1/* Copyright 2003-2013 Joaquin M Lopez Munoz.
2 * Distributed under the Boost Software License, Version 1.0.
3 * (See accompanying file LICENSE_1_0.txt or copy at
4 * http://www.boost.org/LICENSE_1_0.txt)
5 *
6 * See http://www.boost.org/libs/multi_index for library home page.
7 */
8
9#ifndef BOOST_MULTI_INDEX_DETAIL_SCOPE_GUARD_HPP
10#define BOOST_MULTI_INDEX_DETAIL_SCOPE_GUARD_HPP
11
12#if defined(_MSC_VER)
13#pragma once
14#endif
15
16#include <boost/detail/no_exceptions_support.hpp>
17#include <boost/mpl/if.hpp>
18
19namespace boost{
20
21namespace multi_index{
22
23namespace detail{
24
25/* Until some official version of the ScopeGuard idiom makes it into Boost,
26 * we locally define our own. This is a merely reformated version of
27 * ScopeGuard.h as defined in:
28 * Alexandrescu, A., Marginean, P.:"Generic<Programming>: Change the Way You
29 * Write Exception-Safe Code - Forever", C/C++ Users Jornal, Dec 2000,
30 * http://www.drdobbs.com/184403758
31 * with the following modifications:
32 * - General pretty formatting (pretty to my taste at least.)
33 * - Naming style changed to standard C++ library requirements.
34 * - Added scope_guard_impl4 and obj_scope_guard_impl3, (Boost.MultiIndex
35 * needs them). A better design would provide guards for many more
36 * arguments through the Boost Preprocessor Library.
37 * - Added scope_guard_impl_base::touch (see below.)
38 * - Removed RefHolder and ByRef, whose functionality is provided
39 * already by Boost.Ref.
40 * - Removed static make_guard's and make_obj_guard's, so that the code
41 * will work even if BOOST_NO_MEMBER_TEMPLATES is defined. This forces
42 * us to move some private ctors to public, though.
43 *
44 * NB: CodeWarrior Pro 8 seems to have problems looking up safe_execute
45 * without an explicit qualification.
46 *
47 * We also define the following variants of the idiom:
48 *
49 * - make_guard_if_c<bool>( ... )
50 * - make_guard_if<IntegralConstant>( ... )
51 * - make_obj_guard_if_c<bool>( ... )
52 * - make_obj_guard_if<IntegralConstant>( ... )
53 * which may be used with a compile-time constant to yield
54 * a "null_guard" if the boolean compile-time parameter is false,
55 * or conversely, the guard is only constructed if the constant is true.
56 * This is useful to avoid extra tagging, because the returned
57 * null_guard can be optimzed comlpetely away by the compiler.
58 */
59
60class scope_guard_impl_base
61{
62public:
63 scope_guard_impl_base():dismissed_(false){}
64 void dismiss()const{dismissed_=true;}
65
66 /* This helps prevent some "unused variable" warnings under, for instance,
67 * GCC 3.2.
68 */
69 void touch()const{}
70
71protected:
72 ~scope_guard_impl_base(){}
73
74 scope_guard_impl_base(const scope_guard_impl_base& other):
75 dismissed_(other.dismissed_)
76 {
77 other.dismiss();
78 }
79
80 template<typename J>
81 static void safe_execute(J& j){
82 BOOST_TRY{
83 if(!j.dismissed_)j.execute();
84 }
85 BOOST_CATCH(...){}
86 BOOST_CATCH_END
87 }
88
89 mutable bool dismissed_;
90
91private:
92 scope_guard_impl_base& operator=(const scope_guard_impl_base&);
93};
94
95typedef const scope_guard_impl_base& scope_guard;
96
97struct null_guard : public scope_guard_impl_base
98{
99 template< class T1 >
100 null_guard( const T1& )
101 { }
102
103 template< class T1, class T2 >
104 null_guard( const T1&, const T2& )
105 { }
106
107 template< class T1, class T2, class T3 >
108 null_guard( const T1&, const T2&, const T3& )
109 { }
110
111 template< class T1, class T2, class T3, class T4 >
112 null_guard( const T1&, const T2&, const T3&, const T4& )
113 { }
114
115 template< class T1, class T2, class T3, class T4, class T5 >
