boost_ext/boost/multi_index/detail/scope_guard.hpp

   1 /* Copyright 2003-2005 Joaquín M López Muñoz.
   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)&&(_MSC_VER>=1200)
  13 #pragma once
  14 #endif
  15
  16 namespace boost{
  17
  18 namespace multi_index{
  19
  20 namespace detail{
  21
  22 /* Until some official version of the ScopeGuard idiom makes it into Boost,
  23  * we locally define our own. This is a merely reformated version of
  24  * ScopeGuard.h as defined in:
  25  *   Alexandrescu, A., Marginean, P.:"Generic<Programming>: Change the Way You
  26  *     Write Exception-Safe Code - Forever", C/C++ Users Jornal, Dec 2000,
  27  *     http://www.cuj.com/documents/s=8000/cujcexp1812alexandr/
  28  * with the following modifications:
  29  *   - General pretty formatting (pretty to my taste at least.)
  30  *   - Naming style changed to standard C++ library requirements.
  31  *   - safe_execute does not feature a try-catch protection, so we can
  32  *     use this even if BOOST_NO_EXCEPTIONS is defined.
  33  *   - Added scope_guard_impl4 and obj_scope_guard_impl3, (Boost.MultiIndex
  34  *     needs them). A better design would provide guards for many more
  35  *     arguments through the Boost Preprocessor Library.
  36  *   - Added scope_guard_impl_base::touch (see below.)
  37  *   - Removed RefHolder and ByRef, whose functionality is provided
  38  *     already by Boost.Ref.
  39  *   - Removed static make_guard's and make_obj_guard's, so that the code
  40  *     will work even if BOOST_NO_MEMBER_TEMPLATES is defined. This forces
  41  *     us to move some private ctors to public, though.
  42  *
  43  * NB: CodeWarrior Pro 8 seems to have problems looking up safe_execute
  44  * without an explicit qualification.
  45  */
  46
  47 class scope_guard_impl_base
  48 {
  49 public:
  50   scope_guard_impl_base():dismissed_(false){}
  51   void dismiss()const{dismissed_=true;}
  52
  53   /* This helps prevent some "unused variable" warnings under, for instance,
  54    * GCC 3.2.
  55    */
  56   void touch()const{}
  57
  58 protected:
  59   ~scope_guard_impl_base(){}
  60
  61   scope_guard_impl_base(const scope_guard_impl_base& other):
  62     dismissed_(other.dismissed_)
  63   {
  64     other.dismiss();
  65   }
  66
  67   template<typename J>
  68   static void safe_execute(J& j){if(!j.dismissed_)j.execute();}
  69
  70   mutable bool dismissed_;
  71
  72 private:
  73   scope_guard_impl_base& operator=(const scope_guard_impl_base&);
  74 };
  75
  76 typedef const scope_guard_impl_base& scope_guard;
  77
  78 template<typename F>
  79 class scope_guard_impl0:public scope_guard_impl_base
  80 {
  81 public:
  82   scope_guard_impl0(F fun):fun_(fun){}
  83   ~scope_guard_impl0(){scope_guard_impl_base::safe_execute(*this);}
  84   void execute(){fun_();}
  85
  86 protected:
  87
  88   F fun_;
  89 };
  90
  91 template<typename F>
  92 inline scope_guard_impl0<F> make_guard(F fun)
  93 {
  94   return scope_guard_impl0<F>(fun);
  95 }
  96
  97 template<typename F,typename P1>
  98 class scope_guard_impl1:public scope_guard_impl_base
  99 {
 100 public:
 101   scope_guard_impl1(F fun,P1 p1):fun_(fun),p1_(p1){}
 102   ~scope_guard_impl1(){scope_guard_impl_base::safe_execute(*this);}
 103   void execute(){fun_(p1_);}
 104
 105 protected:
 106   F        fun_;
 107   const P1 p1_;
 108 };
 109
 110 template<typename F,typename P1>
 111 inline scope_guard_impl1<F,P1> make_guard(F fun,P1 p1)
 112 {
 113   return scope_guard_impl1<F,P1>(fun,p1);
 114 }
 115
 116 template<typename F,typename P1,typename P2>
 117 class scope_guard_impl2:public scope_guard_impl_base
 118 {
 119 public:
 120   scope_guard_impl2(F fun,P1 p1,P2 p2):fun_(fun),p1_(p1),p2_(p2){}
 121   ~scope_guard_impl2(){scope_guard_impl_base::safe_execute(*this);}
 122   void execute(){fun_(p1_,p2_);}
 123
 124 protected:
 125   F        fun_;
 126   const P1 p1_;
 127   const P2 p2_;
 128 };
 129
 130 template<typename F,typename P1,typename P2>
 131 inline scope_guard_impl2<F,P1,P2> make_guard(F fun,P1 p1,P2 p2)
 132 {
 133   return scope_guard_impl2<F,P1,P2>(fun,p1,p2);
 134 }
 135
 136 template<typename F,typename P1,typename P2,typename P3>
 137 class scope_guard_impl3:public scope_guard_impl_base
 138 {
 139 public:
 140   scope_guard_impl3(F fun,P1 p1,P2 p2,P3 p3):fun_(fun),p1_(p1),p2_(p2),p3_(p3){}
