Resort directory size count after refreshing

After refreshing the view when
size count is selected as the sortRole,
count is 0 at first. When the actual count is loaded,
the sorting is done according to the count being 0. 
This can break the sort order and cause view and model
to be out of sync. 

Making sure we always resort all items
when the directory size/item count is changed fixes this

BUG:473999

src/kitemviews/kfileitemmodel.cpp

@@ -260,6 +260,13 @@ void KFileItemModel::setShowTrashMime(bool show)
     }
 }
 
+void KFileItemModel::scheduleResortAllItems()
+{
+    if (!m_resortAllItemsTimer->isActive()) {
+        m_resortAllItemsTimer->start();
+    }
+}
+
 void KFileItemModel::setShowHiddenFiles(bool show)
 {
     m_dirLister->setShowHiddenFiles(show);

src/kitemviews/kfileitemmodel.h

@@ -205,6 +205,8 @@ public:
     /** set to true to hide application/x-trash files */
     void setShowTrashMime(bool show);
 
+    void scheduleResortAllItems();
+
 Q_SIGNALS:
     /**
      * Is emitted if the loading of a directory has been started. It is

src/kitemviews/kfileitemmodelrolesupdater.cpp

@@ -1346,6 +1346,9 @@ void KFileItemModelRolesUpdater::startDirectorySizeCounting(const KFileItem &ite
                 disconnect(m_model, &KFileItemModel::itemsChanged, this, &KFileItemModelRolesUpdater::slotItemsChanged);
                 m_model->setData(index, data);
                 connect(m_model, &KFileItemModel::itemsChanged, this, &KFileItemModelRolesUpdater::slotItemsChanged);
+                if (m_model->sortRole() == "size") {
+                    m_model->scheduleResortAllItems();
+                }
             }
         });
         return;

src/tests/kfileitemmodeltest.cpp

@@ -92,6 +92,7 @@ private Q_SLOTS:
     void testDeleteFileMoreThanOnce();
     void testInsertAfterExpand();
     void testCurrentDirRemoved();
+    void testSizeSortingAfterRefresh();
 
 private:
     QStringList itemsInModel() const;
@@ -846,6 +847,108 @@ void KFileItemModelTest::testRemoveFilteredExpandedItems()
                            << "file");
 }
 
+void KFileItemModelTest::testSizeSortingAfterRefresh()
+{
+    // testDir structure is as follows
+    // ./
+    // ├─ a
+    // ├─ b
+    // ├─ c/
+    // │  ├─ c-2/
+    // │  │  ├─ c-3
+    // │  ├─ c-1
+    // ├─ d
+    // ├─ e
+
+    QSignalSpy itemsInsertedSpy(m_model, &KFileItemModel::itemsInserted);
+    QSignalSpy itemsMovedSpy(m_model, &KFileItemModel::itemsMoved);
+    QVERIFY(itemsMovedSpy.isValid());
+
+    // Create some files with different sizes and modification times to check the different sorting options
+    QDateTime now = QDateTime::currentDateTime();
+
+    QSet<QByteArray> roles;
+    roles.insert("text");
+    roles.insert("isExpanded");
+    roles.insert("isExpandable");
+    roles.insert("expandedParentsCount");
+    m_model->setRoles(roles);
+
+    m_testDir->createDir("c/c-2");
+    m_testDir->createFile("c/c-2/c-3");
+    m_testDir->createFile("c/c-1");
+
+    m_testDir->createFile("a", "A file", now.addDays(-3));
+    m_testDir->createFile("b", "A larger file", now.addDays(0));
+    m_testDir->createDir("c", now.addDays(-2));
+    m_testDir->createFile("d", "The largest file in this directory", now.addDays(-1));
+    m_testDir->createFile("e", "An even larger file", now.addDays(-4));
+
+    m_model->loadDirectory(m_testDir->url());
+    QVERIFY(itemsInsertedSpy.wait());
+
+    int index = m_model->index(QUrl(m_testDir->url().url() + "/c"));
+    m_model->setExpanded(index, true);
+    QVERIFY(itemsInsertedSpy.wait());
+
+    index = m_model->index(QUrl(m_testDir->url().url() + "/c/c-2"));
+    m_model->setExpanded(index, true);
+    QVERIFY(itemsInsertedSpy.wait());
+
+    // Default: Sort by Name, ascending
+    QCOMPARE(m_model->sortRole(), QByteArray("text"));
+    QCOMPARE(m_model->sortOrder(), Qt::AscendingOrder);
+    QCOMPARE(itemsInModel(),
+             QStringList() << "c"
+                           << "c-2"
+                           << "c-3"
+                           << "c-1"
+                           << "a"
+                           << "b"
+                           << "d"
+                           << "e");
+
+    // Sort by Size, ascending, before refresh
+    m_model->setSortRole("size");
+    QCOMPARE(m_model->sortRole(), QByteArray("size"));
+    QCOMPARE(m_model->sortOrder(), Qt::AscendingOrder);
+    QCOMPARE(itemsInModel(),
+             QStringList() << "c"
+                           << "c-2"
+                           << "c-3"
+                           << "c-1"
+                           << "a"
+                           << "b"
+                           << "e"
+                           << "d");
+
+    // Refresh directory
+    m_model->refreshDirectory(m_model->directory());
+    QVERIFY(itemsInsertedSpy.wait());
+
+    // Expand folders again
+    index = m_model->index(QUrl(m_testDir->url().url() + "/c"));
+    m_model->setExpanded(index, true);
+    QVERIFY(itemsInsertedSpy.wait());
+
+    index = m_model->index(QUrl(m_testDir->url().url() + "/c/c-2"));
+    m_model->setExpanded(index, true);
+    QVERIFY(itemsInsertedSpy.wait());
+
+    // Sort by Size, ascending, after refresh
+    QCOMPARE(m_model->sortRole(), QByteArray("size"));
+    QCOMPARE(m_model->sortOrder(), Qt::AscendingOrder);
+    QCOMPARE(itemsInModel(),
+             QStringList() << "c"
+                           << "c-2"
+                           << "c-3"
+                           << "c-1"
+                           << "a"
+                           << "b"
+                           << "e"
+                           << "d");
+}
+
 void KFileItemModelTest::testSorting()
 {
     // testDir structure is as follows