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-rw-r--r--src/widgets/itemviews/qlistwidget.cpp88
-rw-r--r--tests/auto/widgets/itemviews/qlistwidget/tst_qlistwidget.cpp60
2 files changed, 83 insertions, 65 deletions
diff --git a/src/widgets/itemviews/qlistwidget.cpp b/src/widgets/itemviews/qlistwidget.cpp
index cc0ccf84da8..695cca049e0 100644
--- a/src/widgets/itemviews/qlistwidget.cpp
+++ b/src/widgets/itemviews/qlistwidget.cpp
@@ -308,7 +308,7 @@ void QListModel::sort(int column, Qt::SortOrder order)
}
const auto compare = (order == Qt::AscendingOrder ? &itemLessThan : &itemGreaterThan);
- std::sort(sorting.begin(), sorting.end(), compare);
+ std::stable_sort(sorting.begin(), sorting.end(), compare);
QModelIndexList fromIndexes;
QModelIndexList toIndexes;
const int sortingCount = sorting.size();
@@ -328,76 +328,34 @@ void QListModel::sort(int column, Qt::SortOrder order)
/**
* This function assumes that all items in the model except the items that are between
* (inclusive) start and end are sorted.
- * With these assumptions, this function can ensure that the model is sorted in a
- * much more efficient way than doing a naive 'sort everything'.
- * (provided that the range is relatively small compared to the total number of items)
*/
void QListModel::ensureSorted(int column, Qt::SortOrder order, int start, int end)
{
if (column != 0)
return;
- const int count = end - start + 1;
- QList<QPair<QListWidgetItem *, int>> sorting(count);
- for (int i = 0; i < count; ++i) {
- sorting[i].first = items.at(start + i);
- sorting[i].second = start + i;
- }
-
- const auto compare = (order == Qt::AscendingOrder ? &itemLessThan : &itemGreaterThan);
- std::sort(sorting.begin(), sorting.end(), compare);
-
- QModelIndexList oldPersistentIndexes = persistentIndexList();
- QModelIndexList newPersistentIndexes = oldPersistentIndexes;
- QList<QListWidgetItem*> tmp = items;
- QList<QListWidgetItem*>::iterator lit = tmp.begin();
- bool changed = false;
- for (int i = 0; i < count; ++i) {
- int oldRow = sorting.at(i).second;
- int tmpitepos = lit - tmp.begin();
- QListWidgetItem *item = tmp.takeAt(oldRow);
- if (tmpitepos > tmp.size())
- --tmpitepos;
- lit = tmp.begin() + tmpitepos;
- lit = sortedInsertionIterator(lit, tmp.end(), order, item);
- int newRow = qMax<qsizetype>(lit - tmp.begin(), 0);
- lit = tmp.insert(lit, item);
- if (newRow != oldRow) {
- if (!changed) {
- emit layoutAboutToBeChanged({}, QAbstractItemModel::VerticalSortHint);
- oldPersistentIndexes = persistentIndexList();
- newPersistentIndexes = oldPersistentIndexes;
- changed = true;
- }
- for (int j = i + 1; j < count; ++j) {
- int otherRow = sorting.at(j).second;
- if (oldRow < otherRow && newRow >= otherRow)
- --sorting[j].second;
- else if (oldRow > otherRow && newRow <= otherRow)
- ++sorting[j].second;
- }
- for (int k = 0; k < newPersistentIndexes.size(); ++k) {
- QModelIndex pi = newPersistentIndexes.at(k);
- int oldPersistentRow = pi.row();
- int newPersistentRow = oldPersistentRow;
- if (oldPersistentRow == oldRow)
- newPersistentRow = newRow;
- else if (oldRow < oldPersistentRow && newRow >= oldPersistentRow)
- newPersistentRow = oldPersistentRow - 1;
- else if (oldRow > oldPersistentRow && newRow <= oldPersistentRow)
- newPersistentRow = oldPersistentRow + 1;
- if (newPersistentRow != oldPersistentRow)
- newPersistentIndexes[k] = createIndex(newPersistentRow,
- pi.column(), pi.internalPointer());
- }
- }
- }
-
- if (changed) {
- items = tmp;
- changePersistentIndexList(oldPersistentIndexes, newPersistentIndexes);
- emit layoutChanged({}, QAbstractItemModel::VerticalSortHint);
- }
+ const auto compareLt = [](const QListWidgetItem *left, const QListWidgetItem *right) -> bool {
+ return *left < *right;
+ };
+
+ const auto compareGt = [](const QListWidgetItem *left, const QListWidgetItem *right) -> bool {
+ return *right < *left;
+ };
+
+ /** Check if range [start,end] is already in sorted position in list.
