Paolo Bonzini
6e50bde1e1
MaybeUninit::zeroed() is handy, but it introduces unsafe (and has a pretty heavy syntax in general). Introduce a trait that provides the same functionality while staying within safe Rust. In addition, MaybeUninit::zeroed() is not available as a "const" function until Rust 1.75.0, so this also prepares for having handwritten implementations of the trait until we can assume that version. Reviewed-by: Junjie Mao <junjie.mao@hotmail.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
24 lines
977 B
Rust
24 lines
977 B
Rust
// SPDX-License-Identifier: GPL-2.0-or-later
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/// Encapsulates the requirement that
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/// `MaybeUninit::<Self>::zeroed().assume_init()` does not cause
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/// undefined behavior.
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///
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/// # Safety
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///
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/// Do not add this trait to a type unless all-zeroes is
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/// a valid value for the type. In particular, remember that raw
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/// pointers can be zero, but references and `NonNull<T>` cannot
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/// unless wrapped with `Option<>`.
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pub unsafe trait Zeroable: Default {
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/// SAFETY: If the trait was added to a type, then by definition
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/// this is safe.
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const ZERO: Self = unsafe { ::core::mem::MaybeUninit::<Self>::zeroed().assume_init() };
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}
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unsafe impl Zeroable for crate::bindings::Property__bindgen_ty_1 {}
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unsafe impl Zeroable for crate::bindings::Property {}
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unsafe impl Zeroable for crate::bindings::VMStateDescription {}
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unsafe impl Zeroable for crate::bindings::MemoryRegionOps__bindgen_ty_1 {}
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unsafe impl Zeroable for crate::bindings::MemoryRegionOps__bindgen_ty_2 {}
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