9 files changed, 156 insertions, 17 deletions

diff --git a/src/kitemviews/kfileitemlistview.cpp b/src/kitemviews/kfileitemlistview.cpp
index 3a02d537d..585a972a6 100644
--- a/src/kitemviews/kfileitemlistview.cpp
+++ b/src/kitemviews/kfileitemlistview.cpp
@@ -354,6 +354,15 @@ void KFileItemListView::slotSortRoleChanged(const QByteArray &current, const QBy
     KStandardItemListView::slotSortRoleChanged(current, previous);
 }
 
+void KFileItemListView::slotGroupRoleChanged(const QByteArray &current, const QByteArray &previous)
+{
+    if (!visibleRoles().contains(current)) {
+        applyRolesToModel();
+    }
+
+    KItemListView::slotGroupRoleChanged(current, previous);
+}
+
 void KFileItemListView::triggerVisibleIndexRangeUpdate()
 {
     if (!model()) {
@@ -441,6 +450,11 @@ void KFileItemListView::applyRolesToModel()
     // Assure that the role that is used for sorting will be determined
     roles.insert(fileItemModel->sortRole());
 
+    const QByteArray rawGroupRole = fileItemModel->rawGroupRole();
+    if (!rawGroupRole.isEmpty()) {
+        roles.insert(rawGroupRole);
+    }
+
     fileItemModel->setRoles(roles);
     m_modelRolesUpdater->setRoles(roles);
 }
diff --git a/src/kitemviews/kfileitemlistview.h b/src/kitemviews/kfileitemlistview.h
index eae00f1f0..203daca09 100644
--- a/src/kitemviews/kfileitemlistview.h
+++ b/src/kitemviews/kfileitemlistview.h
@@ -93,6 +93,7 @@ protected:
 protected Q_SLOTS:
     void slotItemsRemoved(const KItemRangeList &itemRanges) override;
     void slotSortRoleChanged(const QByteArray &current, const QByteArray &previous) override;
+    void slotGroupRoleChanged(const QByteArray &current, const QByteArray &previous) override;
 
 private Q_SLOTS:
     void triggerVisibleIndexRangeUpdate();
diff --git a/src/kitemviews/kfileitemmodel.cpp b/src/kitemviews/kfileitemmodel.cpp
index ba33254c0..f4b51ce72 100644
--- a/src/kitemviews/kfileitemmodel.cpp
+++ b/src/kitemviews/kfileitemmodel.cpp
@@ -639,7 +639,7 @@ QList<QPair<int, QVariant>> KFileItemModel::groups() const
         QElapsedTimer timer;
         timer.start();
 #endif
-        switch (typeForRole(sortRole())) {
+        switch (typeForRole(groupRole())) {
         case NameRole:
             m_groups = nameRoleGroups();
             break;
@@ -673,7 +673,7 @@ QList<QPair<int, QVariant>> KFileItemModel::groups() const
             m_groups = ratingRoleGroups();
             break;
         default:
-            m_groups = genericStringRoleGroups(sortRole());
+            m_groups = genericStringRoleGroups(groupRole());
             break;
         }
 
@@ -1232,6 +1232,24 @@ void KFileItemModel::onGroupedSortingChanged(bool current)
     m_groups.clear();
 }
 
+void KFileItemModel::onGroupRoleChanged(const QByteArray &current, const QByteArray &previous, bool resortItems)
+{
+    Q_UNUSED(previous)
+    const RoleType roleType = typeForRole(current);
+
+    if (!m_requestRole[roleType]) {
+        QSet<QByteArray> newRoles = m_roles;
+        newRoles << current;
+        setRoles(newRoles);
+    }
+
+    m_groups.clear();
+
+    if (resortItems) {
+        resortAllItems();
+    }
+}
+
 void KFileItemModel::onSortRoleChanged(const QByteArray &current, const QByteArray &previous, bool resortItems)
 {
     Q_UNUSED(previous)
@@ -1927,7 +1945,7 @@ void KFileItemModel::removeItems(const KItemRangeList &itemRanges, RemoveItemsBe
 
