| 1 |
// Implementation of INVOKE -*- C++ -*- |
| 2 |
|
| 3 |
// Copyright (C) 2016-2021 Free Software Foundation, Inc. |
| 4 |
// |
| 5 |
// This file is part of the GNU ISO C++ Library. This library is free |
| 6 |
// software; you can redistribute it and/or modify it under the |
| 7 |
// terms of the GNU General Public License as published by the |
| 8 |
// Free Software Foundation; either version 3, or (at your option) |
| 9 |
// any later version. |
| 10 |
|
| 11 |
// This library is distributed in the hope that it will be useful, |
| 12 |
// but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 |
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 14 |
// GNU General Public License for more details. |
| 15 |
|
| 16 |
// Under Section 7 of GPL version 3, you are granted additional |
| 17 |
// permissions described in the GCC Runtime Library Exception, version |
| 18 |
// 3.1, as published by the Free Software Foundation. |
| 19 |
|
| 20 |
// You should have received a copy of the GNU General Public License and |
| 21 |
// a copy of the GCC Runtime Library Exception along with this program; |
| 22 |
// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see |
| 23 |
// <http://www.gnu.org/licenses/>. |
| 24 |
|
| 25 |
/** @file include/bits/invoke.h |
| 26 |
* This is an internal header file, included by other library headers. |
| 27 |
* Do not attempt to use it directly. @headername{functional} |
| 28 |
*/ |
| 29 |
|
| 30 |
#ifndef _GLIBCXX_INVOKE_H |
| 31 |
#define _GLIBCXX_INVOKE_H 1 |
| 32 |
|
| 33 |
#pragma GCC system_header |
| 34 |
|
| 35 |
#if __cplusplus < 201103L |
| 36 |
# include <bits/c++0x_warning.h> |
| 37 |
#else |
| 38 |
|
| 39 |
#include <type_traits> |
| 40 |
#include <bits/move.h> // forward |
| 41 |
|
| 42 |
namespace std _GLIBCXX_VISIBILITY(default) |
| 43 |
{ |
| 44 |
_GLIBCXX_BEGIN_NAMESPACE_VERSION |
| 45 |
|
| 46 |
/** |
| 47 |
* @addtogroup utilities |
| 48 |
* @{ |
| 49 |
*/ |
| 50 |
|
| 51 |
// Used by __invoke_impl instead of std::forward<_Tp> so that a |
| 52 |
// reference_wrapper is converted to an lvalue-reference. |
| 53 |
template<typename _Tp, typename _Up = typename __inv_unwrap<_Tp>::type> |
| 54 |
constexpr _Up&& |
| 55 |
__invfwd(typename remove_reference<_Tp>::type& __t) noexcept |
| 56 |
{ return static_cast<_Up&&>(__t); } |
| 57 |
|
| 58 |
template<typename _Res, typename _Fn, typename... _Args> |
| 59 |
constexpr _Res |
| 60 |
__invoke_impl(__invoke_other, _Fn&& __f, _Args&&... __args) |
| 61 |
{ return std::forward<_Fn>(__f)(std::forward<_Args>(__args)...); } |
| 62 |
|
| 63 |
template<typename _Res, typename _MemFun, typename _Tp, typename... _Args> |
| 64 |
constexpr _Res |
| 65 |
__invoke_impl(__invoke_memfun_ref, _MemFun&& __f, _Tp&& __t, |
| 66 |
_Args&&... __args) |
| 67 |
{ return (__invfwd<_Tp>(__t).*__f)(std::forward<_Args>(__args)...); } |
| 68 |
|
| 69 |
template<typename _Res, typename _MemFun, typename _Tp, typename... _Args> |
| 70 |
constexpr _Res |
| 71 |
__invoke_impl(__invoke_memfun_deref, _MemFun&& __f, _Tp&& __t, |
| 72 |
_Args&&... __args) |
| 73 |
{ |
| 74 |
return ((*std::forward<_Tp>(__t)).*__f)(std::forward<_Args>(__args)...); |
| 75 |
} |
| 76 |
|
| 77 |
template<typename _Res, typename _MemPtr, typename _Tp> |
| 78 |
constexpr _Res |
| 79 |
__invoke_impl(__invoke_memobj_ref, _MemPtr&& __f, _Tp&& __t) |
| 80 |
{ return __invfwd<_Tp>(__t).*__f; } |
| 81 |
|
| 82 |
template<typename _Res, typename _MemPtr, typename _Tp> |
| 83 |
constexpr _Res |
| 84 |
__invoke_impl(__invoke_memobj_deref, _MemPtr&& __f, _Tp&& __t) |
| 85 |
