ceph/src/boost/libs/asio/example/cpp17/coroutines_ts/refactored_echo_server.cpp

   1 //
   2 // refactored_echo_server.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 <boost/asio/co_spawn.hpp>
  12 #include <boost/asio/detached.hpp>
  13 #include <boost/asio/io_context.hpp>
  14 #include <boost/asio/ip/tcp.hpp>
  15 #include <boost/asio/signal_set.hpp>
  16 #include <boost/asio/write.hpp>
  17 #include <cstdio>
  18
  19 using boost::asio::ip::tcp;
  20 using boost::asio::awaitable;
  21 using boost::asio::co_spawn;
  22 using boost::asio::detached;
  23 using boost::asio::use_awaitable;
  24 namespace this_coro = boost::asio::this_coro;
  25
  26 awaitable<void> echo_once(tcp::socket& socket)
  27 {
  28   char data[128];
  29   std::size_t n = co_await socket.async_read_some(boost::asio::buffer(data), use_awaitable);
  30   co_await async_write(socket, boost::asio::buffer(data, n), use_awaitable);
  31 }
  32
  33 awaitable<void> echo(tcp::socket socket)
  34 {
  35   try
  36   {
  37     for (;;)
  38     {
  39       // The asynchronous operations to echo a single chunk of data have been
  40       // refactored into a separate function. When this function is called, the
  41       // operations are still performed in the context of the current
  42       // coroutine, and the behaviour is functionally equivalent.
  43       co_await echo_once(socket);
  44     }
  45   }
  46   catch (std::exception& e)
  47   {
  48     std::printf("echo Exception: %s\n", e.what());
  49   }
  50 }
  51
  52 awaitable<void> listener()
  53 {
  54   auto executor = co_await this_coro::executor;
  55   tcp::acceptor acceptor(executor, {tcp::v4(), 55555});
  56   for (;;)
  57   {
  58     tcp::socket socket = co_await acceptor.async_accept(use_awaitable);
  59     co_spawn(executor, echo(std::move(socket)), detached);
  60   }
  61 }
  62
  63 int main()
  64 {
  65   try
  66   {
  67     boost::asio::io_context io_context(1);
  68
  69     boost::asio::signal_set signals(io_context, SIGINT, SIGTERM);
  70     signals.async_wait([&](auto, auto){ io_context.stop(); });
  71
  72     co_spawn(io_context, listener(), detached);
  73
  74     io_context.run();
  75   }
  76   catch (std::exception& e)
  77   {
  78     std::printf("Exception: %s\n", e.what());
  79   }
  80 }