 QList<KFileItemModel::ItemData *> KFileItemModel::createItemDataList(const QUrl &parentUrl, const KFileItemList &items) const
 {
-    if (m_sortRole == TypeRole) {
+    if (m_sortRole == TypeRole || typeForRole(rawGroupRole()) == TypeRole) {
         // Try to resolve the MIME-types synchronously to prevent a reordering of
         // the items when sorting by type (per default MIME-types are resolved
         // asynchronously by KFileItemModelRolesUpdater).
@@ -1991,6 +2009,17 @@ void KFileItemModel::prepareItemsForSorting(QList<ItemData *> &itemDataList)
         // DateRole).
         break;
     }
+
+    if (typeForRole(rawGroupRole()) == TypeRole && m_sortRole != TypeRole) {
+        for (ItemData *itemData : std::as_const(itemDataList)) {
+            if (itemData->values.isEmpty()) {
+                const KFileItem &item = itemData->item;
+                if (item.isDir() || item.isMimeTypeKnown()) {
+                    itemData->values = retrieveData(itemData->item, itemData->parent);
+                }
+            }
+        }
+    }
 }
 
 int KFileItemModel::expandedParentsCount(const ItemData *data)
@@ -2046,7 +2075,8 @@ void KFileItemModel::emitItemsChangedAndTriggerResorting(const KItemRangeList &i
     // Trigger a resorting if necessary. Note that this can happen even if the sort
     // role has not changed at all because the file name can be used as a fallback.
     if (changedRoles.contains(sortRole()) || changedRoles.contains(roleForType(NameRole))
-        || (changedRoles.contains("count") && sortRole() == "size")) { // "count" is used in the "size" sort role, so this might require a resorting.
+        || (changedRoles.contains("count") && sortRole() == "size") // "count" is used in the "size" sort role, so this might require a resorting.
+        || (groupedSorting() && !rawGroupRole().isEmpty() && changedRoles.contains(groupRole()))) {
         for (const KItemRange &range : itemRanges) {
             bool needsResorting = false;
 
@@ -2077,7 +2107,7 @@ void KFileItemModel::emitItemsChangedAndTriggerResorting(const KItemRangeList &i
         }
     }
 
-    if (groupedSorting() && changedRoles.contains(sortRole())) {
+    if (groupedSorting() && (changedRoles.contains(sortRole()) || (!rawGroupRole().isEmpty() && changedRoles.contains(groupRole())))) {
         // The position is still correct, but the groups might have changed
         // if the changed item is either the first or the last item in a
         // group.
@@ -2307,6 +2337,20 @@ QHash<QByteArray, QVariant> KFileItemModel::retrieveData(const KFileItem &item,
     return data;
 }
 
+QString KFileItemModel::groupKeyForItem(const ItemData *item, const QByteArray &role) const
+{
+    switch (typeForRole(role)) {
+    case ModificationTimeRole:
+    case CreationTimeRole:
+    case AccessTimeRole:
+        return QDateTime::fromSecsSinceEpoch(item->values.value(role).toLongLong()).date().toString(Qt::ISODate);
+    case DeletionTimeRole:
+        return item->values.value("deletiontime").toDateTime().date().toString(Qt::ISODate);
+    default:
+        return item->values.value(role).toString();
+    }
+}
+
 bool KFileItemModel::lessThan(const ItemData *a, const ItemData *b, const QCollator &collator) const
 {
     int result = 0;
@@ -2364,6 +2408,17 @@ bool KFileItemModel::lessThan(const ItemData *a, const ItemData *b, const QColla
         }
     }
 
+    if (groupedSorting() && !rawGroupRole().isEmpty() && groupRole() != sortRole()) {
+        const QByteArray gRole = groupRole();
+        const QString groupValueA = groupKeyForItem(a, gRole);
+        const QString groupValueB = groupKeyForItem(b, gRole);
+        const int groupResult = stringCompare(groupValueA, groupValueB, collator);
+        if (groupResult != 0) {
+            // Groups are always in ascending order regardless of the sort order setting.
+            return groupResult < 0;
+        }
+    }
+
     result = sortRoleCompare(a, b, collator);
 
     return (sortOrder() == Qt::AscendingOrder) ? result < 0 : result > 0;
@@ -2375,15 +2430,16 @@ void KFileItemModel::sort(const QList<KFileItemModel::ItemData *>::iterator &beg
         return lessThan(a, b, m_collator);
     };
 
