1 // Copyright 2019 The Fuchsia Authors
2 //
3 // Licensed under a BSD-style license <LICENSE-BSD>, Apache License, Version 2.0
4 // <LICENSE-APACHE or https://www.apache.org/licenses/LICENSE-2.0>, or the MIT
5 // license <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your option.
6 // This file may not be copied, modified, or distributed except according to
7 // those terms.
8 
9 #![allow(warnings)]
10 
11 mod util;
12 
13 use std::{marker::PhantomData, option::IntoIter};
14 
15 use {static_assertions::assert_impl_all, zerocopy::Unaligned};
16 
17 use crate::util::AU16;
18 
19 // A struct is `Unaligned` if:
20 // - `repr(align)` is no more than 1 and either
21 //   - `repr(C)` or `repr(transparent)` and
22 //     - all fields Unaligned
23 //   - `repr(packed)`
24 
25 #[derive(Unaligned)]
26 #[repr(C)]
27 struct Foo {
28     a: u8,
29 }
30 
31 assert_impl_all!(Foo: Unaligned);
32 
33 #[derive(Unaligned)]
34 #[repr(transparent)]
35 struct Bar {
36     a: u8,
37 }
38 
39 assert_impl_all!(Bar: Unaligned);
40 
41 #[derive(Unaligned)]
42 #[repr(packed)]
43 struct Baz {
44     // NOTE: The `u16` type is not guaranteed to have alignment 2, although it
45     // does on many platforms. However, to fix this would require a custom type
46     // with a `#[repr(align(2))]` attribute, and `#[repr(packed)]` types are not
47     // allowed to transitively contain `#[repr(align(...))]` types. Thus, we
48     // have no choice but to use `u16` here. Luckily, these tests run in CI on
49     // platforms on which `u16` has alignment 2, so this isn't that big of a
50     // deal.
51     a: u16,
52 }
53 
54 assert_impl_all!(Baz: Unaligned);
55 
56 #[derive(Unaligned)]
57 #[repr(C, align(1))]
58 struct FooAlign {
59     a: u8,
60 }
61 
62 assert_impl_all!(FooAlign: Unaligned);
63 
64 #[derive(Unaligned)]
65 #[repr(transparent)]
66 struct Unsized {
67     a: [u8],
68 }
69 
70 assert_impl_all!(Unsized: Unaligned);
71 
72 #[derive(Unaligned)]
73 #[repr(C)]
74 struct TypeParams<'a, T: ?Sized, I: Iterator> {
75     a: I::Item,
76     b: u8,
77     c: PhantomData<&'a [u8]>,
78     d: PhantomData<&'static str>,
79     e: PhantomData<String>,
80     f: T,
81 }
82 
83 assert_impl_all!(TypeParams<'static, (), IntoIter<()>>: Unaligned);
84 assert_impl_all!(TypeParams<'static, u8, IntoIter<()>>: Unaligned);
85 assert_impl_all!(TypeParams<'static, [u8], IntoIter<()>>: Unaligned);
86 
87 // Deriving `Unaligned` should work if the struct has bounded parameters.
88 
89 #[derive(Unaligned)]
90 #[repr(transparent)]
91 struct WithParams<'a: 'b, 'b: 'a, const N: usize, T: 'a + 'b + Unaligned>(
92     [T; N],
93     PhantomData<&'a &'b ()>,
94 )
95 where
96     'a: 'b,
97     'b: 'a,
98     T: 'a + 'b + Unaligned;
99 
100 assert_impl_all!(WithParams<'static, 'static, 42, u8>: Unaligned);
101