. CHANGELOG.md
  9. Cargo.toml
  10. Cargo.toml.orig
  11. LICENSE-APACHE
  12. LICENSE-MIT
  13. METADATA
  14. MODULE_LICENSE_APACHE2
  15. OWNERS
  16. README.md
  17. TEST_MAPPING
  18. examples/
  19. patches/
  20. src/
  21. tests/
README.md

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.