ObjectFinder.h

/***************************************************************************
 *   Copyright (C) 2012 by Daniel Calviño Sánchez <danxuliu@gmail.com>     *
 *                                                                         *
 *   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.                                   *
 *                                                                         *
 *   This program 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 this program; If not, see <http://www.gnu.org/licenses/>.  *
 ***************************************************************************/

#ifndef KTUTORIAL_OBJECTFINDER_H
#define KTUTORIAL_OBJECTFINDER_H

#include <QtCore/QObject>
#include <QtCore/QRegExp>

#include "ktutorial_export.h"

namespace ktutorial {

class KTUTORIAL_EXPORT ObjectFinder: public QObject {
Q_OBJECT
public:
    
    explicit ObjectFinder(QObject* parent = 0);

    virtual ~ObjectFinder();

    template <typename T>
    T findObject(const QString& name, const QObject* baseObject) const {
        QList<T> candidateObjects;
        findObjects<T>(name, baseObject, candidateObjects);
        
        if (candidateObjects.isEmpty()) {
            return 0;
        }
        
        if (candidateObjects.count() == 1) {
            return candidateObjects.first();
        }
        
        return getBestMatch(name, candidateObjects);
    }

private:

    class ObjectFinderPrivate* d;

    template <typename T>
    void findObjects(const QString& name, const QObject* ancestor,
                     QList<T>& foundObjects) const {
        if (name.isEmpty() || ancestor == 0) {
            return;
        }

        if (name.indexOf('/') == -1) {
            foundObjects.append(ancestor->findChildren<T>(name));
            return;
        }

        QRegExp slashPattern("/+");
        QString ancestorName = name.left(name.indexOf(slashPattern));
        QString descendantName = name.mid(ancestorName.length() +
                                          slashPattern.matchedLength());

        QList<QObject*> namedAncestors =
                                ancestor->findChildren<QObject*>(ancestorName);
        foreach (QObject* namedAncestor, namedAncestors) {
            findObjects<T>(descendantName, namedAncestor, foundObjects);
        }
    }

    template <typename T>
    T getBestMatch(const QString& name, QList<T> candidateObjects) const {
        QList< QList<QObject*> > objectPaths = getObjectPaths(candidateObjects);
        
        QList<QObject*> bestMatches = getBestMatches(name, objectPaths);
        
        //Should not happen, but just in case
        if (bestMatches.isEmpty()) {
            return 0;
        }
        
        return static_cast<T>(bestMatches[0]);
    }

    template <typename T>
    QList< QList<QObject*> > getObjectPaths(const QList<T> objects) const {
        QList< QList<QObject*> > objectPaths;

        foreach (T candidateObject, objects) {
            QList<QObject*> objectPath;

            QObject* ancestor = candidateObject;
            while (ancestor) {
                objectPath.prepend(ancestor);
                ancestor = ancestor->parent();
            }

            objectPaths.append(objectPath);
        }

        return objectPaths;
    }

    QList<QObject*> getBestMatches(const QString& name,
                           QList< QList<QObject*> > objectPaths) const;

    QList< QList<QObject*> > filterObjectPaths(const QString& name,
                            const QList< QList<QObject*> >& objectPaths) const;

    QList< QList<QObject*> > filterDirectChildren(const QString& name,
                            const QList< QList<QObject*> >& objectPaths) const;

    QList< QList<QObject*> > filterNestedChildrenWithUnnamedAncestors(
        const QString& name, const QList< QList<QObject*> >& objectPaths) const;    

    QList< QList<QObject*> > filterNestedChildren(const QString& name,
                            const QList< QList<QObject*> >& objectPaths) const;

};

}

#endif