paludis  Version 2.6.0
save.hh
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1 /* vim: set sw=4 sts=4 et foldmethod=syntax : */
2 
3 /*
4  * Copyright (c) 2005, 2006, 2007, 2008 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_SAVE_HH
21 #define PALUDIS_GUARD_PALUDIS_SAVE_HH 1
22 
24 #include <functional>
25 
26 /** \file
27  * Declarations for the Save and RunOnDestruction classes.
28  *
29  * \ingroup g_utils
30  *
31  * \section Examples
32  *
33  * - None at this time.
34  */
35 
36 namespace paludis
37 {
38  /**
39  * Save the value of a particular variable and assign it a new value for the
40  * duration of the Save instance's lifetime (RAII, see \ref EffCpp item 13 or
41  * \ref TCppPL section 14.4).
42  *
43  * \ingroup g_utils
44  * \nosubgrouping
45  */
46  template <typename T_>
47  class Save
48  {
49  private:
50  T_ * const _ptr;
51  const T_ _value;
52 
53  Save(const Save &);
54  void operator= (const Save &);
55 
56  public:
57  ///\name Basic operations
58  ///\{
59 
60  /**
61  * Constructor.
62  */
63  Save(T_ * const p) :
64  _ptr(p),
65  _value(*p)
66  {
67  }
68 
69  /**
70  * Constructor, with convenience assignment to new_value.
71  */
72  Save(T_ * const p, const T_ & new_value) :
73  _ptr(p),
74  _value(*p)
75  {
76  *p = new_value;
77  }
78 
79  /**
80  * Destructor.
81  */
83  {
84  *_ptr = _value;
85  }
86 
87  ///\}
88  };
89 
90  /**
91  * Run the supplied function when the class is destructed.
92  *
93  * \ingroup g_utils
94  * \since 0.26
95  */
97  {
98  private:
100  void operator= (const RunOnDestruction &);
101 
102  const std::function<void ()> _f;
103 
104  public:
105  RunOnDestruction(const std::function<void ()> & f) :
106  _f(f)
107  {
108  }
109 
111  {
112  _f();
113  }
114  };
115 
116 }
117 
118 #endif
119 
Definition: about_metadata-fwd.hh:23
Definition: save.hh:47
Save(T_ *const p, const T_ &new_value)
Definition: save.hh:72
~Save()
Definition: save.hh:82
Save(T_ *const p)
Definition: save.hh:63
Definition: save.hh:96
#define PALUDIS_VISIBLE
Definition: attributes.hh:59