qobjectxmlmodel.cpp Example File

webkitwidgets/xmlpatterns/qobjectxmlmodel/qobjectxmlmodel.cpp
/****************************************************************************
**
** Copyright (C) 2015 The Qt Company Ltd.
** Contact: http://www.qt.io/licensing/
**
** This file is part of the examples of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:BSD$
** You may use this file under the terms of the BSD license as follows:
**
** "Redistribution and use in source and binary forms, with or without
** modification, are permitted provided that the following conditions are
** met:
**   * Redistributions of source code must retain the above copyright
**     notice, this list of conditions and the following disclaimer.
**   * Redistributions in binary form must reproduce the above copyright
**     notice, this list of conditions and the following disclaimer in
**     the documentation and/or other materials provided with the
**     distribution.
**   * Neither the name of The Qt Company Ltd nor the names of its
**     contributors may be used to endorse or promote products derived
**     from this software without specific prior written permission.
**
**
** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
**
** $QT_END_LICENSE$
**
****************************************************************************/

#include <QVector>
#include <QtDebug>

#include <QCoreApplication>
#include <QMetaProperty>
#include <QXmlQuery>
#include <QXmlResultItems>

#include "qobjectxmlmodel.h"

/*
<metaObjects>
    <metaObject className="QObject"/>
    <metaObject className="QWidget" superClass="QObject">
    </metaObject>
    ...
</metaObjects>
<QObject objectName="MyWidget" property1="..." property2="..."> <!-- This is root() -->
    <QObject objectName="MyFOO" property1="..."/>
    ....
</QObject>
*/

QObjectXmlModel::QObjectXmlModel(QObject *const object, const QXmlNamePool &np)
    : QSimpleXmlNodeModel(np),
      m_baseURI(QUrl::fromLocalFile(QCoreApplication::applicationFilePath())),
      m_root(object),
      m_allMetaObjects(allMetaObjects())
{
    Q_ASSERT(m_baseURI.isValid());
}

QXmlNodeModelIndex QObjectXmlModel::qObjectSibling(const int pos, const QXmlNodeModelIndex &n) const
{
    Q_ASSERT(pos == 1 || pos == -1);
    Q_ASSERT(asQObject(n));

    const QObject *parent = asQObject(n)->parent();
    if (parent) {
        const QList<QObject *> &children = parent->children();
        const int siblingPos = children.indexOf(asQObject(n)) + pos;

        if (siblingPos >= 0 && siblingPos < children.count())
            return createIndex(children.at(siblingPos));
        else
            return QXmlNodeModelIndex();
    }
    else
        return QXmlNodeModelIndex();
}

QObjectXmlModel::QObjectNodeType QObjectXmlModel::toNodeType(const QXmlNodeModelIndex &n)
{
    return QObjectNodeType(n.additionalData() & (15 << 26));
}

QObjectXmlModel::AllMetaObjects QObjectXmlModel::allMetaObjects() const
{
    QXmlQuery query(namePool());
    query.bindVariable("root", root());
    query.setQuery("declare variable $root external;"
                   "$root/descendant-or-self::QObject");
    Q_ASSERT(query.isValid());

    QXmlResultItems result;
    query.evaluateTo(&result);
    QXmlItem i(result.next());

    AllMetaObjects objects;
    while (!i.isNull()) {
        const QMetaObject *moo = asQObject(i.toNodeModelIndex())->metaObject();
        while (moo) {
            if (!objects.contains(moo))
                objects.append(moo);
            moo = moo->superClass();
        }
        i = result.next();
    }

    Q_ASSERT(!objects.contains(0));
    return objects;
}

QXmlNodeModelIndex QObjectXmlModel::metaObjectSibling(const int pos, const QXmlNodeModelIndex &n) const
{
    Q_ASSERT(pos == 1 || pos == -1);
    Q_ASSERT(!n.isNull());

    const int indexOf = m_allMetaObjects.indexOf(static_cast<const QMetaObject *>(n.internalPointer())) + pos;

    if (indexOf >= 0 && indexOf < m_allMetaObjects.count())
        return createIndex(const_cast<QMetaObject *>(m_allMetaObjects.at(indexOf)), MetaObject);
    else
        return QXmlNodeModelIndex();
}

