1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
|
/* Copyright (C) 2017-2024 Free Software Foundation, Inc.
This file is part of GDB.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#ifndef GDBSUPPORT_TRAITS_H
#define GDBSUPPORT_TRAITS_H
#include <type_traits>
namespace gdb {
/* Implementation of the detection idiom:
- http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/n4502.pdf
- http://en.cppreference.com/w/cpp/experimental/is_detected
*/
struct nonesuch
{
nonesuch () = delete;
~nonesuch () = delete;
nonesuch (const nonesuch &) = delete;
void operator= (const nonesuch &) = delete;
};
namespace detection_detail {
/* Implementation of the detection idiom (negative case). */
template<typename Default, typename AlwaysVoid,
template<typename...> class Op, typename... Args>
struct detector
{
using value_t = std::false_type;
using type = Default;
};
/* Implementation of the detection idiom (positive case). */
template<typename Default, template<typename...> class Op, typename... Args>
struct detector<Default, std::void_t<Op<Args...>>, Op, Args...>
{
using value_t = std::true_type;
using type = Op<Args...>;
};
/* Detect whether Op<Args...> is a valid type, use Default if not. */
template<typename Default, template<typename...> class Op,
typename... Args>
using detected_or = detector<Default, void, Op, Args...>;
/* Op<Args...> if that is a valid type, otherwise Default. */
template<typename Default, template<typename...> class Op,
typename... Args>
using detected_or_t
= typename detected_or<Default, Op, Args...>::type;
} /* detection_detail */
template<template<typename...> class Op, typename... Args>
using is_detected
= typename detection_detail::detector<nonesuch, void, Op, Args...>::value_t;
template<template<typename...> class Op, typename... Args>
using detected_t
= typename detection_detail::detector<nonesuch, void, Op, Args...>::type;
template<typename Default, template<typename...> class Op, typename... Args>
using detected_or = detection_detail::detected_or<Default, Op, Args...>;
template<typename Default, template<typename...> class Op, typename... Args>
using detected_or_t = typename detected_or<Default, Op, Args...>::type;
template<typename Expected, template<typename...> class Op, typename... Args>
using is_detected_exact = std::is_same<Expected, detected_t<Op, Args...>>;
template<typename To, template<typename...> class Op, typename... Args>
using is_detected_convertible
= std::is_convertible<detected_t<Op, Args...>, To>;
/* A few trait helpers -- standard traits but with slightly nicer
names. Uppercase because "and/or", etc. are reserved keywords. */
template<typename Predicate>
using Not = std::negation<Predicate>;
template<typename ...T>
using Or = std::disjunction<T...>;
template<typename ...T>
using And = std::conjunction<T...>;
/* Concepts-light-like helper to make SFINAE logic easier to read. */
template<typename Condition>
using Requires = typename std::enable_if<Condition::value, void>::type;
}
template<typename T>
using RequireLongest = gdb::Requires<gdb::Or<std::is_same<T, LONGEST>,
std::is_same<T, ULONGEST>>>;
#endif /* GDBSUPPORT_TRAITS_H */
|
