• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
1 // -*- C++ -*-
2 //===----------------------------------------------------------------------===//
3 //
4 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5 // See https://llvm.org/LICENSE.txt for license information.
6 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #ifndef _LIBCPP___FUNCTIONAL_BIND_H
11 #define _LIBCPP___FUNCTIONAL_BIND_H
12 
13 #include <__config>
14 #include <__functional/invoke.h>
15 #include <__functional/weak_result_type.h>
16 #include <__type_traits/decay.h>
17 #include <__type_traits/is_reference_wrapper.h>
18 #include <__type_traits/is_void.h>
19 #include <cstddef>
20 #include <tuple>
21 
22 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
23 #  pragma GCC system_header
24 #endif
25 
26 _LIBCPP_BEGIN_NAMESPACE_STD
27 
28 template<class _Tp>
29 struct is_bind_expression : _If<
30     _IsSame<_Tp, __remove_cvref_t<_Tp> >::value,
31     false_type,
32     is_bind_expression<__remove_cvref_t<_Tp> >
33 > {};
34 
35 #if _LIBCPP_STD_VER >= 17
36 template <class _Tp>
37 inline constexpr bool is_bind_expression_v = is_bind_expression<_Tp>::value;
38 #endif
39 
40 template<class _Tp>
41 struct is_placeholder : _If<
42     _IsSame<_Tp, __remove_cvref_t<_Tp> >::value,
43     integral_constant<int, 0>,
44     is_placeholder<__remove_cvref_t<_Tp> >
45 > {};
46 
47 #if _LIBCPP_STD_VER >= 17
48 template <class _Tp>
49 inline constexpr int is_placeholder_v = is_placeholder<_Tp>::value;
50 #endif
51 
52 namespace placeholders
53 {
54 
55 template <int _Np> struct __ph {};
56 
57 // C++17 recommends that we implement placeholders as `inline constexpr`, but allows
58 // implementing them as `extern <implementation-defined>`. Libc++ implements them as
59 // `extern const` in all standard modes to avoid an ABI break in C++03: making them
60 // `inline constexpr` requires removing their definition in the shared library to
61 // avoid ODR violations, which is an ABI break.
62 //
63 // In practice, since placeholders are empty, `extern const` is almost impossible
64 // to distinguish from `inline constexpr` from a usage stand point.
65 _LIBCPP_EXPORTED_FROM_ABI extern const __ph<1>   _1;
66 _LIBCPP_EXPORTED_FROM_ABI extern const __ph<2>   _2;
67 _LIBCPP_EXPORTED_FROM_ABI extern const __ph<3>   _3;
68 _LIBCPP_EXPORTED_FROM_ABI extern const __ph<4>   _4;
69 _LIBCPP_EXPORTED_FROM_ABI extern const __ph<5>   _5;
70 _LIBCPP_EXPORTED_FROM_ABI extern const __ph<6>   _6;
71 _LIBCPP_EXPORTED_FROM_ABI extern const __ph<7>   _7;
72 _LIBCPP_EXPORTED_FROM_ABI extern const __ph<8>   _8;
73 _LIBCPP_EXPORTED_FROM_ABI extern const __ph<9>   _9;
74 _LIBCPP_EXPORTED_FROM_ABI extern const __ph<10> _10;
75 
76 } // namespace placeholders
77 
78 template<int _Np>
79 struct is_placeholder<placeholders::__ph<_Np> >
80     : public integral_constant<int, _Np> {};
81 
82 
83 #ifndef _LIBCPP_CXX03_LANG
84 
85 template <class _Tp, class _Uj>
86 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
87 _Tp&
88 __mu(reference_wrapper<_Tp> __t, _Uj&)
89 {
90     return __t.get();
91 }
92 
93 template <class _Ti, class ..._Uj, size_t ..._Indx>
94 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
95 typename __invoke_of<_Ti&, _Uj...>::type
96 __mu_expand(_Ti& __ti, tuple<_Uj...>& __uj, __tuple_indices<_Indx...>)
97 {
98     return __ti(_VSTD::forward<_Uj>(_VSTD::get<_Indx>(__uj))...);
99 }
100 
101 template <class _Ti, class ..._Uj, __enable_if_t<is_bind_expression<_Ti>::value, int> = 0>
102 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
103 typename __invoke_of<_Ti&, _Uj...>::type
104 __mu(_Ti& __ti, tuple<_Uj...>& __uj)
105 {
106     typedef typename __make_tuple_indices<sizeof...(_Uj)>::type __indices;
107     return _VSTD::__mu_expand(__ti, __uj, __indices());
108 }
109 
110 template <bool IsPh, class _Ti, class _Uj>
111 struct __mu_return2 {};
112 
113 template <class _Ti, class _Uj>
114 struct __mu_return2<true, _Ti, _Uj>
115 {
116     typedef typename tuple_element<is_placeholder<_Ti>::value - 1, _Uj>::type type;
117 };
118 
