database.h

/****************************************************************************
 *   Copyright (C) 2017-2018 Savoir-faire Linux                                  *
 *   Author: Nicolas Jäger <nicolas.jager@savoirfairelinux.com>             *
 *   Author: Sébastien Blin <sebastien.blin@savoirfairelinux.com>           *
 *   Author: Guillaume Roguez <guillaume.roguez@savoirfairelinux.com>       *
 *                                                                          *
 *   This library is free software; you can redistribute it and/or          *
 *   modify it under the terms of the GNU Lesser General Public             *
 *   License as published by the Free Software Foundation; either           *
 *   version 2.1 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      *
 *   Lesser General Public License for more details.                        *
 *                                                                          *
 *   You should have received a copy of the GNU General Public License      *
 *   along with this program.  If not, see <http://www.gnu.org/licenses/>.  *
 ***************************************************************************/
#pragma once

// Std
#include <memory>
#include <string>
#include <stdexcept>

// Qt
#include <qobject.h>
#include <QtSql/QSqlQuery>

namespace lrc
{

/**
  *  @brief Class that communicates with the database.
  *  @note not thread safe.
  */
class Database : public QObject {
    Q_OBJECT

public:
    /**
     * Create a database on the user system.
     * @exception QueryError database query error.
     */
    Database();

    ~Database();

    /**
     * A structure wich contains result(s) returned by a database query.
     */
    struct Result {
        int nbrOfCols = -1; ///< store the number of columns returned.
        /**
         * if nbrOfCols equals three and if the size of payloads equals six,
         * means two rows of data over three columns.
         */
        std::vector<std::string> payloads; ///< store the values.
    };

    /**
     * Generic database query exception.
     * details() returns more information, could be empty.
     */
    class QueryError : public std::runtime_error {
    public:
        explicit QueryError(const QSqlQuery& query);
        virtual std::string details() { return {}; }