QXmlNodeModelIndex QObjectXmlModel::nextFromSimpleAxis(SimpleAxis axis, const QXmlNodeModelIndex &n) const
{
    switch (toNodeType(n))
    {
        case IsQObject:
        {
            switch (axis)
            {
                case Parent:
                    return createIndex(asQObject(n)->parent());

                case FirstChild:
                {
                    if (!asQObject(n) || asQObject(n)->children().isEmpty())
                        return QXmlNodeModelIndex();
                    else
                        return createIndex(asQObject(n)->children().first());
                }

                case NextSibling:
                    return qObjectSibling(1, n);

                case PreviousSibling:
                {
                    if (asQObject(n) == m_root)
                        return createIndex(qint64(0), MetaObjects);
                    else
                        return qObjectSibling(-1, n);
                }
            }
            Q_ASSERT(false);
        }

        case QObjectClassName:
        case QObjectProperty:
        {
            Q_ASSERT(axis == Parent);
            return createIndex(asQObject(n));
        }

        case MetaObjects:
        {
            switch (axis)
            {
                case Parent:
                    return QXmlNodeModelIndex();
                case PreviousSibling:
                    return QXmlNodeModelIndex();
                case NextSibling:
                    return root();
                case FirstChild:
                {
                    return createIndex(const_cast<QMetaObject*>(m_allMetaObjects.first()),MetaObject);
                }
            }
            Q_ASSERT(false);
        }

        case MetaObject:
        {
            switch (axis)
            {
                case FirstChild:
                    return QXmlNodeModelIndex();
                case Parent:
                    return createIndex(qint64(0), MetaObjects);
                case PreviousSibling:
                    return metaObjectSibling(-1, n);
                case NextSibling:
                    return metaObjectSibling(1, n);
            }
        }

        case MetaObjectClassName:
        case MetaObjectSuperClass:
        {
            Q_ASSERT(axis == Parent);
            return createIndex(asQObject(n), MetaObject);
        }
    }

    Q_ASSERT(false);
    return QXmlNodeModelIndex();
}

QVector<QXmlNodeModelIndex> QObjectXmlModel::attributes(const QXmlNodeModelIndex& n) const
{
     QVector<QXmlNodeModelIndex> result;
     QObject *const object = asQObject(n);

     switch(toNodeType(n))
     {
        case IsQObject:
        {
            const QMetaObject *const metaObject = object->metaObject();
            const int count = metaObject->propertyCount();
            result.append(createIndex(object, QObjectClassName));

            for (int i = 0; i < count; ++i) {
                const QMetaProperty qmp(metaObject->property(i));
                const int ii = metaObject->indexOfProperty(qmp.name());
                if (i == ii)
                    result.append(createIndex(object, QObjectProperty | i));
            }
            return result;
        }

        case MetaObject:
        {
            result.append(createIndex(object, MetaObjectClassName));
            result.append(createIndex(object, MetaObjectSuperClass));
            return result;
        }
        default:
            return QVector<QXmlNodeModelIndex>();
     }
}

QObject *QObjectXmlModel::asQObject(const QXmlNodeModelIndex &n)
{
    return static_cast<QObject *>(n.internalPointer());
}

bool QObjectXmlModel::isProperty(const QXmlNodeModelIndex n)
{
    return n.additionalData() & QObjectProperty;
}

QUrl QObjectXmlModel::documentUri(const QXmlNodeModelIndex& ) const
{
    return m_baseURI;
}

QXmlNodeModelIndex::NodeKind QObjectXmlModel::kind(const QXmlNodeModelIndex& n) const
{
    switch (toNodeType(n))
    {
        case IsQObject:
        case MetaObject:
        case MetaObjects:
            return QXmlNodeModelIndex::Element;

        case QObjectProperty:
        case MetaObjectClassName:
        case MetaObjectSuperClass:
        case QObjectClassName:
            return QXmlNodeModelIndex::Attribute;
    }