116 null_guard( const T1&, const T2&, const T3&, const T4&, const T5& )
117 { }
118};
119
120template< bool cond, class T >
121struct null_guard_return
122{
123 typedef typename boost::mpl::if_c<cond,T,null_guard>::type type;
124};
125
126template<typename F>
127class scope_guard_impl0:public scope_guard_impl_base
128{
129public:
130 scope_guard_impl0(F fun):fun_(fun){}
131 ~scope_guard_impl0(){scope_guard_impl_base::safe_execute(*this);}
132 void execute(){fun_();}
133
134protected:
135
136 F fun_;
137};
138
139template<typename F>
140inline scope_guard_impl0<F> make_guard(F fun)
141{
142 return scope_guard_impl0<F>(fun);
143}
144
145template<bool cond, typename F>
146inline typename null_guard_return<cond,scope_guard_impl0<F> >::type
147make_guard_if_c(F fun)
148{
149 return typename null_guard_return<cond,scope_guard_impl0<F> >::type(fun);
150}
151
152template<typename C, typename F>
153inline typename null_guard_return<C::value,scope_guard_impl0<F> >::type
154make_guard_if(F fun)
155{
156 return make_guard_if<C::value>(fun);
157}
158
159template<typename F,typename P1>
160class scope_guard_impl1:public scope_guard_impl_base
161{
162public:
163 scope_guard_impl1(F fun,P1 p1):fun_(fun),p1_(p1){}
164 ~scope_guard_impl1(){scope_guard_impl_base::safe_execute(*this);}
165 void execute(){fun_(p1_);}
166
167protected:
168 F fun_;
169 const P1 p1_;
170};
171
172template<typename F,typename P1>
173inline scope_guard_impl1<F,P1> make_guard(F fun,P1 p1)
174{
175 return scope_guard_impl1<F,P1>(fun,p1);
176}
177
178template<bool cond, typename F,typename P1>
179inline typename null_guard_return<cond,scope_guard_impl1<F,P1> >::type
180make_guard_if_c(F fun,P1 p1)
181{
182 return typename null_guard_return<cond,scope_guard_impl1<F,P1> >::type(fun,p1);
183}
184
185template<typename C, typename F,typename P1>
186inline typename null_guard_return<C::value,scope_guard_impl1<F,P1> >::type
187make_guard_if(F fun,P1 p1)
188{
189 return make_guard_if_c<C::value>(fun,p1);
190}
191
192template<typename F,typename P1,typename P2>
193class scope_guard_impl2:public scope_guard_impl_base
194{
195public:
196 scope_guard_impl2(F fun,P1 p1,P2 p2):fun_(fun),p1_(p1),p2_(p2){}
197 ~scope_guard_impl2(){scope_guard_impl_base::safe_execute(*this);}
198 void execute(){fun_(p1_,p2_);}
199
200protected:
201 F fun_;
202 const P1 p1_;
203 const P2 p2_;
204};
205
206template<typename F,typename P1,typename P2>
207inline scope_guard_impl2<F,P1,P2> make_guard(F fun,P1 p1,P2 p2)
208{
209 return scope_guard_impl2<F,P1,P2>(fun,p1,p2);
210}
211
212template<bool cond, typename F,typename P1,typename P2>
213inline typename null_guard_return<cond,scope_guard_impl2<F,P1,P2> >::type
214make_guard_if_c(F fun,P1 p1,P2 p2)
215{
216 return typename null_guard_return<cond,scope_guard_impl2<F,P1,P2> >::type(fun,p1,p2);
217}
218
219template<typename C, typename F,typename P1,typename P2>
220inline typename null_guard_return<C::value,scope_guard_impl2<F,P1,P2> >::type
221make_guard_if(F fun,P1 p1,P2 p2)
222{
223 return make_guard_if_c<C::value>(fun,p1,p2);
224}
225
226template<typename F,typename P1,typename P2,typename P3>
227class scope_guard_impl3:public scope_guard_impl_base
228{
229public:
230 scope_guard_impl3(F fun,P1 p1,P2 p2,P3 p3):fun_(fun),p1_(p1),p2_(p2),p3_(p3){}
231 ~scope_guard_impl3(){scope_guard_impl_base::safe_execute(*this);}
232 void execute(){fun_(p1_,p2_,p3_);}
233
234protected:
235 F fun_;
236 const P1 p1_;
237 const P2 p2_;
238 const P3 p3_;
239};
240
241template<typename F,typename P1,typename P2,typename P3>
242inline scope_guard_impl3<F,P1,P2,P3> make_guard(F fun,P1 p1,P2 p2,P3 p3)
243{
244 return scope_guard_impl3<F,P1,P2,P3>(fun,p1,p2,p3);
245}
246
