Add natural sorting and case-insensitive sorting for all role-types

Summary:
 Add natural sorting and case-insensitive sorting, for all role-types
that benefit from.

BUG: 406296
FIXED-IN: 19.12.2

Test Plan:
Sort by any role type specified in `isRoleValueNatural()`
Before: Sorting is always case sensitive
After: Sorting according to 'Sorting mode' in configuration.

Reviewers: #dolphin, nicolasfella, meven, elvisangelaccio, ngraham

Reviewed By: #dolphin, meven, elvisangelaccio, ngraham

Subscribers: cfeck, meven, kfm-devel

Tags: #dolphin

Differential Revision: https://phabricator.kde.org/D25741

2 files changed, 39 insertions, 9 deletions

diff --git a/src/kitemviews/kfileitemmodel.cpp b/src/kitemviews/kfileitemmodel.cpp
index ad996a59e..4b35a0248 100644
--- a/src/kitemviews/kfileitemmodel.cpp
+++ b/src/kitemviews/kfileitemmodel.cpp
@@ -1187,12 +1187,20 @@ void KFileItemModel::insertItems(QList<ItemData*>& newItems)
     m_groups.clear();
     prepareItemsForSorting(newItems);
 
-    if (m_sortRole == NameRole && m_naturalSorting) {
-        // Natural sorting of items can be very slow. However, it becomes much
-        // faster if the input sequence is already mostly sorted. Therefore, we
-        // first sort 'newItems' according to the QStrings returned by
-        // KFileItem::text() using QString::operator<(), which is quite fast.
-        parallelMergeSort(newItems.begin(), newItems.end(), nameLessThan, QThread::idealThreadCount());
+    // Natural sorting of items can be very slow. However, it becomes much faster
+    // if the input sequence is already mostly sorted. Therefore, we first sort
+    // 'newItems' according to the QStrings using QString::operator<(), which is quite fast.
+    if (m_naturalSorting) {
+        if (m_sortRole == NameRole) {
+            parallelMergeSort(newItems.begin(), newItems.end(), nameLessThan, QThread::idealThreadCount());
+        } else if (isRoleValueNatural(m_sortRole)) {
+            auto lambdaLessThan = [&] (const KFileItemModel::ItemData* a, const KFileItemModel::ItemData* b)
+            {
+                const QByteArray role = roleForType(m_sortRole);
+                return a->values.value(role).toString() < b->values.value(role).toString();
+            };
+            parallelMergeSort(newItems.begin(), newItems.end(), lambdaLessThan, QThread::idealThreadCount());
+        }
     }
 
     sort(newItems.begin(), newItems.end());
@@ -1726,8 +1734,8 @@ void KFileItemModel::sort(const QList<KFileItemModel::ItemData*>::iterator &begi
         return lessThan(a, b, m_collator);
     };
 
-    if (m_sortRole == NameRole) {
-        // Sorting by name can be expensive, in particular if natural sorting is
+    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.
         static const int numberOfThreads = QThread::idealThreadCount();
         parallelMergeSort(begin, end, lambdaLessThan, numberOfThreads);
@@ -1835,6 +1843,8 @@ int KFileItemModel::sortRoleCompare(const ItemData* a, const ItemData* b, const
             result = -1;
         } else if (roleValueA.isEmpty() && !roleValueB.isEmpty()) {
             result = +1;
+        } else if (isRoleValueNatural(m_sortRole)) {
+            result = stringCompare(roleValueA, roleValueB, collator);
         } else {
             result = QString::compare(roleValueA, roleValueB);
         }
diff --git a/src/kitemviews/kfileitemmodel.h b/src/kitemviews/kfileitemmodel.h
index c2dfd0167..132a76e46 100644
--- a/src/kitemviews/kfileitemmodel.h
+++ b/src/kitemviews/kfileitemmodel.h
@@ -356,6 +356,11 @@ private:
     QHash<QByteArray, QVariant> retrieveData(const KFileItem& item, const ItemData* parent) const;
 
     /**
+     * @return True if role values benefit from natural or case insensitive sorting.
+     */
+    static bool isRoleValueNatural(const RoleType roleType);
+
+    /**
      * @return True if \a a has a KFileItem whose text is 'less than' the one
      *         of \a b according to QString::operator<(const QString&).
      */
@@ -504,12 +509,27 @@ private:
     friend class DolphinPart;                  // Accesses m_dirLister
 };
 
+inline bool KFileItemModel::isRoleValueNatural(RoleType roleType)
+{
+    return (roleType == TypeRole ||
+            roleType == TagsRole ||
+            roleType == CommentRole ||
+            roleType == TitleRole ||
+            roleType == ArtistRole ||
+            roleType == GenreRole ||
+            roleType == AlbumRole ||
+            roleType == PathRole ||
+            roleType == DestinationRole ||
+            roleType == OriginUrlRole ||
+            roleType == OwnerRole ||
+            roleType == GroupRole);
+}
+
 inline bool KFileItemModel::nameLessThan(const ItemData* a, const ItemData* b)
 {
     return a->item.text() < b->item.text();
 }
 
-
 inline bool KFileItemModel::isChildItem(int index) const
 {
     if (m_itemData.at(index)->parent) {