Crate crusty_traits 

Crusty Traits

C <-> Rust Traits

A crate that creates a macro and supporting code to allow for traits to be FFI-safe using C ABI.

Warning: This crate uses unsafe code and may be unsound if used incorrectly. Use at your own risk. If any issues are found please open an issue or a PR.

Usage

Add the following to your Cargo.toml:

[dependencies]
crusty_traits = "0.1"

Then in your code:

use crusty_traits::prelude::*;

#[crusty_trait]
pub trait MyTrait {
    fn method1(&self);
    fn method2(&mut self, value: i32) -> i32;
}

Crate Details

This crate provides a macro crusty_trait that generates the necessary boilerplate code to create a C-compatible vtable for a given Rust trait. This allows Rust traits to be used across FFI boundaries, making it easier to use Rust shared libraries or plugins in C or other languages that can interface with C.

Each trait that is annotated with crusty_trait will have a corresponding vtable struct generated, along with implementations for CRepr and CDrop to manage the memory and lifecycle of the trait objects. The generated vtable struct will contain function pointers for each method in the trait, as well as a drop function to properly clean up the trait object when it is no longer needed.

The trait is also implemented for CRepr<MyTraitVTable> and any CRepr<GEN> where GEN implements AsVTable<&'static MyTraitVTable> (used for super/sub traits) and CDrop, allowing for seamless usage of the trait across FFI boundaries in Rust code.

Re-exports

pub use crusty_traits_types as types;

Modules

prelude

Prelude module that exports all the necessary types and traits for creating FFI-safe traits.

Structs

CRef

A reference to a C-compatible object.

CRefMut

A reference to a C-compatible object.

CRepr

A trait that represents a buffer that can be converted to a C-compatible slice.

Traits

AsVTable

A trait that provides a way to convert a type into a C-compatible vtable.

CDrop

A trait that represents dropping a Rust object in a C-compatible way.

Attribute Macros

crusty_trait

The crusty_trait procedural macro transforms a Rust trait into an FFI-safe trait with a C-compatible vtable.