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

   1 // Support for concurrent programing -*- C++ -*-
   2
   3 // Copyright (C) 2003-2020 Free Software Foundation, Inc.
   4 //
   5 // This file is part of the GNU ISO C++ Library.  This library is free
   6 // software; you can redistribute it and/or modify it under the
   7 // terms of the GNU General Public License as published by the
   8 // Free Software Foundation; either version 3, or (at your option)
   9 // any later version.
  10
  11 // This library is distributed in the hope that it will be useful,
  12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 // GNU General Public License for more details.
  15
  16 // Under Section 7 of GPL version 3, you are granted additional
  17 // permissions described in the GCC Runtime Library Exception, version
  18 // 3.1, as published by the Free Software Foundation.
  19
  20 // You should have received a copy of the GNU General Public License and
  21 // a copy of the GCC Runtime Library Exception along with this program;
  22 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  23 // <http://www.gnu.org/licenses/>.
  24
  25 /** @file ext/concurrence.h
  26  *  This file is a GNU extension to the Standard C++ Library.
  27  */
  28
  29 #ifndef _CONCURRENCE_H
  30 #define _CONCURRENCE_H 1
  31
  32 #pragma GCC system_header
  33
  34 #include <exception>
  35 #include <bits/gthr.h>
  36 #include <bits/functexcept.h>
  37 #include <bits/cpp_type_traits.h>
  38 #include <ext/type_traits.h>
  39
  40 namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
  41 {
  42 _GLIBCXX_BEGIN_NAMESPACE_VERSION
  43
  44   // Available locking policies:
  45   // _S_single    single-threaded code that doesn't need to be locked.
  46   // _S_mutex     multi-threaded code that requires additional support
  47   //              from gthr.h or abstraction layers in concurrence.h.
  48   // _S_atomic    multi-threaded code using atomic operations.
  49   enum _Lock_policy { _S_single, _S_mutex, _S_atomic };
  50
  51   // Compile time constant that indicates prefered locking policy in
  52   // the current configuration.
  53   static const _Lock_policy __default_lock_policy =
  54 #ifndef __GTHREADS
  55   _S_single;
  56 #elif defined _GLIBCXX_HAVE_ATOMIC_LOCK_POLICY
  57   _S_atomic;
  58 #else
  59   _S_mutex;
  60 #endif
  61
  62   // NB: As this is used in libsupc++, need to only depend on
  63   // exception. No stdexception classes, no use of std::string.
  64   class __concurrence_lock_error : public std::exception
  65   {
  66   public:
  67     virtual char const*
  68     what() const throw()
  69     { return "__gnu_cxx::__concurrence_lock_error"; }
  70   };
  71
  72   class __concurrence_unlock_error : public std::exception
  73   {
  74   public:
  75     virtual char const*
  76     what() const throw()
  77     { return "__gnu_cxx::__concurrence_unlock_error"; }
  78   };
  79
  80   class __concurrence_broadcast_error : public std::exception
  81   {
  82   public:
  83     virtual char const*
  84     what() const throw()
  85     { return "__gnu_cxx::__concurrence_broadcast_error"; }
  86   };
  87
  88   class __concurrence_wait_error : public std::exception
  89   {
  90   public:
  91     virtual char const*
  92     what() const throw()
  93     { return "__gnu_cxx::__concurrence_wait_error"; }
  94   };
  95
  96   // Substitute for concurrence_error object in the case of -fno-exceptions.
  97   inline void
  98   __throw_concurrence_lock_error()
  99   { _GLIBCXX_THROW_OR_ABORT(__concurrence_lock_error()); }
 100
 101   inline void
 102   __throw_concurrence_unlock_error()
 103   { _GLIBCXX_THROW_OR_ABORT(__concurrence_unlock_error()); }
 104
 105 #ifdef __GTHREAD_HAS_COND
 106   inline void
 107   __throw_concurrence_broadcast_error()
 108   { _GLIBCXX_THROW_OR_ABORT(__concurrence_broadcast_error()); }
 109
 110   inline void
 111   __throw_concurrence_wait_error()
 112   { _GLIBCXX_THROW_OR_ABORT(__concurrence_wait_error()); }
 113 #endif
 114
 115   class __mutex
 116   {
 117   private:
 118 #if __GTHREADS && defined __GTHREAD_MUTEX_INIT
 119     __gthread_mutex_t _M_mutex = __GTHREAD_MUTEX_INIT;
 120 #else
 121     __gthread_mutex_t _M_mutex;
 122 #endif
 123
 124     __mutex(const __mutex&);
 125     __mutex& operator=(const __mutex&);
 126
 127   public:
 128     __mutex()
 129     {
 130 #if __GTHREADS && ! defined __GTHREAD_MUTEX_INIT
 131       if (__gthread_active_p())
 132         __GTHREAD_MUTEX_INIT_FUNCTION(&_M_mutex);
 133 #endif
 134     }
 135
 136 #if __GTHREADS && ! defined __GTHREAD_MUTEX_INIT
