]> git.saurik.com Git - wxWidgets.git/blob - include/wx/scopeguard.h
cleanup
[wxWidgets.git] / include / wx / scopeguard.h
1 ///////////////////////////////////////////////////////////////////////////////
2 // Name: wx/scopeguard.h
3 // Purpose: declares wxwxScopeGuard and related macros
4 // Author: Vadim Zeitlin
5 // Modified by:
6 // Created: 03.07.2003
7 // RCS-ID: $Id$
8 // Copyright: (c) 2003 Vadim Zeitlin <vadim@wxwidgets.org>
9 // Licence: wxWindows licence
10 ///////////////////////////////////////////////////////////////////////////////
11
12 /*
13 Acknowledgements: this header is heavily based on (well, almost the exact
14 copy of) ScopeGuard.h by Andrei Alexandrescu and Petru Marginean published
15 in December 2000 issue of C/C++ Users Journal.
16 http://www.cuj.com/documents/cujcexp1812alexandr/
17 */
18
19 #ifndef _WX_SCOPEGUARD_H_
20 #define _WX_SCOPEGUARD_H_
21
22 #include "wx/defs.h"
23
24 #include "wx/except.h"
25
26 // ----------------------------------------------------------------------------
27 // helpers
28 // ----------------------------------------------------------------------------
29
30 #ifdef __WATCOMC__
31
32 // WATCOM-FIXME: C++ of Open Watcom 1.3 doesn't like OnScopeExit() created
33 // through template so it must be workarounded with dedicated inlined macro.
34 // For compatibility with Watcom compilers wxPrivate::OnScopeExit must be
35 // replaced with wxPrivateOnScopeExit but in user code (for everyone who
36 // doesn't care about OW compatibility) wxPrivate::OnScopeExit still works.
37
38 #define wxPrivateOnScopeExit(guard) \
39 { \
40 if ( !(guard).WasDismissed() ) \
41 { \
42 wxTRY \
43 { \
44 (guard).Execute(); \
45 } \
46 wxCATCH_ALL(;) \
47 } \
48 }
49
50 #define wxPrivateUse(n) wxUnusedVar(n)
51
52 #else
53
54 #if !defined(__GNUC__) || wxCHECK_GCC_VERSION(2, 95)
55 // namespace support was first implemented in gcc-2.95,
56 // so avoid using it for older versions.
57 namespace wxPrivate
58 {
59 #else
60 #define wxPrivate
61 #endif
62 // in the original implementation this was a member template function of
63 // ScopeGuardImplBase but gcc 2.8 which is still used for OS/2 doesn't
64 // support member templates and so we must make it global
65 template <class ScopeGuardImpl>
66 void OnScopeExit(ScopeGuardImpl& guard)
67 {
68 if ( !guard.WasDismissed() )
69 {
70 // we're called from ScopeGuardImpl dtor and so we must not throw
71 wxTRY
72 {
73 guard.Execute();
74 }
75 wxCATCH_ALL(;) // do nothing, just eat the exception
76 }
77 }
78
79 // just to avoid the warning about unused variables
80 template <class T>
81 void Use(const T& WXUNUSED(t))
82 {
83 }
84 #if !defined(__GNUC__) || wxCHECK_GCC_VERSION(2, 95)
85 } // namespace wxPrivate
86 #endif
87
88 #define wxPrivateOnScopeExit(n) wxPrivate::OnScopeExit(n)
89 #define wxPrivateUse(n) wxPrivate::Use(n)
90
91 #endif
92
93 // ============================================================================
94 // wxScopeGuard for functions and functors
95 // ============================================================================
96
97 // ----------------------------------------------------------------------------
98 // wxScopeGuardImplBase: used by wxScopeGuardImpl[0..N] below
99 // ----------------------------------------------------------------------------
100
101 class wxScopeGuardImplBase
102 {
103 public:
104 wxScopeGuardImplBase() : m_wasDismissed(false) { }
105
106 wxScopeGuardImplBase(const wxScopeGuardImplBase& other)
107 : m_wasDismissed(other.m_wasDismissed)
108 {
109 other.Dismiss();
110 }
111
112 void Dismiss() const { m_wasDismissed = true; }
113
114 // for OnScopeExit() only (we can't make it friend, unfortunately)!
