detail/impl/resolver_thread_pool.ipp

0001 //
0002 // detail/impl/resolver_thread_pool.ipp
0003 // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
0004 //
0005 // Copyright (c) 2003-2025 Christopher M. Kohlhoff (chris at kohlhoff dot com)
0006 //
0007 // Distributed under the Boost Software License, Version 1.0. (See accompanying
0008 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
0009 //
0010
0011 #ifndef BOOST_ASIO_DETAIL_IMPL_RESOLVER_THREAD_POOL_IPP
0012 #define BOOST_ASIO_DETAIL_IMPL_RESOLVER_THREAD_POOL_IPP
0013
0014 #if defined(_MSC_VER) && (_MSC_VER >= 1200)
0015 # pragma once
0016 #endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
0017
0018 #include <boost/asio/detail/config.hpp>
0019 #include <boost/asio/config.hpp>
0020 #include <boost/asio/detail/memory.hpp>
0021 #include <boost/asio/detail/resolver_thread_pool.hpp>
0022 #include <boost/asio/error.hpp>
0023
0024 #include <boost/asio/detail/push_options.hpp>
0025
0026 namespace boost {
0027 namespace asio {
0028 namespace detail {
0029
0030 class resolver_thread_pool::work_scheduler_runner
0031 {
0032 public:
0033   work_scheduler_runner(scheduler_impl& work_scheduler)
0034     : work_scheduler_(work_scheduler)
0035   {
0036   }
0037
0038   void operator()()
0039   {
0040     boost::system::error_code ec;
0041     work_scheduler_.run(ec);
0042   }
0043
0044 private:
0045   scheduler_impl& work_scheduler_;
0046 };
0047
0048 resolver_thread_pool::resolver_thread_pool(execution_context& context)
0049   : execution_context_service_base<resolver_thread_pool>(context),
0050     scheduler_(boost::asio::use_service<scheduler_impl>(context)),
0051     work_scheduler_(scheduler_impl::internal(), context),
0052     work_threads_(execution_context::allocator<void>(context)),
0053     num_work_threads_(config(context).get("resolver", "threads", 0U)),
0054     scheduler_locking_(config(context).get("scheduler", "locking", true)),
0055     shutdown_(false)
0056 {
0057   work_scheduler_.work_started();
0058   if (num_work_threads_ > 0)
0059     start_work_threads();
0060   else
0061     num_work_threads_ = 1;
0062 }
0063
0064 resolver_thread_pool::~resolver_thread_pool()
0065 {
0066   shutdown();
0067 }
0068
0069 void resolver_thread_pool::shutdown()
0070 {
0071   if (!shutdown_)
0072   {
0073     work_scheduler_.work_finished();
0074     work_scheduler_.stop();
0075     work_threads_.join();
0076     work_scheduler_.shutdown();
0077     shutdown_ = true;
0078   }
0079 }
0080
0081 void resolver_thread_pool::notify_fork(execution_context::fork_event fork_ev)
0082 {
0083   if (!work_threads_.empty())
0084   {
0085     if (fork_ev == execution_context::fork_prepare)
0086     {
0087       work_scheduler_.stop();
0088       work_threads_.join();
0089     }
0090   }
0091   else if (fork_ev != execution_context::fork_prepare)
0092   {
0093     work_scheduler_.restart();
0094   }
0095 }
0096
0097 void resolver_thread_pool::start_resolve_op(resolve_op* op)
0098 {
0099   if (scheduler_locking_)
0100   {
0101     start_work_threads();
0102     scheduler_.work_started();
0103     work_scheduler_.post_immediate_completion(op, false);
0104   }
0105   else
0106   {
0107     op->ec_ = boost::asio::error::operation_not_supported;
0108     scheduler_.post_immediate_completion(op, false);
0109   }
0110 }
0111
0112 void resolver_thread_pool::start_work_threads()
0113 {
0114   boost::asio::detail::mutex::scoped_lock lock(mutex_);
0115   if (work_threads_.empty())
0116     for (unsigned int i = 0; i < num_work_threads_; ++i)
0117       work_threads_.create_thread(work_scheduler_runner(work_scheduler_));
0118 }
0119
0120 } // namespace detail
0121 } // namespace asio
0122 } // namespace boost
0123
0124 #include <boost/asio/detail/pop_options.hpp>
0125
0126 #endif // BOOST_ASIO_DETAIL_IMPL_RESOLVER_THREAD_POOL_IPP