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use core::mem::ManuallyDrop;
#[repr(C)]
union DiplomatResultValue<T, E> {
ok: ManuallyDrop<T>,
err: ManuallyDrop<E>,
}
/// A `Result`-like type that can be passed across the FFI boundary
/// as a value. Use this type when returning a result from an FFI
/// function instead of `Result`.
#[repr(C)]
pub struct DiplomatResult<T, E> {
value: DiplomatResultValue<T, E>,
pub is_ok: bool,
}
impl<T, E> Drop for DiplomatResult<T, E> {
fn drop(&mut self) {
unsafe {
if self.is_ok {
let _ = ManuallyDrop::take(&mut self.value.ok);
} else {
let _ = ManuallyDrop::take(&mut self.value.err);
}
}
}
}
impl<T, E> From<Result<T, E>> for DiplomatResult<T, E> {
fn from(result: Result<T, E>) -> Self {
match result {
Result::Ok(ok) => DiplomatResult {
value: DiplomatResultValue {
ok: ManuallyDrop::new(ok),
},
is_ok: true,
},
Result::Err(err) => DiplomatResult {
value: DiplomatResultValue {
err: ManuallyDrop::new(err),
},
is_ok: false,
},
}
}
}
impl<T, E> From<DiplomatResult<T, E>> for Result<T, E> {
fn from(mut result: DiplomatResult<T, E>) -> Result<T, E> {
unsafe {
if result.is_ok {
Ok(ManuallyDrop::take(&mut result.value.ok))
} else {
Err(ManuallyDrop::take(&mut result.value.err))
}
}
}
}
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