AsyncAcceptor.hpp

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/***************************************************
 *       _   _            _                        *
 *      | | | |          (_)                       *
 *      | |_| | ___  _ __ _ _______  _ __          *
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 *      | | | | (_) | |  | |/ / (_) | | | |        *
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 ***************************************************
 * This file is part of Horizon (c).
 *
 * Copyright (c) 2019 Sagun K. (sagunxp@gmail.com).
 * Copyright (c) 2019 Horizon Dev Team.
 *
 * Base Author - Sagun K. (sagunxp@gmail.com)
 *
 * This library is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 * 
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this library.  If not, see <http://www.gnu.org/licenses/>.
 **************************************************/
 
#ifndef HORIZON_NETWORKING_ASYNCACCEPTOR_HPP
#define HORIZON_NETWORKING_ASYNCACCEPTOR_HPP
 
#include "Core/Logging/Logger.hpp"
 
#include <boost/asio.hpp>
#include <functional>
#include <iostream>
#include <atomic>
#include <memory>
#include <tuple>
 
using boost::asio::ip::tcp;
 
namespace Horizon
{
namespace Networking
{
class AsyncAcceptor
{
public:
    typedef std::function<void(std::shared_ptr<tcp::socket>, uint32_t thread_index)> AcceptCallback;
 
    ~AsyncAcceptor()
    {
        _acceptor.reset();
        _socket.reset();
    }
 
    AsyncAcceptor(boost::asio::io_context &io_context, std::string const &listen_ip, uint16_t port)
    : _endpoint(boost::asio::ip::address::from_string(listen_ip), port),
    _acceptor(std::make_shared<tcp::acceptor>(io_context, tcp::endpoint(boost::asio::ip::address::from_string(listen_ip), port))),
    _socket(std::make_shared<tcp::socket>(io_context)), _closed(false), _socket_factory(std::bind(&AsyncAcceptor::default_socket_factory, this))
    {
    }
 
    template <class T> void AsyncAccept();
 
    void async_accept_with_callback(AcceptCallback callback)
    {
        std::shared_ptr<tcp::socket> socket;
 
        uint32_t thread_index;
 
        std::tie(socket, thread_index) = _socket_factory();
 
        _acceptor->async_accept(*socket, [this, socket, callback, thread_index] (boost::system::error_code error)
            {
                if (!error) {
                    try {
                        socket->non_blocking(true);
                        callback(std::move(socket), thread_index);
                    } catch (boost::system::system_error const &err) {
                        HLog(error) << "Networking: AsyncAcceptor failed to initialize client's socket :" << err.what();
                    }
                }
 
                if (!_closed)
                    this->async_accept_with_callback(callback);
            });
    }
 
    bool bind()
    {
        boost::system::error_code errorCode;
 
        _acceptor->open(_endpoint.protocol(), errorCode);
 
        if (errorCode) {
            HLog(error) << "Failed to open acceptor " << errorCode.message().c_str();
            return false;
        }
 
        _acceptor->bind(_endpoint, errorCode);
 
        if (errorCode) {
            HLog(error) << "Could not bind to " << _endpoint.address().to_string().c_str() << ":" << _endpoint.port() << " - "
             << errorCode.message().c_str();
            return false;
        }
 
        _acceptor->listen(boost::asio::socket_base::max_connections, errorCode);
 
        if (errorCode) {
            HLog(error) << "Failed to start listening on " << _endpoint.address().to_string().c_str() << ":" << _endpoint.port() << " " << errorCode.message().c_str();
            return false;
        }
 
        return true;
    }
 
    void close()
    {
        if (_closed.exchange(true))
            return;
 
        _socket->close();
 
        boost::system::error_code error;
        _acceptor->close(error);
 
        _acceptor.reset();
        _socket.reset();
        if (error)
            HLog(error) << "Failed to close acceptor: " << error.message().c_str();
    }
 
    bool is_open() { return !_closed.load(); }
 
    void set_socket_factory(std::function<std::pair<std::shared_ptr<tcp::socket>, uint32_t>()> &&func) { _socket_factory = func; }
 
private:
    std::pair<std::shared_ptr<tcp::socket>, uint32_t> default_socket_factory() { return std::make_pair(_socket, 0); }
 
    tcp::endpoint _endpoint;
    std::shared_ptr<tcp::acceptor> _acceptor;
    std::shared_ptr<tcp::socket> _socket;
    std::atomic<bool> _closed;
    std::function<std::pair<std::shared_ptr<tcp::socket>, uint32_t>()> _socket_factory;
};
 
template <class T>
void AsyncAcceptor::AsyncAccept()
{
    _acceptor->async_accept(_socket, [this] (boost::system::error_code error)
       {
           if (!error) {
               try {
                   std::make_shared<T>(std::move(this->_socket))->start();
               } catch (boost::system::system_error const &err) {
                   std::cerr << "Network Error: failed to retrieve client's remote address " << err.what() << std::endl;
               }
           }
 
           if (!_closed)
               this->AsyncAccept<T>();
       });
}
}
}
 
#endif // HORIZON_NETWORKING_ASYNCACCEPTOR_HPP