247template<bool cond,typename F,typename P1,typename P2,typename P3>
248inline typename null_guard_return<cond,scope_guard_impl3<F,P1,P2,P3> >::type
249make_guard_if_c(F fun,P1 p1,P2 p2,P3 p3)
250{
251 return typename null_guard_return<cond,scope_guard_impl3<F,P1,P2,P3> >::type(fun,p1,p2,p3);
252}
253
254template<typename C,typename F,typename P1,typename P2,typename P3>
255inline typename null_guard_return< C::value,scope_guard_impl3<F,P1,P2,P3> >::type
256make_guard_if(F fun,P1 p1,P2 p2,P3 p3)
257{
258 return make_guard_if_c<C::value>(fun,p1,p2,p3);
259}
260
261template<typename F,typename P1,typename P2,typename P3,typename P4>
262class scope_guard_impl4:public scope_guard_impl_base
263{
264public:
265 scope_guard_impl4(F fun,P1 p1,P2 p2,P3 p3,P4 p4):
266 fun_(fun),p1_(p1),p2_(p2),p3_(p3),p4_(p4){}
267 ~scope_guard_impl4(){scope_guard_impl_base::safe_execute(*this);}
268 void execute(){fun_(p1_,p2_,p3_,p4_);}
269
270protected:
271 F fun_;
272 const P1 p1_;
273 const P2 p2_;
274 const P3 p3_;
275 const P4 p4_;
276};
277
278template<typename F,typename P1,typename P2,typename P3,typename P4>
279inline scope_guard_impl4<F,P1,P2,P3,P4> make_guard(
280 F fun,P1 p1,P2 p2,P3 p3,P4 p4)
281{
282 return scope_guard_impl4<F,P1,P2,P3,P4>(fun,p1,p2,p3,p4);
283}
284
285template<bool cond, typename F,typename P1,typename P2,typename P3,typename P4>
286inline typename null_guard_return<cond,scope_guard_impl4<F,P1,P2,P3,P4> >::type
287make_guard_if_c(
288 F fun,P1 p1,P2 p2,P3 p3,P4 p4)
289{
290 return typename null_guard_return<cond,scope_guard_impl4<F,P1,P2,P3,P4> >::type(fun,p1,p2,p3,p4);
291}
292
293template<typename C, typename F,typename P1,typename P2,typename P3,typename P4>
294inline typename null_guard_return<C::value,scope_guard_impl4<F,P1,P2,P3,P4> >::type
295make_guard_if(
296 F fun,P1 p1,P2 p2,P3 p3,P4 p4)
297{
298 return make_guard_if_c<C::value>(fun,p1,p2,p3,p4);
299}
300
301template<class Obj,typename MemFun>
302class obj_scope_guard_impl0:public scope_guard_impl_base
303{
304public:
305 obj_scope_guard_impl0(Obj& obj,MemFun mem_fun):obj_(obj),mem_fun_(mem_fun){}
306 ~obj_scope_guard_impl0(){scope_guard_impl_base::safe_execute(*this);}
307 void execute(){(obj_.*mem_fun_)();}
308
309protected:
310 Obj& obj_;
311 MemFun mem_fun_;
312};
313
314template<class Obj,typename MemFun>
315inline obj_scope_guard_impl0<Obj,MemFun> make_obj_guard(Obj& obj,MemFun mem_fun)
316{
317 return obj_scope_guard_impl0<Obj,MemFun>(obj,mem_fun);
318}
319
320template<bool cond, class Obj,typename MemFun>
321inline typename null_guard_return<cond,obj_scope_guard_impl0<Obj,MemFun> >::type
322make_obj_guard_if_c(Obj& obj,MemFun mem_fun)
323{
324 return typename null_guard_return<cond,obj_scope_guard_impl0<Obj,MemFun> >::type(obj,mem_fun);
325}
326
327template<typename C, class Obj,typename MemFun>
328inline typename null_guard_return<C::value,obj_scope_guard_impl0<Obj,MemFun> >::type
329make_obj_guard_if(Obj& obj,MemFun mem_fun)
330{
331 return make_obj_guard_if_c<C::value>(obj,mem_fun);
332}
333
334template<class Obj,typename MemFun,typename P1>
335class obj_scope_guard_impl1:public scope_guard_impl_base
336{
337public:
338 obj_scope_guard_impl1(Obj& obj,MemFun mem_fun,P1 p1):
339 obj_(obj),mem_fun_(mem_fun),p1_(p1){}
340 ~obj_scope_guard_impl1(){scope_guard_impl_base::safe_execute(*this);}
341 void execute(){(obj_.*mem_fun_)(p1_);}
342
343protected:
344 Obj& obj_;
345 MemFun mem_fun_;
346 const P1 p1_;
347};
348
349template<class Obj,typename MemFun,typename P1>
350inline obj_scope_guard_impl1<Obj,MemFun,P1> make_obj_guard(
351 Obj& obj,MemFun mem_fun,P1 p1)
352{
353 return obj_scope_guard_impl1<Obj,MemFun,P1>(obj,mem_fun,p1);
354}
355
