libstdc++-v3/include/std/condition_variable

   1 // <condition_variable> -*- C++ -*-
   2
   3 // Copyright (C) 2008-2016 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 include/condition_variable
  26  *  This is a Standard C++ Library header.
  27  */
  28
  29 #ifndef _GLIBCXX_CONDITION_VARIABLE
  30 #define _GLIBCXX_CONDITION_VARIABLE 1
  31
  32 #pragma GCC system_header
  33
  34 #if __cplusplus < 201103L
  35 # include <bits/c++0x_warning.h>
  36 #else
  37
  38 #include <chrono>
  39 #include <bits/std_mutex.h>
  40 #include <ext/concurrence.h>
  41 #include <bits/alloc_traits.h>
  42 #include <bits/allocator.h>
  43 #include <bits/unique_ptr.h>
  44 #include <bits/shared_ptr.h>
  45 #include <bits/cxxabi_forced.h>
  46
  47 #if defined(_GLIBCXX_HAS_GTHREADS) && defined(_GLIBCXX_USE_C99_STDINT_TR1)
  48
  49 namespace std _GLIBCXX_VISIBILITY(default)
  50 {
  51 _GLIBCXX_BEGIN_NAMESPACE_VERSION
  52
  53   /**
  54    * @defgroup condition_variables Condition Variables
  55    * @ingroup concurrency
  56    *
  57    * Classes for condition_variable support.
  58    * @{
  59    */
  60
  61   /// cv_status
  62   enum class cv_status { no_timeout, timeout };
  63
  64   /// condition_variable
  65   class condition_variable
  66   {
  67     typedef chrono::system_clock        __clock_t;
  68     typedef __gthread_cond_t            __native_type;
  69
  70 #ifdef __GTHREAD_COND_INIT
  71     __native_type                       _M_cond = __GTHREAD_COND_INIT;
  72 #else
  73     __native_type                       _M_cond;
  74 #endif
  75
  76   public:
  77     typedef __native_type*              native_handle_type;
  78
  79     condition_variable() noexcept;
  80     ~condition_variable() noexcept;
  81
  82     condition_variable(const condition_variable&) = delete;
  83     condition_variable& operator=(const condition_variable&) = delete;
  84
  85     void
  86     notify_one() noexcept;
  87
  88     void
  89     notify_all() noexcept;
  90
  91     void
  92     wait(unique_lock<mutex>& __lock) noexcept;
  93
  94     template<typename _Predicate>
  95       void
  96       wait(unique_lock<mutex>& __lock, _Predicate __p)
  97       {
  98         while (!__p())
  99           wait(__lock);
 100       }
 101
 102     template<typename _Duration>
 103       cv_status
 104       wait_until(unique_lock<mutex>& __lock,
 105                  const chrono::time_point<__clock_t, _Duration>& __atime)
 106       { return __wait_until_impl(__lock, __atime); }
 107
 108     template<typename _Clock, typename _Duration>
 109       cv_status
 110       wait_until(unique_lock<mutex>& __lock,
 111                  const chrono::time_point<_Clock, _Duration>& __atime)
 112       {
 113         // DR 887 - Sync unknown clock to known clock.
 114         const typename _Clock::time_point __c_entry = _Clock::now();
 115         const __clock_t::time_point __s_entry = __clock_t::now();
 116         const auto __delta = __atime - __c_entry;
 117         const auto __s_atime = __s_entry + __delta;
 118
 119         return __wait_until_impl(__lock, __s_atime);
 120       }
 121
 122     template<typename _Clock, typename _Duration, typename _Predicate>
 123       bool
 124       wait_until(unique_lock<mutex>& __lock,
 125                  const chrono::time_point<_Clock, _Duration>& __atime,
 126                  _Predicate __p)
 127       {
 128         while (!__p())
 129           if (wait_until(__lock, __atime) == cv_status::timeout)
 130             return __p();
 131         return true;
 132       }
 133
 134     template<typename _Rep, typename _Period>
 135       cv_status
 136       wait_for(unique_lock<mutex>& __lock,
 137                const chrono::duration<_Rep, _Period>& __rtime)
 138       { return wait_until(__lock, __clock_t::now() + __rtime); }
 139
 140     template<typename _Rep, typename _Period, typename _Predicate>
 141       bool
 142       wait_for(unique_lock<mutex>& __lock,
 143                const chrono::duration<_Rep, _Period>& __rtime,
 144                _Predicate __p)
 145       { return wait_until(__lock, __clock_t::now() + __rtime, std::move(__p)); }
 146
 147     native_handle_type
 148     native_handle()
 149     { return &_M_cond; }
 150
 151   private:
 152     template<typename _Dur>
 153       cv_status
 154       __wait_until_impl(unique_lock<mutex>& __lock,
 155                         const chrono::time_point<__clock_t, _Dur>& __atime)
 156       {
 157         auto __s = chrono::time_point_cast<chrono::seconds>(__atime);
 158         auto __ns = chrono::duration_cast<chrono::nanoseconds>(__atime - __s);
 159
 160         __gthread_time_t __ts =
 161           {
 162             static_cast<std::time_t>(__s.time_since_epoch().count()),
 163             static_cast<long>(__ns.count())
 164           };
 165
 166         __gthread_cond_timedwait(&_M_cond, __lock.mutex()->native_handle(),
 167                                  &__ts);
 168
 169         return (__clock_t::now() < __atime
 170                 ? cv_status::no_timeout : cv_status::timeout);
 171       }
 172   };
 173
 174   void
 175   notify_all_at_thread_exit(condition_variable&, unique_lock<mutex>);
 176
 177   struct __at_thread_exit_elt
 178   {
 179     __at_thread_exit_elt* _M_next;
 180     void (*_M_cb)(void*);
 181   };
 182
 183   inline namespace _V2 {
 184
 185   /// condition_variable_any
 186   // Like above, but mutex is not required to have try_lock.
