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#ifndef QQUICKPOINTERHANDLER_H
#define QQUICKPOINTERHANDLER_H

//
//  W A R N I N G
//  -------------
//
// This file is not part of the Qt API.  It exists purely as an
// implementation detail.  This header file may change from version to
// version without notice, or even be removed.
//
// We mean it.
//

#include "qevent.h"

#include <QtQuick/private/qquickevents_p_p.h>
#include <QtQuick/private/qquickitem_p.h>

QT_BEGIN_NAMESPACE

Q_DECLARE_LOGGING_CATEGORY(lcPointerHandlerDispatch)

class Q_QUICK_PRIVATE_EXPORT QQuickPointerHandler : public QObject
{
    Q_OBJECT
    Q_PROPERTY(bool enabled READ enabled WRITE setEnabled NOTIFY enabledChanged)
    Q_PROPERTY(bool active READ active NOTIFY activeChanged)
    Q_PROPERTY(QQuickItem * target READ target WRITE setTarget NOTIFY targetChanged)
    Q_PROPERTY(QQuickItem * parent READ parentItem CONSTANT)
    Q_PROPERTY(GrabPermissions grabPermissions READ grabPermissions WRITE setGrabPermissions NOTIFY grabPermissionChanged)

public:
    explicit QQuickPointerHandler(QObject *parent = 0);
    virtual ~QQuickPointerHandler();

    enum GrabPermission {
        TakeOverForbidden = 0x0,
        CanTakeOverFromHandlersOfSameType = 0x01,
        CanTakeOverFromHandlersOfDifferentType= 0x02,
        CanTakeOverFromItems = 0x04,
        CanTakeOverFromAnything = 0x0F,
        ApprovesTakeOverByHandlersOfSameType = 0x10,
        ApprovesTakeOverByHandlersOfDifferentType= 0x20,
        ApprovesTakeOverByItems = 0x40,
        ApprovesCancellation = 0x80,
        ApprovesTakeOverByAnything = 0xF0
    };
    Q_DECLARE_FLAGS(GrabPermissions, GrabPermission)
    Q_FLAG(GrabPermissions)

public:
    bool enabled() const { return m_enabled; }
    void setEnabled(bool enabled);

    bool active() const { return m_active; }

    QQuickItem *target() const;
    void setTarget(QQuickItem *target);

    QQuickItem * parentItem() const { return static_cast<QQuickItem *>(QObject::parent()); }

    void handlePointerEvent(QQuickPointerEvent *event);

    GrabPermissions grabPermissions() const { return static_cast<GrabPermissions>(m_grabPermissions); }
    void setGrabPermissions(GrabPermissions grabPermissions);

Q_SIGNALS:
    void enabledChanged();
    void activeChanged();
    void targetChanged();
    void grabChanged(QQuickEventPoint *point);
    void grabPermissionChanged();
    void canceled(QQuickEventPoint *point);

protected:
    QQuickPointerEvent *currentEvent() { return m_currentEvent; }
    virtual bool wantsPointerEvent(QQuickPointerEvent *event);
    virtual void handlePointerEventImpl(QQuickPointerEvent *event);
    void setActive(bool active);
    virtual void onActiveChanged() { }
    virtual void onGrabChanged(QQuickPointerHandler *grabber, QQuickEventPoint::GrabState stateChange, QQuickEventPoint *point);
    virtual bool canGrab(QQuickEventPoint *point);
    virtual bool approveGrabTransition(QQuickEventPoint *point, QObject *proposedGrabber);
    void setPassiveGrab(QQuickEventPoint *point, bool grab = true);
    bool setExclusiveGrab(QQuickEventPoint *point, bool grab = true);
    void cancelAllGrabs(QQuickEventPoint *point);
    QPointF eventPos(const QQuickEventPoint *point) const;
    bool parentContains(const QQuickEventPoint *point) const;

private:
    QQuickPointerEvent *m_currentEvent;
    QQuickItem *m_target;
    bool m_enabled : 1;
    bool m_active : 1;
    bool m_targetExplicitlySet : 1;
    bool m_hadKeepMouseGrab : 1;    // some handlers override target()->setKeepMouseGrab(); this remembers previous state
    bool m_hadKeepTouchGrab : 1;    // some handlers override target()->setKeepTouchGrab(); this remembers previous state
    uint m_reserved : 19;
    uint8_t m_grabPermissions : 8;

    friend class QQuickEventPoint;
    friend class QQuickWindowPrivate;
};

Q_DECLARE_OPERATORS_FOR_FLAGS(QQuickPointerHandler::GrabPermissions)

QT_END_NAMESPACE

QML_DECLARE_TYPE(QQuickPointerHandler)

#endif // QQUICKPOINTERHANDLER_H