{ return (*std::forward<_Tp>(__t)).*__f; } |
| 86 |
|
| 87 |
/// Invoke a callable object. |
| 88 |
template<typename _Callable, typename... _Args> |
| 89 |
constexpr typename __invoke_result<_Callable, _Args...>::type |
| 90 |
__invoke(_Callable&& __fn, _Args&&... __args) |
| 91 |
noexcept(__is_nothrow_invocable<_Callable, _Args...>::value) |
| 92 |
{ |
| 93 |
using __result = __invoke_result<_Callable, _Args...>; |
| 94 |
using __type = typename __result::type; |
| 95 |
using __tag = typename __result::__invoke_type; |
| 96 |
return std::__invoke_impl<__type>(__tag{}, std::forward<_Callable>(__fn), |
| 97 |
std::forward<_Args>(__args)...); |
| 98 |
} |
| 99 |
|
| 100 |
#if __cplusplus >= 201703L |
| 101 |
// INVOKE<R>: Invoke a callable object and convert the result to R. |
| 102 |
template<typename _Res, typename _Callable, typename... _Args> |
| 103 |
constexpr enable_if_t<is_invocable_r_v<_Res, _Callable, _Args...>, _Res> |
| 104 |
__invoke_r(_Callable&& __fn, _Args&&... __args) |
| 105 |
noexcept(is_nothrow_invocable_r_v<_Res, _Callable, _Args...>) |
| 106 |
{ |
| 107 |
using __result = __invoke_result<_Callable, _Args...>; |
| 108 |
using __type = typename __result::type; |
| 109 |
using __tag = typename __result::__invoke_type; |
| 110 |
if constexpr (is_void_v<_Res>) |
| 111 |
std::__invoke_impl<__type>(__tag{}, std::forward<_Callable>(__fn), |
| 112 |
std::forward<_Args>(__args)...); |
| 113 |
else |
| 114 |
return std::__invoke_impl<__type>(__tag{}, |
| 115 |
std::forward<_Callable>(__fn), |
| 116 |
std::forward<_Args>(__args)...); |
| 117 |
} |
| 118 |
#else // C++11 |
| 119 |
template<typename _Res, typename _Callable, typename... _Args> |
| 120 |
using __can_invoke_as_void = __enable_if_t< |
| 121 |
__and_<is_void<_Res>, __is_invocable<_Callable, _Args...>>::value, |
| 122 |
_Res |
| 123 |
>; |
| 124 |
|
| 125 |
template<typename _Res, typename _Callable, typename... _Args> |
| 126 |
using __can_invoke_as_nonvoid = __enable_if_t< |
| 127 |
__and_<__not_<is_void<_Res>>, |
| 128 |
is_convertible<typename __invoke_result<_Callable, _Args...>::type, |
| 129 |
_Res> |
| 130 |
>::value, |
| 131 |
_Res |
| 132 |
>; |
| 133 |
|
| 134 |
// INVOKE<R>: Invoke a callable object and convert the result to R. |
| 135 |
template<typename _Res, typename _Callable, typename... _Args> |
| 136 |
constexpr __can_invoke_as_nonvoid<_Res, _Callable, _Args...> |
| 137 |
__invoke_r(_Callable&& __fn, _Args&&... __args) |
| 138 |
{ |
| 139 |
using __result = __invoke_result<_Callable, _Args...>; |
| 140 |
using __type = typename __result::type; |
| 141 |
using __tag = typename __result::__invoke_type; |
| 142 |
return std::__invoke_impl<__type>(__tag{}, std::forward<_Callable>(__fn), |
| 143 |
std::forward<_Args>(__args)...); |
| 144 |
} |
| 145 |
|
| 146 |
// INVOKE<R> when R is cv void |
| 147 |
template<typename _Res, typename _Callable, typename... _Args> |
| 148 |
_GLIBCXX14_CONSTEXPR __can_invoke_as_void<_Res, _Callable, _Args...> |
| 149 |
__invoke_r(_Callable&& __fn, _Args&&... __args) |
| 150 |
{ |
| 151 |
using __result = __invoke_result<_Callable, _Args...>; |
| 152 |
using __type = typename __result::type; |
| 153 |
using __tag = typename __result::__invoke_type; |
| 154 |
std::__invoke_impl<__type>(__tag{}, std::forward<_Callable>(__fn), |
| 155 |
std::forward<_Args>(__args)...); |
| 156 |
} |
| 157 |
#endif // C++11 |
| 158 |
|
| 159 |
_GLIBCXX_END_NAMESPACE_VERSION |
| 160 |
} // namespace std |
| 161 |
|
| 162 |
#endif // C++11 |
| 163 |
|
| 164 |
#endif // _GLIBCXX_INVOKE_H |