115 bool WasDismissed() const { return m_wasDismissed; }
116
117 protected:
118 ~wxScopeGuardImplBase() { }
119
120 // must be mutable for copy ctor to work
121 mutable bool m_wasDismissed;
122
123 private:
124 wxScopeGuardImplBase& operator=(const wxScopeGuardImplBase&);
125 };
126
127 // ----------------------------------------------------------------------------
128 // wxScopeGuardImpl0: scope guard for actions without parameters
129 // ----------------------------------------------------------------------------
130
131 template <class F>
132 class wxScopeGuardImpl0 : public wxScopeGuardImplBase
133 {
134 public:
135 static wxScopeGuardImpl0<F> MakeGuard(F fun)
136 {
137 return wxScopeGuardImpl0<F>(fun);
138 }
139
140 ~wxScopeGuardImpl0() { wxPrivateOnScopeExit(*this); }
141
142 void Execute() { m_fun(); }
143
144 protected:
145 wxScopeGuardImpl0(F fun) : m_fun(fun) { }
146
147 F m_fun;
148
149 wxScopeGuardImpl0& operator=(const wxScopeGuardImpl0&);
150 };
151
152 template <class F>
153 inline wxScopeGuardImpl0<F> wxMakeGuard(F fun)
154 {
155 return wxScopeGuardImpl0<F>::MakeGuard(fun);
156 }
157
158 // ----------------------------------------------------------------------------
159 // wxScopeGuardImpl1: scope guard for actions with 1 parameter
160 // ----------------------------------------------------------------------------
161
162 template <class F, class P1>
163 class wxScopeGuardImpl1 : public wxScopeGuardImplBase
164 {
165 public:
166 static wxScopeGuardImpl1<F, P1> MakeGuard(F fun, P1 p1)
167 {
168 return wxScopeGuardImpl1<F, P1>(fun, p1);
169 }
170
171 ~wxScopeGuardImpl1() { wxPrivateOnScopeExit(* this); }
172
173 void Execute() { m_fun(m_p1); }
174
175 protected:
176 wxScopeGuardImpl1(F fun, P1 p1) : m_fun(fun), m_p1(p1) { }
177
178 F m_fun;
179 const P1 m_p1;
180
181 wxScopeGuardImpl1& operator=(const wxScopeGuardImpl1&);
182 };
183
184 template <class F, class P1>
185 inline wxScopeGuardImpl1<F, P1> wxMakeGuard(F fun, P1 p1)
186 {
187 return wxScopeGuardImpl1<F, P1>::MakeGuard(fun, p1);
188 }
189
190 // ----------------------------------------------------------------------------
191 // wxScopeGuardImpl2: scope guard for actions with 2 parameters
192 // ----------------------------------------------------------------------------
193
194 template <class F, class P1, class P2>
195 class wxScopeGuardImpl2 : public wxScopeGuardImplBase
196 {
197 public:
198 static wxScopeGuardImpl2<F, P1, P2> MakeGuard(F fun, P1 p1, P2 p2)
199 {
200 return wxScopeGuardImpl2<F, P1, P2>(fun, p1, p2);
201 }
202
203 ~wxScopeGuardImpl2() { wxPrivateOnScopeExit(*this); }
204
205 void Execute() { m_fun(m_p1, m_p2); }
206
207 protected:
208 wxScopeGuardImpl2(F fun, P1 p1, P2 p2) : m_fun(fun), m_p1(p1), m_p2(p2) { }
209
210 F m_fun;
211 const P1 m_p1;
212 const P2 m_p2;
213
214 wxScopeGuardImpl2& operator=(const wxScopeGuardImpl2&);
215 };
216
217 template <class F, class P1, class P2>
218 inline wxScopeGuardImpl2<F, P1, P2> wxMakeGuard(F fun, P1 p1, P2 p2)
219 {
220 return wxScopeGuardImpl2<F, P1, P2>::MakeGuard(fun, p1, p2);
221 }
222
223 // ============================================================================
224 // wxScopeGuards for object methods
225 // ============================================================================
226
227 // ----------------------------------------------------------------------------
228 // wxObjScopeGuardImpl0
229 // ----------------------------------------------------------------------------
230
231 template <class Obj, class MemFun>
232 class wxObjScopeGuardImpl0 : public wxScopeGuardImplBase
233 {
234 public:
235 static wxObjScopeGuardImpl0<Obj, MemFun>
236 MakeObjGuard(Obj& obj, MemFun memFun)
237 {
238 return wxObjScopeGuardImpl0<Obj, MemFun>(obj, memFun);
239 }
240
241 ~wxObjScopeGuardImpl0() { wxPrivateOnScopeExit(*this); }
242
243 void Execute() { (m_obj.*m_memfun)(); }
244
245 protected:
246 wxObjScopeGuardImpl0(Obj& obj, MemFun memFun)
247 : m_obj(obj), m_memfun(memFun) { }
248
249 Obj& m_obj;
250 MemFun m_memfun;
251 };
252
253 template <class Obj, class MemFun>
