root/db/db_reader.hh

/*  This file is part of Alue, the multiprotocol Internet discussion daemon

    Copyright © 2010 Antti-Juhani Kaijanaho

    Alue 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.

    Alue 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 Alue.  If not, see <http://www.gnu.org/licenses/>.

 */

#ifndef GUARD_DB_DB_READER_HH
#define GUARD_DB_DB_READER_HH

#include "illformed_db.hh"
#include "../util.hh"

#include <boost/noncopyable.hpp>
#include <iostream>

namespace db
{
        class rollback {};

        class db_reader : public boost::noncopyable
        {
                std::istream &dbfile;
                boost::scoped_ptr<std::string> line_pushed_back;
                void prim_readline(std::string &line) {
                        if (line_pushed_back)
                        {
                                line = *line_pushed_back;
                                line_pushed_back.reset();
                        }
                        else
                                std::getline(dbfile, line);
                }
        public:
                db_reader(std::istream &is) : dbfile(is) {}
                void readline(std::string &line) {
                        prim_readline(line);
                        if (line.substr(0, 7) == ".BEGIN ") throw rollback();
                }
                void pushback_line(std::string line) {
                        BOOST_ASSERT(!line_pushed_back);
                        line_pushed_back.reset(new std::string(line));
                }

                std::string readline(std::string &line, std::string cmd){
                        readline(line);
                        util::strip(line);
                        if (line.substr(0, cmd.length()+1) != cmd + " ")
                                throw illformed_db(cmd + " missing");
                        return line.substr(cmd.length()+1);
                }

                void endrec(std::string &line) {
                        prim_readline(line);
                        if (!dbfile || line.substr(0, 7) == ".BEGIN ") 
                                throw rollback();
                        util::strip(line);
                        if (line != ".END") throw illformed_db(".END missing");
                }
                bool valid() { return dbfile; }
        };
}

#endif /* GUARD_DB_DB_READER_HH */