interoptopus 0.1.0

Interoptopus

Create FFI bindings to your favorite language. Composable. Escape hatches included.

Overview

• you wrote an extern "C" API in Rust
• the types at the FFI boundary are (mostly) owned by yourself
• you prefer to keep all your binding-related information (e.g., documentation) in Rust code

Known limitations

• not used in production yet
• somewhat verbose if you don't own most of your types (still possible, just more work)
• if you target only a single language and don't care about your FFI layer other solutions might be better

Supported Languages

(*) Ok, right now I don't really recommend writing a new backend just yet as lots of internals might change. That said, it should only take a few hours and feedback is more than welcome.

Example

Slightly abridged, see the examples/hello_world for full code:

use interoptopus::{ffi_function, ffi_type};
use interoptopus_backend_csharp::Interop;

#[ffi_type]
#[repr(C)]
pub struct Vec2f32 {
pub x: f32,
pub y: f32,
pub z: f32,
}

/// A function which does something with the vector.
#[ffi_function]
#[no_mangle]
pub extern "C" fn my_game_function(input: Option<&Vec2f32>) -> Vec2f32 {
Vec2f32 { x: 2.0, y: 4.0, z: 6.0 }
}

// This ultimately defines our FFI exports, all functions have to be listed here.
interoptopus::inventory_function!(ffi_inventory, [], [my_game_function]);

#[test]
fn generate_csharp_bindings() {
use interoptopus::writer::IndentWriter;

let library = ffi_inventory();

let config = interoptopus_backend_csharp::Config {
namespace: "My.Company".to_string(),
class: "InteropClass".to_string(),
dll_name: "hello_world".to_string(),
..interoptopus_backend_csharp::Config::default()
};

let generator = interoptopus_backend_csharp::Generator::new(config, library);

generator.write_to(my_file)?;
}

With a Cargo.toml:

[dependencies]
interoptopus = { version = "0.1", features = ["derive"] }
interoptopus_backend_csharp = "0.1"

Will produce:

using System;
using System.Runtime.InteropServices;

namespace My.Company
{
public static class InteropClass
{
public const string NativeLib = "hello_world";

/// A function which does something with the vector.
[DllImport(NativeLib, CallingConvention = CallingConvention.Cdecl, EntryPoint = "my_game_function")]
public static extern Vec2f32 my_game_function(ref Vec2f32 input);
}

[Serializable]
[StructLayout(LayoutKind.Sequential)]
public partial struct Vec2f32
{
public float x;
public float y;
public float z;
}
}

For other languages (Python, C, ...) see examples folder.