contrib/gcc-4.4/libstdc++-v3/include/ext/concurrence.h

   1 // Support for concurrent programing -*- C++ -*-
   2
   3 // Copyright (C) 2003, 2004, 2005, 2006, 2007, 2009
   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 concurrence.h
  27  *  This is an internal header file, included by other library headers.
  28  *  You should not attempt to use it directly.
  29  */
  30
  31 #ifndef _CONCURRENCE_H
  32 #define _CONCURRENCE_H 1
  33
  34 #include <exception>
  35 #include <bits/gthr.h>
  36 #include <bits/functexcept.h>
  37
  38 _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
  39
  40   // Available locking policies:
  41   // _S_single    single-threaded code that doesn't need to be locked.
  42   // _S_mutex     multi-threaded code that requires additional support
  43   //              from gthr.h or abstraction layers in concurrence.h.
  44   // _S_atomic    multi-threaded code using atomic operations.
  45   enum _Lock_policy { _S_single, _S_mutex, _S_atomic };
  46
  47   // Compile time constant that indicates prefered locking policy in
  48   // the current configuration.
  49   static const _Lock_policy __default_lock_policy =
  50 #ifdef __GTHREADS
  51 #if (defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_2) \
  52      && defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4))
  53   _S_atomic;
  54 #else
  55   _S_mutex;
  56 #endif
  57 #else
  58   _S_single;
  59 #endif
  60
  61   // NB: As this is used in libsupc++, need to only depend on
  62   // exception. No stdexception classes, no use of std::string.
  63   class __concurrence_lock_error : public std::exception
  64   {
  65   public:
  66     virtual char const*
  67     what() const throw()
  68     { return "__gnu_cxx::__concurrence_lock_error"; }
  69   };
  70
  71   class __concurrence_unlock_error : public std::exception
  72   {
  73   public:
  74     virtual char const*
  75     what() const throw()
  76     { return "__gnu_cxx::__concurrence_unlock_error"; }
  77   };
  78
  79   class __concurrence_broadcast_error : public std::exception
  80   {
  81   public:
  82     virtual char const*
  83     what() const throw()
  84     { return "__gnu_cxx::__concurrence_broadcast_error"; }
  85   };
  86
  87   class __concurrence_wait_error : public std::exception
  88   {
  89   public:
  90     virtual char const*
  91     what() const throw()
  92     { return "__gnu_cxx::__concurrence_wait_error"; }
  93   };
  94
  95   // Substitute for concurrence_error object in the case of -fno-exceptions.
  96   inline void
  97   __throw_concurrence_lock_error()
  98   {
  99 #if __EXCEPTIONS
 100     throw __concurrence_lock_error();
 101 #else
 102     __builtin_abort();
 103 #endif
 104   }
 105
 106   inline void
 107   __throw_concurrence_unlock_error()
 108   {
 109 #if __EXCEPTIONS
 110     throw __concurrence_unlock_error();
 111 #else
 112     __builtin_abort();
 113 #endif
 114   }
 115
 116 #ifdef __GTHREAD_HAS_COND
 117   inline void
 118   __throw_concurrence_broadcast_error()
 119   {
 120 #if __EXCEPTIONS
 121     throw __concurrence_broadcast_error();
 122 #else
 123     __builtin_abort();
 124 #endif
 125   }
 126
 127   inline void
 128   __throw_concurrence_wait_error()
 129   {
 130 #if __EXCEPTIONS
 131     throw __concurrence_wait_error();
 132 #else
 133     __builtin_abort();
 134 #endif
 135   }
 136 #endif
 137
 138   class __mutex
 139   {
 140   private:
 141     __gthread_mutex_t _M_mutex;
 142
 143     __mutex(const __mutex&);
 144     __mutex& operator=(const __mutex&);
 145
 146   public:
 147     __mutex()
 148     {
 149 #if __GTHREADS
 150       if (__gthread_active_p())
 151         {
 152 #if defined __GTHREAD_MUTEX_INIT
 153           __gthread_mutex_t __tmp = __GTHREAD_MUTEX_INIT;
 154           _M_mutex = __tmp;
 155 #else
 156           __GTHREAD_MUTEX_INIT_FUNCTION(&_M_mutex);
 157 #endif
 158         }
 159 #endif
 160     }
 161
 162     void lock()
 163     {
 164 #if __GTHREADS
