ceph/src/boost/libs/asio/example/cpp03/http/server2/io_context_pool.cpp

   1 //
   2 // io_context_pool.cpp
   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 #include "server.hpp"
  12 #include <stdexcept>
  13 #include <boost/thread/thread.hpp>
  14 #include <boost/bind/bind.hpp>
  15 #include <boost/shared_ptr.hpp>
  16
  17 namespace http {
  18 namespace server2 {
  19
  20 io_context_pool::io_context_pool(std::size_t pool_size)
  21   : next_io_context_(0)
  22 {
  23   if (pool_size == 0)
  24     throw std::runtime_error("io_context_pool size is 0");
  25
  26   // Give all the io_contexts work to do so that their run() functions will not
  27   // exit until they are explicitly stopped.
  28   for (std::size_t i = 0; i < pool_size; ++i)
  29   {
  30     io_context_ptr io_context(new boost::asio::io_context);
  31     io_contexts_.push_back(io_context);
  32     work_.push_back(boost::asio::make_work_guard(*io_context));
  33   }
  34 }
  35
  36 void io_context_pool::run()
  37 {
  38   // Create a pool of threads to run all of the io_contexts.
  39   std::vector<boost::shared_ptr<boost::thread> > threads;
  40   for (std::size_t i = 0; i < io_contexts_.size(); ++i)
  41   {
  42     boost::shared_ptr<boost::thread> thread(new boost::thread(
  43           boost::bind(&boost::asio::io_context::run, io_contexts_[i])));
  44     threads.push_back(thread);
  45   }
  46
  47   // Wait for all threads in the pool to exit.
  48   for (std::size_t i = 0; i < threads.size(); ++i)
  49     threads[i]->join();
  50 }
  51
  52 void io_context_pool::stop()
  53 {
  54   // Explicitly stop all io_contexts.
  55   for (std::size_t i = 0; i < io_contexts_.size(); ++i)
  56     io_contexts_[i]->stop();
  57 }
  58
  59 boost::asio::io_context& io_context_pool::get_io_context()
  60 {
  61   // Use a round-robin scheme to choose the next io_context to use.
  62   boost::asio::io_context& io_context = *io_contexts_[next_io_context_];
  63   ++next_io_context_;
  64   if (next_io_context_ == io_contexts_.size())
  65     next_io_context_ = 0;
  66   return io_context;
  67 }
  68
  69 } // namespace server2
  70 } // namespace http