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

   1 // Support for concurrent programing -*- C++ -*-
   2
   3 // Copyright (C) 2003-2016 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 #ifdef __GTHREADS
  55 #if (defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_2) \
  56      && defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4))
  57   _S_atomic;
  58 #else
  59   _S_mutex;
  60 #endif
  61 #else
  62   _S_single;
  63 #endif
  64
  65   // NB: As this is used in libsupc++, need to only depend on
  66   // exception. No stdexception classes, no use of std::string.
  67   class __concurrence_lock_error : public std::exception
  68   {
  69   public:
  70     virtual char const*
  71     what() const throw()
  72     { return "__gnu_cxx::__concurrence_lock_error"; }
  73   };
  74
  75   class __concurrence_unlock_error : public std::exception
  76   {
  77   public:
  78     virtual char const*
  79     what() const throw()
  80     { return "__gnu_cxx::__concurrence_unlock_error"; }
  81   };
  82
  83   class __concurrence_broadcast_error : public std::exception
  84   {
  85   public:
  86     virtual char const*
  87     what() const throw()
  88     { return "__gnu_cxx::__concurrence_broadcast_error"; }
  89   };
  90
  91   class __concurrence_wait_error : public std::exception
  92   {
  93   public:
  94     virtual char const*
  95     what() const throw()
  96     { return "__gnu_cxx::__concurrence_wait_error"; }
  97   };
  98
  99   // Substitute for concurrence_error object in the case of -fno-exceptions.
 100   inline void
 101   __throw_concurrence_lock_error()
 102   { _GLIBCXX_THROW_OR_ABORT(__concurrence_lock_error()); }
 103
 104   inline void
 105   __throw_concurrence_unlock_error()
 106   { _GLIBCXX_THROW_OR_ABORT(__concurrence_unlock_error()); }
 107
 108 #ifdef __GTHREAD_HAS_COND
 109   inline void
 110   __throw_concurrence_broadcast_error()
 111   { _GLIBCXX_THROW_OR_ABORT(__concurrence_broadcast_error()); }
 112
 113   inline void
 114   __throw_concurrence_wait_error()
 115   { _GLIBCXX_THROW_OR_ABORT(__concurrence_wait_error()); }
 116 #endif
 117
 118   class __mutex
 119   {
 120   private:
 121 #if __GTHREADS && defined __GTHREAD_MUTEX_INIT
 122     __gthread_mutex_t _M_mutex = __GTHREAD_MUTEX_INIT;
 123 #else
 124     __gthread_mutex_t _M_mutex;
 125 #endif
 126
 127     __mutex(const __mutex&);
 128     __mutex& operator=(const __mutex&);
 129
 130   public:
 131     __mutex()
 132     {
 133 #if __GTHREADS && ! defined __GTHREAD_MUTEX_INIT
 134       if (__gthread_active_p())
 135         __GTHREAD_MUTEX_INIT_FUNCTION(&_M_mutex);
 136 #endif
 137     }
 138
 139 #if __GTHREADS && ! defined __GTHREAD_MUTEX_INIT
 140     ~__mutex()
 141     {
 142       if (__gthread_active_p())
 143         __gthread_mutex_destroy(&_M_mutex);
 144     }
 145 #endif
 146
 147     void lock()
 148     {
 149 #if __GTHREADS
 150       if (__gthread_active_p())
 151         {
 152           if (__gthread_mutex_lock(&_M_mutex) != 0)
 153             __throw_concurrence_lock_error();
 154         }
 155 #endif
 156     }
 157
 158     void unlock()
 159     {
 160 #if __GTHREADS
 161       if (__gthread_active_p())
 162         {
 163           if (__gthread_mutex_unlock(&_M_mutex) != 0)
 164             __throw_concurrence_unlock_error();
 165         }
 166 #endif
 167     }
 168
 169     __gthread_mutex_t* gthread_mutex(void)
 170       { return &_M_mutex; }
 171   };
 172
 173   class __recursive_mutex
 174   {
 175   private:
 176 #if __GTHREADS && defined __GTHREAD_RECURSIVE_MUTEX_INIT
 177     __gthread_recursive_mutex_t _M_mutex = __GTHREAD_RECURSIVE_MUTEX_INIT;
