1/// A macro for defining #[cfg] if-else statements.
2///
3/// This is similar to the `if/elif` C preprocessor macro by allowing definition
4/// of a cascade of `#[cfg]` cases, emitting the implementation which matches
5/// first.
6///
7/// This allows you to conveniently provide a long list #[cfg]'d blocks of code
8/// without having to rewrite each clause multiple times.
9macro_rules! cfg_if {
10 // match if/else chains with a final `else`
11 ($(
12 if #[cfg($($meta:meta),*)] { $($it:item)* }
13 ) else * else {
14 $($it2:item)*
15 }) => {
16 cfg_if! {
17 @__items
18 () ;
19 $( ( ($($meta),*) ($($it)*) ), )*
20 ( () ($($it2)*) ),
21 }
22 };
23
24 // match if/else chains lacking a final `else`
25 (
26 if #[cfg($($i_met:meta),*)] { $($i_it:item)* }
27 $(
28 else if #[cfg($($e_met:meta),*)] { $($e_it:item)* }
29 )*
30 ) => {
31 cfg_if! {
32 @__items
33 () ;
34 ( ($($i_met),*) ($($i_it)*) ),
35 $( ( ($($e_met),*) ($($e_it)*) ), )*
36 ( () () ),
37 }
38 };
39
40 // Internal and recursive macro to emit all the items
41 //
42 // Collects all the negated `cfg`s in a list at the beginning and after the
43 // semicolon is all the remaining items
44 (@__items ($($not:meta,)*) ; ) => {};
45 (@__items ($($not:meta,)*) ; ( ($($m:meta),*) ($($it:item)*) ),
46 $($rest:tt)*) => {
47 // Emit all items within one block, applying an appropriate #[cfg]. The
48 // #[cfg] will require all `$m` matchers specified and must also negate
49 // all previous matchers.
50 cfg_if! { @__apply cfg(all($($m,)* not(any($($not),*)))), $($it)* }
51
52 // Recurse to emit all other items in `$rest`, and when we do so add all
53 // our `$m` matchers to the list of `$not` matchers as future emissions
54 // will have to negate everything we just matched as well.
55 cfg_if! { @__items ($($not,)* $($m,)*) ; $($rest)* }
56 };
57
58 // Internal macro to Apply a cfg attribute to a list of items
59 (@__apply $m:meta, $($it:item)*) => {
60 $(#[$m] $it)*
61 };
62}
63
64/// Create an internal crate prelude with `core` reexports and common types.
65macro_rules! prelude {
66 () => {
67 /// Frequently-used types that are available on all platforms
68 ///
69 /// We need to reexport the core types so this works with `rust-dep-of-std`.
70 mod prelude {
71 // Exports from `core`
72 #[allow(unused_imports)]
73 pub(crate) use ::core::clone::Clone;
74 #[allow(unused_imports)]
75 pub(crate) use ::core::marker::{Copy, Send, Sync};
76 #[allow(unused_imports)]
77 pub(crate) use ::core::option::Option;
78 #[allow(unused_imports)]
79 pub(crate) use ::core::{fmt, hash, iter, mem};
80
81 // Commonly used types defined in this crate
82 #[allow(unused_imports)]
83 pub(crate) use crate::{
84 c_char, c_double, c_float, c_int, c_long, c_longlong, c_short, c_uchar, c_uint,
85 c_ulong, c_ulonglong, c_ushort, c_void, intptr_t, size_t, ssize_t, uintptr_t,
86 };
87 }
88 };
89}
90
91/// Implement `Clone` and `Copy` for a struct, as well as `Debug`, `Eq`, `Hash`, and
92/// `PartialEq` if the `extra_traits` feature is enabled.
93///
94/// Use [`s_no_extra_traits`] for structs where the `extra_traits` feature does not
95/// make sense, and for unions.
96macro_rules! s {
97 ($(
98 $(#[$attr:meta])*
99 pub $t:ident $i:ident { $($field:tt)* }
100 )*) => ($(
101 s!(it: $(#[$attr])* pub $t $i { $($field)* });
102 )*);
103
104 (it: $(#[$attr:meta])* pub union $i:ident { $($field:tt)* }) => (
105 compile_error!("unions cannot derive extra traits, use s_no_extra_traits instead");
106 );
107
108 (it: $(#[$attr:meta])* pub struct $i:ident { $($field:tt)* }) => (
109 __item! {
110 #[repr(C)]
111 #[cfg_attr(
112 feature = "extra_traits",
113 ::core::prelude::v1::derive(Debug, Eq, Hash, PartialEq)
114 )]
115 #[::core::prelude::v1::derive(::core::clone::Clone, ::core::marker::Copy)]
116 #[allow(deprecated)]
117 $(#[$attr])*
118 pub struct $i { $($field)* }
119 }
120 );
121}
122
123/// Implement `Clone` and `Copy` for a tuple struct, as well as `Debug`, `Eq`, `Hash`,
124/// and `PartialEq` if the `extra_traits` feature is enabled.
