asio/example/cpp11/buffers/reference_counted.cpp
2019-03-07 16:18:56 +11:00

123 lines
2.5 KiB
C++

//
// reference_counted.cpp
// ~~~~~~~~~~~~~~~~~~~~~
//
// Copyright (c) 2003-2019 Christopher M. Kohlhoff (chris at kohlhoff dot com)
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
#include <boost/asio.hpp>
#include <iostream>
#include <memory>
#include <utility>
#include <vector>
#include <ctime>
using boost::asio::ip::tcp;
// A reference-counted non-modifiable buffer class.
class shared_const_buffer
{
public:
// Construct from a std::string.
explicit shared_const_buffer(const std::string& data)
: data_(new std::vector<char>(data.begin(), data.end())),
buffer_(boost::asio::buffer(*data_))
{
}
// Implement the ConstBufferSequence requirements.
typedef boost::asio::const_buffer value_type;
typedef const boost::asio::const_buffer* const_iterator;
const boost::asio::const_buffer* begin() const { return &buffer_; }
const boost::asio::const_buffer* end() const { return &buffer_ + 1; }
private:
std::shared_ptr<std::vector<char> > data_;
boost::asio::const_buffer buffer_;
};
class session
: public std::enable_shared_from_this<session>
{
public:
session(tcp::socket socket)
: socket_(std::move(socket))
{
}
void start()
{
do_write();
}
private:
void do_write()
{
std::time_t now = std::time(0);
shared_const_buffer buffer(std::ctime(&now));
auto self(shared_from_this());
boost::asio::async_write(socket_, buffer,
[self](boost::system::error_code /*ec*/, std::size_t /*length*/)
{
});
}
// The socket used to communicate with the client.
tcp::socket socket_;
};
class server
{
public:
server(boost::asio::io_context& io_context, short port)
: acceptor_(io_context, tcp::endpoint(tcp::v4(), port))
{
do_accept();
}
private:
void do_accept()
{
acceptor_.async_accept(
[this](boost::system::error_code ec, tcp::socket socket)
{
if (!ec)
{
std::make_shared<session>(std::move(socket))->start();
}
do_accept();
});
}
tcp::acceptor acceptor_;
};
int main(int argc, char* argv[])
{
try
{
if (argc != 2)
{
std::cerr << "Usage: reference_counted <port>\n";
return 1;
}
boost::asio::io_context io_context;
server s(io_context, std::atoi(argv[1]));
io_context.run();
}
catch (std::exception& e)
{
std::cerr << "Exception: " << e.what() << "\n";
}
return 0;
}