libstdc++-v3/include/ext/concurrence.h

   1 // Support for concurrent programing -*- C++ -*-
   2
   3 // Copyright (C) 2003, 2004, 2005, 2006, 2007
   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 2, 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 // You should have received a copy of the GNU General Public License along
  18 // with this library; see the file COPYING.  If not, write to the Free
  19 // Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
  20 // USA.
  21
  22 // As a special exception, you may use this file as part of a free software
  23 // library without restriction.  Specifically, if other files instantiate
  24 // templates or use macros or inline functions from this file, or you compile
  25 // this file and link it with other files to produce an executable, this
  26 // file does not by itself cause the resulting executable to be covered by
  27 // the GNU General Public License.  This exception does not however
  28 // invalidate any other reasons why the executable file might be covered by
  29 // the GNU General Public License.
  30
  31 /** @file concurrence.h
  32  *  This is an internal header file, included by other library headers.
  33  *  You should not attempt to use it directly.
  34  */
  35
  36 #ifndef _CONCURRENCE_H
  37 #define _CONCURRENCE_H 1
  38
  39 #include <exception>
  40 #include <bits/gthr.h>
  41 #include <bits/functexcept.h>
  42
  43 _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
  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     __gthread_mutex_t _M_mutex;
 147
 148     __mutex(const __mutex&);
 149     __mutex& operator=(const __mutex&);
 150
 151   public:
 152     __mutex()
 153     {
 154 #if __GTHREADS
 155       if (__gthread_active_p())
 156         {
 157 #if defined __GTHREAD_MUTEX_INIT
 158           __gthread_mutex_t __tmp = __GTHREAD_MUTEX_INIT;
 159           _M_mutex = __tmp;
 160 #else
 161           __GTHREAD_MUTEX_INIT_FUNCTION(&_M_mutex);
 162 #endif
 163         }
 164 #endif
 165     }
 166
 167     void lock()
 168     {
 169 #if __GTHREADS
 170       if (__gthread_active_p())
 171         {
 172           if (__gthread_mutex_lock(&_M_mutex) != 0)
 173             __throw_concurrence_lock_error();
 174         }
 175 #endif
 176     }
 177
 178     void unlock()
 179     {
 180 #if __GTHREADS
 181       if (__gthread_active_p())
 182         {
 183           if (__gthread_mutex_unlock(&_M_mutex) != 0)
 184             __throw_concurrence_unlock_error();
 185         }
 186 #endif
 187     }
 188
 189     __gthread_mutex_t* gthread_mutex(void)
 190       { return &_M_mutex; }
 191   };
 192
 193   class __recursive_mutex
 194   {
 195   private:
 196     __gthread_recursive_mutex_t _M_mutex;
 197
 198     __recursive_mutex(const __recursive_mutex&);
 199     __recursive_mutex& operator=(const __recursive_mutex&);
 200
 201   public:
 202     __recursive_mutex()
 203     {
 204 #if __GTHREADS
 205       if (__gthread_active_p())
 206         {
 207 #if defined __GTHREAD_RECURSIVE_MUTEX_INIT
 208           __gthread_recursive_mutex_t __tmp = __GTHREAD_RECURSIVE_MUTEX_INIT;
 209           _M_mutex = __tmp;
 210 #else
 211           __GTHREAD_RECURSIVE_MUTEX_INIT_FUNCTION(&_M_mutex);
 212 #endif
 213         }
 214 #endif
 215     }
 216
 217     void lock()
 218     {
 219 #if __GTHREADS
 220       if (__gthread_active_p())
 221         {
 222           if (__gthread_recursive_mutex_lock(&_M_mutex) != 0)
 223             __throw_concurrence_lock_error();
 224         }
 225 #endif
 226     }
 227
 228     void unlock()
 229     {
 230 #if __GTHREADS
 231       if (__gthread_active_p())
 232         {
 233           if (__gthread_recursive_mutex_unlock(&_M_mutex) != 0)
 234             __throw_concurrence_unlock_error();
 235         }
 236 #endif
 237     }
 238
 239     __gthread_recursive_mutex_t* gthread_recursive_mutex(void)
 240       { return &_M_mutex; }
 241   };
 242
 243   /// @brief  Scoped lock idiom.
 244   // Acquire the mutex here with a constructor call, then release with
 245   // the destructor call in accordance with RAII style.
 246   class __scoped_lock
 247   {
 248   public:
 249     typedef __mutex __mutex_type;
 250
 251   private:
 252     __mutex_type& _M_device;
 253
 254     __scoped_lock(const __scoped_lock&);
 255     __scoped_lock& operator=(const __scoped_lock&);
 256
 257   public:
 258     explicit __scoped_lock(__mutex_type& __name) : _M_device(__name)
 259     { _M_device.lock(); }
 260
 261     ~__scoped_lock() throw()
 262     { _M_device.unlock(); }
 263   };
 264
 265 #ifdef __GTHREAD_HAS_COND
 266   class __cond
 267   {
 268   private:
 269     __gthread_cond_t _M_cond;
 270
 271     __cond(const __cond&);
 272     __cond& operator=(const __cond&);
 273
 274   public:
 275     __cond()
 276     {
 277 #if __GTHREADS
 278       if (__gthread_active_p())
 279         {
 280 #if defined __GTHREAD_COND_INIT
 281           __gthread_cond_t __tmp = __GTHREAD_COND_INIT;
 282           _M_cond = __tmp;
 283 #else
 284           __GTHREAD_MUTEX_INIT_FUNCTION(&_M_cond);
 285 #endif
 286         }
 287 #endif
 288     }
 289
 290     void broadcast()
 291     {
 292 #if __GTHREADS
 293       if (__gthread_active_p())
 294         {
 295           if (__gthread_cond_broadcast(&_M_cond) != 0)
 296             __throw_concurrence_broadcast_error();
 297         }
 298 #endif
 299     }
 300
 301     void wait(__mutex *mutex)
 302     {
 303 #if __GTHREADS
 304       {
 305           if (__gthread_cond_wait(&_M_cond, mutex->gthread_mutex()) != 0)
 306             __throw_concurrence_wait_error();
 307       }
 308 #endif
 309     }
 310
 311     void wait_recursive(__recursive_mutex *mutex)
 312     {
 313 #if __GTHREADS
 314       {
 315           if (__gthread_cond_wait_recursive(&_M_cond,
 316                                             mutex->gthread_recursive_mutex())
 317               != 0)
 318             __throw_concurrence_wait_error();
 319       }
 320 #endif
 321     }
 322   };
 323 #endif
 324
 325 _GLIBCXX_END_NAMESPACE
 326
 327 #endif