objc_encode/
encode.rs

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1use core::ffi::c_void;
2
3use crate::Encoding;
4
5/// Types that have an Objective-C type encoding.
6///
7/// Unsafe because Objective-C will make assumptions about the type (like its
8/// size and alignment) from its encoding, so the implementer must verify that
9/// the encoding is accurate.
10pub unsafe trait Encode {
11    /// Returns the Objective-C type encoding for Self.
12    const ENCODING: Encoding<'static>;
13}
14
15macro_rules! encode_impls {
16    ($($t:ty : $e:ident,)*) => ($(
17        unsafe impl Encode for $t {
18            const ENCODING: Encoding<'static> = Encoding::$e;
19        }
20    )*);
21}
22
23encode_impls!(
24    i8: Char,
25    i16: Short,
26    i32: Int,
27    i64: LongLong,
28    u8: UChar,
29    u16: UShort,
30    u32: UInt,
31    u64: ULongLong,
32    f32: Float,
33    f64: Double,
34    bool: Bool,
35    (): Void,
36    *mut i8: String,
37    *const i8: String,
38    *mut u8: String,
39    *const u8: String,
40);
41
42unsafe impl Encode for isize {
43    #[cfg(target_pointer_width = "32")]
44    const ENCODING: Encoding<'static> = i32::ENCODING;
45
46    #[cfg(target_pointer_width = "64")]
47    const ENCODING: Encoding<'static> = i64::ENCODING;
48}
49
50unsafe impl Encode for usize {
51    #[cfg(target_pointer_width = "32")]
52    const ENCODING: Encoding<'static> = u32::ENCODING;
53
54    #[cfg(target_pointer_width = "64")]
55    const ENCODING: Encoding<'static> = u64::ENCODING;
56}
57
58unsafe impl Encode for *mut c_void {
59    const ENCODING: Encoding<'static> = Encoding::Pointer(&Encoding::Void);
60}
61
62unsafe impl Encode for *const c_void {
63    const ENCODING: Encoding<'static> = Encoding::Pointer(&Encoding::Void);
64}
65
66// TODO: Replace this with a const generics implementation when they stabilise (#44580)
67macro_rules! slice_encode_impl {
68    ($($n:literal),* $(,)?) => {
69        $(
70            unsafe impl<T: Encode> Encode for [T; $n] {
71                const ENCODING: Encoding<'static> = Encoding::Array($n, &<T as Encode>::ENCODING);
72            }
73        )*
74    };
75}
76
77slice_encode_impl!(
78    1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26,
79    27, 28, 29, 30, 31, 32
80);
81
82/*
83External crates cannot implement Encode for pointers or Optionals, but they
84*can* implement it for references. rust-lang/rust#25126
85
86As a workaround, we provide implementations for these types that return the
87same encoding as references.
88*/
89unsafe impl<T: 'static> Encode for *const T where for<'a> &'a T: Encode {
90    const ENCODING: Encoding<'static> = <&T as Encode>::ENCODING;
91}
92
93unsafe impl<T: 'static> Encode for *mut T where for<'a> &'a mut T: Encode {
94    const ENCODING: Encoding<'static> = <&mut T>::ENCODING;
95}
96
97unsafe impl<'a, T: 'a> Encode for Option<&'a T> where &'a T: Encode {
98    const ENCODING: Encoding<'static> = <&T>::ENCODING;
99}
100
101unsafe impl<'a, T: 'a> Encode for Option<&'a mut T> where &'a mut T: Encode {
102    const ENCODING: Encoding<'static> = <&mut T>::ENCODING;
103}
objc_encode/encode.rs

objc_encode/
encode.rs
