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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-06-12 05:43:14 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-06-12 05:43:14 +0000 |
commit | 8dd16259287f58f9273002717ec4d27e97127719 (patch) | |
tree | 3863e62a53829a84037444beab3abd4ed9dfc7d0 /third_party/rust/zerocopy-derive/tests/struct_as_bytes.rs | |
parent | Releasing progress-linux version 126.0.1-1~progress7.99u1. (diff) | |
download | firefox-8dd16259287f58f9273002717ec4d27e97127719.tar.xz firefox-8dd16259287f58f9273002717ec4d27e97127719.zip |
Merging upstream version 127.0.
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'third_party/rust/zerocopy-derive/tests/struct_as_bytes.rs')
-rw-r--r-- | third_party/rust/zerocopy-derive/tests/struct_as_bytes.rs | 161 |
1 files changed, 161 insertions, 0 deletions
diff --git a/third_party/rust/zerocopy-derive/tests/struct_as_bytes.rs b/third_party/rust/zerocopy-derive/tests/struct_as_bytes.rs new file mode 100644 index 0000000000..3c71bf07b5 --- /dev/null +++ b/third_party/rust/zerocopy-derive/tests/struct_as_bytes.rs @@ -0,0 +1,161 @@ +// Copyright 2019 The Fuchsia Authors +// +// Licensed under a BSD-style license <LICENSE-BSD>, Apache License, Version 2.0 +// <LICENSE-APACHE or https://www.apache.org/licenses/LICENSE-2.0>, or the MIT +// license <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your option. +// This file may not be copied, modified, or distributed except according to +// those terms. + +#![allow(warnings)] + +mod util; + +use std::{marker::PhantomData, mem::ManuallyDrop, option::IntoIter}; + +use {static_assertions::assert_impl_all, zerocopy::AsBytes}; + +use self::util::AU16; + +// A struct is `AsBytes` if: +// - all fields are `AsBytes` +// - `repr(C)` or `repr(transparent)` and +// - no padding (size of struct equals sum of size of field types) +// - `repr(packed)` + +#[derive(AsBytes)] +#[repr(C)] +struct CZst; + +assert_impl_all!(CZst: AsBytes); + +#[derive(AsBytes)] +#[repr(C)] +struct C { + a: u8, + b: u8, + c: AU16, +} + +assert_impl_all!(C: AsBytes); + +#[derive(AsBytes)] +#[repr(transparent)] +struct Transparent { + a: u8, + b: CZst, +} + +assert_impl_all!(Transparent: AsBytes); + +#[derive(AsBytes)] +#[repr(transparent)] +struct TransparentGeneric<T: ?Sized> { + a: CZst, + b: T, +} + +assert_impl_all!(TransparentGeneric<u64>: AsBytes); +assert_impl_all!(TransparentGeneric<[u64]>: AsBytes); + +#[derive(AsBytes)] +#[repr(C, packed)] +struct CZstPacked; + +assert_impl_all!(CZstPacked: AsBytes); + +#[derive(AsBytes)] +#[repr(C, packed)] +struct CPacked { + a: u8, + // NOTE: The `u16` type is not guaranteed to have alignment 2, although it + // does on many platforms. However, to fix this would require a custom type + // with a `#[repr(align(2))]` attribute, and `#[repr(packed)]` types are not + // allowed to transitively contain `#[repr(align(...))]` types. Thus, we + // have no choice but to use `u16` here. Luckily, these tests run in CI on + // platforms on which `u16` has alignment 2, so this isn't that big of a + // deal. + b: u16, +} + +assert_impl_all!(CPacked: AsBytes); + +#[derive(AsBytes)] +#[repr(C, packed(2))] +// The same caveats as for CPacked apply - we're assuming u64 is at least +// 4-byte aligned by default. Without packed(2), this should fail, as there +// would be padding between a/b assuming u64 is 4+ byte aligned. +struct CPacked2 { + a: u16, + b: u64, +} + +assert_impl_all!(CPacked2: AsBytes); + +#[derive(AsBytes)] +#[repr(C, packed)] +struct CPackedGeneric<T, U: ?Sized> { + t: T, + // Unsized types stored in `repr(packed)` structs must not be dropped + // because dropping them in-place might be unsound depending on the + // alignment of the outer struct. Sized types can be dropped by first being + // moved to an aligned stack variable, but this isn't possible with unsized + // types. + u: ManuallyDrop<U>, +} + +assert_impl_all!(CPackedGeneric<u8, AU16>: AsBytes); +assert_impl_all!(CPackedGeneric<u8, [AU16]>: AsBytes); + +#[derive(AsBytes)] +#[repr(packed)] +struct Packed { + a: u8, + // NOTE: The `u16` type is not guaranteed to have alignment 2, although it + // does on many platforms. However, to fix this would require a custom type + // with a `#[repr(align(2))]` attribute, and `#[repr(packed)]` types are not + // allowed to transitively contain `#[repr(align(...))]` types. Thus, we + // have no choice but to use `u16` here. Luckily, these tests run in CI on + // platforms on which `u16` has alignment 2, so this isn't that big of a + // deal. + b: u16, +} + +assert_impl_all!(Packed: AsBytes); + +#[derive(AsBytes)] +#[repr(packed)] +struct PackedGeneric<T, U: ?Sized> { + t: T, + // Unsized types stored in `repr(packed)` structs must not be dropped + // because dropping them in-place might be unsound depending on the + // alignment of the outer struct. Sized types can be dropped by first being + // moved to an aligned stack variable, but this isn't possible with unsized + // types. + u: ManuallyDrop<U>, +} + +assert_impl_all!(PackedGeneric<u8, AU16>: AsBytes); +assert_impl_all!(PackedGeneric<u8, [AU16]>: AsBytes); + +#[derive(AsBytes)] +#[repr(transparent)] +struct Unsized { + a: [u8], +} + +assert_impl_all!(Unsized: AsBytes); + +// Deriving `AsBytes` should work if the struct has bounded parameters. + +#[derive(AsBytes)] +#[repr(transparent)] +struct WithParams<'a: 'b, 'b: 'a, const N: usize, T: 'a + 'b + AsBytes>( + [T; N], + PhantomData<&'a &'b ()>, +) +where + 'a: 'b, + 'b: 'a, + T: 'a + 'b + AsBytes; + +assert_impl_all!(WithParams<'static, 'static, 42, u8>: AsBytes); |