]>
Commit | Line | Data |
---|---|---|
1 | ///////////////////////////////////////////////////////////////////////////// | |
2 | // Name: scopeguard.h | |
3 | // Purpose: interface of global functions | |
4 | // Author: wxWidgets team | |
5 | // RCS-ID: $Id$ | |
6 | // Licence: wxWindows license | |
7 | ///////////////////////////////////////////////////////////////////////////// | |
8 | ||
9 | /** | |
10 | @class wxScopeGuard | |
11 | ||
12 | Scope guard is an object which allows executing an action on scope exit. | |
13 | ||
14 | The objects of this class must be constructed using wxMakeGuard() function. | |
15 | ||
16 | @nolibrary | |
17 | @category{misc} | |
18 | */ | |
19 | class wxScopeGuard | |
20 | { | |
21 | public: | |
22 | /** | |
23 | Call this method to dismiss the execution of the action on scope exit. | |
24 | ||
25 | A typical example: | |
26 | @code | |
27 | Update1(); | |
28 | ||
29 | // ensure that changes done so far are rolled back if the next | |
30 | // operation throws | |
31 | wxScopeGuard guard = wxMakeGuard(RollBack); | |
32 | Update2(); | |
33 | ||
34 | // it didn't throw so commit the changes, i.e. avoid rolling back | |
35 | guard.Dismiss(); | |
36 | @endcode | |
37 | */ | |
38 | void Dismiss(); | |
39 | }; | |
40 | ||
41 | /** @addtogroup group_funcmacro_misc */ | |
42 | //@{ | |
43 | /** | |
44 | Returns a scope guard object which will call the specified function with | |
45 | the given parameters on scope exit. | |
46 | ||
47 | This function is overloaded to take several parameters up to some | |
48 | implementation-defined (but relatively low) limit. | |
49 | ||
50 | The @a func should be a functor taking parameters of the types P1, ..., PN, | |
51 | i.e. the expression @c func(p1, ..., pN) should be valid. | |
52 | */ | |
53 | template <typename F, typename P1, ..., typename PN> | |
54 | wxScopeGuard wxMakeGuard(F func, P1 p1, ..., PN pN); | |
55 | ||
56 | //@} | |
57 | ||
58 | /** @addtogroup group_funcmacro_misc */ | |
59 | //@{ | |
60 | /** | |
61 | Ensure that the global @a function with a few (up to some | |
62 | implementation-defined limit) is executed on scope exit, whether due to a | |
63 | normal function return or because an exception has been thrown. | |
64 | ||
65 | A typical example of its usage: | |
66 | ||
67 | @code | |
68 | void *buf = malloc(size); | |
69 | wxON_BLOCK_EXIT1(free, buf); | |
70 | @endcode | |
71 | ||
72 | Please see the original article by Andrei Alexandrescu and Petru Marginean | |
73 | published in December 2000 issue of C/C++ Users Journal for more details. | |
74 | ||
75 | @see wxON_BLOCK_EXIT_OBJ0() | |
76 | ||
77 | @header{wx/scopeguard.h} | |
78 | */ | |
79 | #define wxON_BLOCK_EXIT(function, ...) | |
80 | #define wxON_BLOCK_EXIT0(function) | |
81 | #define wxON_BLOCK_EXIT1(function, p1) | |
82 | #define wxON_BLOCK_EXIT2(function, p1, p2) | |
83 | #define wxON_BLOCK_EXIT3(function, p1, p2, p3) | |
84 | //@} | |
85 | ||
86 | /** @addtogroup group_funcmacro_misc */ | |
87 | //@{ | |
88 | /** | |
89 | This family of macros is similar to wxON_BLOCK_EXIT(), but calls a method | |
90 | of the given object instead of a free function. | |
91 | ||
92 | @header{wx/scopeguard.h} | |
93 | */ | |
94 | #define wxON_BLOCK_EXIT_OBJ(object, method, ...) | |
95 | #define wxON_BLOCK_EXIT_OBJ0(object, method) | |
96 | #define wxON_BLOCK_EXIT_OBJ1(object, method, p1) | |
97 | #define wxON_BLOCK_EXIT_OBJ2(object, method, p1, p2) | |
98 | #define wxON_BLOCK_EXIT_OBJ3(object, method, p1, p2, p3) | |
99 | //@} | |
100 | ||
101 | /** @addtogroup group_funcmacro_misc */ | |
102 | //@{ | |
103 | /** | |
104 | This family of macros is similar to wxON_BLOCK_OBJ(), but calls a method | |
105 | of @c this object instead of a method of the specified object. | |
106 | ||
107 | @header{wx/scopeguard.h} | |
108 | */ | |
109 | #define wxON_BLOCK_EXIT_THIS(method, ...) | |
110 | #define wxON_BLOCK_EXIT_THIS0(method) | |
111 | #define wxON_BLOCK_EXIT_THIS1(method, p1) | |
112 | #define wxON_BLOCK_EXIT_THIS2(method, p1, p2) | |
113 | #define wxON_BLOCK_EXIT_THIS3(method, p1, p2, p3) | |
114 | //@} | |
115 | ||
116 | /** @addtogroup group_funcmacro_misc */ | |
117 | //@{ | |
118 | /** | |
119 | This macro sets a variable to the specified value on scope exit. | |
120 | ||
121 | Example of usage: | |
122 | @code | |
123 | void foo() | |
124 | { | |
125 | bool isDoingSomething = true; | |
126 | { | |
127 | wxON_BLOCK_EXIT_SET(isDoingSomething, false); | |
128 | ... do something ... | |
129 | } | |
130 | ... isDoingSomething is false now ... | |
131 | } | |
132 | @endcode | |
133 | ||
134 | Notice that @a value is copied, i.e. stored by value, so it can be a | |
135 | temporary object returned by a function call, for example. | |
136 | ||
137 | @see wxON_BLOCK_EXIT_OBJ0(), wxON_BLOCK_EXIT_NULL() | |
138 | ||
139 | @header{wx/scopeguard.h} | |
140 | */ | |
141 | #define wxON_BLOCK_EXIT_SET(var, value) | |
142 | ||
143 | /** | |
144 | This macro sets the pointer passed to it as argument to NULL on scope exit. | |
145 | ||
146 | It must be used instead of wxON_BLOCK_EXIT_SET() when the value being set | |
147 | is @c NULL. | |
148 | ||
149 | @header{wx/scopeguard.h} | |
150 | */ | |
151 | #define wxON_BLOCK_EXIT_NULL(ptr) | |
152 | ||
153 | //@} | |
154 |