Restore directories-first order of passwords tree view on non-Mac platforms

Since commit b4dc9e69e7c553 ("Auto update CHANGELOG and sorting of treeview")
directories are no longer listed first in the tree view of passwords.

This is because a simple sort of the tree view widget (as enabled by the
aforementioned commit) does its work by sorting the backing
StoreModel (QSortFilterProxyModel), which in turn does just a simple
lexicographical order sort on the path of each its item.

Before that commit the sort was done by QFileSystemModel via
QFileSystemModelSorter, which always places its directories first on
non-Mac platforms.

Unfortunately, QFileSystemModelSorter is an internal Qt helper class, so we
can't just use it directly, we need to open-code a bit of logic from
QFileSystemModelSorter::compareNodes() into StoreModel::lessThan() to
restore the old behavior.

2 files changed, 18 insertions, 0 deletions

diff --git a/src/storemodel.cpp b/src/storemodel.cpp
index b6fef94c..06c3c036 100644
--- a/src/storemodel.cpp
+++ b/src/storemodel.cpp
@@ -256,3 +256,19 @@ bool StoreModel::dropMimeData(const QMimeData *data, Qt::DropAction action,
   }
   return true;
 }
+
+bool StoreModel::lessThan(const QModelIndex &source_left,
+                          const QModelIndex &source_right) const {
+/* matches logic in QFileSystemModelSorter::compareNodes() */
+#ifndef Q_OS_MAC
+  if (fs && (source_left.column() == 0 || source_left.column() == 1)) {
+    bool leftD = fs->isDir(source_left);
+    bool rightD = fs->isDir(source_right);
+
+    if (leftD ^ rightD)
+      return leftD;
+  }
+#endif
+
+  return QSortFilterProxyModel::lessThan(source_left, source_right);
+}
diff --git a/src/storemodel.h b/src/storemodel.h
index 66486b10..6c8053e9 100644
--- a/src/storemodel.h
+++ b/src/storemodel.h
@@ -23,6 +23,8 @@ public:
   bool ShowThis(const QModelIndex) const;
   void setModelAndStore(QFileSystemModel *sourceModel, QString passStore);
   QVariant data(const QModelIndex &index, int role) const;
+  bool lessThan(const QModelIndex &source_left,
+                const QModelIndex &source_right) const override;
 
   // QAbstractItemModel interface
 public: