ceph/src/boost/libs/multi_index/include/boost/multi_index/detail/scope_guard.hpp

   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
  19 namespace boost{
  20
  21 namespace multi_index{
  22
  23 namespace 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
  60 class scope_guard_impl_base
  61 {
  62 public:
  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
  71 protected:
  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
  91 private:
  92   scope_guard_impl_base& operator=(const scope_guard_impl_base&);
  93 };
  94
  95 typedef const scope_guard_impl_base& scope_guard;
  96
  97 struct 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
 120 template< bool cond, class T >
 121 struct null_guard_return
 122 {
 123     typedef typename boost::mpl::if_c<cond,T,null_guard>::type type;
 124 };
 125
 126 template<typename F>
 127 class scope_guard_impl0:public scope_guard_impl_base
 128 {
 129 public:
 130   scope_guard_impl0(F fun):fun_(fun){}
 131   ~scope_guard_impl0(){scope_guard_impl_base::safe_execute(*this);}
 132   void execute(){fun_();}
 133
 134 protected:
 135
 136   F fun_;
 137 };
 138
 139 template<typename F>
 140 inline scope_guard_impl0<F> make_guard(F fun)
 141 {
 142   return scope_guard_impl0<F>(fun);
 143 }
 144
 145 template<bool cond, typename F>
 146 inline typename null_guard_return<cond,scope_guard_impl0<F> >::type
 147 make_guard_if_c(F fun)
 148 {
 149   return typename null_guard_return<cond,scope_guard_impl0<F> >::type(fun);
 150 }
 151
 152 template<typename C, typename F>
 153 inline typename null_guard_return<C::value,scope_guard_impl0<F> >::type
 154 make_guard_if(F fun)
 155 {
 156   return make_guard_if<C::value>(fun);
 157 }
 158
 159 template<typename F,typename P1>
 160 class scope_guard_impl1:public scope_guard_impl_base
 161 {
 162 public:
 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
 167 protected:
 168   F        fun_;
 169   const P1 p1_;
 170 };
 171
 172 template<typename F,typename P1>
 173 inline scope_guard_impl1<F,P1> make_guard(F fun,P1 p1)
 174 {
 175   return scope_guard_impl1<F,P1>(fun,p1);
 176 }
 177
 178 template<bool cond, typename F,typename P1>
 179 inline typename null_guard_return<cond,scope_guard_impl1<F,P1> >::type
 180 make_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
 185 template<typename C, typename F,typename P1>
 186 inline typename null_guard_return<C::value,scope_guard_impl1<F,P1> >::type
 187 make_guard_if(F fun,P1 p1)
 188 {
 189   return make_guard_if_c<C::value>(fun,p1);
 190 }
 191
 192 template<typename F,typename P1,typename P2>
 193 class scope_guard_impl2:public scope_guard_impl_base
 194 {
 195 public:
 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
 200 protected:
 201   F        fun_;
 202   const P1 p1_;
 203   const P2 p2_;
 204 };
 205
 206 template<typename F,typename P1,typename P2>
 207 inline 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
 212 template<bool cond, typename F,typename P1,typename P2>
 213 inline typename null_guard_return<cond,scope_guard_impl2<F,P1,P2> >::type
 214 make_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
 219 template<typename C, typename F,typename P1,typename P2>
 220 inline typename null_guard_return<C::value,scope_guard_impl2<F,P1,P2> >::type
 221 make_guard_if(F fun,P1 p1,P2 p2)
 222 {
 223   return make_guard_if_c<C::value>(fun,p1,p2);
 224 }
 225
 226 template<typename F,typename P1,typename P2,typename P3>
 227 class scope_guard_impl3:public scope_guard_impl_base
 228 {
 229 public:
 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
 234 protected:
 235   F        fun_;
 236   const P1 p1_;
 237   const P2 p2_;
 238   const P3 p3_;
 239 };
 240
 241 template<typename F,typename P1,typename P2,typename P3>
 242 inline 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
 247 template<bool cond,typename F,typename P1,typename P2,typename P3>
 248 inline typename null_guard_return<cond,scope_guard_impl3<F,P1,P2,P3> >::type
 249 make_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
 254 template<typename C,typename F,typename P1,typename P2,typename P3>
 255 inline typename null_guard_return< C::value,scope_guard_impl3<F,P1,P2,P3> >::type
 256 make_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
 261 template<typename F,typename P1,typename P2,typename P3,typename P4>
 262 class scope_guard_impl4:public scope_guard_impl_base
 263 {
 264 public:
 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
