a11y: Prevent one case of losing a11y interface when setting event child

9a369a25ddfac9352cabde65c8476c7433dc6c3a added a
QAccessibleEvent ctor that takes a QAccessibleInterface*
instead of a QObject*.

Retrieving the QAccessibleInterface* later is done using the
interface's unique ID stored in the m_uniqueId member.

However, the fact that m_uniqueId is a member
of the union alongside with m_child means that setting
a child via QAccessibleEvent::setChild also overwrites
the stored unique ID, which breaks retrieving the accessible
interface later.

Fix this for the case where the QAccessibleInterface has
an associated QObject by assigning m_object in the ctor as well.
This means that a QAccessibleEvent created using either of the two
constructors (the one taking the QObject* and the one taking
the QAccessibleInterface* associated with the object) now behaves
the same.

Fixing the case where there is no associated QObject would require
further changes (e.g. adding a member for the QAccessibleInterface*
or making the m_uniqueId member a separate member instead of having
it in a union with m_child). However, I see no way to do so without
breaking the ABI, so that is left unchanged.

This also adds a corresponding test case.

Fixes: QTBUG-105988
Pick-to: 6.4
Change-Id: I71a548af0277a5034e9e207f066fa3e25c5393f3
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>
This commit is contained in:
Michael Weghorn 2022-08-26 14:51:04 +02:00 committed by Tor Arne Vestbø
parent 063344c8b9
commit 0c0eadc484
2 changed files with 30 additions and 1 deletions

View File

@ -287,7 +287,7 @@ public:
}
inline QAccessibleEvent(QAccessibleInterface *iface, QAccessible::Event typ)
: m_type(typ), m_object(nullptr)
: m_type(typ)
{
Q_ASSERT(iface);
Q_ASSERT(m_type != QAccessible::ValueChanged);
@ -299,6 +299,7 @@ public:
Q_ASSERT(m_type != QAccessible::TextUpdated);
Q_ASSERT(m_type != QAccessible::TableModelChanged);
m_uniqueId = QAccessible::uniqueId(iface);
m_object = iface->object();
}
virtual ~QAccessibleEvent();

View File

@ -163,6 +163,7 @@ public slots:
void cleanup();
private slots:
void eventTest();
void eventWithChildTest();
void customWidget();
void deletedWidget();
void subclassedWidget();
@ -353,6 +354,33 @@ void tst_QAccessibility::eventTest()
QTestAccessibility::clearEvents();
}
void tst_QAccessibility::eventWithChildTest()
{
// make sure that QAccessibleEvent created using either of the two QAccessibleEvent
// behaves the same when the same underlying QObject is used
QWidget widget;
QWidget childWidget(&widget);
// QAccessibleEvent constructor called with the QObject*
QAccessibleEvent event1(&widget, QAccessible::Focus);
// QAccessibleEvent constructor called with the QAccessibleInterface* for the same QObject*
QAccessibleInterface *iface = QAccessible::queryAccessibleInterface(&widget);
QAccessibleEvent event2(iface, QAccessible::Focus);
QVERIFY(event1.accessibleInterface() != nullptr);
QVERIFY(event2.accessibleInterface() != nullptr);
QCOMPARE(event1.accessibleInterface(), event2.accessibleInterface());
// set same child for both
event1.setChild(0);
event2.setChild(0);
QVERIFY(event1.accessibleInterface() != nullptr);
QVERIFY(event2.accessibleInterface() != nullptr);
QCOMPARE(event1.accessibleInterface(), event2.accessibleInterface());
}
void tst_QAccessibility::customWidget()
{
{