1 //
2 // range_based_for.cpp
3 // ~~~~~~~~~~~~~~~~~~~
4 //
5 // Copyright (c) 2003-2020 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
25 class connection_iter
26 {
27 friend class connections;
28 tcp::acceptor* acceptor_ = nullptr;
29 tcp::socket socket_;
30
connection_iter(tcp::acceptor & a,tcp::socket s)31 connection_iter(tcp::acceptor& a, tcp::socket s)
32 : acceptor_(&a), socket_(std::move(s)) {}
33
34 public:
operator *()35 tcp::socket operator*()
36 {
37 return std::move(socket_);
38 }
39
operator ++()40 awaitable<void> operator++()
41 {
42 socket_ = co_await acceptor_->async_accept(use_awaitable);
43 }
44
operator ==(const connection_iter &) const45 bool operator==(const connection_iter&) const noexcept
46 {
47 return false;
48 }
49
operator !=(const connection_iter &) const50 bool operator!=(const connection_iter&) const noexcept
51 {
52 return true;
53 }
54 };
55
56 class connections
57 {
58 tcp::acceptor& acceptor_;
59
60 public:
connections(tcp::acceptor & a)61 explicit connections(tcp::acceptor& a) : acceptor_(a) {}
62
begin()63 awaitable<connection_iter> begin()
64 {
65 tcp::socket s = co_await acceptor_.async_accept(use_awaitable);
66 co_return connection_iter(acceptor_, std::move(s));
67 }
68
end()69 connection_iter end()
70 {
71 return connection_iter(acceptor_,
72 tcp::socket(acceptor_.get_executor()));
73 }
74 };
75
listener(tcp::acceptor acceptor)76 awaitable<void> listener(tcp::acceptor acceptor)
77 {
78 for co_await (tcp::socket s : connections(acceptor))
79 {
80 co_await boost::asio::async_write(s, boost::asio::buffer("hello\r\n", 7), use_awaitable);
81 }
82 }
83
main()84 int main()
85 {
86 try
87 {
88 boost::asio::io_context io_context(1);
89
90 boost::asio::signal_set signals(io_context, SIGINT, SIGTERM);
91 signals.async_wait([&](auto, auto){ io_context.stop(); });
92
93 tcp::acceptor acceptor(io_context, {tcp::v4(), 55555});
94 co_spawn(io_context, listener(std::move(acceptor)), detached);
95
96 io_context.run();
97 }
98 catch (std::exception& e)
99 {
100 std::printf("Exception: %s\n", e.what());
101 }
102 }
103