Add a method to clear the data to QStandardItemModel

After the behavior of setItemData has been changed following QTBUG-45114,
QStandardItemModel was lacking an interface to clear all the data from a single index.

Task-number: QTBUG-69616
Change-Id: Ide0b5bb6358439fc42c474df8b044fbace6def8d
Reviewed-by: André Hartmann <aha_1980@gmx.de>
Reviewed-by: David Faure <david.faure@kdab.com>

src/corelib/itemmodels/qabstractitemmodel.cpp

@@ -1866,6 +1866,23 @@ bool QAbstractItemModel::setData(const QModelIndex &index, const QVariant &value
     return false;
 }
 
+#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
+/*!
+    \since 6.0
+    Removes the data stored in all the roles for the given \a index.
+    Returns \c{true} if successful; otherwise returns \c{false}.
+    The dataChanged() signal should be emitted if the data was successfully
+    removed.
+    The base class implementation returns \c{false}
+    \sa data(), itemData(), setData(), setItemData()
+*/
+bool QAbstractItemModel::clearItemData(const QModelIndex &index)
+{
+    Q_UNUSED(index);
+    return false;
+}
+#endif
+
 /*!
     \fn QVariant QAbstractItemModel::data(const QModelIndex &index, int role) const = 0
 

src/corelib/itemmodels/qabstractitemmodel.h

@@ -198,6 +198,9 @@ public:
 
     virtual QMap<int, QVariant> itemData(const QModelIndex &index) const;
     virtual bool setItemData(const QModelIndex &index, const QMap<int, QVariant> &roles);
+#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
+    virtual bool clearItemData(const QModelIndex &index);
+#endif
 
     virtual QStringList mimeTypes() const;
     virtual QMimeData *mimeData(const QModelIndexList &indexes) const;

src/gui/itemmodels/qstandarditemmodel.cpp

@@ -930,6 +930,21 @@ void QStandardItem::setData(const QVariant &value, int role)
         d->model->d_func()->itemChanged(this, roles);
 }
 
+/*!
+    \since 5.12
+    Removes all the data from all roles previously set.
+    \sa data(), setData()
+*/
+void QStandardItem::clearData()
+{
+    Q_D(QStandardItem);
+    if (d->values.isEmpty())
+        return;
+    d->values.clear();
+    if (d->model)
+        d->model->d_func()->itemChanged(this, QVector<int>{});
+}
+
 /*!
     Returns the item's data for the given \a role, or an invalid
     QVariant if there is no data for the role.
@@ -2990,6 +3005,23 @@ bool QStandardItemModel::setData(const QModelIndex &index, const QVariant &value
     return true;
 }
 
+/*!
+  \since 5.12
+  Removes the data stored in all the roles for the given \a index.
+  \sa setData(), data()
+*/
+bool QStandardItemModel::clearItemData(const QModelIndex &index)
+{
+    if (!checkIndex(index, CheckIndexOption::IndexIsValid))
+        return false;
+    Q_D(QStandardItemModel);
+    QStandardItem *item = d->itemFromIndex(index);
+    if (!item)
+        return false;
+    item->clearData();
+    return true;
+}
+
 /*!
   \reimp
 */

src/gui/itemmodels/qstandarditemmodel.h

@@ -69,6 +69,7 @@ public:
 
     virtual QVariant data(int role = Qt::UserRole + 1) const;
     virtual void setData(const QVariant &value, int role = Qt::UserRole + 1);
+    void clearData();
 
     inline QString text() const {
         return qvariant_cast<QString>(data(Qt::DisplayRole));
@@ -343,6 +344,8 @@ public:
 
     QVariant data(const QModelIndex &index, int role = Qt::DisplayRole) const override;
     bool setData(const QModelIndex &index, const QVariant &value, int role = Qt::EditRole) override;
+    // Qt 6: add override keyword
+    bool clearItemData(const QModelIndex &index);
 
     QVariant headerData(int section, Qt::Orientation orientation,
                         int role = Qt::DisplayRole) const override;

tests/auto/gui/itemmodels/qstandarditem/tst_qstandarditem.cpp

@@ -69,8 +69,20 @@ private slots:
     void sortChildren();
     void subclassing();
     void lessThan();
+    void clearData();
 };
 
+void tst_QStandardItem::clearData()
+{
+    QStandardItem item;
+    item.setData(QStringLiteral("Test"), Qt::EditRole);
+    item.setData(5, Qt::UserRole);
+    item.clearData();
+    QCOMPARE(item.data(Qt::EditRole), QVariant());
+    QCOMPARE(item.data(Qt::UserRole), QVariant());
+    QCOMPARE(item.data(Qt::DisplayRole), QVariant());
+}
+
 void tst_QStandardItem::ctor()
 {
     QStandardItem item;

tests/auto/gui/itemmodels/qstandarditemmodel/tst_qstandarditemmodel.cpp

@@ -98,6 +98,7 @@ private slots:
     void checkChildren();
     void data();
     void clear();
+    void clearItemData();
     void sort_data();
     void sort();
     void sortRole_data();
@@ -752,6 +753,27 @@ void tst_QStandardItemModel::data()
 
 }
 
+void tst_QStandardItemModel::clearItemData()
+{
+    currentRoles.clear();
+    QVERIFY(!m_model->clearItemData(QModelIndex()));
+    QCOMPARE(currentRoles, {});
+    const QModelIndex idx = m_model->index(0, 0);
+    const QMap<int, QVariant> oldData = m_model->itemData(idx);
+    m_model->setData(idx, QLatin1String("initialitem"), Qt::DisplayRole);
+    m_model->setData(idx, QLatin1String("tooltip"), Qt::ToolTipRole);
+    m_model->setData(idx, 5, Qt::UserRole);
+    currentRoles.clear();
+    QVERIFY(m_model->clearItemData(idx));
+    QCOMPARE(idx.data(Qt::UserRole), QVariant());
+    QCOMPARE(idx.data(Qt::ToolTipRole), QVariant());
+    QCOMPARE(idx.data(Qt::DisplayRole), QVariant());
+    QCOMPARE(idx.data(Qt::EditRole), QVariant());
+    QCOMPARE(currentRoles, {});
+    m_model->setItemData(idx, oldData);
+    currentRoles.clear();
+}
+
 void tst_QStandardItemModel::clear()
 {
     QStandardItemModel model;