119 template <class _Ti, class _Uj, __enable_if_t<0 < is_placeholder<_Ti>::value, int> = 0>
120 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
121 typename __mu_return2<0 < is_placeholder<_Ti>::value, _Ti, _Uj>::type
122 __mu(_Ti&, _Uj& __uj)
123 {
124     const size_t __indx = is_placeholder<_Ti>::value - 1;
125     return _VSTD::forward<typename tuple_element<__indx, _Uj>::type>(_VSTD::get<__indx>(__uj));
126 }
127 
128 template <class _Ti, class _Uj, __enable_if_t<!is_bind_expression<_Ti>::value &&
129                                               is_placeholder<_Ti>::value == 0 &&
130                                               !__is_reference_wrapper<_Ti>::value, int> = 0>
131 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
132 _Ti&
133 __mu(_Ti& __ti, _Uj&)
134 {
135     return __ti;
136 }
137 
138 template <class _Ti, bool IsReferenceWrapper, bool IsBindEx, bool IsPh,
139           class _TupleUj>
140 struct __mu_return_impl;
141 
142 template <bool _Invokable, class _Ti, class ..._Uj>
143 struct __mu_return_invokable  // false
144 {
145     typedef __nat type;
146 };
147 
148 template <class _Ti, class ..._Uj>
149 struct __mu_return_invokable<true, _Ti, _Uj...>
150 {
151     typedef typename __invoke_of<_Ti&, _Uj...>::type type;
152 };
153 
154 template <class _Ti, class ..._Uj>
155 struct __mu_return_impl<_Ti, false, true, false, tuple<_Uj...> >
156     : public __mu_return_invokable<__invokable<_Ti&, _Uj...>::value, _Ti, _Uj...>
157 {
158 };
159 
160 template <class _Ti, class _TupleUj>
161 struct __mu_return_impl<_Ti, false, false, true, _TupleUj>
162 {
163     typedef typename tuple_element<is_placeholder<_Ti>::value - 1,
164                                    _TupleUj>::type&& type;
165 };
166 
167 template <class _Ti, class _TupleUj>
168 struct __mu_return_impl<_Ti, true, false, false, _TupleUj>
169 {
170     typedef typename _Ti::type& type;
171 };
172 
173 template <class _Ti, class _TupleUj>
174 struct __mu_return_impl<_Ti, false, false, false, _TupleUj>
175 {
176     typedef _Ti& type;
177 };
178 
179 template <class _Ti, class _TupleUj>
180 struct __mu_return
181     : public __mu_return_impl<_Ti,
182                               __is_reference_wrapper<_Ti>::value,
183                               is_bind_expression<_Ti>::value,
184                               0 < is_placeholder<_Ti>::value &&
185                               is_placeholder<_Ti>::value <= tuple_size<_TupleUj>::value,
186                               _TupleUj>
187 {
188 };
189 
190 template <class _Fp, class _BoundArgs, class _TupleUj>
191 struct __is_valid_bind_return
192 {
193     static const bool value = false;
194 };
195 
196 template <class _Fp, class ..._BoundArgs, class _TupleUj>
197 struct __is_valid_bind_return<_Fp, tuple<_BoundArgs...>, _TupleUj>
198 {
199     static const bool value = __invokable<_Fp,
200                     typename __mu_return<_BoundArgs, _TupleUj>::type...>::value;
201 };
202 
203 template <class _Fp, class ..._BoundArgs, class _TupleUj>
204 struct __is_valid_bind_return<_Fp, const tuple<_BoundArgs...>, _TupleUj>
205 {
206     static const bool value = __invokable<_Fp,
207                     typename __mu_return<const _BoundArgs, _TupleUj>::type...>::value;
208 };
209 
210 template <class _Fp, class _BoundArgs, class _TupleUj,
211           bool = __is_valid_bind_return<_Fp, _BoundArgs, _TupleUj>::value>
212 struct __bind_return;
213 
214 template <class _Fp, class ..._BoundArgs, class _TupleUj>
215 struct __bind_return<_Fp, tuple<_BoundArgs...>, _TupleUj, true>
216 {
217     typedef typename __invoke_of
218     <
219         _Fp&,
220         typename __mu_return
221         <
222             _BoundArgs,
223             _TupleUj
224         >::type...
225     >::type type;
226 };
227 
228 template <class _Fp, class ..._BoundArgs, class _TupleUj>
229 struct __bind_return<_Fp, const tuple<_BoundArgs...>, _TupleUj, true>
230 {
231     typedef typename __invoke_of
232     <
233         _Fp&,
234         typename __mu_return
235         <
236             const _BoundArgs,
237             _TupleUj
238         >::type...