 137     ~__mutex()
 138     {
 139       if (__gthread_active_p())
 140         __gthread_mutex_destroy(&_M_mutex);
 141     }
 142 #endif
 143
 144     void lock()
 145     {
 146 #if __GTHREADS
 147       if (__gthread_active_p())
 148         {
 149           if (__gthread_mutex_lock(&_M_mutex) != 0)
 150             __throw_concurrence_lock_error();
 151         }
 152 #endif
 153     }
 154
 155     void unlock()
 156     {
 157 #if __GTHREADS
 158       if (__gthread_active_p())
 159         {
 160           if (__gthread_mutex_unlock(&_M_mutex) != 0)
 161             __throw_concurrence_unlock_error();
 162         }
 163 #endif
 164     }
 165
 166     __gthread_mutex_t* gthread_mutex(void)
 167       { return &_M_mutex; }
 168   };
 169
 170   class __recursive_mutex
 171   {
 172   private:
 173 #if __GTHREADS && defined __GTHREAD_RECURSIVE_MUTEX_INIT
 174     __gthread_recursive_mutex_t _M_mutex = __GTHREAD_RECURSIVE_MUTEX_INIT;
 175 #else
 176     __gthread_recursive_mutex_t _M_mutex;
 177 #endif
 178
 179     __recursive_mutex(const __recursive_mutex&);
 180     __recursive_mutex& operator=(const __recursive_mutex&);
 181
 182   public:
 183     __recursive_mutex()
 184     {
 185 #if __GTHREADS && ! defined __GTHREAD_RECURSIVE_MUTEX_INIT
 186       if (__gthread_active_p())
 187         __GTHREAD_RECURSIVE_MUTEX_INIT_FUNCTION(&_M_mutex);
 188 #endif
 189     }
 190
 191 #if __GTHREADS && ! defined __GTHREAD_RECURSIVE_MUTEX_INIT
 192     ~__recursive_mutex()
 193     {
 194       if (__gthread_active_p())
 195         __gthread_recursive_mutex_destroy(&_M_mutex);
 196     }
 197 #endif
 198
 199     void lock()
 200     {
 201 #if __GTHREADS
 202       if (__gthread_active_p())
 203         {
 204           if (__gthread_recursive_mutex_lock(&_M_mutex) != 0)
 205             __throw_concurrence_lock_error();
 206         }
 207 #endif
 208     }
 209
 210     void unlock()
 211     {
 212 #if __GTHREADS
 213       if (__gthread_active_p())
 214         {
 215           if (__gthread_recursive_mutex_unlock(&_M_mutex) != 0)
 216             __throw_concurrence_unlock_error();
 217         }
 218 #endif
 219     }
 220
 221     __gthread_recursive_mutex_t* gthread_recursive_mutex(void)
 222     { return &_M_mutex; }
 223   };
 224
 225   /// Scoped lock idiom.
 226   // Acquire the mutex here with a constructor call, then release with
 227   // the destructor call in accordance with RAII style.
 228   class __scoped_lock
 229   {
 230   public:
 231     typedef __mutex __mutex_type;
 232
 233   private:
 234     __mutex_type& _M_device;
 235
 236     __scoped_lock(const __scoped_lock&);
 237     __scoped_lock& operator=(const __scoped_lock&);
 238
 239   public:
 240     explicit __scoped_lock(__mutex_type& __name) : _M_device(__name)
 241     { _M_device.lock(); }
 242
 243     ~__scoped_lock() throw()
 244     { _M_device.unlock(); }
 245   };
 246
 247 #ifdef __GTHREAD_HAS_COND
 248   class __cond
 249   {
 250   private:
 251 #if __GTHREADS && defined __GTHREAD_COND_INIT
 252     __gthread_cond_t _M_cond = __GTHREAD_COND_INIT;
 253 #else
 254     __gthread_cond_t _M_cond;
 255 #endif
 256
 257     __cond(const __cond&);
 258     __cond& operator=(const __cond&);
 259
 260   public:
 261     __cond()
 262     {
 263 #if __GTHREADS && ! defined __GTHREAD_COND_INIT
 264       if (__gthread_active_p())
 265         __GTHREAD_COND_INIT_FUNCTION(&_M_cond);
 266 #endif
 267     }
 268
 269 #if __GTHREADS && ! defined __GTHREAD_COND_INIT
 270     ~__cond()
 271     {
 272       if (__gthread_active_p())
 273         __gthread_cond_destroy(&_M_cond);
 274     }
 275 #endif
 276
 277     void broadcast()
 278     {
 279 #if __GTHREADS
 280       if (__gthread_active_p())
 281         {
 282           if (__gthread_cond_broadcast(&_M_cond) != 0)
 283             __throw_concurrence_broadcast_error();
 284         }
 285 #endif
 286     }
 287
 288     void wait(__mutex *mutex)
 289     {
 290 #if __GTHREADS
 291       {
 292           if (__gthread_cond_wait(&_M_cond, mutex->gthread_mutex()) != 0)
 293             __throw_concurrence_wait_error();
 294       }
 295 #endif
 296     }
 297
 298     void wait_recursive(__recursive_mutex *mutex)
 299     {
 300 #if __GTHREADS
 301       {
 302           if (__gthread_cond_wait_recursive(&_M_cond,
 303                                             mutex->gthread_recursive_mutex())
 304               != 0)
 305             __throw_concurrence_wait_error();
 306       }
 307 #endif
 308     }
 309   };
 310 #endif
 311
 312 _GLIBCXX_END_NAMESPACE_VERSION
 313 } // namespace
 314
 315 #endif