Function handle_callback

src/function.rs:212–239

(_location: &str, _c: C, f: F)

}

pub unsafe fn handle_callback<F, T, C>(_location: &str, _c: C, f: F) -> C::R
where
    F: FnOnce(Python) -> PyResult<T>,
    F: panic::UnwindSafe,
    C: CallbackConverter<T>,
{
    let ret = panic::catch_unwind(|| {
        let py = Python::assume_gil_acquired();
        match f(py) {
            Ok(val) => C::convert(val, py),
            Err(e) => {
                e.restore(py);
                C::error_value()
            }
        }
    });
    match ret {
        Ok(r) => r,
        Err(err) => {
            // Protect against panics in C::error_value() causing UB
            let guard = AbortOnDrop("handle_panic() / C::error_value()");
            handle_panic(Python::assume_gil_acquired(), err);
            let errval = C::error_value();
            mem::forget(guard);
            errval
        }
    }
}

// This only needs `&dyn Any`, but we keep a `Box` all the way to avoid the
// risk of a subtle bug in the caller where `&Box<dyn Any>` is coerced to