    Q_ASSERT(false);
    return QXmlNodeModelIndex::Element;
}

QXmlNodeModelIndex::DocumentOrder QObjectXmlModel::compareOrder(const QXmlNodeModelIndex& , const QXmlNodeModelIndex& ) const
{
    return QXmlNodeModelIndex::Follows; // TODO
}

QXmlNodeModelIndex QObjectXmlModel::root() const
{
    return createIndex(m_root);
}

QXmlNodeModelIndex QObjectXmlModel::root(const QXmlNodeModelIndex& n) const
{
    QObject *p = asQObject(n);
    Q_ASSERT(p);

    do {
        QObject *const candidate = p->parent();
        if (candidate)
            p = candidate;
        else
            break;
    }
    while (true);

    return createIndex(p);
}

/*!
  We simply throw all of them into a QList and
  return an iterator over it.
 */
QXmlNodeModelIndex::List QObjectXmlModel::ancestors(const QXmlNodeModelIndex n) const
{
    const QObject *p = asQObject(n);
    Q_ASSERT(p);

    QXmlNodeModelIndex::List result;
    do {
        QObject *const candidate = p->parent();
        if (candidate) {
            result.append(createIndex(candidate, 0));
            p = candidate;
        }
        else
            break;
    }
    while (true);

    return result;
}

QMetaProperty QObjectXmlModel::toMetaProperty(const QXmlNodeModelIndex &n)
{
    const int propertyOffset = n.additionalData() & (~QObjectProperty);
    const QObject *const qo = asQObject(n);
    return qo->metaObject()->property(propertyOffset);
}

QXmlName QObjectXmlModel::name(const QXmlNodeModelIndex &n) const
{
    switch (toNodeType(n))
    {
        case IsQObject:
            return QXmlName(namePool(), QLatin1String("QObject"));
        case MetaObject:
            return QXmlName(namePool(), QLatin1String("metaObject"));
        case QObjectClassName:
        case MetaObjectClassName:
            return QXmlName(namePool(), QLatin1String("className"));
        case QObjectProperty:
            return QXmlName(namePool(), toMetaProperty(n).name());
        case MetaObjects:
            return QXmlName(namePool(), QLatin1String("metaObjects"));
        case MetaObjectSuperClass:
            return QXmlName(namePool(), QLatin1String("superClass"));
    }

    Q_ASSERT(false);
    return QXmlName();
}

QVariant QObjectXmlModel::typedValue(const QXmlNodeModelIndex &n) const
{
    switch (toNodeType(n))
    {
        case QObjectProperty:
        {
           const QVariant &candidate = toMetaProperty(n).read(asQObject(n));
           if (isTypeSupported(candidate.type()))
               return candidate;
           else
               return QVariant();
        }

        case MetaObjectClassName:
            return QVariant(static_cast<QMetaObject*>(n.internalPointer())->className());

        case MetaObjectSuperClass:
        {
            const QMetaObject *const superClass = static_cast<QMetaObject*>(n.internalPointer())->superClass();
            if (superClass)
                return QVariant(superClass->className());
            else
                return QVariant();
        }

        case QObjectClassName:
            return QVariant(asQObject(n)->metaObject()->className());

        default:
            return QVariant();
    }
}

/*!
 Returns \c true if QVariants of type \a type can be used
 in QtXmlPatterns, otherwise \c false.
 */
bool QObjectXmlModel::isTypeSupported(QVariant::Type type)
{
    /* See data/qatomicvalue.cpp too. */
    switch (type)
    {
        /* Fallthrough all these. */
        case QVariant::Char:
        case QVariant::String:
        case QVariant::Url:
        case QVariant::Bool:
        case QVariant::ByteArray:
        case QVariant::Int:
        case QVariant::LongLong:
        case QVariant::ULongLong:
        case QVariant::Date:
        case QVariant::DateTime:
        case QVariant::Time:
        case QVariant::Double:
            return true;
        default:
            return false;
    }
}

© 2016 The Qt Company Ltd. Documentation contributions included herein are the copyrights of their respective owners. The documentation provided herein is licensed under the terms of the GNU Free Documentation License version 1.3 as published by the Free Software Foundation. Qt and respective logos are trademarks of The Qt Company Ltd. in Finland and/or other countries worldwide. All other trademarks are property of their respective owners.