File indexing completed on 2024-04-28 15:27:41

 /*
  *  SPDX-FileCopyrightText: 2018 Marco Martin <mart@kde.org>
  *
  *  SPDX-License-Identifier: LGPL-2.0-or-later
  */
 
 #ifndef DELEGATERECYCLER_H
 #define DELEGATERECYCLER_H
 
 #include <QPointer>
 #include <QQuickItem>
 #include <QVariant>
 
 class DelegateRecyclerAttached : public QObject
 {
     Q_OBJECT
 
 public:
     DelegateRecyclerAttached(QObject *parent = nullptr);
     ~DelegateRecyclerAttached() override;
 
 Q_SIGNALS:
     void pooled();
     void reused();
 };
 
 /**
  * This class may be used as a delegate of a QtQuick.ListView or a QtQuick.GridView
  * in the case the intended delegate is a bit heavy, with many objects inside.
  * This will ensure the delegate instances will be put back in a common pool after
  * destruction, so when scrolling a big list, the delegates from old delete items will
  * be taken from the pool and reused, minimizing the need of instantiating new objects
  * and deleting old ones. It ensures scrolling of lists with heavy delegates is
  * smoother and helps with memory fragmentations as well.
  *
  * @note org::kde::kirigami::CardsListView and org::kde::kirigami::CardsGridView
  * are already using this recycler, so do NOT use it as a delegate for those 2 views.
  * Also, do NOT use this with a QtQuick.Repeater.
  *
  * @since org.kde.kirigami 2.4
  */
 class DelegateRecycler : public QQuickItem
 {
     Q_OBJECT
 
     /**
      * The Component the actual delegates will be built from.
      *
      * @note the component may not be a child of this object, therefore it can't be
      * declared inside the DelegateRecycler declaration.
      *
      * The DelegateRecycler will not take ownership of the delegate Component, so it's up
      * to the caller to delete it (usually with the normal child/parent relationship)
      */
     Q_PROPERTY(QQmlComponent *sourceComponent READ sourceComponent WRITE setSourceComponent RESET resetSourceComponent NOTIFY sourceComponentChanged)
 
 public:
     DelegateRecycler(QQuickItem *parent = nullptr);
     ~DelegateRecycler() override;
 
     QQmlComponent *sourceComponent() const;
     void setSourceComponent(QQmlComponent *component);
     void resetSourceComponent();
 
     static DelegateRecyclerAttached *qmlAttachedProperties(QObject *object);
 
 protected:
 #if QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
     void geometryChanged(const QRectF &newGeometry, const QRectF &oldGeometry) override;
 #else
     void geometryChange(const QRectF &newGeometry, const QRectF &oldGeometry) override;
 #endif
     void focusInEvent(QFocusEvent *event) override;
 
     void updateHints();
     void updateSize(bool parentResized);
 
 Q_SIGNALS:
     void sourceComponentChanged();
 
 private Q_SLOTS:
     void syncIndex();
     void syncModel();
     void syncModelProperties();
     void syncModelData();
 
 private:
     QPointer<QQmlComponent> m_sourceComponent;
     QPointer<QQuickItem> m_item;
     QObject *m_propertiesTracker = nullptr;
     bool m_updatingSize = false;
     bool m_widthFromItem = false;
     bool m_heightFromItem = false;
 };
 
 QML_DECLARE_TYPEINFO(DelegateRecycler, QML_HAS_ATTACHED_PROPERTIES)
 
 #endif