-    if (m_sortRole == NameRole || isRoleValueNatural(m_sortRole)) {
-        // Sorting by string can be expensive, in particular if natural sorting is
-        // enabled. Use all CPU cores to speed up the sorting process.
+    const QByteArray rawRole = rawGroupRole();
+    const bool groupKeyIsString = !rawRole.isEmpty() && groupRole() != sortRole()
+        && isRoleValueNatural(typeForRole(rawRole));
+    // String-based sorts benefit from parallelism; non-string sorts use one thread
+    // to avoid non-reentrant comparison functions (bug 312679).
+    const bool primaryKeyIsString = m_sortRole == NameRole || isRoleValueNatural(m_sortRole) || groupKeyIsString;
+    if (primaryKeyIsString) {
         static const int numberOfThreads = QThread::idealThreadCount();
         parallelMergeSort(begin, end, lambdaLessThan, numberOfThreads);
     } else {
-        // Sorting by other roles is quite fast. Use only one thread to prevent
-        // problems caused by non-reentrant comparison functions, see
-        // https://bugs.kde.org/show_bug.cgi?id=312679
         mergeSort(begin, end, lambdaLessThan);
     }
 }
diff --git a/src/kitemviews/kfileitemmodel.h b/src/kitemviews/kfileitemmodel.h
index 2a6e710c3..0ac5d9261 100644
--- a/src/kitemviews/kfileitemmodel.h
+++ b/src/kitemviews/kfileitemmodel.h
@@ -293,6 +293,7 @@ protected:
     void onGroupedSortingChanged(bool current) override;
     void onSortRoleChanged(const QByteArray &current, const QByteArray &previous, bool resortItems = true) override;
     void onSortOrderChanged(Qt::SortOrder current, Qt::SortOrder previous) override;
+    void onGroupRoleChanged(const QByteArray &current, const QByteArray &previous, bool resortItems = true) override;
 
 private Q_SLOTS:
     /**
@@ -447,6 +448,8 @@ private:
      */
     bool lessThan(const ItemData *a, const ItemData *b, const QCollator &collator) const;
 
+    QString groupKeyForItem(const ItemData *item, const QByteArray &role) const;
+
     /**
      * Sorts the items between \a begin and \a end using the comparison
      * function lessThan().
diff --git a/src/kitemviews/kfileitemmodelrolesupdater.cpp b/src/kitemviews/kfileitemmodelrolesupdater.cpp
index 38fa58436..33cf6341c 100644
--- a/src/kitemviews/kfileitemmodelrolesupdater.cpp
+++ b/src/kitemviews/kfileitemmodelrolesupdater.cpp
@@ -281,6 +281,14 @@ void KFileItemModelRolesUpdater::setPaused(bool paused)
 void KFileItemModelRolesUpdater::setRoles(const QSet<QByteArray> &roles)
 {
     if (m_roles != roles) {
+        const QSet<QByteArray> addedRoles = roles - m_roles;
+        for (const QByteArray &role : addedRoles) {
+            if (m_resolvableRoles.contains(role)) {
+                m_finishedItems.clear();
+                break;
+            }
+        }
+
         m_roles = roles;
 
 #if HAVE_BALOO
diff --git a/src/kitemviews/kitemlistview.cpp b/src/kitemviews/kitemlistview.cpp
index b87216d4b..d24c2426d 100644
--- a/src/kitemviews/kitemlistview.cpp
+++ b/src/kitemviews/kitemlistview.cpp
@@ -1477,8 +1477,8 @@ void KItemListView::slotItemsChanged(const KItemRangeList &itemRanges, const QSe
             }
         }
 
