Messages in this thread |  | | Date | Sat, 28 Jan 2023 12:14:29 +0100 | Subject | Re: [PATCH 4/5] rust: types: implement `ForeignOwnable` for the unit type | From | "Vincenzo Palazzo" <> |
| |
On Thu Jan 19, 2023 at 6:40 PM CET, Wedson Almeida Filho wrote: > This allows us to use the unit type `()` when we have no object whose > ownership must be managed but one implementing the `ForeignOwnable` > trait is needed. > > Signed-off-by: Wedson Almeida Filho <wedsonaf@gmail.com>
Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
> --- > rust/kernel/types.rs | 13 +++++++++++++ > 1 file changed, 13 insertions(+) > > diff --git a/rust/kernel/types.rs b/rust/kernel/types.rs > index e037c262f23e..8f80cffbff59 100644 > --- a/rust/kernel/types.rs > +++ b/rust/kernel/types.rs > @@ -85,6 +85,19 @@ impl<T: 'static> ForeignOwnable for Box<T> { > } > } > > +impl ForeignOwnable for () { > + type Borrowed<'a> = (); > + > + fn into_foreign(self) -> *const core::ffi::c_void { > + // We use 1 to be different from a null pointer. > + 1usize as _ > + } > + > + unsafe fn borrow<'a>(_: *const core::ffi::c_void) -> Self::Borrowed<'a> {} > + > + unsafe fn from_foreign(_: *const core::ffi::c_void) -> Self {} > +} > + > /// Runs a cleanup function/closure when dropped. > /// > /// The [`ScopeGuard::dismiss`] function prevents the cleanup function from running. > -- > 2.34.1
|  |