 141   ~scope_guard_impl3(){scope_guard_impl_base::safe_execute(*this);}
 142   void execute(){fun_(p1_,p2_,p3_);}
 143
 144 protected:
 145   F        fun_;
 146   const P1 p1_;
 147   const P2 p2_;
 148   const P3 p3_;
 149 };
 150
 151 template<typename F,typename P1,typename P2,typename P3>
 152 inline scope_guard_impl3<F,P1,P2,P3> make_guard(F fun,P1 p1,P2 p2,P3 p3)
 153 {
 154   return scope_guard_impl3<F,P1,P2,P3>(fun,p1,p2,p3);
 155 }
 156
 157 template<typename F,typename P1,typename P2,typename P3,typename P4>
 158 class scope_guard_impl4:public scope_guard_impl_base
 159 {
 160 public:
 161   scope_guard_impl4(F fun,P1 p1,P2 p2,P3 p3,P4 p4):
 162     fun_(fun),p1_(p1),p2_(p2),p3_(p3),p4_(p4){}
 163   ~scope_guard_impl4(){scope_guard_impl_base::safe_execute(*this);}
 164   void execute(){fun_(p1_,p2_,p3_,p4_);}
 165
 166 protected:
 167   F        fun_;
 168   const P1 p1_;
 169   const P2 p2_;
 170   const P3 p3_;
 171   const P4 p4_;
 172 };
 173
 174 template<typename F,typename P1,typename P2,typename P3,typename P4>
 175 inline scope_guard_impl4<F,P1,P2,P3,P4> make_guard(
 176   F fun,P1 p1,P2 p2,P3 p3,P4 p4)
 177 {
 178   return scope_guard_impl4<F,P1,P2,P3,P4>(fun,p1,p2,p3,p4);
 179 }
 180
 181 template<class Obj,typename MemFun>
 182 class obj_scope_guard_impl0:public scope_guard_impl_base
 183 {
 184 public:
 185   obj_scope_guard_impl0(Obj& obj,MemFun mem_fun):obj_(obj),mem_fun_(mem_fun){}
 186   ~obj_scope_guard_impl0(){scope_guard_impl_base::safe_execute(*this);}
 187   void execute(){(obj_.*mem_fun_)();}
 188
 189 protected:
 190   Obj&   obj_;
 191   MemFun mem_fun_;
 192 };
 193
 194 template<class Obj,typename MemFun>
 195 inline obj_scope_guard_impl0<Obj,MemFun> make_obj_guard(Obj& obj,MemFun mem_fun)
 196 {
 197   return obj_scope_guard_impl0<Obj,MemFun>(obj,mem_fun);
 198 }
 199
 200 template<class Obj,typename MemFun,typename P1>
 201 class obj_scope_guard_impl1:public scope_guard_impl_base
 202 {
 203 public:
 204   obj_scope_guard_impl1(Obj& obj,MemFun mem_fun,P1 p1):
 205     obj_(obj),mem_fun_(mem_fun),p1_(p1){}
 206   ~obj_scope_guard_impl1(){scope_guard_impl_base::safe_execute(*this);}
 207   void execute(){(obj_.*mem_fun_)(p1_);}
 208
 209 protected:
 210   Obj&     obj_;
 211   MemFun   mem_fun_;
 212   const P1 p1_;
 213 };
 214
 215 template<class Obj,typename MemFun,typename P1>
 216 inline obj_scope_guard_impl1<Obj,MemFun,P1> make_obj_guard(
 217   Obj& obj,MemFun mem_fun,P1 p1)
 218 {
 219   return obj_scope_guard_impl1<Obj,MemFun,P1>(obj,mem_fun,p1);
 220 }
 221
 222 template<class Obj,typename MemFun,typename P1,typename P2>
 223 class obj_scope_guard_impl2:public scope_guard_impl_base
 224 {
 225 public:
 226   obj_scope_guard_impl2(Obj& obj,MemFun mem_fun,P1 p1,P2 p2):
 227     obj_(obj),mem_fun_(mem_fun),p1_(p1),p2_(p2)
 228   {}
 229   ~obj_scope_guard_impl2(){scope_guard_impl_base::safe_execute(*this);}
 230   void execute(){(obj_.*mem_fun_)(p1_,p2_);}
 231
 232 protected:
 233   Obj&     obj_;
 234   MemFun   mem_fun_;
 235   const P1 p1_;
 236   const P2 p2_;
 237 };
 238
 239 template<class Obj,typename MemFun,typename P1,typename P2>
 240 inline obj_scope_guard_impl2<Obj,MemFun,P1,P2>
 241 make_obj_guard(Obj& obj,MemFun mem_fun,P1 p1,P2 p2)
 242 {
 243   return obj_scope_guard_impl2<Obj,MemFun,P1,P2>(obj,mem_fun,p1,p2);
 244 }
 245
 246 template<class Obj,typename MemFun,typename P1,typename P2,typename P3>
 247 class obj_scope_guard_impl3:public scope_guard_impl_base
 248 {
 249 public:
 250   obj_scope_guard_impl3(Obj& obj,MemFun mem_fun,P1 p1,P2 p2,P3 p3):
 251     obj_(obj),mem_fun_(mem_fun),p1_(p1),p2_(p2),p3_(p3)
 252   {}
 253   ~obj_scope_guard_impl3(){scope_guard_impl_base::safe_execute(*this);}
 254   void execute(){(obj_.*mem_fun_)(p1_,p2_,p3_);}
 255
 256 protected:
 257   Obj&     obj_;
 258   MemFun   mem_fun_;
 259   const P1 p1_;
 260   const P2 p2_;
 261   const P3 p3_;
 262 };
 263
 264 template<class Obj,typename MemFun,typename P1,typename P2,typename P3>
 265 inline obj_scope_guard_impl3<Obj,MemFun,P1,P2,P3>
 266 make_obj_guard(Obj& obj,MemFun mem_fun,P1 p1,P2 p2,P3 p3)
 267 {
 268   return obj_scope_guard_impl3<Obj,MemFun,P1,P2,P3>(obj,mem_fun,p1,p2,p3);
 269 }
 270
 271 } /* namespace multi_index::detail */
 272
 273 } /* namespace multi_index */
 274
 275 } /* namespace boost */
 276
 277 #endif