Improvements for slow sorting roles

If the sorting is done for data which is resolved asynchronously
(e.g. rating), it is important to give a visual feedback about
the state of the sorting. This is done now by a progress
indication in the statusbar.

Also optimizations for "Sort by type" have been done: Although
resolving a type can be expensive in the most often case it is a
very cheap operation. So it the sorting is done by type, try
to resolve the type synchronously for at least 200 ms to prevent
a asynchronous resorting. This is usually sufficient to have
resolved types even for directories with several thousands of
items.

BUG: 292733
FIXED-IN: 4.9.0

1 files changed, 50 insertions, 0 deletions

diff --git a/src/kitemviews/kfileitemmodel.cpp b/src/kitemviews/kfileitemmodel.cpp
index 7644ae5ef..685af8972 100644
--- a/src/kitemviews/kfileitemmodel.cpp
+++ b/src/kitemviews/kfileitemmodel.cpp
@@ -38,6 +38,7 @@ KFileItemModel::KFileItemModel(KDirLister* dirLister, QObject* parent) :
     m_naturalSorting(KGlobalSettings::naturalSorting()),
     m_sortFoldersFirst(true),
     m_sortRole(NameRole),
+    m_sortProgressPercent(-1),
     m_roles(),
     m_caseSensitivity(Qt::CaseInsensitive),
     m_itemData(),
@@ -878,6 +879,13 @@ void KFileItemModel::insertItems(const KFileItemList& items)
         return;
     }
 
+    if (m_sortRole == 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).
+        determineMimeTypes(items, 200);
+    }
+
 #ifdef KFILEITEMMODEL_DEBUG
     QElapsedTimer timer;
     timer.start();
@@ -1829,6 +1837,34 @@ KFileItemList KFileItemModel::childItems(const KFileItem& item) const
     return items;
 }
 
+void KFileItemModel::emitSortProgress(int resolvedCount)
+{
+    // Be tolerant against a resolvedCount with a wrong range.
+    // Although there should not be a case where KFileItemModelRolesUpdater
+    // (= caller) provides a wrong range, it is important to emit
+    // a useful progress information even if there is an unexpected
+    // implementation issue.
+
+    const int itemCount = count();
+    if (resolvedCount >= itemCount) {
+        m_sortProgressPercent = -1;
+        if (m_resortAllItemsTimer->isActive()) {
+            m_resortAllItemsTimer->stop();
+            resortAllItems();
+        }
+
+        emit sortProgress(100);
+    } else if (itemCount > 0) {
+        resolvedCount = qBound(0, resolvedCount, itemCount);
+
+        const int progress = resolvedCount * 100 / itemCount;
+        if (m_sortProgressPercent != progress) {
+            m_sortProgressPercent = progress;
+            emit sortProgress(progress);
+        }
+    }
+}
+
 const KFileItemModel::RoleInfoMap* KFileItemModel::rolesInfoMap(int& count)
 {
     static const RoleInfoMap rolesInfoMap[] = {
@@ -1861,4 +1897,18 @@ const KFileItemModel::RoleInfoMap* KFileItemModel::rolesInfoMap(int& count)
     return rolesInfoMap;
 }
 
+void KFileItemModel::determineMimeTypes(const KFileItemList& items, int timeout)
+{
+    QElapsedTimer timer;
+    timer.start();
+    foreach (KFileItem item, items) {
+        item.determineMimeType();
+        if (timer.elapsed() > timeout) {
+            // Don't block the user interface, let the remaining items
+            // be resolved asynchronously.
+            return;
+        }
+    }
+}
+
 #include "kfileitemmodel.moc"