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reorganize util mod.

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This commit is contained in:
Dario Nieuwenhuis 2022-04-05 21:17:29 +02:00
parent aee19185b7
commit c8bd792b7a
4 changed files with 69 additions and 67 deletions
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73
embassy/src/util/mod.rs
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@ -1,74 +1,13 @@
//! Misc utilities
mod forever;
mod select_all;
mod select;
mod steal;
mod unborrow;
mod yield_now;
pub use forever::*;
pub use select_all::*;
pub use select::*;
pub use steal::*;
pub use unborrow::*;
pub use yield_now::*;
/// Unsafely unborrow an owned singleton out of a `&mut`.
///
/// It is intended to be implemented for owned peripheral singletons, such as `USART3` or `AnyPin`.
/// Unborrowing an owned `T` yields the same `T`. Unborrowing a `&mut T` yields a copy of the T.
///
/// This allows writing HAL drivers that either own or borrow their peripherals, but that don't have
/// to store pointers in the borrowed case.
///
/// Safety: this trait can be used to copy non-Copy types. Implementors must not cause
/// immediate UB when copied, and must not cause UB when copies are later used, provided they
/// are only used according the [`Self::unborrow`] safety contract.
///
pub unsafe trait Unborrow {
/// Unborrow result type
type Target;
/// Unborrow a value.
///
/// Safety: This returns a copy of a singleton that's normally not
/// copiable. The returned copy must ONLY be used while the lifetime of `self` is
/// valid, as if it were accessed through `self` every time.
unsafe fn unborrow(self) -> Self::Target;
}
unsafe impl<'a, T: Unborrow> Unborrow for &'a mut T {
type Target = T::Target;
unsafe fn unborrow(self) -> Self::Target {
T::unborrow(core::ptr::read(self))
}
}
pub trait Steal {
unsafe fn steal() -> Self;
}
macro_rules! unsafe_impl_unborrow_tuples {
($($t:ident),+) => {
unsafe impl<$($t),+> Unborrow for ($($t),+)
where
$(
$t: Unborrow<Target = $t>
),+
{
type Target = ($($t),+);
unsafe fn unborrow(self) -> Self::Target {
self
}
}
};
}
unsafe_impl_unborrow_tuples!(A, B);
unsafe_impl_unborrow_tuples!(A, B, C);
unsafe_impl_unborrow_tuples!(A, B, C, D);
unsafe_impl_unborrow_tuples!(A, B, C, D, E);
unsafe_impl_unborrow_tuples!(A, B, C, D, E, F);
unsafe_impl_unborrow_tuples!(A, B, C, D, E, F, G);
unsafe_impl_unborrow_tuples!(A, B, C, D, E, F, G, H);
unsafe_impl_unborrow_tuples!(A, B, C, D, E, F, G, H, I);
unsafe_impl_unborrow_tuples!(A, B, C, D, E, F, G, H, I, J);
unsafe_impl_unborrow_tuples!(A, B, C, D, E, F, G, H, I, J, K);
unsafe_impl_unborrow_tuples!(A, B, C, D, E, F, G, H, I, J, K, L);

0
embassy/src/util/select_all.rs → embassy/src/util/select.rs
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3
embassy/src/util/steal.rs Normal file
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@ -0,0 +1,3 @@
pub trait Steal {
unsafe fn steal() -> Self;
}

60
embassy/src/util/unborrow.rs Normal file
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@ -0,0 +1,60 @@
/// Unsafely unborrow an owned singleton out of a `&mut`.
///
/// It is intended to be implemented for owned peripheral singletons, such as `USART3` or `AnyPin`.
/// Unborrowing an owned `T` yields the same `T`. Unborrowing a `&mut T` yields a copy of the T.
///
/// This allows writing HAL drivers that either own or borrow their peripherals, but that don't have
/// to store pointers in the borrowed case.
///
/// Safety: this trait can be used to copy non-Copy types. Implementors must not cause
/// immediate UB when copied, and must not cause UB when copies are later used, provided they
/// are only used according the [`Self::unborrow`] safety contract.
///
pub unsafe trait Unborrow {
/// Unborrow result type
type Target;
/// Unborrow a value.
///
/// Safety: This returns a copy of a singleton that's normally not
/// copiable. The returned copy must ONLY be used while the lifetime of `self` is
/// valid, as if it were accessed through `self` every time.
unsafe fn unborrow(self) -> Self::Target;
}
unsafe impl<'a, T: Unborrow> Unborrow for &'a mut T {
type Target = T::Target;
unsafe fn unborrow(self) -> Self::Target {
T::unborrow(core::ptr::read(self))
}
}
macro_rules! unsafe_impl_unborrow_tuples {
($($t:ident),+) => {
unsafe impl<$($t),+> Unborrow for ($($t),+)
where
$(
$t: Unborrow<Target = $t>
),+
{
type Target = ($($t),+);
unsafe fn unborrow(self) -> Self::Target {
self
}
}
};
}
unsafe_impl_unborrow_tuples!(A, B);
unsafe_impl_unborrow_tuples!(A, B, C);
unsafe_impl_unborrow_tuples!(A, B, C, D);
unsafe_impl_unborrow_tuples!(A, B, C, D, E);
unsafe_impl_unborrow_tuples!(A, B, C, D, E, F);
unsafe_impl_unborrow_tuples!(A, B, C, D, E, F, G);
unsafe_impl_unborrow_tuples!(A, B, C, D, E, F, G, H);
unsafe_impl_unborrow_tuples!(A, B, C, D, E, F, G, H, I);
unsafe_impl_unborrow_tuples!(A, B, C, D, E, F, G, H, I, J);
unsafe_impl_unborrow_tuples!(A, B, C, D, E, F, G, H, I, J, K);
unsafe_impl_unborrow_tuples!(A, B, C, D, E, F, G, H, I, J, K, L);