 187   class condition_variable_any
 188   {
 189     typedef chrono::system_clock        __clock_t;
 190     condition_variable                  _M_cond;
 191     shared_ptr<mutex>                   _M_mutex;
 192
 193     // scoped unlock - unlocks in ctor, re-locks in dtor
 194     template<typename _Lock>
 195       struct _Unlock
 196       {
 197         explicit _Unlock(_Lock& __lk) : _M_lock(__lk) { __lk.unlock(); }
 198
 199         ~_Unlock() noexcept(false)
 200         {
 201           if (uncaught_exception())
 202             {
 203               __try
 204               { _M_lock.lock(); }
 205               __catch(const __cxxabiv1::__forced_unwind&)
 206               { __throw_exception_again; }
 207               __catch(...)
 208               { }
 209             }
 210           else
 211             _M_lock.lock();
 212         }
 213
 214         _Unlock(const _Unlock&) = delete;
 215         _Unlock& operator=(const _Unlock&) = delete;
 216
 217         _Lock& _M_lock;
 218       };
 219
 220   public:
 221     condition_variable_any() : _M_mutex(std::make_shared<mutex>()) { }
 222     ~condition_variable_any() = default;
 223
 224     condition_variable_any(const condition_variable_any&) = delete;
 225     condition_variable_any& operator=(const condition_variable_any&) = delete;
 226
 227     void
 228     notify_one() noexcept
 229     {
 230       lock_guard<mutex> __lock(*_M_mutex);
 231       _M_cond.notify_one();
 232     }
 233
 234     void
 235     notify_all() noexcept
 236     {
 237       lock_guard<mutex> __lock(*_M_mutex);
 238       _M_cond.notify_all();
 239     }
 240
 241     template<typename _Lock>
 242       void
 243       wait(_Lock& __lock)
 244       {
 245         shared_ptr<mutex> __mutex = _M_mutex;
 246         unique_lock<mutex> __my_lock(*__mutex);
 247         _Unlock<_Lock> __unlock(__lock);
 248         // *__mutex must be unlocked before re-locking __lock so move
 249         // ownership of *__mutex lock to an object with shorter lifetime.
 250         unique_lock<mutex> __my_lock2(std::move(__my_lock));
 251         _M_cond.wait(__my_lock2);
 252       }
 253
 254
 255     template<typename _Lock, typename _Predicate>
 256       void
 257       wait(_Lock& __lock, _Predicate __p)
 258       {
 259         while (!__p())
 260           wait(__lock);
 261       }
 262
 263     template<typename _Lock, typename _Clock, typename _Duration>
 264       cv_status
 265       wait_until(_Lock& __lock,
 266                  const chrono::time_point<_Clock, _Duration>& __atime)
 267       {
 268         shared_ptr<mutex> __mutex = _M_mutex;
 269         unique_lock<mutex> __my_lock(*__mutex);
 270         _Unlock<_Lock> __unlock(__lock);
 271         // *__mutex must be unlocked before re-locking __lock so move
 272         // ownership of *__mutex lock to an object with shorter lifetime.
 273         unique_lock<mutex> __my_lock2(std::move(__my_lock));
 274         return _M_cond.wait_until(__my_lock2, __atime);
 275       }
 276
 277     template<typename _Lock, typename _Clock,
 278              typename _Duration, typename _Predicate>
 279       bool
 280       wait_until(_Lock& __lock,
 281                  const chrono::time_point<_Clock, _Duration>& __atime,
 282                  _Predicate __p)
 283       {
 284         while (!__p())
 285           if (wait_until(__lock, __atime) == cv_status::timeout)
 286             return __p();
 287         return true;
 288       }
 289
 290     template<typename _Lock, typename _Rep, typename _Period>
 291       cv_status
 292       wait_for(_Lock& __lock, const chrono::duration<_Rep, _Period>& __rtime)
 293       { return wait_until(__lock, __clock_t::now() + __rtime); }
 294
 295     template<typename _Lock, typename _Rep,
 296              typename _Period, typename _Predicate>
 297       bool
 298       wait_for(_Lock& __lock,
 299                const chrono::duration<_Rep, _Period>& __rtime, _Predicate __p)
 300       { return wait_until(__lock, __clock_t::now() + __rtime, std::move(__p)); }
 301   };
 302
 303   } // end inline namespace
 304
 305   // @} group condition_variables
 306 _GLIBCXX_END_NAMESPACE_VERSION
 307 } // namespace
 308
 309 #endif // _GLIBCXX_HAS_GTHREADS && _GLIBCXX_USE_C99_STDINT_TR1
 310
 311 #endif // C++11
 312
 313 #endif // _GLIBCXX_CONDITION_VARIABLE