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#include "qfxkeyproxy.h"
#include <QGraphicsScene>
#include <QKeyEvent>

QT_BEGIN_NAMESPACE

QML_DEFINE_TYPE(Qt,4,6,(QT_VERSION&0x00ff00)>>8,KeyProxy,QFxKeyProxy)

/*!
    \qmlclass KeyProxy
    \brief The KeyProxy item proxies key events to a number of other items.
    \inherits Item

    KeyProxy provides a way to forward key presses, key releases, and keyboard input
    coming from input methods to other items. This can be useful when you want
    one item to handle some keys (e.g. the up and down arrow keys), and another item to
    handle other keys (e.g. the left and right arrow keys).

    To receive key events, the KeyProxy item must be in the current focus chain,
    just like any other item.

    KeyProxy is an invisible item: it is never painted.

    A simple KeyProxy that forward key events to two lists:
    \qml
    ListView { id: List1 ... }
    ListView { id: List2 ... }
    KeyProxy {
        focus: true
        targets: [List1, List2]
    }
    \endqml
*/

/*!
    \internal
    \class QFxKeyProxy
    \brief The QFxKeyProxy class proxies key events to a number of other items.
*/

class QFxKeyProxyPrivate
{
public:
    QFxKeyProxyPrivate() : inPress(false), inRelease(false), inIM(false), imeItem(0) {}
    QList<QFxItem *> targets;

    QGraphicsItem *finalFocusProxy(QGraphicsItem *item)
    {
        QGraphicsItem *fp;
        while ((fp = item->focusProxy()))
            item = fp;
        return item;
    }

    //loop detection
    bool inPress:1;
    bool inRelease:1;
    bool inIM:1;

    QGraphicsItem *imeItem;
};

QFxKeyProxy::QFxKeyProxy(QFxItem *parent)
: QFxItem(parent), d(new QFxKeyProxyPrivate)
{
    setFlag(QGraphicsItem::ItemAcceptsInputMethod);
}

QFxKeyProxy::~QFxKeyProxy()
{
    delete d; d = 0;
}

/*!
    \qmlproperty list<Item> KeyProxy::targets

    An ordered list of the items that will be forwarded key events.

    The events will be forwarded to the targets in turn until one of them
    accepts the event.
*/

QList<QFxItem *> *QFxKeyProxy::targets() const
{
    return &d->targets;
}

void QFxKeyProxy::keyPressEvent(QKeyEvent *e)
{
    if (!scene())
        return;
    if (!d->inPress) {
        d->inPress = true;
        for (int ii = 0; ii < d->targets.count(); ++ii) {
            QGraphicsItem *i = d->finalFocusProxy(d->targets.at(ii));
            if (i) {
                scene()->sendEvent(i, e);
                if (e->isAccepted()) {
                    d->inPress = false;
                    return;
                }
            }
        }
        d->inPress = false;
    }
}

void QFxKeyProxy::keyReleaseEvent(QKeyEvent *e)
{
    if (!scene())
        return;
    if (!d->inRelease) {
        d->inRelease = true;
        for (int ii = 0; ii < d->targets.count(); ++ii) {
            QGraphicsItem *i = d->finalFocusProxy(d->targets.at(ii));
            if (i) {
                scene()->sendEvent(i, e);
                if (e->isAccepted()) {
                    d->inRelease = false;
                    return;
                }
            }
        }
        d->inRelease = false;
    }
}

void QFxKeyProxy::inputMethodEvent(QInputMethodEvent *e)
{
    if (!scene())
        return;
    if (!d->inIM) {
        d->inIM = true;
        for (int ii = 0; ii < d->targets.count(); ++ii) {
            QGraphicsItem *i = d->finalFocusProxy(d->targets.at(ii));
            if (i && (i->flags() & ItemAcceptsInputMethod)) {
                scene()->sendEvent(i, e);
                if (e->isAccepted()) {
                    d->imeItem = i;
                    d->inIM = false;
                    return;
                }
            }
        }
        d->inIM = false;
    }
}

class QFxItemAccessor : public QGraphicsItem
{
public:
    QVariant doInputMethodQuery(Qt::InputMethodQuery query) const {
        return QGraphicsItem::inputMethodQuery(query);
    }
};

QVariant QFxKeyProxy::inputMethodQuery(Qt::InputMethodQuery query) const
{   
    for (int ii = 0; ii < d->targets.count(); ++ii) {
            QGraphicsItem *i = d->finalFocusProxy(d->targets.at(ii));
        if (i && (i->flags() & ItemAcceptsInputMethod) && i == d->imeItem) { //### how robust is i == d->imeItem check?
            QVariant v = static_cast<QFxItemAccessor *>(i)->doInputMethodQuery(query);
            if (v.type() == QVariant::RectF)
                v = mapRectFromItem(i, v.toRectF());  //### cost?
            return v;
        }
    }
    return QFxItem::inputMethodQuery(query);
}

QT_END_NAMESPACE