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#include "qmlgraphicsloader_p_p.h"

#include <qmlengine_p.h>

QT_BEGIN_NAMESPACE

QmlGraphicsLoaderPrivate::QmlGraphicsLoaderPrivate()
    : item(0), component(0), ownComponent(false)
    , resizeMode(QmlGraphicsLoader::SizeLoaderToItem)
{
}

QmlGraphicsLoaderPrivate::~QmlGraphicsLoaderPrivate()
{
}

void QmlGraphicsLoaderPrivate::clear()
{
    if (ownComponent) {
        delete component;
        component = 0;
        ownComponent = false;
    }
    source = QUrl();

    if (item) {
        // We can't delete immediately because our item may have triggered
        // the Loader to load a different item.
        item->setVisible(false);
        static_cast<QGraphicsItem*>(item)->setParentItem(0);
        item->deleteLater();
        item = 0;
    }
}

void QmlGraphicsLoaderPrivate::initResize()
{
    Q_Q(QmlGraphicsLoader);

    QmlGraphicsItem *resizeItem = 0;
    if (resizeMode == QmlGraphicsLoader::SizeLoaderToItem)
        resizeItem = item;
    else if (resizeMode == QmlGraphicsLoader::SizeItemToLoader)
        resizeItem = q;
    if (resizeItem) {
        QObject::connect(resizeItem, SIGNAL(widthChanged()), q, SLOT(_q_updateSize()));
        QObject::connect(resizeItem, SIGNAL(heightChanged()), q, SLOT(_q_updateSize()));
    }
    _q_updateSize();
}


QML_DEFINE_TYPE(Qt,4,6,Loader,QmlGraphicsLoader)

/*!
    \qmlclass Loader QmlGraphicsLoader
    \inherits Item

    \brief The Loader item allows dynamically loading an Item-based
    subtree from a QML URL or Component.

    Loader instantiates an item from a component. The component to
    instantiate may be specified directly by the \c sourceComponent
    property, or loaded from a URL via the \c source property.

    It is also an effective means of delaying the creation of a component
    until it is required:
    \code
    Loader { id: pageLoader }
    Rectangle {
        MouseRegion { anchors.fill: parent; onClicked: pageLoader.source = "Page1.qml" }
    }
    \endcode

    If the Loader source is changed, any previous items instantiated
    will be destroyed.  Setting \c source to an empty string
    will destroy the currently instantiated items, freeing resources
    and leaving the Loader empty.  For example:

    \code
    pageLoader.source = ""
    \endcode

    unloads "Page1.qml" and frees resources consumed by it.

    \sa {dynamic-object-creation}{Dynamic Object Creation}
*/

/*!
    \internal
    \class QmlGraphicsLoader
    \qmlclass Loader
 */

/*!
    Create a new QmlGraphicsLoader instance.
 */
QmlGraphicsLoader::QmlGraphicsLoader(QmlGraphicsItem *parent)
  : QmlGraphicsItem(*(new QmlGraphicsLoaderPrivate), parent)
{
}

/*!
    Destroy the loader instance.
 */
QmlGraphicsLoader::~QmlGraphicsLoader()
{
}

/*!
    \qmlproperty url Loader::source
    This property holds the URL of the QML component to
    instantiate.

    \sa sourceComponent, status, progress
*/
QUrl QmlGraphicsLoader::source() const
{
    Q_D(const QmlGraphicsLoader);
    return d->source;
}

void QmlGraphicsLoader::setSource(const QUrl &url)
{
    Q_D(QmlGraphicsLoader);
    if (d->source == url)
        return;

    d->clear();

    d->source = url;
    if (d->source.isEmpty()) {
        emit sourceChanged();
        emit statusChanged();
        emit progressChanged();
        emit itemChanged();
        return;
    }

    d->component = new QmlComponent(qmlEngine(this), d->source, this);
    d->ownComponent = true;
    if (!d->component->isLoading()) {
        d->_q_sourceLoaded();
    } else {
        connect(d->component, SIGNAL(statusChanged(QmlComponent::Status)),
                this, SLOT(_q_sourceLoaded()));
        connect(d->component, SIGNAL(progressChanged(qreal)),
                this, SIGNAL(progressChanged()));
        emit statusChanged();
        emit progressChanged();
        emit sourceChanged();
        emit itemChanged();
    }
}

/*!
    \qmlproperty Component Loader::sourceComponent
    The sourceComponent property holds the \l{Component} to instantiate.

