1 /* scoped_restore, a simple class for saving and restoring a value
3 Copyright (C) 2016-2017 Free Software Foundation, Inc.
5 This file is part of GDB.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
20 #ifndef SCOPED_RESTORE_H
21 #define SCOPED_RESTORE_H
23 /* Base class for scoped_restore_tmpl. */
24 struct scoped_restore_base
28 /* A convenience typedef. Users of make_scoped_restore declare the
29 local RAII object as having this type. */
30 typedef const scoped_restore_base
&scoped_restore
;
32 /* An RAII-based object that saves a variable's value, and then
33 restores it again when this object is destroyed. */
35 class scoped_restore_tmpl
: public scoped_restore_base
39 /* Create a new scoped_restore object that saves the current value
40 of *VAR. *VAR will be restored when this scoped_restore object
42 scoped_restore_tmpl (T
*var
)
48 /* Create a new scoped_restore object that saves the current value
49 of *VAR, and sets *VAR to VALUE. *VAR will be restored when this
50 scoped_restore object is destroyed. This is templated on T2 to
51 allow passing VALUEs of types convertible to T.
52 E.g.: T='base'; T2='derived'. */
53 template <typename T2
>
54 scoped_restore_tmpl (T
*var
, T2 value
)
61 scoped_restore_tmpl (const scoped_restore_tmpl
<T
> &other
)
62 : m_saved_var (other
.m_saved_var
),
63 m_saved_value (other
.m_saved_value
)
65 other
.m_saved_var
= NULL
;
68 ~scoped_restore_tmpl ()
70 if (m_saved_var
!= NULL
)
71 *m_saved_var
= m_saved_value
;
76 /* No need for this. It is intentionally not defined anywhere. */
77 scoped_restore_tmpl
&operator= (const scoped_restore_tmpl
&);
79 /* The saved variable. */
80 mutable T
*m_saved_var
;
82 /* The saved value. */
83 const T m_saved_value
;
86 /* Make a scoped_restore. This is useful because it lets template
87 argument deduction work. */
89 scoped_restore_tmpl
<T
> make_scoped_restore (T
*var
)
91 return scoped_restore_tmpl
<T
> (var
);
94 /* Make a scoped_restore. This is useful because it lets template
95 argument deduction work. */
96 template<typename T
, typename T2
>
97 scoped_restore_tmpl
<T
> make_scoped_restore (T
*var
, T2 value
)
99 return scoped_restore_tmpl
<T
> (var
, value
);
102 #endif /* SCOPED_RESTORE_H */
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