-        if (m_grouped && roles.contains(m_model->sortRole())) {
-            // The sort-role has been changed which might result
+        if (m_grouped && roles.contains(m_model->groupRole())) {
+            // The group-role data has been changed which might result
             // in modified group headers
             updateVisibleGroupHeaders();
             doLayout(NoAnimation);
@@ -1543,6 +1543,16 @@ void KItemListView::slotSortRoleChanged(const QByteArray &current, const QByteAr
     }
 }
 
+void KItemListView::slotGroupRoleChanged(const QByteArray &current, const QByteArray &previous)
+{
+    Q_UNUSED(current)
+    Q_UNUSED(previous)
+    if (m_grouped) {
+        updateVisibleGroupHeaders();
+        doLayout(NoAnimation);
+    }
+}
+
 void KItemListView::slotCurrentChanged(int current, int previous)
 {
     // In SingleSelection mode (e.g., in the Places Panel), the current item is
@@ -1826,6 +1836,7 @@ void KItemListView::setModel(KItemModelBase *model)
         disconnect(m_model, &KItemModelBase::groupedSortingChanged, this, &KItemListView::slotGroupedSortingChanged);
         disconnect(m_model, &KItemModelBase::sortOrderChanged, this, &KItemListView::slotSortOrderChanged);
         disconnect(m_model, &KItemModelBase::sortRoleChanged, this, &KItemListView::slotSortRoleChanged);
+        disconnect(m_model, &KItemModelBase::groupRoleChanged, this, &KItemListView::slotGroupRoleChanged);
 
         m_sizeHintResolver->itemsRemoved(KItemRangeList() << KItemRange(0, m_model->count()));
     }
@@ -1843,6 +1854,7 @@ void KItemListView::setModel(KItemModelBase *model)
         connect(m_model, &KItemModelBase::groupedSortingChanged, this, &KItemListView::slotGroupedSortingChanged);
         connect(m_model, &KItemModelBase::sortOrderChanged, this, &KItemListView::slotSortOrderChanged);
         connect(m_model, &KItemModelBase::sortRoleChanged, this, &KItemListView::slotSortRoleChanged);
+        connect(m_model, &KItemModelBase::groupRoleChanged, this, &KItemListView::slotGroupRoleChanged);
 
         const int itemCount = m_model->count();
         if (itemCount > 0) {
@@ -2251,7 +2263,7 @@ void KItemListView::updateGroupHeaderForWidget(KItemListWidget *widget)
     const int groupIndex = groupIndexForItem(index);
     Q_ASSERT(groupIndex >= 0);
     groupHeader->setData(groups.at(groupIndex).second);
-    groupHeader->setRole(model()->sortRole());
+    groupHeader->setRole(model()->groupRole());
     groupHeader->setStyleOption(m_styleOption);
     groupHeader->setScrollOrientation(scrollOrientation());
     groupHeader->setItemIndex(index);
diff --git a/src/kitemviews/kitemlistview.h b/src/kitemviews/kitemlistview.h
index 8dc83d528..20c34ceea 100644
--- a/src/kitemviews/kitemlistview.h
+++ b/src/kitemviews/kitemlistview.h
@@ -441,6 +441,7 @@ protected Q_SLOTS:
     virtual void slotGroupedSortingChanged(bool current);
     virtual void slotSortOrderChanged(Qt::SortOrder current, Qt::SortOrder previous);
     virtual void slotSortRoleChanged(const QByteArray &current, const QByteArray &previous);
+    virtual void slotGroupRoleChanged(const QByteArray &current, const QByteArray &previous);
     virtual void slotCurrentChanged(int current, int previous);
     virtual void slotSelectionChanged(const KItemSet &current, const KItemSet &previous);
 
