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 _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
  42
  43   // Available locking policies:
  44   // _S_single    single-threaded code that doesn't need to be locked.
  45   // _S_mutex     multi-threaded code that requires additional support
  46   //              from gthr.h or abstraction layers in concurrence.h.
  47   // _S_atomic    multi-threaded code using atomic operations.
  48   enum _Lock_policy { _S_single, _S_mutex, _S_atomic };
  49
  50   // Compile time constant that indicates prefered locking policy in
  51   // the current configuration.
  52   static const _Lock_policy __default_lock_policy =
  53 #ifdef __GTHREADS
  54 #if (defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_2) \
  55      && defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4))
  56   _S_atomic;
  57 #else
  58   _S_mutex;
  59 #endif
  60 #else
  61   _S_single;
  62 #endif
  63
  64   // NB: As this is used in libsupc++, need to only depend on
  65   // exception. No stdexception classes, no use of std::string.
  66   class __concurrence_lock_error : public std::exception
  67   {
  68   public:
  69     virtual char const*
  70     what() const throw()
  71     { return "__gnu_cxx::__concurrence_lock_error"; }
  72   };
  73
  74   class __concurrence_unlock_error : public std::exception
  75   {
  76   public:
  77     virtual char const*
  78     what() const throw()
  79     { return "__gnu_cxx::__concurrence_unlock_error"; }
  80   };
  81
  82   class __concurrence_broadcast_error : public std::exception
  83   {
  84   public:
  85     virtual char const*
  86     what() const throw()
  87     { return "__gnu_cxx::__concurrence_broadcast_error"; }
  88   };
  89
  90   class __concurrence_wait_error : public std::exception
  91   {
  92   public:
  93     virtual char const*
  94     what() const throw()
  95     { return "__gnu_cxx::__concurrence_wait_error"; }
  96   };
  97
  98   // Substitute for concurrence_error object in the case of -fno-exceptions.
  99   inline void
 100   __throw_concurrence_lock_error()
 101   {
 102 #if __EXCEPTIONS
 103     throw __concurrence_lock_error();
 104 #else
 105     __builtin_abort();
 106 #endif
 107   }
 108
 109   inline void
 110   __throw_concurrence_unlock_error()
 111   {
 112 #if __EXCEPTIONS
 113     throw __concurrence_unlock_error();
 114 #else
 115     __builtin_abort();
 116 #endif
 117   }
 118
 119 #ifdef __GTHREAD_HAS_COND
 120   inline void
 121   __throw_concurrence_broadcast_error()
 122   {
 123 #if __EXCEPTIONS
 124     throw __concurrence_broadcast_error();
 125 #else
 126     __builtin_abort();
 127 #endif
 128   }
 129
 130   inline void
 131   __throw_concurrence_wait_error()
 132   {
 133 #if __EXCEPTIONS
 134     throw __concurrence_wait_error();
 135 #else
 136     __builtin_abort();
 137 #endif
 138   }
 139 #endif
 140
 141   class __mutex
 142   {
 143   private:
 144     __gthread_mutex_t _M_mutex;
 145
 146     __mutex(const __mutex&);
 147     __mutex& operator=(const __mutex&);
 148
 149   public:
 150     __mutex()
 151     {
 152 #if __GTHREADS
 153       if (__gthread_active_p())
 154         {
 155 #if defined __GTHREAD_MUTEX_INIT
 156           __gthread_mutex_t __tmp = __GTHREAD_MUTEX_INIT;
 157           _M_mutex = __tmp;
 158 #else
 159           __GTHREAD_MUTEX_INIT_FUNCTION(&_M_mutex);
 160 #endif
 161         }
 162 #endif
 163     }
 164
 165 #if __GTHREADS && ! defined __GTHREAD_MUTEX_INIT
 166     ~__mutex()
 167     {
 168       if (__gthread_active_p())
 169         __gthread_mutex_destroy(&_M_mutex);
 170     }
 171 #endif
 172
 173     void lock()
 174     {
 175 #if __GTHREADS
 176       if (__gthread_active_p())
 177         {
 178           if (__gthread_mutex_lock(&_M_mutex) != 0)
 179             __throw_concurrence_lock_error();
 180         }
 181 #endif
 182     }
 183
 184     void unlock()
 185     {
 186 #if __GTHREADS
 187       if (__gthread_active_p())
 188         {
 189           if (__gthread_mutex_unlock(&_M_mutex) != 0)
 190             __throw_concurrence_unlock_error();
 191         }
 192 #endif
 193     }
 194
 195     __gthread_mutex_t* gthread_mutex(void)
 196       { return &_M_mutex; }
 197   };
 198
 199   class __recursive_mutex
 200   {
 201   private:
 202     __gthread_recursive_mutex_t _M_mutex;
 203
 204     __recursive_mutex(const __recursive_mutex&);
 205     __recursive_mutex& operator=(const __recursive_mutex&);
 206
 207   public:
 208     __recursive_mutex()
 209     {
 210 #if __GTHREADS
 211       if (__gthread_active_p())
 212         {
 213 #if defined __GTHREAD_RECURSIVE_MUTEX_INIT
 214           __gthread_recursive_mutex_t __tmp = __GTHREAD_RECURSIVE_MUTEX_INIT;
