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
|
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
* Version: MPL 1.1 / GPLv3+ / LGPLv3+
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License or as specified alternatively below. You may obtain a copy of
* the License at http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* Major Contributor(s):
* Copyright (C) 2010 Red Hat, Inc., David Tardon <dtardon@redhat.com>
* (initial developer)
*
* All Rights Reserved.
*
* For minor contributions see the git repository.
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU General Public License Version 3 or later (the "GPLv3+"), or
* the GNU Lesser General Public License Version 3 or later (the "LGPLv3+"),
* in which case the provisions of the GPLv3+ or the LGPLv3+ are applicable
* instead of those above.
*/
namespace detail
{
template<typename T>
struct has_clone
{
template<typename U, U x>
struct test;
typedef char yes;
typedef struct { char a[2]; } no;
template<typename U>
static yes& check_sig(U*, test<U* (U::*)() const, &U::clone>* = 0);
template<typename U>
static no& check_sig(...);
enum
{
value = sizeof(check_sig<T>(0)) == sizeof(yes)
};
};
template<typename T, bool HasClone>
struct cloner
{
static T* clone(T* const other)
{
return new T(*other);
}
};
template<typename T>
struct cloner<T, true>
{
static T* clone(T* const other)
{
return other->clone();
}
};
}
/** Creates a new copy of the passed object.
If other is 0, just returns 0. Otherwise, if other has function
named clone with signature T* (T::*)() const, the function is called.
Otherwise, copy constructor is used.
@returns 0 or newly allocated object
*/
template<typename T>
T* clone(T* const other)
{
return other ? ::detail::cloner<T, ::detail::has_clone<T>::value>::clone(other) : 0;
}
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
|
