Greg Kroah-Hartman
598cf27219
Link: https://lore.kernel.org/r/20260217200002.683975158@linuxfoundation.org Tested-by: Florian Fainelli <florian.fainelli@broadcom.com> Tested-by: Takeshi Ogasawara <takeshi.ogasawara@futuring-girl.com> Tested-by: Peter Schneider <pschneider1968@googlemail.com> Tested-by: Jon Hunter <jonathanh@nvidia.com> Tested-by: Salvatore Bonaccorso <carnil@debian.org> Tested-by: Brett A C Sheffield <bacs@librecast.net> Tested-by: Mark Brown <broonie@kernel.org> Tested-by: Luna Jernberg <droidbittin@gmail.com> Tested-by: Ronald Warsow <rwarsow@gmx.de> Tested-by: Justin M. Forbes <jforbes@fedoraproject.org> Tested-by: Ron Economos <re@w6rz.net> Tested-by: Miguel Ojeda <ojeda@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
61 lines
1.4 KiB
Rust
61 lines
1.4 KiB
Rust
// SPDX-License-Identifier: Apache-2.0 OR MIT
|
|
|
|
use std::iter;
|
|
use std::mem::ManuallyDrop;
|
|
use std::ops::{Deref, DerefMut};
|
|
use std::option;
|
|
use std::slice;
|
|
|
|
#[repr(transparent)]
|
|
pub(crate) struct NoDrop<T: ?Sized>(ManuallyDrop<T>);
|
|
|
|
impl<T> NoDrop<T> {
|
|
pub(crate) fn new(value: T) -> Self
|
|
where
|
|
T: TrivialDrop,
|
|
{
|
|
NoDrop(ManuallyDrop::new(value))
|
|
}
|
|
}
|
|
|
|
impl<T: ?Sized> Deref for NoDrop<T> {
|
|
type Target = T;
|
|
fn deref(&self) -> &Self::Target {
|
|
&self.0
|
|
}
|
|
}
|
|
|
|
impl<T: ?Sized> DerefMut for NoDrop<T> {
|
|
fn deref_mut(&mut self) -> &mut Self::Target {
|
|
&mut self.0
|
|
}
|
|
}
|
|
|
|
pub(crate) trait TrivialDrop {}
|
|
|
|
impl<T> TrivialDrop for iter::Empty<T> {}
|
|
impl<T> TrivialDrop for slice::Iter<'_, T> {}
|
|
impl<T> TrivialDrop for slice::IterMut<'_, T> {}
|
|
impl<T> TrivialDrop for option::IntoIter<&T> {}
|
|
impl<T> TrivialDrop for option::IntoIter<&mut T> {}
|
|
|
|
#[test]
|
|
fn test_needs_drop() {
|
|
use std::mem::needs_drop;
|
|
|
|
struct NeedsDrop;
|
|
|
|
impl Drop for NeedsDrop {
|
|
fn drop(&mut self) {}
|
|
}
|
|
|
|
assert!(needs_drop::<NeedsDrop>());
|
|
|
|
// Test each of the types with a handwritten TrivialDrop impl above.
|
|
assert!(!needs_drop::<iter::Empty<NeedsDrop>>());
|
|
assert!(!needs_drop::<slice::Iter<NeedsDrop>>());
|
|
assert!(!needs_drop::<slice::IterMut<NeedsDrop>>());
|
|
assert!(!needs_drop::<option::IntoIter<&NeedsDrop>>());
|
|
assert!(!needs_drop::<option::IntoIter<&mut NeedsDrop>>());
|
|
}
|