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Diffstat (limited to 'src/FbTk/DefaultValue.hh')
-rw-r--r-- | src/FbTk/DefaultValue.hh | 82 |
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diff --git a/src/FbTk/DefaultValue.hh b/src/FbTk/DefaultValue.hh new file mode 100644 index 0000000..a89ad0a --- /dev/null +++ b/src/FbTk/DefaultValue.hh | |||
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1 | // DefaultValue.hh | ||
2 | // Copyright (c) 2007 Fluxbox Team (fluxgen at fluxbox dot org) | ||
3 | // | ||
4 | // Permission is hereby granted, free of charge, to any person obtaining a | ||
5 | // copy of this software and associated documentation files (the "Software"), | ||
6 | // to deal in the Software without restriction, including without limitation | ||
7 | // the rights to use, copy, modify, merge, publish, distribute, sublicense, | ||
8 | // and/or sell copies of the Software, and to permit persons to whom the | ||
9 | // Software is furnished to do so, subject to the following conditions: | ||
10 | // | ||
11 | // The above copyright notice and this permission notice shall be included in | ||
12 | // all copies or substantial portions of the Software. | ||
13 | // | ||
14 | // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | ||
15 | // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | ||
16 | // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL | ||
17 | // THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | ||
18 | // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING | ||
19 | // FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER | ||
20 | // DEALINGS IN THE SOFTWARE. | ||
21 | |||
22 | #ifndef FBTK_DEFAULTVALUE_HH | ||
23 | #define FBTK_DEFAULTVALUE_HH | ||
24 | |||
25 | namespace FbTk { | ||
26 | |||
27 | // classes for overriding default values without having to listen for changes | ||
28 | template <typename T> | ||
29 | class DefaultValue { | ||
30 | public: | ||
31 | DefaultValue(const T &def): | ||
32 | m_default(def), m_actual(def), m_use_default(true) { } | ||
33 | |||
34 | inline const T &get() const { return m_use_default ? m_default : m_actual; } | ||
35 | inline void set(const T &val) { m_use_default = false; m_actual = val; } | ||
36 | inline void restoreDefault() { m_use_default = true; } | ||
37 | inline void isDefault() const { return m_use_default; } | ||
38 | |||
39 | inline DefaultValue<T> &operator =(const T &val) { | ||
40 | set(val); return *this; | ||
41 | } | ||
42 | |||
43 | inline operator T() const { return get(); } | ||
44 | |||
45 | private: | ||
46 | const T &m_default; | ||
47 | T m_actual; | ||
48 | bool m_use_default; | ||
49 | }; | ||
50 | |||
51 | // designed for use with built-in types T, thus no need to return references | ||
52 | template <typename T, typename Receiver> | ||
53 | class DefaultAccessor { | ||
54 | public: | ||
55 | typedef T (Receiver:: *Accessor)() const; | ||
56 | DefaultAccessor(const Receiver &r, Accessor a): | ||
57 | m_receiver(r), m_accessor(a), m_actual((r.*a)()), | ||
58 | m_use_default(true) { } | ||
59 | |||
60 | inline const T get() const { | ||
61 | return m_use_default ? (m_receiver.*m_accessor)() : m_actual; | ||
62 | } | ||
63 | inline void set(const T &val) { m_use_default = false; m_actual = val; } | ||
64 | inline void restoreDefault() { m_use_default = true; } | ||
65 | inline void isDefault() const { return m_use_default; } | ||
66 | |||
67 | inline DefaultAccessor<T, Receiver> &operator =(const T &val) { | ||
68 | set(val); return *this; | ||
69 | } | ||
70 | |||
71 | inline operator T() const { return get(); } | ||
72 | |||
73 | private: | ||
74 | const Receiver &m_receiver; | ||
75 | Accessor &m_accessor; | ||
76 | T m_actual; | ||
77 | bool m_use_default; | ||
78 | }; | ||
79 | |||
80 | }; // end namespace FbTk | ||
81 | |||
82 | #endif // FBTK_DEFAULTVALUE_HH | ||