libt2n: (gerd) some documentation improvement as preparation for release

[libt2n] / src / command_server.cpp

/***************************************************************************
 *   Copyright (C) 2006 by Gerd v. Egidy                                   *
 *   gve@intra2net.com                                                     *
 *                                                                         *
 *   This library is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU Lesser General Public License version   *
 *   2.1 as published by the Free Software Foundation.                     *
 *                                                                         *
 *   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 Lesser General Public License for more details.                   *
 *                                                                         *
 *   You should have received a copy of the GNU Lesser General Public      *
 *   License along with this program; if not, write to the                 *
 *   Free Software Foundation, Inc.,                                       *
 *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
 ***************************************************************************/

#include <string>
#include <sstream>
#include <stdexcept>
#include <iostream>

#include <boost/archive/binary_oarchive.hpp>
#include <boost/archive/binary_iarchive.hpp>
#include <boost/archive/xml_oarchive.hpp>
#include <boost/archive/xml_iarchive.hpp>
#include <boost/serialization/serialization.hpp>

#include <boost/bind.hpp>

#include "command_server.hxx"
#include "container.hxx"
#include "log.hxx"

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

using namespace std;

namespace libt2n
{

command_server::command_server(server& _s)
    : s(_s), guard_handle(0)
{
    // register callback
    s.add_callback(new_connection,bind(&command_server::send_hello, boost::ref(*this), _1));
}

/// send a hello message to a new connection
void command_server::send_hello(unsigned int conn_id)
{
    server_connection* sc=s.get_connection(conn_id);

    std::ostringstream hello;

    hello << "T2Nv" << PROTOCOL_VERSION << ';';

    int byteordercheck=1;
    hello.write((char*)&byteordercheck,sizeof(byteordercheck));

    hello << ';';

    sc->write(hello.str());
}

/// handle a command including deserialization and answering
void command_server::handle_packet(const std::string& packet, server_connection* conn)
{
    OBJLOGSTREAM(s,debug,"handling packet from connection " << conn->get_id());

    // deserialize packet
    std::istringstream ifs(packet);
    boost::archive::binary_iarchive ia(ifs);
    command_container ccont;
    result_container res;

    try
    {
        ia >> ccont;
    }
    catch(boost::archive::archive_exception &e)
    {
        std::ostringstream msg;
        msg << "archive_exception while deserializing on server-side, "
               "code " << e.code << " (" << e.what() << ")";
        res.set_exception(new t2n_serialization_error(msg.str()));
    }
    catch(...)
        { throw; }

    if (!res.has_exception())
    {
        std::ostream* ostr;
        if ((ostr=s.get_logstream(fulldebug))!=NULL)
        {
            (*ostr) << "decoded packet data: " << std::endl;
            boost::archive::xml_oarchive xo(*ostr);
            xo << BOOST_SERIALIZATION_NVP(ccont);
        }

        command* cmd=cast_command(ccont.get_command());

        if (cmd)
        {
            try
            {
                res.set_result((*cmd)());
            }
            catch (t2n_exception &e)
                { res.set_exception(e.clone()); }
            catch (...)
                { throw; }
        }
        else
        {
            std::ostringstream msg;
            if (ccont.get_command()!=NULL)
                msg << "illegal command of type " << typeid(ccont.get_command()).name() << " called";
            else
                msg << "NULL command called";
            res.set_exception(new t2n_command_error(msg.str()));
        }
    }

    std::ostringstream ofs;
    boost::archive::binary_oarchive oa(ofs);

    try
    {
        oa << res;
    }
    catch(boost::archive::archive_exception &e)
    {
        std::ostringstream msg;
        msg << "archive_exception while serializing on server-side, "
               "code " << e.code << " (" << e.what() << ")";
        res.set_exception(new t2n_serialization_error(msg.str()));
        oa << res;
    }
    catch(...)
        { throw; }

    std::ostream* ostr;
    if ((ostr=s.get_logstream(fulldebug))!=NULL)
    {
        (*ostr) << "returning result, decoded data: " << std::endl;
        boost::archive::xml_oarchive xo(*ostr);
        xo << BOOST_SERIALIZATION_NVP(res);
    }

    conn->write(ofs.str());
}

/** @brief handle incoming commands
    @param[in,out] usec_timeout wait until new data is found, max timeout usecs.
            -1: wait endless, 0: instant return
*/
void command_server::handle(long long usec_timeout, long long* usec_timeout_remaining)
{
    guard_handle++;
    try
    {
        if (s.fill_buffer(usec_timeout,usec_timeout_remaining))
        {
            std::string packet;
            unsigned int conn_id;

            while (s.get_packet(packet,conn_id))
            {
                server_connection* conn=s.get_connection(conn_id);
                if (!conn)
                    EXCEPTIONSTREAM(error,logic_error,"illegal connection id " << conn_id << " received");

                try
                    { handle_packet(packet,conn); }
                catch (t2n_transfer_error &e)
                {
                    // shut down a connection with transfer errors (usually write errors)
                    conn->close();
                }
                catch(...)
                    { throw; }
            }
        }
    }
    catch(...)
    {
        guard_handle--;
        throw;
    }
    guard_handle--;

    // don't call cleanup on re-entered handle-calls
    if (guard_handle == 0)
        s.cleanup();
}

}