125///
126/// This is the same as [`s`] but works for tuple structs.
127macro_rules! s_paren {
128 ($(
129 $(#[$attr:meta])*
130 pub struct $i:ident ( $($field:tt)* );
131 )*) => ($(
132 __item! {
133 #[cfg_attr(
134 feature = "extra_traits",
135 ::core::prelude::v1::derive(Debug, Eq, Hash, PartialEq)
136 )]
137 #[::core::prelude::v1::derive(::core::clone::Clone, ::core::marker::Copy)]
138 $(#[$attr])*
139 pub struct $i ( $($field)* );
140 }
141 )*);
142}
143
144/// Implement `Clone` and `Copy` for a struct with no `extra_traits` feature.
145///
146/// Most items will prefer to use [`s`].
147macro_rules! s_no_extra_traits {
148 ($(
149 $(#[$attr:meta])*
150 pub $t:ident $i:ident { $($field:tt)* }
151 )*) => ($(
152 s_no_extra_traits!(it: $(#[$attr])* pub $t $i { $($field)* });
153 )*);
154
155 (it: $(#[$attr:meta])* pub union $i:ident { $($field:tt)* }) => (
156 __item! {
157 #[repr(C)]
158 #[::core::prelude::v1::derive(::core::clone::Clone, ::core::marker::Copy)]
159 $(#[$attr])*
160 pub union $i { $($field)* }
161 }
162
163 #[cfg(feature = "extra_traits")]
164 impl ::core::fmt::Debug for $i {
165 fn fmt(&self, f: &mut ::core::fmt::Formatter<'_>) -> ::core::fmt::Result {
166 f.debug_struct(::core::stringify!($i)).finish_non_exhaustive()
167 }
168 }
169 );
170
171 (it: $(#[$attr:meta])* pub struct $i:ident { $($field:tt)* }) => (
172 __item! {
173 #[repr(C)]
174 #[::core::prelude::v1::derive(::core::clone::Clone, ::core::marker::Copy)]
175 $(#[$attr])*
176 pub struct $i { $($field)* }
177 }
178 );
179}
180
181/// Specify that an enum should have no traits that aren't specified in the macro
182/// invocation, i.e. no `Clone` or `Copy`.
183macro_rules! missing {
184 ($(
185 $(#[$attr:meta])*
186 pub enum $i:ident {}
187 )*) => ($(
188 $(#[$attr])*
189 #[allow(missing_copy_implementations)]
190 pub enum $i { }
191 )*);
192}
193
194/// Implement `Clone` and `Copy` for an enum, as well as `Debug`, `Eq`, `Hash`, and
195/// `PartialEq` if the `extra_traits` feature is enabled.
196macro_rules! e {
197 ($(
198 $(#[$attr:meta])*
199 pub enum $i:ident { $($field:tt)* }
200 )*) => ($(
201 __item! {
202 #[cfg_attr(
203 feature = "extra_traits",
204 ::core::prelude::v1::derive(Debug, Eq, Hash, PartialEq)
205 )]
206 #[::core::prelude::v1::derive(::core::clone::Clone, ::core::marker::Copy)]
207 $(#[$attr])*
208 pub enum $i { $($field)* }
209 }
210 )*);
211}
212
213// This is a pretty horrible hack to allow us to conditionally mark some functions as 'const',
214// without requiring users of this macro to care "libc_const_extern_fn".
215//
216// When 'libc_const_extern_fn' is enabled, we emit the captured 'const' keyword in the expanded
217// function.
218//
219// When 'libc_const_extern_fn' is disabled, we always emit a plain 'pub unsafe extern fn'.
220// Note that the expression matched by the macro is exactly the same - this allows
221// users of this macro to work whether or not 'libc_const_extern_fn' is enabled
222//
223// Unfortunately, we need to duplicate most of this macro between the 'cfg_if' blocks.
224// This is because 'const unsafe extern fn' won't even parse on older compilers,
225// so we need to avoid emitting it at all of 'libc_const_extern_fn'.
226//
227// Specifically, moving the 'cfg_if' into the macro body will *not* work. Doing so would cause the
228// '#[cfg(libc_const_extern_fn)]' to be emitted into user code. The 'cfg' gate will not stop Rust
229// from trying to parse the 'pub const unsafe extern fn', so users would get a compiler error even
230// when the 'libc_const_extern_fn' feature is disabled.