    \qml
    Item {
        Component {
            id: redSquare
            Rectangle { color: "red"; width: 10; height: 10 }
        }

        Loader { sourceComponent: redSquare }
        Loader { sourceComponent: redSquare; x: 10 }
    }
    \endqml

    \sa source, progress
*/

QmlComponent *QmlGraphicsLoader::sourceComponent() const
{
    Q_D(const QmlGraphicsLoader);
    return d->component;
}

void QmlGraphicsLoader::setSourceComponent(QmlComponent *comp)
{
    Q_D(QmlGraphicsLoader);
    if (comp == d->component)
        return;

    d->clear();

    d->component = comp;
    d->ownComponent = false;
    if (!d->component) {
        emit sourceChanged();
        emit statusChanged();
        emit progressChanged();
        emit itemChanged();
        return;
    }

    if (!d->component->isLoading()) {
        d->_q_sourceLoaded();
    } else {
        connect(d->component, SIGNAL(statusChanged(QmlComponent::Status)),
                this, SLOT(_q_sourceLoaded()));
        connect(d->component, SIGNAL(progressChanged(qreal)),
                this, SIGNAL(progressChanged()));
        emit progressChanged();
        emit sourceChanged();
        emit statusChanged();
        emit itemChanged();
    }
}

void QmlGraphicsLoaderPrivate::_q_sourceLoaded()
{
    Q_Q(QmlGraphicsLoader);

    if (component) {
        QmlContext *ctxt = new QmlContext(qmlContext(q));
        ctxt->addDefaultObject(q);

        if (!component->errors().isEmpty()) {
            qWarning() << component->errors();
            emit q->sourceChanged();
            emit q->statusChanged();
            emit q->progressChanged();
            return;
        }

        QObject *obj = component->create(ctxt);
        if (obj) {
            ctxt->setParent(obj);
            item = qobject_cast<QmlGraphicsItem *>(obj);
            if (item) {
                item->setParentItem(q);
//                item->setFocus(true);
                initResize();
            }
        } else {
            delete obj;
            delete ctxt;
            source = QUrl();
        }
        emit q->sourceChanged();
        emit q->statusChanged();
        emit q->progressChanged();
        emit q->itemChanged();
    }
}

/*!
    \qmlproperty enum Loader::status

    This property holds the status of QML loading.  It can be one of:
    \list
    \o Null - no QML source has been set
    \o Ready - the QML source has been loaded
    \o Loading - the QML source is currently being loaded
    \o Error - an error occurred while loading the QML source
    \endlist

    \sa progress
*/

QmlGraphicsLoader::Status QmlGraphicsLoader::status() const
{
    Q_D(const QmlGraphicsLoader);

    if (d->component)
        return static_cast<QmlGraphicsLoader::Status>(d->component->status());

    if (d->item)
        return Ready;

    return d->source.isEmpty() ? Null : Error;
}

/*!
    \qmlproperty real Loader::progress

    This property holds the progress of QML data loading, from 0.0 (nothing loaded)
    to 1.0 (finished).

    \sa status
*/
qreal QmlGraphicsLoader::progress() const
{
    Q_D(const QmlGraphicsLoader);

    if (d->item)
        return 1.0;

    if (d->component)
        return d->component->progress();

    return 0.0;
}

/*!
    \qmlproperty enum Loader::resizeMode

    This property determines how the Loader or item are resized:
    \list
    \o NoResize - no item will be resized
    \o SizeLoaderToItem - the Loader will be sized to the size of the item, unless the size of the Loader has been otherwise specified.
    \o SizeItemToLoader - the item will be sized to the size of the Loader.
    \endlist

    The default resizeMode is SizeLoaderToItem.
*/
QmlGraphicsLoader::ResizeMode QmlGraphicsLoader::resizeMode() const
{
    Q_D(const QmlGraphicsLoader);
    return d->resizeMode;
}

void QmlGraphicsLoader::setResizeMode(ResizeMode mode)
{
    Q_D(QmlGraphicsLoader);
    if (mode == d->resizeMode)
        return;

    if (d->item) {
        QmlGraphicsItem *resizeItem = 0;
        if (d->resizeMode == SizeLoaderToItem)
            resizeItem = d->item;
        else if (d->resizeMode == SizeItemToLoader)
            resizeItem = this;
        if (resizeItem) {
            disconnect(resizeItem, SIGNAL(widthChanged()), this, SLOT(_q_updateSize()));
            disconnect(resizeItem, SIGNAL(heightChanged()), this, SLOT(_q_updateSize()));
        }
    }

    d->resizeMode = mode;
    d->initResize();
}

void QmlGraphicsLoaderPrivate::_q_updateSize()
{
    Q_Q(QmlGraphicsLoader);
    if (!item)
        return;
    switch (resizeMode) {
    case QmlGraphicsLoader::SizeLoaderToItem:
        q->setImplicitWidth(item->width());
        q->setImplicitHeight(item->height());
        break;
    case QmlGraphicsLoader::SizeItemToLoader:
        item->setWidth(q->width());
        item->setHeight(q->height());
        break;
    default:
        break;
    }
}

/*!
    \qmlproperty Item Loader::item
    This property holds the top-level item created from source.
*/
QmlGraphicsItem *QmlGraphicsLoader::item() const
{
    Q_D(const QmlGraphicsLoader);
    return d->item;
}

#include <moc_qmlgraphicsloader_p.cpp>

QT_END_NAMESPACE