Trait interoptopus::patterns::result::FFIError

pub trait FFIError: Sized {
    const SUCCESS: Self;
    const NULL: Self;
    const PANIC: Self;
}

A trait you should implement for enums that signal errors in FFI calls.

Once implemented, the enum can be used in services to automatically convert Result<(), E> types to FFI enums.

Example

use interoptopus::patterns::result::FFIError;
use interoptopus::ffi_type;

// Some Error used in your application.
pub enum Error {
    Bad,
}

// The error FFI users should see
#[ffi_type(patterns(ffi_error))]
#[repr(C)]
enum MyFFIError {
    Ok = 0,
    NullPassed = 1,
    Panic = 2,
    OtherError = 3,
}

// Gives special meaning to some of your error variants.
impl FFIError for MyFFIError {
    const SUCCESS: Self = Self::Ok;
    const NULL: Self = Self::NullPassed;
    const PANIC: Self = Self::Panic;
}

// How to map an `Error` to an `MyFFIError`.
impl From<Error> for MyFFIError {
    fn from(x: Error) -> Self {
        match x {
            Error::Bad => Self::OtherError,
        }
    }
}

Associated Constants

const SUCCESS: Self

The variant to return when everything went OK, usually the variant with value 0.

const NULL: Self

Signals a null pointer was passed where an actual element was needed.

const PANIC: Self

The panic variant. Once this is observed no further calls should be attempted.

Implementors