254 inline wxObjScopeGuardImpl0<Obj, MemFun> wxMakeObjGuard(Obj& obj, MemFun memFun)
255 {
256 return wxObjScopeGuardImpl0<Obj, MemFun>::MakeObjGuard(obj, memFun);
257 }
258
259 template <class Obj, class MemFun, class P1>
260 class wxObjScopeGuardImpl1 : public wxScopeGuardImplBase
261 {
262 public:
263 static wxObjScopeGuardImpl1<Obj, MemFun, P1>
264 MakeObjGuard(Obj& obj, MemFun memFun, P1 p1)
265 {
266 return wxObjScopeGuardImpl1<Obj, MemFun, P1>(obj, memFun, p1);
267 }
268
269 ~wxObjScopeGuardImpl1() { wxPrivateOnScopeExit(*this); }
270
271 void Execute() { (m_obj.*m_memfun)(m_p1); }
272
273 protected:
274 wxObjScopeGuardImpl1(Obj& obj, MemFun memFun, P1 p1)
275 : m_obj(obj), m_memfun(memFun), m_p1(p1) { }
276
277 Obj& m_obj;
278 MemFun m_memfun;
279 const P1 m_p1;
280 };
281
282 template <class Obj, class MemFun, class P1>
283 inline wxObjScopeGuardImpl1<Obj, MemFun, P1>
284 wxMakeObjGuard(Obj& obj, MemFun memFun, P1 p1)
285 {
286 return wxObjScopeGuardImpl1<Obj, MemFun, P1>::MakeObjGuard(obj, memFun, p1);
287 }
288
289 template <class Obj, class MemFun, class P1, class P2>
290 class wxObjScopeGuardImpl2 : public wxScopeGuardImplBase
291 {
292 public:
293 static wxObjScopeGuardImpl2<Obj, MemFun, P1, P2>
294 MakeObjGuard(Obj& obj, MemFun memFun, P1 p1, P2 p2)
295 {
296 return wxObjScopeGuardImpl2<Obj, MemFun, P1, P2>(obj, memFun, p1, p2);
297 }
298
299 ~wxObjScopeGuardImpl2() { wxPrivateOnScopeExit(*this); }
300
301 void Execute() { (m_obj.*m_memfun)(m_p1, m_p2); }
302
303 protected:
304 wxObjScopeGuardImpl2(Obj& obj, MemFun memFun, P1 p1, P2 p2)
305 : m_obj(obj), m_memfun(memFun), m_p1(p1), m_p2(p2) { }
306
307 Obj& m_obj;
308 MemFun m_memfun;
309 const P1 m_p1;
310 const P2 m_p2;
311 };
312
313 template <class Obj, class MemFun, class P1, class P2>
314 inline wxObjScopeGuardImpl2<Obj, MemFun, P1, P2>
315 wxMakeObjGuard(Obj& obj, MemFun memFun, P1 p1, P2 p2)
316 {
317 return wxObjScopeGuardImpl2<Obj, MemFun, P1, P2>::
318 MakeObjGuard(obj, memFun, p1, p2);
319 }
320
321 // ============================================================================
322 // public stuff
323 // ============================================================================
324
325 // wxScopeGuard is just a reference, see the explanation in CUJ article
326 typedef const wxScopeGuardImplBase& wxScopeGuard;
327
328 // when an unnamed scope guard is needed, the macros below may be used
329 //
330 // NB: the original code has a single (and much nicer) ON_BLOCK_EXIT macro
331 // but this results in compiler warnings about unused variables and I
332 // didn't find a way to work around this other than by having different
333 // macros with different names
334
335 #define wxGuardName wxMAKE_UNIQUE_NAME(scopeGuard)
336
337 #define wxON_BLOCK_EXIT0_IMPL(n, f) \
338 wxScopeGuard n = wxMakeGuard(f); \
339 wxPrivateUse(n)
340 #define wxON_BLOCK_EXIT0(f) \
341 wxON_BLOCK_EXIT0_IMPL(wxGuardName, f)
342
343 #define wxON_BLOCK_EXIT_OBJ0_IMPL(n, o, m) \
344 wxScopeGuard n = wxMakeObjGuard(o, m); \
345 wxPrivateUse(n)
346 #define wxON_BLOCK_EXIT_OBJ0(o, m) \
347 wxON_BLOCK_EXIT_OBJ0_IMPL(wxGuardName, o, &m)
348
349 #define wxON_BLOCK_EXIT1_IMPL(n, f, p1) \
350 wxScopeGuard n = wxMakeGuard(f, p1); \
351 wxPrivateUse(n)
352 #define wxON_BLOCK_EXIT1(f, p1) \
353 wxON_BLOCK_EXIT1_IMPL(wxGuardName, f, p1)
354
355 #define wxON_BLOCK_EXIT_OBJ1_IMPL(n, o, m, p1) \
356 wxScopeGuard n = wxMakeObjGuard(o, m, p1); \
357 wxPrivateUse(n)
358 #define wxON_BLOCK_EXIT_OBJ1(o, m, p1) \
359 wxON_BLOCK_EXIT_OBJ1_IMPL(wxGuardName, o, &m, p1)
360
361 #define wxON_BLOCK_EXIT2_IMPL(n, f, p1, p2) \
362 wxScopeGuard n = wxMakeGuard(f, p1, p2); \
363 wxPrivateUse(n)
364 #define wxON_BLOCK_EXIT2(f, p1, p2) \
365 wxON_BLOCK_EXIT2_IMPL(wxGuardName, f, p1, p2)
366
367 #define wxON_BLOCK_EXIT_OBJ2_IMPL(n, o, m, p1, p2) \
368 wxScopeGuard n = wxMakeObjGuard(o, m, p1, p2); \
369 wxPrivateUse(n)
370 #define wxON_BLOCK_EXIT_OBJ2(o, m, p1, p2) \
371 wxON_BLOCK_EXIT_OBJ2_IMPL(wxGuardName, o, &m, p1, p2)
372
373 #endif // _WX_SCOPEGUARD_H_