 178 #else
 179     __gthread_recursive_mutex_t _M_mutex;
 180 #endif
 181
 182     __recursive_mutex(const __recursive_mutex&);
 183     __recursive_mutex& operator=(const __recursive_mutex&);
 184
 185   public:
 186     __recursive_mutex()
 187     {
 188 #if __GTHREADS && ! defined __GTHREAD_RECURSIVE_MUTEX_INIT
 189       if (__gthread_active_p())
 190         __GTHREAD_RECURSIVE_MUTEX_INIT_FUNCTION(&_M_mutex);
 191 #endif
 192     }
 193
 194 #if __GTHREADS && ! defined __GTHREAD_RECURSIVE_MUTEX_INIT
 195     ~__recursive_mutex()
 196     {
 197       if (__gthread_active_p())
 198         __gthread_recursive_mutex_destroy(&_M_mutex);
 199     }
 200 #endif
 201
 202     void lock()
 203     {
 204 #if __GTHREADS
 205       if (__gthread_active_p())
 206         {
 207           if (__gthread_recursive_mutex_lock(&_M_mutex) != 0)
 208             __throw_concurrence_lock_error();
 209         }
 210 #endif
 211     }
 212
 213     void unlock()
 214     {
 215 #if __GTHREADS
 216       if (__gthread_active_p())
 217         {
 218           if (__gthread_recursive_mutex_unlock(&_M_mutex) != 0)
 219             __throw_concurrence_unlock_error();
 220         }
 221 #endif
 222     }
 223
 224     __gthread_recursive_mutex_t* gthread_recursive_mutex(void)
 225     { return &_M_mutex; }
 226   };
 227
 228   /// Scoped lock idiom.
 229   // Acquire the mutex here with a constructor call, then release with
 230   // the destructor call in accordance with RAII style.
 231   class __scoped_lock
 232   {
 233   public:
 234     typedef __mutex __mutex_type;
 235
 236   private:
 237     __mutex_type& _M_device;
 238
 239     __scoped_lock(const __scoped_lock&);
 240     __scoped_lock& operator=(const __scoped_lock&);
 241
 242   public:
 243     explicit __scoped_lock(__mutex_type& __name) : _M_device(__name)
 244     { _M_device.lock(); }
 245
 246     ~__scoped_lock() throw()
 247     { _M_device.unlock(); }
 248   };
 249
 250 #ifdef __GTHREAD_HAS_COND
 251   class __cond
 252   {
 253   private:
 254 #if __GTHREADS && defined __GTHREAD_COND_INIT
 255     __gthread_cond_t _M_cond = __GTHREAD_COND_INIT;
 256 #else
 257     __gthread_cond_t _M_cond;
 258 #endif
 259
 260     __cond(const __cond&);
 261     __cond& operator=(const __cond&);
 262
 263   public:
 264     __cond()
 265     {
 266 #if __GTHREADS && ! defined __GTHREAD_COND_INIT
 267       if (__gthread_active_p())
 268         __GTHREAD_COND_INIT_FUNCTION(&_M_cond);
 269 #endif
 270     }
 271
 272 #if __GTHREADS && ! defined __GTHREAD_COND_INIT
 273     ~__cond()
 274     {
 275       if (__gthread_active_p())
 276         __gthread_cond_destroy(&_M_cond);
 277     }
 278 #endif
 279
 280     void broadcast()
 281     {
 282 #if __GTHREADS
 283       if (__gthread_active_p())
 284         {
 285           if (__gthread_cond_broadcast(&_M_cond) != 0)
 286             __throw_concurrence_broadcast_error();
 287         }
 288 #endif
 289     }
 290
 291     void wait(__mutex *mutex)
 292     {
 293 #if __GTHREADS
 294       {
 295           if (__gthread_cond_wait(&_M_cond, mutex->gthread_mutex()) != 0)
 296             __throw_concurrence_wait_error();
 297       }
 298 #endif
 299     }
 300
 301     void wait_recursive(__recursive_mutex *mutex)
 302     {
 303 #if __GTHREADS
 304       {
 305           if (__gthread_cond_wait_recursive(&_M_cond,
 306                                             mutex->gthread_recursive_mutex())
 307               != 0)
 308             __throw_concurrence_wait_error();
 309       }
 310 #endif
 311     }
 312   };
 313 #endif
 314
 315 _GLIBCXX_END_NAMESPACE_VERSION
 316 } // namespace
 317
 318 #endif