libstdc++-v3/src/c++11/future.cc

   1 // future -*- C++ -*-
   2
   3 // Copyright (C) 2009-2018 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 #include <future>
  26 #include <bits/functexcept.h>
  27
  28 namespace
  29 {
  30   struct future_error_category : public std::error_category
  31   {
  32     virtual const char*
  33     name() const noexcept
  34     { return "future"; }
  35
  36     _GLIBCXX_DEFAULT_ABI_TAG
  37     virtual std::string message(int __ec) const
  38     {
  39       std::string __msg;
  40       switch (std::future_errc(__ec))
  41       {
  42       case std::future_errc::broken_promise:
  43           __msg = "Broken promise";
  44           break;
  45       case std::future_errc::future_already_retrieved:
  46           __msg = "Future already retrieved";
  47           break;
  48       case std::future_errc::promise_already_satisfied:
  49           __msg = "Promise already satisfied";
  50           break;
  51       case std::future_errc::no_state:
  52           __msg = "No associated state";
  53           break;
  54       default:
  55           __msg = "Unknown error";
  56           break;
  57       }
  58       return __msg;
  59     }
  60   };
  61
  62   const future_error_category&
  63   __future_category_instance() noexcept
  64   {
  65     static const future_error_category __fec{};
  66     return __fec;
  67   }
  68 }
  69
  70 namespace std _GLIBCXX_VISIBILITY(default)
  71 {
  72 _GLIBCXX_BEGIN_NAMESPACE_VERSION
  73
  74   void
  75   __throw_future_error(int __i __attribute__((unused)))
  76   { _GLIBCXX_THROW_OR_ABORT(future_error(make_error_code(future_errc(__i)))); }
  77
  78   const error_category& future_category() noexcept
  79   { return __future_category_instance(); }
  80
  81   future_error::~future_error() noexcept { }
  82
  83   const char*
  84   future_error::what() const noexcept { return logic_error::what(); }
  85
  86 #ifdef _GLIBCXX_HAS_GTHREADS
  87   __future_base::_Result_base::_Result_base() = default;
  88
  89   __future_base::_Result_base::~_Result_base() = default;
  90
  91   void
  92   __future_base::_State_baseV2::_Make_ready::_S_run(void* p)
  93   {
  94     unique_ptr<_Make_ready> mr{static_cast<_Make_ready*>(p)};
  95     if (auto state = mr->_M_shared_state.lock())
  96       {
  97         // Use release MO to synchronize with observers of the ready state.
  98         state->_M_status._M_store_notify_all(_Status::__ready,
  99             memory_order_release);
 100       }
 101   }
 102
 103   // defined in src/c++11/condition_variable.cc
 104   extern void
 105   __at_thread_exit(__at_thread_exit_elt* elt);
 106
 107   void
 108   __future_base::_State_baseV2::_Make_ready::_M_set()
 109   {
 110     _M_cb = &_Make_ready::_S_run;
 111     __at_thread_exit(this);
 112   }
 113 #endif // _GLIBCXX_HAS_GTHREADS
 114
 115 _GLIBCXX_END_NAMESPACE_VERSION
 116 } // namespace std