356template<bool cond, class Obj,typename MemFun,typename P1>
357inline typename null_guard_return<cond,obj_scope_guard_impl1<Obj,MemFun,P1> >::type
358make_obj_guard_if_c( Obj& obj,MemFun mem_fun,P1 p1)
359{
360 return typename null_guard_return<cond,obj_scope_guard_impl1<Obj,MemFun,P1> >::type(obj,mem_fun,p1);
361}
362
363template<typename C, class Obj,typename MemFun,typename P1>
364inline typename null_guard_return<C::value,obj_scope_guard_impl1<Obj,MemFun,P1> >::type
365make_obj_guard_if( Obj& obj,MemFun mem_fun,P1 p1)
366{
367 return make_obj_guard_if_c<C::value>(obj,mem_fun,p1);
368}
369
370template<class Obj,typename MemFun,typename P1,typename P2>
371class obj_scope_guard_impl2:public scope_guard_impl_base
372{
373public:
374 obj_scope_guard_impl2(Obj& obj,MemFun mem_fun,P1 p1,P2 p2):
375 obj_(obj),mem_fun_(mem_fun),p1_(p1),p2_(p2)
376 {}
377 ~obj_scope_guard_impl2(){scope_guard_impl_base::safe_execute(*this);}
378 void execute(){(obj_.*mem_fun_)(p1_,p2_);}
379
380protected:
381 Obj& obj_;
382 MemFun mem_fun_;
383 const P1 p1_;
384 const P2 p2_;
385};
386
387template<class Obj,typename MemFun,typename P1,typename P2>
388inline obj_scope_guard_impl2<Obj,MemFun,P1,P2>
389make_obj_guard(Obj& obj,MemFun mem_fun,P1 p1,P2 p2)
390{
391 return obj_scope_guard_impl2<Obj,MemFun,P1,P2>(obj,mem_fun,p1,p2);
392}
393
394template<bool cond, class Obj,typename MemFun,typename P1,typename P2>
395inline typename null_guard_return<cond,obj_scope_guard_impl2<Obj,MemFun,P1,P2> >::type
396make_obj_guard_if_c(Obj& obj,MemFun mem_fun,P1 p1,P2 p2)
397{
398 return typename null_guard_return<cond,obj_scope_guard_impl2<Obj,MemFun,P1,P2> >::type(obj,mem_fun,p1,p2);
399}
400
401template<typename C, class Obj,typename MemFun,typename P1,typename P2>
402inline typename null_guard_return<C::value,obj_scope_guard_impl2<Obj,MemFun,P1,P2> >::type
403make_obj_guard_if(Obj& obj,MemFun mem_fun,P1 p1,P2 p2)
404{
405 return make_obj_guard_if_c<C::value>(obj,mem_fun,p1,p2);
406}
407
408template<class Obj,typename MemFun,typename P1,typename P2,typename P3>
409class obj_scope_guard_impl3:public scope_guard_impl_base
410{
411public:
412 obj_scope_guard_impl3(Obj& obj,MemFun mem_fun,P1 p1,P2 p2,P3 p3):
413 obj_(obj),mem_fun_(mem_fun),p1_(p1),p2_(p2),p3_(p3)
414 {}
415 ~obj_scope_guard_impl3(){scope_guard_impl_base::safe_execute(*this);}
416 void execute(){(obj_.*mem_fun_)(p1_,p2_,p3_);}
417
418protected:
419 Obj& obj_;
420 MemFun mem_fun_;
421 const P1 p1_;
422 const P2 p2_;
423 const P3 p3_;
424};
425
426template<class Obj,typename MemFun,typename P1,typename P2,typename P3>
427inline obj_scope_guard_impl3<Obj,MemFun,P1,P2,P3>
428make_obj_guard(Obj& obj,MemFun mem_fun,P1 p1,P2 p2,P3 p3)
429{
430 return obj_scope_guard_impl3<Obj,MemFun,P1,P2,P3>(obj,mem_fun,p1,p2,p3);
431}
432
433template<bool cond, class Obj,typename MemFun,typename P1,typename P2,typename P3>
434inline typename null_guard_return<cond,obj_scope_guard_impl3<Obj,MemFun,P1,P2,P3> >::type
435make_obj_guard_if_c(Obj& obj,MemFun mem_fun,P1 p1,P2 p2,P3 p3)
436{
437 return typename null_guard_return<cond,obj_scope_guard_impl3<Obj,MemFun,P1,P2,P3> >::type(obj,mem_fun,p1,p2,p3);
438}
439
440template<typename C, class Obj,typename MemFun,typename P1,typename P2,typename P3>
441inline typename null_guard_return<C::value,obj_scope_guard_impl3<Obj,MemFun,P1,P2,P3> >::type
442make_obj_guard_if(Obj& obj,MemFun mem_fun,P1 p1,P2 p2,P3 p3)
443{
444 return make_obj_guard_if_c<C::value>(obj,mem_fun,p1,p2,p3);
445}
446
447} /* namespace multi_index::detail */
448
449} /* namespace multi_index */
450
451} /* namespace boost */
452
453#endif
454

source code of boost/boost/multi_index/detail/scope_guard.hpp