ceph/src/boost/boost/asio/impl/thread_pool.ipp

   1 //
   2 // impl/thread_pool.ipp
   3 // ~~~~~~~~~~~~~~~~~~~~
   4 //
   5 // Copyright (c) 2003-2022 Christopher M. Kohlhoff (chris at kohlhoff dot com)
   6 //
   7 // Distributed under the Boost Software License, Version 1.0. (See accompanying
   8 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   9 //
  10
  11 #ifndef BOOST_ASIO_IMPL_THREAD_POOL_IPP
  12 #define BOOST_ASIO_IMPL_THREAD_POOL_IPP
  13
  14 #if defined(_MSC_VER) && (_MSC_VER >= 1200)
  15 # pragma once
  16 #endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
  17
  18 #include <boost/asio/detail/config.hpp>
  19 #include <stdexcept>
  20 #include <boost/asio/thread_pool.hpp>
  21 #include <boost/asio/detail/throw_exception.hpp>
  22
  23 #include <boost/asio/detail/push_options.hpp>
  24
  25 namespace boost {
  26 namespace asio {
  27
  28 struct thread_pool::thread_function
  29 {
  30   detail::scheduler* scheduler_;
  31
  32   void operator()()
  33   {
  34 #if !defined(BOOST_ASIO_NO_EXCEPTIONS)
  35     try
  36     {
  37 #endif// !defined(BOOST_ASIO_NO_EXCEPTIONS)
  38       boost::system::error_code ec;
  39       scheduler_->run(ec);
  40 #if !defined(BOOST_ASIO_NO_EXCEPTIONS)
  41     }
  42     catch (...)
  43     {
  44       std::terminate();
  45     }
  46 #endif// !defined(BOOST_ASIO_NO_EXCEPTIONS)
  47   }
  48 };
  49
  50 #if !defined(BOOST_ASIO_NO_TS_EXECUTORS)
  51 namespace detail {
  52
  53 inline long default_thread_pool_size()
  54 {
  55   std::size_t num_threads = thread::hardware_concurrency() * 2;
  56   num_threads = num_threads == 0 ? 2 : num_threads;
  57   return static_cast<long>(num_threads);
  58 }
  59
  60 } // namespace detail
  61
  62 thread_pool::thread_pool()
  63   : scheduler_(add_scheduler(new detail::scheduler(*this, 0, false))),
  64     num_threads_(detail::default_thread_pool_size())
  65 {
  66   scheduler_.work_started();
  67
  68   thread_function f = { &scheduler_ };
  69   threads_.create_threads(f, static_cast<std::size_t>(num_threads_));
  70 }
  71 #endif // !defined(BOOST_ASIO_NO_TS_EXECUTORS)
  72
  73 namespace detail {
  74
  75 inline long clamp_thread_pool_size(std::size_t n)
  76 {
  77   if (n > 0x7FFFFFFF)
  78   {
  79     std::out_of_range ex("thread pool size");
  80     boost::asio::detail::throw_exception(ex);
  81   }
  82   return static_cast<long>(n & 0x7FFFFFFF);
  83 }
  84
  85 } // namespace detail
  86
  87 thread_pool::thread_pool(std::size_t num_threads)
  88   : scheduler_(add_scheduler(new detail::scheduler(
  89           *this, num_threads == 1 ? 1 : 0, false))),
  90     num_threads_(detail::clamp_thread_pool_size(num_threads))
  91 {
  92   scheduler_.work_started();
  93
  94   thread_function f = { &scheduler_ };
  95   threads_.create_threads(f, static_cast<std::size_t>(num_threads_));
  96 }
  97
  98 thread_pool::~thread_pool()
  99 {
 100   stop();
 101   join();
 102 }
 103
 104 void thread_pool::stop()
 105 {
 106   scheduler_.stop();
 107 }
 108
 109 void thread_pool::attach()
 110 {
 111   ++num_threads_;
 112   thread_function f = { &scheduler_ };
 113   f();
 114 }
 115
 116 void thread_pool::join()
 117 {
 118   if (!threads_.empty())
 119   {
 120     scheduler_.work_finished();
 121     threads_.join();
 122   }
 123 }
 124
 125 detail::scheduler& thread_pool::add_scheduler(detail::scheduler* s)
 126 {
 127   detail::scoped_ptr<detail::scheduler> scoped_impl(s);
 128   boost::asio::add_service<detail::scheduler>(*this, scoped_impl.get());
 129   return *scoped_impl.release();
 130 }
 131
 132 void thread_pool::wait()
 133 {
 134   scheduler_.work_finished();
 135   threads_.join();
 136 }
 137
 138 } // namespace asio
 139 } // namespace boost
 140
 141 #include <boost/asio/detail/pop_options.hpp>
 142
 143 #endif // BOOST_ASIO_IMPL_THREAD_POOL_IPP