hydra.src/hydra/Record.h

/*
 * Copyright (c) 2009 Aleksander B. Demko
 * This source code is distributed under the MIT license.
 * See the accompanying file LICENSE.MIT.txt for details.
 */

#ifndef __INCLUDED_HYDRA_RECORD_H__
#define __INCLUDED_HYDRA_RECORD_H__

#include <QDataStream>

namespace hydra
{
  class Record;
}

// forward, for the friendship thing
QDataStream & operator << (QDataStream & stream, const hydra::Record &rec);
QDataStream & operator >> (QDataStream & stream, hydra::Record &rec);

/**
 * Something that is saved/load from the db.
 *
 * @author Aleksander Demko
 */ 
class hydra::Record
{
  public:
    class Exception : public std::exception
    {
      public:
#ifdef HYDRA_ASSERT_RECORD_ERRORS
        Exception(void) { assert(false && "[Record::Exception thrown]\n"); }    // thrown during reads or writes
#endif
        virtual const char* what(void) const throw();
    };
    class IOException : public Exception { };       // raw IO error
    class FormatException : public Exception { };   // stream format error
    class VersionException : public Exception { };  // bad version of objects on stream

  public:
    virtual ~Record() { }

  protected:
    /// saver, throws exceptions on errors
    virtual void save(QDataStream &out) const = 0;
    /// loader, throws exceptions on errors
    virtual void load(QDataStream &in) = 0;

  private:
    friend QDataStream & ::operator << (QDataStream & stream, const hydra::Record &rec);
    friend QDataStream & ::operator >> (QDataStream & stream, hydra::Record &rec);
};

// now declare their bodies as theyre inline
inline QDataStream & operator << (QDataStream & stream, const hydra::Record &rec) { rec.save(stream); return stream; }
inline QDataStream & operator >> (QDataStream & stream, hydra::Record &rec) { rec.load(stream); return stream; }

#endif