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. |
9 | macro_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] $it)* |
61 | }; |
62 | } |
63 | |
64 | macro_rules! s { |
65 | ($($(#[$attr:meta])* pub $t:ident $i:ident { $($field:tt)* })*) => ($( |
66 | s!(it: $(#[$attr])* pub $t $i { $($field)* }); |
67 | )*); |
68 | (it: $(#[$attr:meta])* pub union $i:ident { $($field:tt)* }) => ( |
69 | compile_error!("unions cannot derive extra traits, use s_no_extra_traits instead" ); |
70 | ); |
71 | (it: $(#[$attr:meta])* pub struct $i:ident { $($field:tt)* }) => ( |
72 | __item! { |
73 | #[repr(C)] |
74 | #[cfg_attr(feature = "extra_traits" , derive(Debug, Eq, Hash, PartialEq))] |
75 | #[allow(deprecated)] |
76 | $(#[$attr])* |
77 | pub struct $i { $($field)* } |
78 | } |
79 | #[allow(deprecated)] |
80 | impl ::Copy for $i {} |
81 | #[allow(deprecated)] |
82 | impl ::Clone for $i { |
83 | fn clone(&self) -> $i { *self } |
84 | } |
85 | ); |
86 | } |
87 | |
88 | macro_rules! s_no_extra_traits { |
89 | ($($(#[$attr:meta])* pub $t:ident $i:ident { $($field:tt)* })*) => ($( |
90 | s_no_extra_traits!(it: $(#[$attr])* pub $t $i { $($field)* }); |
91 | )*); |
92 | (it: $(#[$attr:meta])* pub union $i:ident { $($field:tt)* }) => ( |
93 | cfg_if! { |
94 | if #[cfg(libc_union)] { |
95 | __item! { |
96 | #[repr(C)] |
97 | $(#[$attr])* |
98 | pub union $i { $($field)* } |
99 | } |
100 | |
101 | impl ::Copy for $i {} |
102 | impl ::Clone for $i { |
103 | fn clone(&self) -> $i { *self } |
104 | } |
105 | } |
106 | } |
107 | ); |
108 | (it: $(#[$attr:meta])* pub struct $i:ident { $($field:tt)* }) => ( |
109 | __item! { |
110 | #[repr(C)] |
111 | $(#[$attr])* |
112 | pub struct $i { $($field)* } |
113 | } |
114 | #[allow(deprecated)] |
115 | impl ::Copy for $i {} |
116 | #[allow(deprecated)] |
117 | impl ::Clone for $i { |
118 | fn clone(&self) -> $i { *self } |
119 | } |
120 | ); |
121 | } |
122 | |
123 | macro_rules! e { |
124 | ($($(#[$attr:meta])* pub enum $i:ident { $($field:tt)* })*) => ($( |
125 | __item! { |
126 | #[cfg_attr(feature = "extra_traits" , derive(Debug, Eq, Hash, PartialEq))] |
127 | $(#[$attr])* |
128 | pub enum $i { $($field)* } |
129 | } |
130 | impl ::Copy for $i {} |
131 | impl ::Clone for $i { |
132 | fn clone(&self) -> $i { *self } |
133 | } |
134 | )*); |
135 | } |
136 | |
137 | macro_rules! s_paren { |
138 | ($($(#[$attr:meta])* pub struct $i:ident ( $($field:tt)* ); )* ) => ($( |
139 | __item! { |
140 | #[cfg_attr(feature = "extra_traits" , derive(Debug, Eq, Hash, PartialEq))] |
141 | $(#[$attr])* |
142 | pub struct $i ( $($field)* ); |
143 | } |
144 | impl ::Copy for $i {} |
145 | impl ::Clone for $i { |
146 | fn clone(&self) -> $i { *self } |
147 | } |
148 | )*); |
149 | } |
150 | |
151 | // This is a pretty horrible hack to allow us to conditionally mark |
152 | // some functions as 'const', without requiring users of this macro |
153 | // to care about the "const-extern-fn" feature. |
154 | // |
155 | // When 'const-extern-fn' is enabled, we emit the captured 'const' keyword |
156 | // in the expanded function. |
157 | // |
158 | // When 'const-extern-fn' is disabled, we always emit a plain 'pub unsafe extern fn'. |
159 | // Note that the expression matched by the macro is exactly the same - this allows |
160 | // users of this macro to work whether or not 'const-extern-fn' is enabled |
161 | // |
162 | // Unfortunately, we need to duplicate most of this macro between the 'cfg_if' blocks. |
163 | // This is because 'const unsafe extern fn' won't even parse on older compilers, |
164 | // so we need to avoid emitting it at all of 'const-extern-fn'. |
165 | // |
166 | // Specifically, moving the 'cfg_if' into the macro body will *not* work. |
167 | // Doing so would cause the '#[cfg(feature = "const-extern-fn")]' to be emitted |
168 | // into user code. The 'cfg' gate will not stop Rust from trying to parse the |
169 | // 'pub const unsafe extern fn', so users would get a compiler error even when |
170 | // the 'const-extern-fn' feature is disabled |
171 | // |
172 | // Note that users of this macro need to place 'const' in a weird position |
173 | // (after the closing ')' for the arguments, but before the return type). |
174 | // This was the only way I could satisfy the following two requirements: |
