annotate base/XmlExportable.h @ 168:04baa690f90d

* Start adding StorageAdviser class to determine whether caches should be
  on disc or in memory

/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */

/*
    Sonic Visualiser
    An audio file viewer and annotation editor.
    Centre for Digital Music, Queen Mary, University of London.
    This file copyright 2006 Chris Cannam.
    
    This program 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 2 of the
    License, or (at your option) any later version.  See the file
    COPYING included with this distribution for more information.
*/

#ifndef _XML_EXPORTABLE_H_
#define _XML_EXPORTABLE_H_

#include <QString>
#include <QColor>

class QTextStream;

class XmlExportable
{
public:
    virtual ~XmlExportable() { }

    /**
     * Stream this exportable object out to XML on a text stream.
     * 
     * The default implementation calls toXmlString and streams the
     * resulting string.  This is only appropriate for objects with
     * short representations.  Bigger objects should override this
     * method so as to write to the stream directly and override
     * toXmlString with a method that calls this one, so that the
     * direct streaming method can be used when appropriate.
     */
    virtual void toXml(QTextStream &stream,
                       QString indent = "",
                       QString extraAttributes = "") const;

    /**
     * Convert this exportable object to XML in a string.
     */
    virtual QString toXmlString(QString indent = "",
				QString extraAttributes = "") const = 0;

    static QString encodeEntities(QString);

    static QString encodeColour(QColor);

    static int getObjectExportId(const void *); // thread-safe
};

#endif