1 //
2 // reference_counted.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.hpp>
12 #include <boost/bind/bind.hpp>
13 #include <boost/enable_shared_from_this.hpp>
14 #include <boost/shared_ptr.hpp>
15 #include <iostream>
16 #include <vector>
17
18 using boost::asio::ip::tcp;
19
20 // A reference-counted non-modifiable buffer class.
21 class shared_const_buffer
22 {
23 public:
24 // Construct from a std::string.
shared_const_buffer(const std::string & data)25 explicit shared_const_buffer(const std::string& data)
26 : data_(new std::vector<char>(data.begin(), data.end())),
27 buffer_(boost::asio::buffer(*data_))
28 {
29 }
30
31 // Implement the ConstBufferSequence requirements.
32 typedef boost::asio::const_buffer value_type;
33 typedef const boost::asio::const_buffer* const_iterator;
begin() const34 const boost::asio::const_buffer* begin() const { return &buffer_; }
end() const35 const boost::asio::const_buffer* end() const { return &buffer_ + 1; }
36
37 private:
38 boost::shared_ptr<std::vector<char> > data_;
39 boost::asio::const_buffer buffer_;
40 };
41
42 class session
43 : public boost::enable_shared_from_this<session>
44 {
45 public:
session(boost::asio::io_context & io_context)46 session(boost::asio::io_context& io_context)
47 : socket_(io_context)
48 {
49 }
50
socket()51 tcp::socket& socket()
52 {
53 return socket_;
54 }
55
start()56 void start()
57 {
58 using namespace std; // For time_t, time and ctime.
59 time_t now = time(0);
60 shared_const_buffer buffer(ctime(&now));
61 boost::asio::async_write(socket_, buffer,
62 boost::bind(&session::handle_write, shared_from_this()));
63 }
64
handle_write()65 void handle_write()
66 {
67 }
68
69 private:
70 // The socket used to communicate with the client.
71 tcp::socket socket_;
72 };
73
74 typedef boost::shared_ptr<session> session_ptr;
75
76 class server
77 {
78 public:
server(boost::asio::io_context & io_context,short port)79 server(boost::asio::io_context& io_context, short port)
80 : io_context_(io_context),
81 acceptor_(io_context, tcp::endpoint(tcp::v4(), port))
82 {
83 session_ptr new_session(new session(io_context_));
84 acceptor_.async_accept(new_session->socket(),
85 boost::bind(&server::handle_accept, this, new_session,
86 boost::asio::placeholders::error));
87 }
88
handle_accept(session_ptr new_session,const boost::system::error_code & error)89 void handle_accept(session_ptr new_session,
90 const boost::system::error_code& error)
91 {
92 if (!error)
93 {
94 new_session->start();
95 }
96
97 new_session.reset(new session(io_context_));
98 acceptor_.async_accept(new_session->socket(),
99 boost::bind(&server::handle_accept, this, new_session,
100 boost::asio::placeholders::error));
101 }
102
103 private:
104 boost::asio::io_context& io_context_;
105 tcp::acceptor acceptor_;
106 };
107
main(int argc,char * argv[])108 int main(int argc, char* argv[])
109 {
110 try
111 {
112 if (argc != 2)
113 {
114 std::cerr << "Usage: reference_counted <port>\n";
115 return 1;
116 }
117
118 boost::asio::io_context io_context;
119
120 using namespace std; // For atoi.
121 server s(io_context, atoi(argv[1]));
122
123 io_context.run();
124 }
125 catch (std::exception& e)
126 {
127 std::cerr << "Exception: " << e.what() << "\n";
128 }
129
130 return 0;
131 }
132