diff --git a/src/kitemviews/kitemmodelbase.cpp b/src/kitemviews/kitemmodelbase.cpp
index 82e491220..a4f7b0890 100644
--- a/src/kitemviews/kitemmodelbase.cpp
+++ b/src/kitemviews/kitemmodelbase.cpp
@@ -50,13 +50,41 @@ bool KItemModelBase::groupedSorting() const
 void KItemModelBase::setSortRole(const QByteArray &role, bool resortItems)
 {
     if (role != m_sortRole) {
-        const QByteArray previous = m_sortRole;
+        const QByteArray previousSortRole = m_sortRole;
         m_sortRole = role;
-        onSortRoleChanged(role, previous, resortItems);
-        Q_EMIT sortRoleChanged(role, previous);
+        onSortRoleChanged(role, previousSortRole, resortItems);
+        Q_EMIT sortRoleChanged(role, previousSortRole);
+
+        if (m_groupRole.isEmpty()) {
+            onGroupRoleChanged(role, previousSortRole, false);
+            Q_EMIT groupRoleChanged(role, previousSortRole);
+        }
+    }
+}
+
+void KItemModelBase::setGroupRole(const QByteArray &role)
+{
+    if (role != m_groupRole) {
+        const QByteArray previousEffective = groupRole();
+        m_groupRole = role;
+        const QByteArray currentEffective = groupRole();
+        if (currentEffective != previousEffective) {
+            onGroupRoleChanged(currentEffective, previousEffective);
+            Q_EMIT groupRoleChanged(currentEffective, previousEffective);
+        }
     }
 }
 
+QByteArray KItemModelBase::groupRole() const
+{
+    return m_groupRole.isEmpty() ? m_sortRole : m_groupRole;
+}
+
+QByteArray KItemModelBase::rawGroupRole() const
+{
+    return m_groupRole;
+}
+
 QByteArray KItemModelBase::sortRole() const
 {
     return m_sortRole;
@@ -149,6 +177,13 @@ void KItemModelBase::onSortRoleChanged(const QByteArray &current, const QByteArr
     Q_UNUSED(resortItems)
 }
 
+void KItemModelBase::onGroupRoleChanged(const QByteArray &current, const QByteArray &previous, bool resortItems)
+{
+    Q_UNUSED(current)
+    Q_UNUSED(previous)
+    Q_UNUSED(resortItems)
+}
+
 void KItemModelBase::onSortOrderChanged(Qt::SortOrder current, Qt::SortOrder previous)
 {
     Q_UNUSED(current)
diff --git a/src/kitemviews/kitemmodelbase.h b/src/kitemviews/kitemmodelbase.h
index 42a9c54c9..68d1d5d8a 100644
--- a/src/kitemviews/kitemmodelbase.h
+++ b/src/kitemviews/kitemmodelbase.h
@@ -76,6 +76,10 @@ public:
     void setSortRole(const QByteArray &role, bool resortItems = true);
     QByteArray sortRole() const;
 
+    void setGroupRole(const QByteArray &role);
+    QByteArray groupRole() const;
+    QByteArray rawGroupRole() const;
+
     /**
      * Sets the sort order to \a order. The method KItemModelBase::onSortOrderChanged() will be
      * called so that model-implementations can react on the sort order change. Afterwards the
@@ -248,6 +252,8 @@ Q_SIGNALS:
     void sortRoleChanged(const QByteArray &current, const QByteArray &previous);
     void sortOrderChanged(Qt::SortOrder current, Qt::SortOrder previous);
 
+    void groupRoleChanged(const QByteArray &current, const QByteArray &previous);
+
 protected:
     /**
      * Is invoked if the grouped sorting has been changed by KItemModelBase::setGroupedSorting(). Allows
@@ -266,6 +272,8 @@ protected:
      */
     virtual void onSortRoleChanged(const QByteArray &current, const QByteArray &previous, bool resortItems = true);
 
+    virtual void onGroupRoleChanged(const QByteArray &current, const QByteArray &previous, bool resortItems = true);
+
     /**
      * Is invoked if the sort order has been changed by KItemModelBase::setSortOrder(). Allows
      * to react on the changed sort order before the signal sortOrderChanged() will be emitted.
@@ -279,6 +287,7 @@ protected:
 private:
     bool m_groupedSorting;
     QByteArray m_sortRole;
+    QByteArray m_groupRole;
     Qt::SortOrder m_sortOrder;
 };