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//
// chat_server.cpp
// ~~~~~~~~~~~~~~~
//
// Copyright (c) 2003-2015 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 <cstdlib>
#include <deque>
#include <iostream>
#include <list>
#include <memory>
#include <set>
#include <utility>
#include <boost/asio.hpp>
#include "chat_message.hpp"
using boost::asio::ip::tcp;
//----------------------------------------------------------------------
typedef std::deque<chat_message> chat_message_queue;
//----------------------------------------------------------------------
class chat_participant
{
public:
virtual ~chat_participant() {}
virtual void deliver(const chat_message& msg) = 0;
};
typedef std::shared_ptr<chat_participant> chat_participant_ptr;
//----------------------------------------------------------------------
class chat_room
{
public:
void join(chat_participant_ptr participant)
{
participants_.insert(participant);
for (auto msg: recent_msgs_)
participant->deliver(msg);
}
void leave(chat_participant_ptr participant)
{
participants_.erase(participant);
}
void deliver(const chat_message& msg)
{
recent_msgs_.push_back(msg);
while (recent_msgs_.size() > max_recent_msgs)
recent_msgs_.pop_front();
for (auto participant: participants_)
participant->deliver(msg);
}
private:
std::set<chat_participant_ptr> participants_;
enum { max_recent_msgs = 100 };
chat_message_queue recent_msgs_;
};
//----------------------------------------------------------------------
class chat_session
: public chat_participant,
public std::enable_shared_from_this<chat_session>
{
public:
chat_session(tcp::socket socket, chat_room& room)
: socket_(std::move(socket)),
room_(room)
{
}
void start()
{
room_.join(shared_from_this());
do_read_header();
}
void deliver(const chat_message& msg)
{
bool write_in_progress = !write_msgs_.empty();
write_msgs_.push_back(msg);
if (!write_in_progress)
{
do_write();
}
}
private:
void do_read_header()
{
auto self(shared_from_this());
boost::asio::async_read(socket_,
boost::asio::buffer(read_msg_.data(), chat_message::header_length),
[this, self](boost::system::error_code ec, std::size_t /*length*/)
{
if (!ec && read_msg_.decode_header())
{
do_read_body();
}
else
{
room_.leave(shared_from_this());
}
});
}
void do_read_body()
{
auto self(shared_from_this());
boost::asio::async_read(socket_,
boost::asio::buffer(read_msg_.body(), read_msg_.body_length()),
[this, self](boost::system::error_code ec, std::size_t /*length*/)
{
if (!ec)
{
room_.deliver(read_msg_);
do_read_header();
}
else
{
room_.leave(shared_from_this());
}
});
}
void do_write()
{
auto self(shared_from_this());
boost::asio::async_write(socket_,
boost::asio::buffer(write_msgs_.front().data(),
write_msgs_.front().length()),
[this, self](boost::system::error_code ec, std::size_t /*length*/)
{
if (!ec)
{
write_msgs_.pop_front();
if (!write_msgs_.empty())
{
do_write();
}
}
else
{
room_.leave(shared_from_this());
}
});
}
tcp::socket socket_;
chat_room& room_;
chat_message read_msg_;
chat_message_queue write_msgs_;
};
//----------------------------------------------------------------------
class chat_server
{
public:
chat_server(boost::asio::io_service& io_service,
const tcp::endpoint& endpoint)
: acceptor_(io_service, endpoint),
socket_(io_service)
{
do_accept();
}
private:
void do_accept()
{
acceptor_.async_accept(socket_,
[this](boost::system::error_code ec)
{
if (!ec)
{
std::make_shared<chat_session>(std::move(socket_), room_)->start();
}
do_accept();
});
}
tcp::acceptor acceptor_;
tcp::socket socket_;
chat_room room_;
};
//----------------------------------------------------------------------
int main(int argc, char* argv[])
{
try
{
if (argc < 2)
{
std::cerr << "Usage: chat_server <port> [<port> ...]\n";
return 1;
}
boost::asio::io_service io_service;
std::list<chat_server> servers;
for (int i = 1; i < argc; ++i)
{
tcp::endpoint endpoint(tcp::v4(), std::atoi(argv[i]));
servers.emplace_back(io_service, endpoint);
}
io_service.run();
}
catch (std::exception& e)
{
std::cerr << "Exception: " << e.what() << "\n";
}
return 0;
}
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