neon/handle/
internal.rs

1use std::{fmt::Debug, mem};
2
3use crate::types::Value;
4
5pub trait SuperType<T: Value> {
6    fn upcast_internal(v: &T) -> Self;
7}
8
9#[doc(hidden)]
10/// Trait asserting that `Self` is a transparent wrapper around `Self::Inner`
11/// with identical representation and may be safely transmuted.
12///
13/// # Safety
14/// `Self` must be `#[repr(transparent)]` with a field `Self::Inner`
15pub unsafe trait TransparentNoCopyWrapper: Sized {
16    type Inner: Debug + Copy;
17
18    // A default implementation cannot be provided because it would create
19    // dependently sized types. This may be supported in a future Rust version.
20    fn into_inner(self) -> Self::Inner;
21
22    fn wrap_ref(s: &Self::Inner) -> &Self {
23        unsafe { mem::transmute(s) }
24    }
25
26    fn wrap_mut(s: &mut Self::Inner) -> &mut Self {
27        unsafe { mem::transmute(s) }
28    }
29}