231
232// FIXME(ctest): ctest can't handle `const extern` functions, we should be able to remove this
233// cfg completely.
234// FIXME(ctest): ctest can't handle `$(,)?` so we use `$(,)*` which isn't quite correct.
235cfg_if! {
236 if #[cfg(libc_const_extern_fn)] {
237 /// Define an `unsafe` function that is const as long as `libc_const_extern_fn` is enabled.
238 macro_rules! f {
239 ($(
240 $(#[$attr:meta])*
241 pub $({$constness:ident})* fn $i:ident($($arg:ident: $argty:ty),* $(,)*) -> $ret:ty
242 $body:block
243 )*) => ($(
244 #[inline]
245 $(#[$attr])*
246 pub $($constness)* unsafe extern fn $i($($arg: $argty),*) -> $ret
247 $body
248 )*)
249 }
250
251 /// Define a safe function that is const as long as `libc_const_extern_fn` is enabled.
252 macro_rules! safe_f {
253 ($(
254 $(#[$attr:meta])*
255 pub $({$constness:ident})* fn $i:ident($($arg:ident: $argty:ty),* $(,)*) -> $ret:ty
256 $body:block
257 )*) => ($(
258 #[inline]
259 $(#[$attr])*
260 pub $($constness)* extern fn $i($($arg: $argty),*) -> $ret
261 $body
262 )*)
263 }
264
265 /// A nonpublic function that is const as long as `libc_const_extern_fn` is enabled.
266 macro_rules! const_fn {
267 ($(
268 $(#[$attr:meta])*
269 $({$constness:ident})* fn $i:ident($($arg:ident: $argty:ty),* $(,)*) -> $ret:ty
270 $body:block
271 )*) => ($(
272 #[inline]
273 $(#[$attr])*
274 $($constness)* fn $i($($arg: $argty),*) -> $ret
275 $body
276 )*)
277 }
278 } else {
279 /// Define an `unsafe` function that is const as long as `libc_const_extern_fn` is enabled.
280 macro_rules! f {
281 ($(
282 $(#[$attr:meta])*
283 pub $({$constness:ident})* fn $i:ident($($arg:ident: $argty:ty),* $(,)*) -> $ret:ty
284 $body:block
285 )*) => ($(
286 #[inline]
287 $(#[$attr])*
288 pub unsafe extern fn $i($($arg: $argty),*) -> $ret
289 $body
290 )*)
291 }
292
293 /// Define a safe function that is const as long as `libc_const_extern_fn` is enabled.
294 macro_rules! safe_f {
295 ($(
296 $(#[$attr:meta])*
297 pub $({$constness:ident})* fn $i:ident($($arg:ident: $argty:ty),* $(,)*) -> $ret:ty
298 $body:block
299 )*) => ($(
300 #[inline]
301 $(#[$attr])*
302 pub extern fn $i($($arg: $argty),*) -> $ret
303 $body
304 )*)
305 }
306
307 /// A nonpublic function that is const as long as `libc_const_extern_fn` is enabled.
308 macro_rules! const_fn {
309 ($(
310 $(#[$attr:meta])*
311 $({$constness:ident})* fn $i:ident($($arg:ident: $argty:ty),* $(,)*) -> $ret:ty
312 $body:block
313 )*) => ($(
314 #[inline]
315 $(#[$attr])*
316 fn $i($($arg: $argty),*) -> $ret
317 $body
318 )*)
319 }
320 }
321}
322
323macro_rules! __item {
324 ($i:item) => {
325 $i
326 };
327}
328
329// This macro is used to deprecate items that should be accessed via the mach2 crate
330macro_rules! deprecated_mach {
331 (pub const $id:ident: $ty:ty = $expr:expr;) => {
332 #[deprecated(
333 since = "0.2.55",
334 note = "Use the `mach2` crate instead",
335 )]
336 #[allow(deprecated)]
337 pub const $id: $ty = $expr;
338 };
339 ($(pub const $id:ident: $ty:ty = $expr:expr;)*) => {
340 $(
341 deprecated_mach!(
342 pub const $id: $ty = $expr;
343 );
344 )*
345 };
346 (pub type $id:ident = $ty:ty;) => {
347 #[deprecated(
348 since = "0.2.55",
349 note = "Use the `mach2` crate instead",
350 )]
351 #[allow(deprecated)]
352 pub type $id = $ty;
353 };
354 ($(pub type $id:ident = $ty:ty;)*) => {
355 $(
356 deprecated_mach!(
357 pub type $id = $ty;
358 );
359 )*
360 }
361}
362