239     >::type type;
240 };
241 
242 template <class _Fp, class _BoundArgs, size_t ..._Indx, class _Args>
243 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
244 typename __bind_return<_Fp, _BoundArgs, _Args>::type
245 __apply_functor(_Fp& __f, _BoundArgs& __bound_args, __tuple_indices<_Indx...>,
246                 _Args&& __args)
247 {
248     return _VSTD::__invoke(__f, _VSTD::__mu(_VSTD::get<_Indx>(__bound_args), __args)...);
249 }
250 
251 template<class _Fp, class ..._BoundArgs>
252 class __bind : public __weak_result_type<__decay_t<_Fp> >
253 {
254 protected:
255     using _Fd = __decay_t<_Fp>;
256     typedef tuple<__decay_t<_BoundArgs>...> _Td;
257 private:
258     _Fd __f_;
259     _Td __bound_args_;
260 
261     typedef typename __make_tuple_indices<sizeof...(_BoundArgs)>::type __indices;
262 public:
263     template <class _Gp, class ..._BA,
264               __enable_if_t<is_constructible<_Fd, _Gp>::value && !is_same<__libcpp_remove_reference_t<_Gp>, __bind>::value, int> = 0>
265       _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
266       explicit __bind(_Gp&& __f, _BA&& ...__bound_args)
267         : __f_(_VSTD::forward<_Gp>(__f)),
268           __bound_args_(_VSTD::forward<_BA>(__bound_args)...) {}
269 
270     template <class ..._Args>
271         _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
272         typename __bind_return<_Fd, _Td, tuple<_Args&&...> >::type
273         operator()(_Args&& ...__args)
274         {
275             return _VSTD::__apply_functor(__f_, __bound_args_, __indices(),
276                                   tuple<_Args&&...>(_VSTD::forward<_Args>(__args)...));
277         }
278 
279     template <class ..._Args>
280         _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
281         typename __bind_return<const _Fd, const _Td, tuple<_Args&&...> >::type
282         operator()(_Args&& ...__args) const
283         {
284             return _VSTD::__apply_functor(__f_, __bound_args_, __indices(),
285                                    tuple<_Args&&...>(_VSTD::forward<_Args>(__args)...));
286         }
287 };
288 
289 template<class _Fp, class ..._BoundArgs>
290 struct is_bind_expression<__bind<_Fp, _BoundArgs...> > : public true_type {};
291 
292 template<class _Rp, class _Fp, class ..._BoundArgs>
293 class __bind_r
294     : public __bind<_Fp, _BoundArgs...>
295 {
296     typedef __bind<_Fp, _BoundArgs...> base;
297     typedef typename base::_Fd _Fd;
298     typedef typename base::_Td _Td;
299 public:
300     typedef _Rp result_type;
301 
302 
303     template <class _Gp, class ..._BA,
304               __enable_if_t<is_constructible<_Fd, _Gp>::value && !is_same<__libcpp_remove_reference_t<_Gp>, __bind_r>::value, int> = 0>
305       _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
306       explicit __bind_r(_Gp&& __f, _BA&& ...__bound_args)
307         : base(_VSTD::forward<_Gp>(__f),
308                _VSTD::forward<_BA>(__bound_args)...) {}
309 
310     template <class ..._Args, __enable_if_t<is_convertible<typename __bind_return<_Fd, _Td, tuple<_Args&&...> >::type,
311                                                            result_type>::value || is_void<_Rp>::value, int> = 0>
312         _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
313         result_type
314         operator()(_Args&& ...__args)
315         {
316             typedef __invoke_void_return_wrapper<_Rp> _Invoker;
317             return _Invoker::__call(static_cast<base&>(*this), _VSTD::forward<_Args>(__args)...);
318         }
319 
320     template <class ..._Args, __enable_if_t<is_convertible<typename __bind_return<const _Fd, const _Td, tuple<_Args&&...> >::type,
321                                                            result_type>::value || is_void<_Rp>::value, int> = 0>
322         _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
323         result_type
324         operator()(_Args&& ...__args) const
325         {
326             typedef __invoke_void_return_wrapper<_Rp> _Invoker;
327             return _Invoker::__call(static_cast<base const&>(*this), _VSTD::forward<_Args>(__args)...);
328         }
329 };
330 
331 template<class _Rp, class _Fp, class ..._BoundArgs>
332 struct is_bind_expression<__bind_r<_Rp, _Fp, _BoundArgs...> > : public true_type {};
333 
334 template<class _Fp, class ..._BoundArgs>
335 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
336 __bind<_Fp, _BoundArgs...>
337 bind(_Fp&& __f, _BoundArgs&&... __bound_args)
338 {
339     typedef __bind<_Fp, _BoundArgs...> type;
340     return type(_VSTD::forward<_Fp>(__f), _VSTD::forward<_BoundArgs>(__bound_args)...);
341 }
342 
343 template<class _Rp, class _Fp, class ..._BoundArgs>
344 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
345 __bind_r<_Rp, _Fp, _BoundArgs...>
346 bind(_Fp&& __f, _BoundArgs&&... __bound_args)
347 {
348     typedef __bind_r<_Rp, _Fp, _BoundArgs...> type;
349     return type(_VSTD::forward<_Fp>(__f), _VSTD::forward<_BoundArgs>(__bound_args)...);
350 }
351 
352 #endif // _LIBCPP_CXX03_LANG
353 
354 _LIBCPP_END_NAMESPACE_STD
355 
356 #endif // _LIBCPP___FUNCTIONAL_BIND_H
357