QAccessible: consistently respect rootIndex of item views

Accessibility implementations rely on correct information about the
model dimensions when operating on item views. An item view that has a
root index set needs to report it's size based on the root index, rather
than for the view's model directly.

Pass the rootIndex to all calls to QAbstractItemModel::column/rowCount.
Refactor the code to avoid excessive dereferencing of a QPointer, apply
const and fix/improve coding style in touched lines.

Emit a ModelReset notification when the root index changes, or (in the
case of QListView) when the model column changes.

Split long Q_ASSERTs into multiple lines to be able to better trace the
exact reason for an assertion, and replace the assert with an early
return of nil when it's plausible that a cached cell is no longer part
of the view (i.e. because the root index changed).

Add a test case that verifies that changing the root index changes the
dimension of the view as reported through the accessibility interface.

Pick-to: 6.6 6.5
Fixes: QTBUG-114423
Change-Id: I7897b79b2e1d10c789cc866b7f5c5dabdabe6770
Reviewed-by: Jan Arve Sæther <jan-arve.saether@qt.io>

1 files changed, 7 insertions, 3 deletions

diff --git a/src/plugins/platforms/cocoa/qcocoaaccessibilityelement.mm b/src/plugins/platforms/cocoa/qcocoaaccessibilityelement.mm
index 7a1bab7351..85c395e2bf 100644
--- a/src/plugins/platforms/cocoa/qcocoaaccessibilityelement.mm
+++ b/src/plugins/platforms/cocoa/qcocoaaccessibilityelement.mm
@@ -130,7 +130,8 @@ static void convertLineOffset(QAccessibleTextInterface *text, int *line, int *of
                     if (tableInterface) {
                         auto *tableElement = [QMacAccessibilityElement elementWithInterface:table];
                         Q_ASSERT(tableElement);
-                        Q_ASSERT(tableElement->rows && int(tableElement->rows.count) > m_rowIndex);
+                        Q_ASSERT(tableElement->rows);
+                        Q_ASSERT(int(tableElement->rows.count) > m_rowIndex);
                         auto *rowElement = tableElement->rows[m_rowIndex];
                         if (!rowElement->columns) {
                             rowElement->columns = [rowElement populateTableRow:rowElement->columns
@@ -490,7 +491,8 @@ static void convertLineOffset(QAccessibleTextInterface *text, int *line, int *of
         // a synthetic cell without interface - shortcut to the row
         QMacAccessibilityElement *tableElement =
                     [QMacAccessibilityElement elementWithId:axid];
-        Q_ASSERT(tableElement && tableElement->rows && int(tableElement->rows.count) > m_rowIndex);
+        Q_ASSERT(tableElement && tableElement->rows);
+        Q_ASSERT(int(tableElement->rows.count) > m_rowIndex);
         QMacAccessibilityElement *rowElement = tableElement->rows[m_rowIndex];
         return rowElement;
     }
@@ -520,7 +522,9 @@ static void convertLineOffset(QAccessibleTextInterface *text, int *line, int *of
                 rowIndex = m_rowIndex;
             else if (QAccessibleTableCellInterface *cell = iface->tableCellInterface())
                 rowIndex = cell->rowIndex();
-            Q_ASSERT(tableElement->rows && int([tableElement->rows count]) > rowIndex);
+            Q_ASSERT(tableElement->rows);
+            if (rowIndex > int([tableElement->rows count]))
+                return nil;
             QMacAccessibilityElement *rowElement = tableElement->rows[rowIndex];
             return NSAccessibilityUnignoredAncestor(rowElement);
         }