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

   1 // Support for concurrent programing -*- C++ -*-
   2
   3 // Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
   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     __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 #if __GTHREADS && ! defined __GTHREAD_MUTEX_INIT
 168     ~__mutex()
 169     {
 170       if (__gthread_active_p())
 171         __gthread_mutex_destroy(&_M_mutex);
 172     }
 173 #endif
 174
 175     void lock()
 176     {
 177 #if __GTHREADS
 178       if (__gthread_active_p())
 179         {
 180           if (__gthread_mutex_lock(&_M_mutex) != 0)
 181             __throw_concurrence_lock_error();
 182         }
 183 #endif
 184     }
 185
 186     void unlock()
 187     {
 188 #if __GTHREADS
 189       if (__gthread_active_p())
 190         {
 191           if (__gthread_mutex_unlock(&_M_mutex) != 0)
 192             __throw_concurrence_unlock_error();
 193         }
 194 #endif
 195     }
 196
 197     __gthread_mutex_t* gthread_mutex(void)
 198       { return &_M_mutex; }
 199   };
 200
 201   class __recursive_mutex
 202   {
 203   private:
 204     __gthread_recursive_mutex_t _M_mutex;
 205
 206     __recursive_mutex(const __recursive_mutex&);
 207     __recursive_mutex& operator=(const __recursive_mutex&);
 208
 209   public:
 210     __recursive_mutex()
 211     {
 212 #if __GTHREADS
 213       if (__gthread_active_p())
 214         {
 215 #if defined __GTHREAD_RECURSIVE_MUTEX_INIT
 216           __gthread_recursive_mutex_t __tmp = __GTHREAD_RECURSIVE_MUTEX_INIT;
 217           _M_mutex = __tmp;
 218 #else
 219           __GTHREAD_RECURSIVE_MUTEX_INIT_FUNCTION(&_M_mutex);
 220 #endif
 221         }
 222 #endif
 223     }
 224
 225 #if __GTHREADS && ! defined __GTHREAD_RECURSIVE_MUTEX_INIT
 226     ~__recursive_mutex()
 227     {
 228       if (__gthread_active_p())
 229         _S_destroy(&_M_mutex);
 230     }
 231 #endif
 232
 233     void lock()
 234     {
 235 #if __GTHREADS
 236       if (__gthread_active_p())
 237         {
 238           if (__gthread_recursive_mutex_lock(&_M_mutex) != 0)
 239             __throw_concurrence_lock_error();
 240         }
 241 #endif
 242     }
 243
 244     void unlock()
 245     {
 246 #if __GTHREADS
 247       if (__gthread_active_p())
 248         {
 249           if (__gthread_recursive_mutex_unlock(&_M_mutex) != 0)
 250             __throw_concurrence_unlock_error();
 251         }
 252 #endif
 253     }
 254
 255     __gthread_recursive_mutex_t* gthread_recursive_mutex(void)
 256     { return &_M_mutex; }
 257
 258 #if __GTHREADS && ! defined __GTHREAD_RECURSIVE_MUTEX_INIT
 259     // FIXME: gthreads doesn't define __gthread_recursive_mutex_destroy
 260     // so we need to obtain a __gthread_mutex_t to destroy
 261   private:
 262     template<typename _Mx, typename _Rm>
 263       static void
 264       _S_destroy_win32(_Mx* __mx, _Rm const* __rmx)
 265       {
 266         __mx->counter = __rmx->counter;
 267         __mx->sema = __rmx->sema;
 268         __gthread_mutex_destroy(__mx);
 269       }
 270
 271     // matches a gthr-win32.h recursive mutex
 272     template<typename _Rm>
 273       static typename __enable_if<sizeof(&_Rm::sema), void>::__type
 274       _S_destroy(_Rm* __mx)
 275       {
 276         __gthread_mutex_t __tmp;
 277         _S_destroy_win32(&__tmp, __mx);
 278       }
 279
 280     // matches a recursive mutex with a member 'actual'
 281     template<typename _Rm>
 282       static typename __enable_if<sizeof(&_Rm::actual), void>::__type
 283       _S_destroy(_Rm* __mx)
 284       { __gthread_mutex_destroy(&__mx->actual); }
 285
 286     // matches when there's only one mutex type
 287     template<typename _Rm>
 288       static typename
 289       __enable_if<std::__are_same<_Rm, __gthread_mutex_t>::__value,
 290         void>::__type
 291       _S_destroy(_Rm* __mx)
 292       { __gthread_mutex_destroy(__mx); }
 293 #endif
 294   };
 295
 296   /// Scoped lock idiom.
 297   // Acquire the mutex here with a constructor call, then release with
 298   // the destructor call in accordance with RAII style.
 299   class __scoped_lock
 300   {
 301   public:
 302     typedef __mutex __mutex_type;
 303
 304   private:
 305     __mutex_type& _M_device;
 306
 307     __scoped_lock(const __scoped_lock&);
 308     __scoped_lock& operator=(const __scoped_lock&);
 309
 310   public:
 311     explicit __scoped_lock(__mutex_type& __name) : _M_device(__name)
 312     { _M_device.lock(); }
 313
 314     ~__scoped_lock() throw()
 315     { _M_device.unlock(); }
 316   };
 317
 318 #ifdef __GTHREAD_HAS_COND
 319   class __cond
 320   {
 321   private:
 322     __gthread_cond_t _M_cond;
 323
 324     __cond(const __cond&);
 325     __cond& operator=(const __cond&);
 326
 327   public:
 328     __cond()
 329     {
 330 #if __GTHREADS
 331       if (__gthread_active_p())
 332         {
 333 #if defined __GTHREAD_COND_INIT
 334           __gthread_cond_t __tmp = __GTHREAD_COND_INIT;
 335           _M_cond = __tmp;
 336 #else
 337           __GTHREAD_COND_INIT_FUNCTION(&_M_cond);
 338 #endif
 339         }
 340 #endif
 341     }
 342
 343 #if __GTHREADS && ! defined __GTHREAD_COND_INIT
 344     ~__cond()
 345     {
 346       if (__gthread_active_p())
 347         __gthread_cond_destroy(&_M_cond);
 348     }
 349 #endif
 350
 351     void broadcast()
 352     {
 353 #if __GTHREADS
 354       if (__gthread_active_p())
 355         {
 356           if (__gthread_cond_broadcast(&_M_cond) != 0)
 357             __throw_concurrence_broadcast_error();
 358         }
 359 #endif
 360     }
 361
 362     void wait(__mutex *mutex)
 363     {
 364 #if __GTHREADS
 365       {
 366           if (__gthread_cond_wait(&_M_cond, mutex->gthread_mutex()) != 0)
 367             __throw_concurrence_wait_error();
 368       }
 369 #endif
 370     }
 371
 372     void wait_recursive(__recursive_mutex *mutex)
 373     {
 374 #if __GTHREADS
 375       {
 376           if (__gthread_cond_wait_recursive(&_M_cond,
 377                                             mutex->gthread_recursive_mutex())
 378               != 0)
 379             __throw_concurrence_wait_error();
 380       }
 381 #endif
 382     }
 383   };
 384 #endif
 385
 386 _GLIBCXX_END_NAMESPACE_VERSION
 387 } // namespace
 388
 389 #endif