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

   1 //
   2 // echo_server_with_as_single_default.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/experimental/as_single.hpp>
  12 #include <boost/asio/co_spawn.hpp>
  13 #include <boost/asio/detached.hpp>
  14 #include <boost/asio/io_context.hpp>
  15 #include <boost/asio/ip/tcp.hpp>
  16 #include <boost/asio/signal_set.hpp>
  17 #include <boost/asio/write.hpp>
  18 #include <cstdio>
  19
  20 using boost::asio::experimental::as_single_t;
  21 using boost::asio::ip::tcp;
  22 using boost::asio::awaitable;
  23 using boost::asio::co_spawn;
  24 using boost::asio::detached;
  25 using boost::asio::use_awaitable_t;
  26 using default_token = as_single_t<use_awaitable_t<>>;
  27 using tcp_acceptor = default_token::as_default_on_t<tcp::acceptor>;
  28 using tcp_socket = default_token::as_default_on_t<tcp::socket>;
  29 namespace this_coro = boost::asio::this_coro;
  30
  31 awaitable<void> echo(tcp_socket socket)
  32 {
  33   char data[1024];
  34   for (;;)
  35   {
  36     auto [e1, nread] = co_await socket.async_read_some(boost::asio::buffer(data));
  37     if (nread == 0) break;
  38     auto [e2, nwritten] = co_await async_write(socket, boost::asio::buffer(data, nread));
  39     if (nwritten != nread) break;
  40   }
  41 }
  42
  43 awaitable<void> listener()
  44 {
  45   auto executor = co_await this_coro::executor;
  46   tcp_acceptor acceptor(executor, {tcp::v4(), 55555});
  47   for (;;)
  48   {
  49     if (auto [e, socket] = co_await acceptor.async_accept(); socket.is_open())
  50       co_spawn(executor, echo(std::move(socket)), detached);
  51   }
  52 }
  53
  54 int main()
  55 {
  56   try
  57   {
  58     boost::asio::io_context io_context(1);
  59
  60     boost::asio::signal_set signals(io_context, SIGINT, SIGTERM);
  61     signals.async_wait([&](auto, auto){ io_context.stop(); });
  62
  63     co_spawn(io_context, listener(), detached);
  64
  65     io_context.run();
  66   }
  67   catch (std::exception& e)
  68   {
  69     std::printf("Exception: %s\n", e.what());
  70   }
  71 }