+ * Take for this the assumption, that outside [start,end] the list
+ * is already sorted. Therefore the sorted check has to be extended
+ * to the first element that is known to be sorted before the range
+ * [start, end], which is (start-1) and the first element after the
+ * range [start, end], which is (end+2) due to end being included.
+ */
+ const auto beginChangedIterator = items.constBegin() + qMax(start - 1, 0);
+ const auto endChangedIterator = items.constBegin() + qMin(end + 2, items.size());
+ const bool needsSorting = !std::is_sorted(beginChangedIterator, endChangedIterator,
+ order == Qt::AscendingOrder ? compareLt : compareGt);
+
+ if (needsSorting)
+ sort(column, order);
}
bool QListModel::itemLessThan(const QPair<QListWidgetItem*,int> &left,
diff --git a/tests/auto/widgets/itemviews/qlistwidget/tst_qlistwidget.cpp b/tests/auto/widgets/itemviews/qlistwidget/tst_qlistwidget.cpp
index 07973d72252..f017e0e06b4 100644
--- a/tests/auto/widgets/itemviews/qlistwidget/tst_qlistwidget.cpp
+++ b/tests/auto/widgets/itemviews/qlistwidget/tst_qlistwidget.cpp
@@ -75,6 +75,8 @@ private slots:
void sortItems();
void sortHiddenItems();
void sortHiddenItems_data();
+ void sortCheckStability_data();
+ void sortCheckStability();
void closeEditor();
void setData_data();
void setData();
@@ -1131,6 +1133,64 @@ void tst_QListWidget::sortHiddenItems()
delete tw;
}
+void tst_QListWidget::sortCheckStability_data() {
+ QTest::addColumn<Qt::SortOrder>("order");
+ QTest::addColumn<QVariantList>("initialList");
+ QTest::addColumn<QVariantList>("expectedList");
+
+ QTest::newRow("ascending strings")
+ << Qt::AscendingOrder
+ << QVariantList{ QString("a"), QString("b"), QString("b"), QString("a")}
+ << QVariantList{ QString("a"), QString("a"), QString("b"), QString("b")};
+
+ QTest::newRow("descending strings")
+ << Qt::DescendingOrder
+ << QVariantList{ QString("a"), QString("b"), QString("b"), QString("a")}
+ << QVariantList{ QString("b"), QString("b"), QString("a"), QString("a")};
+
+ QTest::newRow("ascending numbers")
+ << Qt::AscendingOrder
+ << QVariantList{ 1, 2, 2, 1}
+ << QVariantList{ 1, 1, 2, 2};
+
+ QTest::newRow("descending numbers")
+ << Qt::DescendingOrder
+ << QVariantList{ 1, 2, 2, 1}
+ << QVariantList{ 2, 2, 1, 1};
+}
+
+void tst_QListWidget::sortCheckStability() {
+ QFETCH(Qt::SortOrder, order);
+ QFETCH(const QVariantList, initialList);
+ QFETCH(const QVariantList, expectedList);
+
+ for (const QVariant &data : initialList) {
+ QListWidgetItem *item = new QListWidgetItem(testWidget);
+ item->setData(Qt::DisplayRole, data);
+ }
+
+ QAbstractItemModel *model = testWidget->model();
+ QList<QPersistentModelIndex> persistent;
+ for (int j = 0; j < model->rowCount(QModelIndex()); ++j)
+ persistent << model->index(j, 0, QModelIndex());
+
+ testWidget->sortItems(order);
+
+ QCOMPARE(testWidget->count(), expectedList.size());
+ for (int i = 0; i < testWidget->count(); ++i)
+ QCOMPARE(testWidget->item(i)->text(), expectedList.at(i).toString());
+
+ QVector<QListWidgetItem*> itemOrder(testWidget->count());
+ for (int i = 0; i < testWidget->count(); ++i)
+ itemOrder[i] = testWidget->item(i);
+
+ qobject_cast<QListModel*>(testWidget->model())->ensureSorted(0, order, 1, 1);
+ testWidget->sortItems(order);
+
+ for (int i = 0; i < testWidget->count(); ++i)
+ QCOMPARE(itemOrder[i],testWidget->item(i));
+}
+
class TestListWidget : public QListWidget
{
Q_OBJECT
generated by cgit v1.2.3 (git 2.25.1) at 2025-07-10 02:35:53 +0000