 165       if (__gthread_active_p())
 166         {
 167           if (__gthread_mutex_lock(&_M_mutex) != 0)
 168             __throw_concurrence_lock_error();
 169         }
 170 #endif
 171     }
 172
 173     void unlock()
 174     {
 175 #if __GTHREADS
 176       if (__gthread_active_p())
 177         {
 178           if (__gthread_mutex_unlock(&_M_mutex) != 0)
 179             __throw_concurrence_unlock_error();
 180         }
 181 #endif
 182     }
 183
 184     __gthread_mutex_t* gthread_mutex(void)
 185       { return &_M_mutex; }
 186   };
 187
 188   class __recursive_mutex
 189   {
 190   private:
 191     __gthread_recursive_mutex_t _M_mutex;
 192
 193     __recursive_mutex(const __recursive_mutex&);
 194     __recursive_mutex& operator=(const __recursive_mutex&);
 195
 196   public:
 197     __recursive_mutex()
 198     {
 199 #if __GTHREADS
 200       if (__gthread_active_p())
 201         {
 202 #if defined __GTHREAD_RECURSIVE_MUTEX_INIT
 203           __gthread_recursive_mutex_t __tmp = __GTHREAD_RECURSIVE_MUTEX_INIT;
 204           _M_mutex = __tmp;
 205 #else
 206           __GTHREAD_RECURSIVE_MUTEX_INIT_FUNCTION(&_M_mutex);
 207 #endif
 208         }
 209 #endif
 210     }
 211
 212     void lock()
 213     {
 214 #if __GTHREADS
 215       if (__gthread_active_p())
 216         {
 217           if (__gthread_recursive_mutex_lock(&_M_mutex) != 0)
 218             __throw_concurrence_lock_error();
 219         }
 220 #endif
 221     }
 222
 223     void unlock()
 224     {
 225 #if __GTHREADS
 226       if (__gthread_active_p())
 227         {
 228           if (__gthread_recursive_mutex_unlock(&_M_mutex) != 0)
 229             __throw_concurrence_unlock_error();
 230         }
 231 #endif
 232     }
 233
 234     __gthread_recursive_mutex_t* gthread_recursive_mutex(void)
 235       { return &_M_mutex; }
 236   };
 237
 238   /// Scoped lock idiom.
 239   // Acquire the mutex here with a constructor call, then release with
 240   // the destructor call in accordance with RAII style.
 241   class __scoped_lock
 242   {
 243   public:
 244     typedef __mutex __mutex_type;
 245
 246   private:
 247     __mutex_type& _M_device;
 248
 249     __scoped_lock(const __scoped_lock&);
 250     __scoped_lock& operator=(const __scoped_lock&);
 251
 252   public:
 253     explicit __scoped_lock(__mutex_type& __name) : _M_device(__name)
 254     { _M_device.lock(); }
 255
 256     ~__scoped_lock() throw()
 257     { _M_device.unlock(); }
 258   };
 259
 260 #ifdef __GTHREAD_HAS_COND
 261   class __cond
 262   {
 263   private:
 264     __gthread_cond_t _M_cond;
 265
 266     __cond(const __cond&);
 267     __cond& operator=(const __cond&);
 268
 269   public:
 270     __cond()
 271     {
 272 #if __GTHREADS
 273       if (__gthread_active_p())
 274         {
 275 #if defined __GTHREAD_COND_INIT
 276           __gthread_cond_t __tmp = __GTHREAD_COND_INIT;
 277           _M_cond = __tmp;
 278 #else
 279           __GTHREAD_COND_INIT_FUNCTION(&_M_cond);
 280 #endif
 281         }
 282 #endif
 283     }
 284
 285     void broadcast()
 286     {
 287 #if __GTHREADS
 288       if (__gthread_active_p())
 289         {
 290           if (__gthread_cond_broadcast(&_M_cond) != 0)
 291             __throw_concurrence_broadcast_error();
 292         }
 293 #endif
 294     }
 295
 296     void wait(__mutex *mutex)
 297     {
 298 #if __GTHREADS
 299       {
 300           if (__gthread_cond_wait(&_M_cond, mutex->gthread_mutex()) != 0)
 301             __throw_concurrence_wait_error();
 302       }
 303 #endif
 304     }
 305
 306     void wait_recursive(__recursive_mutex *mutex)
 307     {
 308 #if __GTHREADS
 309       {
 310           if (__gthread_cond_wait_recursive(&_M_cond,
 311                                             mutex->gthread_recursive_mutex())
 312               != 0)
 313             __throw_concurrence_wait_error();
 314       }
 315 #endif
 316     }
 317   };
 318 #endif
 319
 320 _GLIBCXX_END_NAMESPACE
 321
 322 #endif