i686-linux-gnu-4.7/usr/include/c++/4.7/ext/concurrence.h

   1 // Support for concurrent programing -*- C++ -*-
   2
   3 // Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012
   4 // Free Software Foundation, Inc.
   5 //
   6 // This file is part of the GNU ISO C++ Library.  This library is free
   7 // software; you can redistribute it and/or modify it under the
   8 // terms of the GNU General Public License as published by the
   9 // Free Software Foundation; either version 3, or (at your option)
  10 // any later version.
  11
  12 // This library is distributed in the hope that it will be useful,
  13 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 // GNU General Public License for more details.
  16
  17 // Under Section 7 of GPL version 3, you are granted additional
  18 // permissions described in the GCC Runtime Library Exception, version
  19 // 3.1, as published by the Free Software Foundation.
  20
  21 // You should have received a copy of the GNU General Public License and
  22 // a copy of the GCC Runtime Library Exception along with this program;
  23 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  24 // <http://www.gnu.org/licenses/>.
  25
  26 /** @file ext/concurrence.h
  27  *  This file is a GNU extension to the Standard C++ Library.
  28  */
  29
  30 #ifndef _CONCURRENCE_H
  31 #define _CONCURRENCE_H 1
  32
  33 #pragma GCC system_header
  34
  35 #include <exception>
  36 #include <bits/gthr.h>
  37 #include <bits/functexcept.h>
  38 #include <bits/cpp_type_traits.h>
  39 #include <ext/type_traits.h>
  40
  41 namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
  42 {
  43 _GLIBCXX_BEGIN_NAMESPACE_VERSION
  44
  45   // Available locking policies:
  46   // _S_single    single-threaded code that doesn't need to be locked.
  47   // _S_mutex     multi-threaded code that requires additional support
  48   //              from gthr.h or abstraction layers in concurrence.h.
  49   // _S_atomic    multi-threaded code using atomic operations.
  50   enum _Lock_policy { _S_single, _S_mutex, _S_atomic };
  51
  52   // Compile time constant that indicates prefered locking policy in
  53   // the current configuration.
  54   static const _Lock_policy __default_lock_policy =
  55 #ifdef __GTHREADS
  56 #if (defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_2) \
  57      && defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4))
  58   _S_atomic;
  59 #else
  60   _S_mutex;
  61 #endif
  62 #else
  63   _S_single;
  64 #endif
  65
  66   // NB: As this is used in libsupc++, need to only depend on
  67   // exception. No stdexception classes, no use of std::string.
  68   class __concurrence_lock_error : public std::exception
  69   {
  70   public:
  71     virtual char const*
  72     what() const throw()
  73     { return "__gnu_cxx::__concurrence_lock_error"; }
  74   };
  75
  76   class __concurrence_unlock_error : public std::exception
  77   {
  78   public:
  79     virtual char const*
  80     what() const throw()
  81     { return "__gnu_cxx::__concurrence_unlock_error"; }
  82   };
  83
  84   class __concurrence_broadcast_error : public std::exception
  85   {
  86   public:
  87     virtual char const*
  88     what() const throw()
  89     { return "__gnu_cxx::__concurrence_broadcast_error"; }
  90   };
  91
  92   class __concurrence_wait_error : public std::exception
  93   {
  94   public:
  95     virtual char const*
  96     what() const throw()
  97     { return "__gnu_cxx::__concurrence_wait_error"; }
  98   };
  99
 100   // Substitute for concurrence_error object in the case of -fno-exceptions.