175 | // 1. Avoid ambiguity errors from 'macro_rules!' (which happen when writing '$foo:ident fn' |
176 | // 2. Allow users of this macro to mix 'pub fn foo' and 'pub const fn bar' within the same |
177 | // 'f!' block |
178 | cfg_if! { |
179 | if #[cfg(libc_const_extern_fn)] { |
180 | macro_rules! f { |
181 | ($($(#[$attr:meta])* pub $({$constness:ident})* fn $i:ident( |
182 | $($arg:ident: $argty:ty),* |
183 | ) -> $ret:ty { |
184 | $($body:stmt);* |
185 | })*) => ($( |
186 | #[inline] |
187 | $(#[$attr])* |
188 | pub $($constness)* unsafe extern fn $i($($arg: $argty),* |
189 | ) -> $ret { |
190 | $($body);* |
191 | } |
192 | )*) |
193 | } |
194 | |
195 | macro_rules! safe_f { |
196 | ($($(#[$attr:meta])* pub $({$constness:ident})* fn $i:ident( |
197 | $($arg:ident: $argty:ty),* |
198 | ) -> $ret:ty { |
199 | $($body:stmt);* |
200 | })*) => ($( |
201 | #[inline] |
202 | $(#[$attr])* |
203 | pub $($constness)* extern fn $i($($arg: $argty),* |
204 | ) -> $ret { |
205 | $($body);* |
206 | } |
207 | )*) |
208 | } |
209 | |
210 | macro_rules! const_fn { |
211 | ($($(#[$attr:meta])* $({$constness:ident})* fn $i:ident( |
212 | $($arg:ident: $argty:ty),* |
213 | ) -> $ret:ty { |
214 | $($body:stmt);* |
215 | })*) => ($( |
216 | #[inline] |
217 | $(#[$attr])* |
218 | $($constness)* fn $i($($arg: $argty),* |
219 | ) -> $ret { |
220 | $($body);* |
221 | } |
222 | )*) |
223 | } |
224 | |
225 | } else { |
226 | macro_rules! f { |
227 | ($($(#[$attr:meta])* pub $({$constness:ident})* fn $i:ident( |
228 | $($arg:ident: $argty:ty),* |
229 | ) -> $ret:ty { |
230 | $($body:stmt);* |
231 | })*) => ($( |
232 | #[inline] |
233 | $(#[$attr])* |
234 | pub unsafe extern fn $i($($arg: $argty),* |
235 | ) -> $ret { |
236 | $($body);* |
237 | } |
238 | )*) |
239 | } |
240 | |
241 | macro_rules! safe_f { |
242 | ($($(#[$attr:meta])* pub $({$constness:ident})* fn $i:ident( |
243 | $($arg:ident: $argty:ty),* |
244 | ) -> $ret:ty { |
245 | $($body:stmt);* |
246 | })*) => ($( |
247 | #[inline] |
248 | $(#[$attr])* |
249 | pub extern fn $i($($arg: $argty),* |
250 | ) -> $ret { |
251 | $($body);* |
252 | } |
253 | )*) |
254 | } |
255 | |
256 | macro_rules! const_fn { |
257 | ($($(#[$attr:meta])* $({$constness:ident})* fn $i:ident( |
258 | $($arg:ident: $argty:ty),* |
259 | ) -> $ret:ty { |
260 | $($body:stmt);* |
261 | })*) => ($( |
262 | #[inline] |
263 | $(#[$attr])* |
264 | fn $i($($arg: $argty),* |
265 | ) -> $ret { |
266 | $($body);* |
267 | } |
268 | )*) |
269 | } |
270 | } |
271 | } |
272 | |
273 | macro_rules! __item { |
274 | ($i:item) => { |
275 | $i |
276 | }; |
277 | } |
278 | |
279 | macro_rules! align_const { |
280 | ($($(#[$attr:meta])* |
281 | pub const $name:ident : $t1:ty |
282 | = $t2:ident { $($field:tt)* };)*) => ($( |
283 | #[cfg(libc_align)] |
284 | $(#[$attr])* |
285 | pub const $name : $t1 = $t2 { |
286 | $($field)* |
287 | }; |
288 | #[cfg(not(libc_align))] |
289 | $(#[$attr])* |
290 | pub const $name : $t1 = $t2 { |
291 | $($field)* |
292 | __align: [], |
293 | }; |
294 | )*) |
295 | } |
296 | |
297 | // This macro is used to deprecate items that should be accessed via the mach2 crate |
298 | macro_rules! deprecated_mach { |
299 | (pub const $id:ident: $ty:ty = $expr:expr;) => { |
300 | #[deprecated( |
301 | since = "0.2.55" , |
302 | note = "Use the `mach2` crate instead" , |
303 | )] |
304 | #[allow(deprecated)] |
305 | pub const $id: $ty = $expr; |
306 | }; |
307 | ($(pub const $id:ident: $ty:ty = $expr:expr;)*) => { |
308 | $( |
309 | deprecated_mach!( |
310 | pub const $id: $ty = $expr; |
311 | ); |
312 | )* |
313 | }; |
314 | (pub type $id:ident = $ty:ty;) => { |
315 | #[deprecated( |
316 | since = "0.2.55" , |
317 | note = "Use the `mach2` crate instead" , |
318 | )] |
319 | #[allow(deprecated)] |
320 | pub type $id = $ty; |
321 | }; |
322 | ($(pub type $id:ident = $ty:ty;)*) => { |
323 | $( |
324 | deprecated_mach!( |
325 | pub type $id = $ty; |
326 | ); |
327 | )* |
328 | } |
329 | } |
330 | |
331 | #[cfg (not(libc_ptr_addr_of))] |
332 | macro_rules! ptr_addr_of { |
333 | ($place:expr) => { |
334 | &$place |
335 | }; |
336 | } |
337 | |
338 | #[cfg (libc_ptr_addr_of)] |
339 | macro_rules! ptr_addr_of { |
340 | ($place:expr) => { |
341 | ::core::ptr::addr_of!($place) |
342 | }; |
343 | } |
344 | |