paludis  Version 2.6.0
singleton.hh
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1 /* vim: set sw=4 sts=4 et foldmethod=syntax : */
2 
3 /*
4  * Copyright (c) 2005, 2006, 2007, 2010 Ciaran McCreesh
5  *
6  * This file is part of the Paludis package manager. Paludis is free software;
7  * you can redistribute it and/or modify it under the terms of the GNU General
8  * Public License version 2, as published by the Free Software Foundation.
9  *
10  * Paludis is distributed in the hope that it will be useful, but WITHOUT ANY
11  * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
12  * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
13  * details.
14  *
15  * You should have received a copy of the GNU General Public License along with
16  * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
17  * Place, Suite 330, Boston, MA 02111-1307 USA
18  */
19 
20 #ifndef PALUDIS_GUARD_PALUDIS_SINGLETON_HH
21 #define PALUDIS_GUARD_PALUDIS_SINGLETON_HH 1
22 
24 
25 /** \file
26  * Singleton pattern.
27  *
28  * \ingroup g_oo
29  *
30  * \section Examples
31  *
32  * - None at this time.
33  */
34 
35 namespace paludis
36 {
37  /**
38  * Singletons have a single instance and are created when first used.
39  *
40  * \ingroup g_oo
41  * \nosubgrouping
42  */
43  template <typename OurType_>
45  {
46  private:
47  static OurType_ * * _get_instance_ptr();
48 
49  class DeleteOnDestruction;
50  friend class DeleteOnDestruction;
51 
52  static void _delete(OurType_ * const p);
53 
54  public:
55  ///\name Basic operations
56  ///\{
57 
58  Singleton() = default;
59  Singleton(const Singleton &) = delete;
60  const Singleton & operator= (const Singleton &) = delete;
61 
62  ///\}
63 
64  ///\name Singleton operations
65  ///\{
66 
67  /**
68  * Fetch our instance.
69  */
70  static OurType_ * get_instance()
71  PALUDIS_ATTRIBUTE((warn_unused_result));
72 
73  /**
74  * Destroy our instance.
75  */
76  static void destroy_instance();
77 
78  ///\}
79  };
80 }
81 
82 #endif
Definition: about_metadata-fwd.hh:23
Definition: singleton.hh:44
#define PALUDIS_ATTRIBUTE(x)
Definition: attributes.hh:53
#define PALUDIS_VISIBLE
Definition: attributes.hh:59