From cdb4a7909d256b1565383884f271214d4796cdbb Mon Sep 17 00:00:00 2001
From: Kai Uwe Broulik <kde@privat.broulik.de>
Date: Tue, 16 Nov 2021 20:35:05 +0100
Subject: [PATCH] KFileItemModelRolesUpdater: Generate thumbnails for visible
 files first

Folder thumbnails are not cached as we cannot know whether something
inside a folder changed. Moreover, they are also a collage of several
files and might even traverse into subdirectories. This takes time.
---
 src/kitemviews/kfileitemmodelrolesupdater.cpp | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/kitemviews/kfileitemmodelrolesupdater.cpp b/src/kitemviews/kfileitemmodelrolesupdater.cpp
index 978f5df6e..3804a1907 100644
--- a/src/kitemviews/kfileitemmodelrolesupdater.cpp
+++ b/src/kitemviews/kfileitemmodelrolesupdater.cpp
@@ -1405,10 +1405,19 @@ QList<int> KFileItemModelRolesUpdater::indexesToResolve() const
                                (2 * m_maximumVisibleItems)));
 
     // Add visible items.
+    // Resolve files first, their previews are quicker.
+    QList<int> visibleDirs;
     for (int i = m_firstVisibleIndex; i <= m_lastVisibleIndex; ++i) {
-        result.append(i);
+        const KFileItem item = m_model->fileItem(i);
+        if (item.isDir()) {
+            visibleDirs.append(i);
+        } else {
+            result.append(i);
+        }
     }
 
+    result.append(visibleDirs);
+
     // We need a reasonable upper limit for number of items to resolve after
     // and before the visible range. m_maximumVisibleItems can be quite large
     // when using Compact View.