 101   inline void
 102   __throw_concurrence_lock_error()
 103   {
 104 #if __EXCEPTIONS
 105     throw __concurrence_lock_error();
 106 #else
 107     __builtin_abort();
 108 #endif
 109   }
 110
 111   inline void
 112   __throw_concurrence_unlock_error()
 113   {
 114 #if __EXCEPTIONS
 115     throw __concurrence_unlock_error();
 116 #else
 117     __builtin_abort();
 118 #endif
 119   }
 120
 121 #ifdef __GTHREAD_HAS_COND
 122   inline void
 123   __throw_concurrence_broadcast_error()
 124   {
 125 #if __EXCEPTIONS
 126     throw __concurrence_broadcast_error();
 127 #else
 128     __builtin_abort();
 129 #endif
 130   }
 131
 132   inline void
 133   __throw_concurrence_wait_error()
 134   {
 135 #if __EXCEPTIONS
 136     throw __concurrence_wait_error();
 137 #else
 138     __builtin_abort();
 139 #endif
 140   }
 141 #endif
 142
 143   class __mutex
 144   {
 145   private:
 146 #if __GTHREADS && defined __GTHREAD_MUTEX_INIT
 147     __gthread_mutex_t _M_mutex = __GTHREAD_MUTEX_INIT;
 148 #else
 149     __gthread_mutex_t _M_mutex;
 150 #endif
 151
 152     __mutex(const __mutex&);
 153     __mutex& operator=(const __mutex&);
 154
 155   public:
 156     __mutex()
 157     {
 158 #if __GTHREADS && ! defined __GTHREAD_MUTEX_INIT
 159       if (__gthread_active_p())
 160         __GTHREAD_MUTEX_INIT_FUNCTION(&_M_mutex);
 161 #endif
 162     }
 163
 164 #if __GTHREADS && ! defined __GTHREAD_MUTEX_INIT
 165     ~__mutex()
 166     {
 167       if (__gthread_active_p())
 168         __gthread_mutex_destroy(&_M_mutex);
 169     }
 170 #endif
 171
 172     void lock()
 173     {
 174 #if __GTHREADS
 175       if (__gthread_active_p())
 176         {
 177           if (__gthread_mutex_lock(&_M_mutex) != 0)
 178             __throw_concurrence_lock_error();
 179         }
 180 #endif
 181     }
 182
 183     void unlock()
 184     {
 185 #if __GTHREADS
 186       if (__gthread_active_p())
 187         {
 188           if (__gthread_mutex_unlock(&_M_mutex) != 0)
 189             __throw_concurrence_unlock_error();
 190         }
 191 #endif
 192     }
 193
 194     __gthread_mutex_t* gthread_mutex(void)
 195       { return &_M_mutex; }
 196   };
 197
 198   class __recursive_mutex
 199   {
 200   private:
 201 #if __GTHREADS && defined __GTHREAD_RECURSIVE_MUTEX_INIT
 202     __gthread_recursive_mutex_t _M_mutex = __GTHREAD_RECURSIVE_MUTEX_INIT;
 203 #else
 204     __gthread_recursive_mutex_t _M_mutex;
 205 #endif
 206
 207     __recursive_mutex(const __recursive_mutex&);
 208     __recursive_mutex& operator=(const __recursive_mutex&);
 209
 210   public:
 211     __recursive_mutex()
 212     {
 213 #if __GTHREADS && ! defined __GTHREAD_RECURSIVE_MUTEX_INIT
 214       if (__gthread_active_p())
 215         __GTHREAD_RECURSIVE_MUTEX_INIT_FUNCTION(&_M_mutex);
 216 #endif
 217     }
 218
 219 #if __GTHREADS && ! defined __GTHREAD_RECURSIVE_MUTEX_INIT
 220     ~__recursive_mutex()
 221     {
 222       if (__gthread_active_p())
 223         _S_destroy(&_M_mutex);
 224     }
 225 #endif
 226
 227     void lock()
 228     {
 229 #if __GTHREADS
 230       if (__gthread_active_p())
 231         {
 232           if (__gthread_recursive_mutex_lock(&_M_mutex) != 0)
 233             __throw_concurrence_lock_error();
 234         }
 235 #endif
 236     }
 237
 238     void unlock()
 239     {
 240 #if __GTHREADS
 241       if (__gthread_active_p())
 242         {
 243           if (__gthread_recursive_mutex_unlock(&_M_mutex) != 0)
 244             __throw_concurrence_unlock_error();
 245         }
 246 #endif
 247     }
 248
 249     __gthread_recursive_mutex_t* gthread_recursive_mutex(void)
 250     { return &_M_mutex; }
 251
 252 #if __GTHREADS && ! defined __GTHREAD_RECURSIVE_MUTEX_INIT
 253     // FIXME: gthreads doesn't define __gthread_recursive_mutex_destroy
 254     // so we need to obtain a __gthread_mutex_t to destroy
 255   private:
 256     template<typename _Mx, typename _Rm>
 257       static void
 258       _S_destroy_win32(_Mx* __mx, _Rm const* __rmx)
 259       {
 260         __mx->counter = __rmx->counter;
 261         __mx->sema = __rmx->sema;
 262         __gthread_mutex_destroy(__mx);
 263       }
 264
 265     // matches a gthr-win32.h recursive mutex
 266     template<typename _Rm>
 267       static typename __enable_if<(bool)sizeof(&_Rm::sema), void>::__type
 268       _S_destroy(_Rm* __mx)
 269       {
 270         __gthread_mutex_t __tmp;
 271         _S_destroy_win32(&__tmp, __mx);
 272       }
 273
 274     // matches a recursive mutex with a member 'actual'
 275     template<typename _Rm>
 276       static typename __enable_if<(bool)sizeof(&_Rm::actual), void>::__type
 277       _S_destroy(_Rm* __mx)
 278       { __gthread_mutex_destroy(&__mx->actual); }
 279
 280     // matches when there's only one mutex type
 281     template<typename _Rm>
 282       static typename
 283       __enable_if<std::__are_same<_Rm, __gthread_mutex_t>::__value,
 284         void>::__type
 285       _S_destroy(_Rm* __mx)
 286       { __gthread_mutex_destroy(__mx); }
 287 #endif
 288   };
 289
 290   /// Scoped lock idiom.
 291   // Acquire the mutex here with a constructor call, then release with
 292   // the destructor call in accordance with RAII style.
 293   class __scoped_lock
 294   {
 295   public:
 296     typedef __mutex __mutex_type;
 297
 298   private:
 299     __mutex_type& _M_device;
 300
 301     __scoped_lock(const __scoped_lock&);
 302     __scoped_lock& operator=(const __scoped_lock&);
 303
 304   public:
 305     explicit __scoped_lock(__mutex_type& __name) : _M_device(__name)
 306     { _M_device.lock(); }
 307
 308     ~__scoped_lock() throw()
 309     { _M_device.unlock(); }
 310   };
 311
 312 #ifdef __GTHREAD_HAS_COND
 313   class __cond
 314   {
 315   private:
 316 #if __GTHREADS && defined __GTHREAD_COND_INIT
 317     __gthread_cond_t _M_cond = __GTHREAD_COND_INIT;
 318 #else
 319     __gthread_cond_t _M_cond;
 320 #endif
 321
 322     __cond(const __cond&);
 323     __cond& operator=(const __cond&);
 324
 325   public:
 326     __cond()
 327     {
 328 #if __GTHREADS && ! defined __GTHREAD_COND_INIT
 329       if (__gthread_active_p())
 330         __GTHREAD_COND_INIT_FUNCTION(&_M_cond);
 331 #endif
 332     }
 333
 334 #if __GTHREADS && ! defined __GTHREAD_COND_INIT
 335     ~__cond()
 336     {
 337       if (__gthread_active_p())
 338         __gthread_cond_destroy(&_M_cond);
 339     }
 340 #endif
 341
 342     void broadcast()
 343     {
 344 #if __GTHREADS
 345       if (__gthread_active_p())
 346         {
 347           if (__gthread_cond_broadcast(&_M_cond) != 0)
 348             __throw_concurrence_broadcast_error();
 349         }
 350 #endif
 351     }
 352
 353     void wait(__mutex *mutex)
 354     {
 355 #if __GTHREADS
 356       {
 357           if (__gthread_cond_wait(&_M_cond, mutex->gthread_mutex()) != 0)
 358             __throw_concurrence_wait_error();
 359       }
 360 #endif
 361     }
 362
 363     void wait_recursive(__recursive_mutex *mutex)
 364     {
 365 #if __GTHREADS
 366       {
 367           if (__gthread_cond_wait_recursive(&_M_cond,
 368                                             mutex->gthread_recursive_mutex())
 369               != 0)
 370             __throw_concurrence_wait_error();
 371       }
 372 #endif
 373     }
 374   };
 375 #endif
 376
 377 _GLIBCXX_END_NAMESPACE_VERSION
 378 } // namespace
 379
 380 #endif