 215           _M_mutex = __tmp;
 216 #else
 217           __GTHREAD_RECURSIVE_MUTEX_INIT_FUNCTION(&_M_mutex);
 218 #endif
 219         }
 220 #endif
 221     }
 222
 223 #if __GTHREADS && ! defined __GTHREAD_RECURSIVE_MUTEX_INIT
 224     ~__recursive_mutex()
 225     {
 226       if (__gthread_active_p())
 227         _S_destroy(&_M_mutex);
 228     }
 229 #endif
 230
 231     void lock()
 232     {
 233 #if __GTHREADS
 234       if (__gthread_active_p())
 235         {
 236           if (__gthread_recursive_mutex_lock(&_M_mutex) != 0)
 237             __throw_concurrence_lock_error();
 238         }
 239 #endif
 240     }
 241
 242     void unlock()
 243     {
 244 #if __GTHREADS
 245       if (__gthread_active_p())
 246         {
 247           if (__gthread_recursive_mutex_unlock(&_M_mutex) != 0)
 248             __throw_concurrence_unlock_error();
 249         }
 250 #endif
 251     }
 252
 253     __gthread_recursive_mutex_t* gthread_recursive_mutex(void)
 254     { return &_M_mutex; }
 255
 256 #if __GTHREADS && ! defined __GTHREAD_RECURSIVE_MUTEX_INIT
 257     // FIXME: gthreads doesn't define __gthread_recursive_mutex_destroy
 258     // so we need to obtain a __gthread_mutex_t to destroy
 259   private:
 260     template<typename _Mx, typename _Rm>
 261       static void
 262       _S_destroy_win32(_Mx* __mx, _Rm const* __rmx)
 263       {
 264         __mx->counter = __rmx->counter;
 265         __mx->sema = __rmx->sema;
 266         __gthread_mutex_destroy(__mx);
 267       }
 268
 269     // matches a gthr-win32.h recursive mutex
 270     template<typename _Rm>
 271       static typename __enable_if<sizeof(&_Rm::sema), void>::__type
 272       _S_destroy(_Rm* __mx)
 273       {
 274         __gthread_mutex_t __tmp;
 275         _S_destroy_win32(&__tmp, __mx);
 276       }
 277
 278     // matches a recursive mutex with a member 'actual'
 279     template<typename _Rm>
 280       static typename __enable_if<sizeof(&_Rm::actual), void>::__type
 281       _S_destroy(_Rm* __mx)
 282       { __gthread_mutex_destroy(&__mx->actual); }
 283
 284     // matches when there's only one mutex type
 285     template<typename _Rm>
 286       static typename
 287       __enable_if<std::__are_same<_Rm, __gthread_mutex_t>::__value,
 288         void>::__type
 289       _S_destroy(_Rm* __mx)
 290       { __gthread_mutex_destroy(__mx); }
 291 #endif
 292   };
 293
 294   /// Scoped lock idiom.
 295   // Acquire the mutex here with a constructor call, then release with
 296   // the destructor call in accordance with RAII style.
 297   class __scoped_lock
 298   {
 299   public:
 300     typedef __mutex __mutex_type;
 301
 302   private:
 303     __mutex_type& _M_device;
 304
 305     __scoped_lock(const __scoped_lock&);
 306     __scoped_lock& operator=(const __scoped_lock&);
 307
 308   public:
 309     explicit __scoped_lock(__mutex_type& __name) : _M_device(__name)
 310     { _M_device.lock(); }
 311
 312     ~__scoped_lock() throw()
 313     { _M_device.unlock(); }
 314   };
 315
 316 #ifdef __GTHREAD_HAS_COND
 317   class __cond
 318   {
 319   private:
 320     __gthread_cond_t _M_cond;
 321
 322     __cond(const __cond&);
 323     __cond& operator=(const __cond&);
 324
 325   public:
 326     __cond()
 327     {
 328 #if __GTHREADS
 329       if (__gthread_active_p())
 330         {
 331 #if defined __GTHREAD_COND_INIT
 332           __gthread_cond_t __tmp = __GTHREAD_COND_INIT;
 333           _M_cond = __tmp;
 334 #else
 335           __GTHREAD_COND_INIT_FUNCTION(&_M_cond);
 336 #endif
 337         }
 338 #endif
 339     }
 340
 341 #if __GTHREADS && ! defined __GTHREAD_COND_INIT
 342     ~__cond()
 343     {
 344       if (__gthread_active_p())
 345         __gthread_cond_destroy(&_M_cond);
 346     }
 347 #endif
 348
 349     void broadcast()
 350     {
 351 #if __GTHREADS
 352       if (__gthread_active_p())
 353         {
 354           if (__gthread_cond_broadcast(&_M_cond) != 0)
 355             __throw_concurrence_broadcast_error();
 356         }
 357 #endif
 358     }
 359
 360     void wait(__mutex *mutex)
 361     {
 362 #if __GTHREADS
 363       {
 364           if (__gthread_cond_wait(&_M_cond, mutex->gthread_mutex()) != 0)
 365             __throw_concurrence_wait_error();
 366       }
 367 #endif
 368     }
 369
 370     void wait_recursive(__recursive_mutex *mutex)
 371     {
 372 #if __GTHREADS
 373       {
 374           if (__gthread_cond_wait_recursive(&_M_cond,
 375                                             mutex->gthread_recursive_mutex())
 376               != 0)
 377             __throw_concurrence_wait_error();
 378       }
 379 #endif
 380     }
 381   };
 382 #endif
 383
 384 _GLIBCXX_END_NAMESPACE
 385
 386 #endif