bytemuck/
zeroable_in_option.rs

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1use super::*;
2
3// Note(Lokathor): This is the neat part!!
4unsafe impl<T: ZeroableInOption> Zeroable for Option<T> {}
5
6/// Trait for types which are [Zeroable](Zeroable) when wrapped in
7/// [Option](core::option::Option).
8///
9/// ## Safety
10///
11/// * `Option<YourType>` must uphold the same invariants as
12///   [Zeroable](Zeroable).
13pub unsafe trait ZeroableInOption: Sized {}
14
15unsafe impl ZeroableInOption for NonZeroI8 {}
16unsafe impl ZeroableInOption for NonZeroI16 {}
17unsafe impl ZeroableInOption for NonZeroI32 {}
18unsafe impl ZeroableInOption for NonZeroI64 {}
19unsafe impl ZeroableInOption for NonZeroI128 {}
20unsafe impl ZeroableInOption for NonZeroIsize {}
21unsafe impl ZeroableInOption for NonZeroU8 {}
22unsafe impl ZeroableInOption for NonZeroU16 {}
23unsafe impl ZeroableInOption for NonZeroU32 {}
24unsafe impl ZeroableInOption for NonZeroU64 {}
25unsafe impl ZeroableInOption for NonZeroU128 {}
26unsafe impl ZeroableInOption for NonZeroUsize {}
27
28// Note: this does not create NULL vtable because we get `None` anyway.
29unsafe impl<T: ?Sized> ZeroableInOption for NonNull<T> {}
30unsafe impl<T: ?Sized> ZeroableInOption for &'_ T {}
31unsafe impl<T: ?Sized> ZeroableInOption for &'_ mut T {}
32
33#[cfg(feature = "extern_crate_alloc")]
34#[cfg_attr(feature = "nightly_docs", doc(cfg(feature = "extern_crate_alloc")))]
35unsafe impl<T: ?Sized> ZeroableInOption for alloc::boxed::Box<T> {}
36
37#[cfg(feature = "zeroable_unwind_fn")]
38macro_rules! impl_for_unwind_fn {
39    ($($ArgTy:ident),* $(,)?) => {
40        unsafe impl<$($ArgTy,)* R> ZeroableInOption for extern "C-unwind" fn($($ArgTy,)*) -> R {}
41        unsafe impl<$($ArgTy,)* R> ZeroableInOption for unsafe extern "C-unwind" fn($($ArgTy,)*) -> R {}
42        unsafe impl<$($ArgTy,)* R> ZeroableInOption for extern "system-unwind" fn($($ArgTy,)*) -> R {}
43        unsafe impl<$($ArgTy,)* R> ZeroableInOption for unsafe extern "system-unwind" fn($($ArgTy,)*) -> R {}
44    };
45}
46
47macro_rules! impl_for_fn {
48    ($($ArgTy:ident),* $(,)?) => {
49        unsafe impl<$($ArgTy,)* R> ZeroableInOption for fn($($ArgTy,)*) -> R {}
50        unsafe impl<$($ArgTy,)* R> ZeroableInOption for unsafe fn($($ArgTy,)*) -> R {}
51        unsafe impl<$($ArgTy,)* R> ZeroableInOption for extern "C" fn($($ArgTy,)*) -> R {}
52        unsafe impl<$($ArgTy,)* R> ZeroableInOption for unsafe extern "C" fn($($ArgTy,)*) -> R {}
53        unsafe impl<$($ArgTy,)* R> ZeroableInOption for extern "system" fn($($ArgTy,)*) -> R {}
54        unsafe impl<$($ArgTy,)* R> ZeroableInOption for unsafe extern "system" fn($($ArgTy,)*) -> R {}
55        #[cfg(feature = "zeroable_unwind_fn")]
56        impl_for_unwind_fn!($($ArgTy),*);
57    };
58}
59
60
61
62impl_for_fn!();
63impl_for_fn!(A);
64impl_for_fn!(A, B);
65impl_for_fn!(A, B, C);
66impl_for_fn!(A, B, C, D);
67impl_for_fn!(A, B, C, D, E);
68impl_for_fn!(A, B, C, D, E, F);
69impl_for_fn!(A, B, C, D, E, F, G);
70impl_for_fn!(A, B, C, D, E, F, G, H);
71impl_for_fn!(A, B, C, D, E, F, G, H, I);
72impl_for_fn!(A, B, C, D, E, F, G, H, I, J);
73impl_for_fn!(A, B, C, D, E, F, G, H, I, J, K);
74impl_for_fn!(A, B, C, D, E, F, G, H, I, J, K, L);
75impl_for_fn!(A, B, C, D, E, F, G, H, I, J, K, L, M);
bytemuck/zeroable_in_option.rs

bytemuck/
zeroable_in_option.rs
