1// Implementation of INVOKE -*- C++ -*-
2
3// Copyright (C) 2016-2019 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
41namespace std _GLIBCXX_VISIBILITY(default)
42{
43_GLIBCXX_BEGIN_NAMESPACE_VERSION
44
45 /**
46 * @addtogroup utilities
47 * @{
48 */
49
50 // Used by __invoke_impl instead of std::forward<_Tp> so that a
51 // reference_wrapper is converted to an lvalue-reference.
52 template<typename _Tp, typename _Up = typename __inv_unwrap<_Tp>::type>
53 constexpr _Up&&
54 __invfwd(typename remove_reference<_Tp>::type& __t) noexcept
55 { return static_cast<_Up&&>(__t); }
56
57 template<typename _Res, typename _Fn, typename... _Args>
58 constexpr _Res
59 __invoke_impl(__invoke_other, _Fn&& __f, _Args&&... __args)
60 { return std::forward<_Fn>(__f)(std::forward<_Args>(__args)...); }
61
62 template<typename _Res, typename _MemFun, typename _Tp, typename... _Args>
63 constexpr _Res
64 __invoke_impl(__invoke_memfun_ref, _MemFun&& __f, _Tp&& __t,
65 _Args&&... __args)
66 { return (__invfwd<_Tp>(__t).*__f)(std::forward<_Args>(__args)...); }
67
68 template<typename _Res, typename _MemFun, typename _Tp, typename... _Args>
69 constexpr _Res
70 __invoke_impl(__invoke_memfun_deref, _MemFun&& __f, _Tp&& __t,
71 _Args&&... __args)
72 {
73 return ((*std::forward<_Tp>(__t)).*__f)(std::forward<_Args>(__args)...);
74 }
75
76 template<typename _Res, typename _MemPtr, typename _Tp>
77 constexpr _Res
78 __invoke_impl(__invoke_memobj_ref, _MemPtr&& __f, _Tp&& __t)
79 { return __invfwd<_Tp>(__t).*__f; }
80
81 template<typename _Res, typename _MemPtr, typename _Tp>
82 constexpr _Res
83 __invoke_impl(__invoke_memobj_deref, _MemPtr&& __f, _Tp&& __t)
84 { return (*std::forward<_Tp>(__t)).*__f; }
85
86 /// Invoke a callable object.
87 template<typename _Callable, typename... _Args>
88 constexpr typename __invoke_result<_Callable, _Args...>::type
89 __invoke(_Callable&& __fn, _Args&&... __args)
90 noexcept(__is_nothrow_invocable<_Callable, _Args...>::value)
91 {
92 using __result = __invoke_result<_Callable, _Args...>;
93 using __type = typename __result::type;
94 using __tag = typename __result::__invoke_type;
95 return std::__invoke_impl<__type>(__tag{}, std::forward<_Callable>(__fn),
96 std::forward<_Args>(__args)...);
97 }
98
99_GLIBCXX_END_NAMESPACE_VERSION
100} // namespace std
101
102#endif // C++11
103
104#endif // _GLIBCXX_INVOKE_H
105