diff options
Diffstat (limited to 'rust/pin-init/src')
| -rw-r--r-- | rust/pin-init/src/lib.rs | 30 | ||||
| -rw-r--r-- | rust/pin-init/src/macros.rs | 59 |
2 files changed, 89 insertions, 0 deletions
diff --git a/rust/pin-init/src/lib.rs b/rust/pin-init/src/lib.rs index 774f8ca033bc..05a0cd6ad8f4 100644 --- a/rust/pin-init/src/lib.rs +++ b/rust/pin-init/src/lib.rs @@ -413,6 +413,36 @@ pub use ::pin_init_internal::pinned_drop; /// ``` pub use ::pin_init_internal::Zeroable; +/// Derives the [`Zeroable`] trait for the given struct if all fields implement [`Zeroable`]. +/// +/// Contrary to the derive macro named [`macro@Zeroable`], this one silently fails when a field +/// doesn't implement [`Zeroable`]. +/// +/// # Examples +/// +/// ``` +/// use pin_init::MaybeZeroable; +/// +/// // implmements `Zeroable` +/// #[derive(MaybeZeroable)] +/// pub struct DriverData { +/// id: i64, +/// buf_ptr: *mut u8, +/// len: usize, +/// } +/// +/// // does not implmement `Zeroable` +/// #[derive(MaybeZeroable)] +/// pub struct DriverData2 { +/// id: i64, +/// buf_ptr: *mut u8, +/// len: usize, +/// // this field doesn't implement `Zeroable` +/// other_data: &'static i32, +/// } +/// ``` +pub use ::pin_init_internal::MaybeZeroable; + /// Initialize and pin a type directly on the stack. /// /// # Examples diff --git a/rust/pin-init/src/macros.rs b/rust/pin-init/src/macros.rs index 332d7e08925b..935d77745d1d 100644 --- a/rust/pin-init/src/macros.rs +++ b/rust/pin-init/src/macros.rs @@ -1443,3 +1443,62 @@ macro_rules! __derive_zeroable { }; }; } + +#[doc(hidden)] +#[macro_export] +macro_rules! __maybe_derive_zeroable { + (parse_input: + @sig( + $(#[$($struct_attr:tt)*])* + $vis:vis struct $name:ident + $(where $($whr:tt)*)? + ), + @impl_generics($($impl_generics:tt)*), + @ty_generics($($ty_generics:tt)*), + @body({ + $( + $(#[$($field_attr:tt)*])* + $field_vis:vis $field:ident : $field_ty:ty + ),* $(,)? + }), + ) => { + // SAFETY: Every field type implements `Zeroable` and padding bytes may be zero. + #[automatically_derived] + unsafe impl<$($impl_generics)*> $crate::Zeroable for $name<$($ty_generics)*> + where + $( + // the `for<'__dummy>` HRTB makes this not error without the `trivial_bounds` + // feature <https://github.com/rust-lang/rust/issues/48214#issuecomment-2557829956>. + $field_ty: for<'__dummy> $crate::Zeroable, + )* + $($($whr)*)? + {} + }; + (parse_input: + @sig( + $(#[$($struct_attr:tt)*])* + $vis:vis union $name:ident + $(where $($whr:tt)*)? + ), + @impl_generics($($impl_generics:tt)*), + @ty_generics($($ty_generics:tt)*), + @body({ + $( + $(#[$($field_attr:tt)*])* + $field_vis:vis $field:ident : $field_ty:ty + ),* $(,)? + }), + ) => { + // SAFETY: Every field type implements `Zeroable` and padding bytes may be zero. + #[automatically_derived] + unsafe impl<$($impl_generics)*> $crate::Zeroable for $name<$($ty_generics)*> + where + $( + // the `for<'__dummy>` HRTB makes this not error without the `trivial_bounds` + // feature <https://github.com/rust-lang/rust/issues/48214#issuecomment-2557829956>. + $field_ty: for<'__dummy> $crate::Zeroable, + )* + $($($whr)*)? + {} + }; +} |