 270 protected:
 271   F        fun_;
 272   const P1 p1_;
 273   const P2 p2_;
 274   const P3 p3_;
 275   const P4 p4_;
 276 };
 277
 278 template<typename F,typename P1,typename P2,typename P3,typename P4>
 279 inline 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
 285 template<bool cond, typename F,typename P1,typename P2,typename P3,typename P4>
 286 inline typename null_guard_return<cond,scope_guard_impl4<F,P1,P2,P3,P4> >::type
 287 make_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
 293 template<typename C, typename F,typename P1,typename P2,typename P3,typename P4>
 294 inline typename null_guard_return<C::value,scope_guard_impl4<F,P1,P2,P3,P4> >::type
 295 make_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
 301 template<class Obj,typename MemFun>
 302 class obj_scope_guard_impl0:public scope_guard_impl_base
 303 {
 304 public:
 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
 309 protected:
 310   Obj&   obj_;
 311   MemFun mem_fun_;
 312 };
 313
 314 template<class Obj,typename MemFun>
 315 inline 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
 320 template<bool cond, class Obj,typename MemFun>
 321 inline typename null_guard_return<cond,obj_scope_guard_impl0<Obj,MemFun> >::type
 322 make_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
 327 template<typename C, class Obj,typename MemFun>
 328 inline typename null_guard_return<C::value,obj_scope_guard_impl0<Obj,MemFun> >::type
 329 make_obj_guard_if(Obj& obj,MemFun mem_fun)
 330 {
 331   return make_obj_guard_if_c<C::value>(obj,mem_fun);
 332 }
 333
 334 template<class Obj,typename MemFun,typename P1>
 335 class obj_scope_guard_impl1:public scope_guard_impl_base
 336 {
 337 public:
 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
 343 protected:
 344   Obj&     obj_;
 345   MemFun   mem_fun_;
 346   const P1 p1_;
 347 };
 348
 349 template<class Obj,typename MemFun,typename P1>
 350 inline 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
 356 template<bool cond, class Obj,typename MemFun,typename P1>
 357 inline typename null_guard_return<cond,obj_scope_guard_impl1<Obj,MemFun,P1> >::type
 358 make_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
 363 template<typename C, class Obj,typename MemFun,typename P1>
 364 inline typename null_guard_return<C::value,obj_scope_guard_impl1<Obj,MemFun,P1> >::type
 365 make_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
 370 template<class Obj,typename MemFun,typename P1,typename P2>
 371 class obj_scope_guard_impl2:public scope_guard_impl_base
 372 {
 373 public:
 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
 380 protected:
 381   Obj&     obj_;
 382   MemFun   mem_fun_;
 383   const P1 p1_;
 384   const P2 p2_;
 385 };
 386
 387 template<class Obj,typename MemFun,typename P1,typename P2>
 388 inline obj_scope_guard_impl2<Obj,MemFun,P1,P2>
 389 make_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
 394 template<bool cond, class Obj,typename MemFun,typename P1,typename P2>
 395 inline typename null_guard_return<cond,obj_scope_guard_impl2<Obj,MemFun,P1,P2> >::type
 396 make_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
 401 template<typename C, class Obj,typename MemFun,typename P1,typename P2>
 402 inline typename null_guard_return<C::value,obj_scope_guard_impl2<Obj,MemFun,P1,P2> >::type
 403 make_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
 408 template<class Obj,typename MemFun,typename P1,typename P2,typename P3>
 409 class obj_scope_guard_impl3:public scope_guard_impl_base
 410 {
 411 public:
 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
 418 protected:
 419   Obj&     obj_;
 420   MemFun   mem_fun_;
 421   const P1 p1_;
 422   const P2 p2_;
 423   const P3 p3_;
 424 };
 425
 426 template<class Obj,typename MemFun,typename P1,typename P2,typename P3>
 427 inline obj_scope_guard_impl3<Obj,MemFun,P1,P2,P3>
 428 make_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
 433 template<bool cond, class Obj,typename MemFun,typename P1,typename P2,typename P3>
 434 inline typename null_guard_return<cond,obj_scope_guard_impl3<Obj,MemFun,P1,P2,P3> >::type
 435 make_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
 440 template<typename C, class Obj,typename MemFun,typename P1,typename P2,typename P3>
 441 inline typename null_guard_return<C::value,obj_scope_guard_impl3<Obj,MemFun,P1,P2,P3> >::type
 442 make_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