wasm: a11y - Implement support for disabled attribute

Fixes: QTBUG-137449
Change-Id: I6aa07c7108b5ad14c12e6f24e71b8dda12fec483
Reviewed-by: Morten Johan Sørvig <morten.sorvig@qt.io>

src/plugins/platforms/wasm/qwasmaccessibility.cpp

@@ -454,7 +454,7 @@ void QWasmAccessibility::setHtmlElementVisibility(QAccessibleInterface *iface, b
 
     container.call<void>("appendChild", element);
 
-    visible = visible && !iface->state().invisible && !iface->state().disabled;
+    visible = visible && !iface->state().invisible;
     setProperty(element, "ariaHidden", !visible); // ariaHidden mean completely hidden; maybe some sort of soft-hidden should be used.
 }
 
@@ -513,6 +513,12 @@ void QWasmAccessibility::setHtmlElementFocus(QAccessibleInterface *iface)
     element.call<void>("focus");
 }
 
+void QWasmAccessibility::setHtmlElementDisabled(QAccessibleInterface *iface)
+{
+    auto element = ensureHtmlElement(iface);
+    setAttribute(element, "aria-disabled", iface->state().disabled);
+}
+
 void QWasmAccessibility::handleStaticTextUpdate(QAccessibleEvent *event)
 {
     switch (event->type()) {
@@ -677,6 +683,7 @@ void QWasmAccessibility::populateAccessibilityTree(QAccessibleInterface *iface)
         setHtmlElementVisibility(iface, true);
         setHtmlElementGeometry(iface);
         setHtmlElementTextName(iface);
+        setHtmlElementDisabled(iface);
         handleIdentifierUpdate(iface);
         handleDescriptionChanged(iface);
     }
@@ -853,6 +860,12 @@ void QWasmAccessibility::notifyAccessibilityUpdate(QAccessibleEvent *event)
     // Handle some common event types. See
     // https://doc.qt.io/qt-5/qaccessible.html#Event-enum
     switch (event->type()) {
+    case QAccessible::StateChanged: {
+        QAccessibleStateChangeEvent *stateChangeEvent = (QAccessibleStateChangeEvent *)event;
+        if (stateChangeEvent->changedStates().disabled)
+            setHtmlElementDisabled(iface);
+    } break;
+
     case QAccessible::DescriptionChanged:
         handleDescriptionChanged(iface);
         return;

src/plugins/platforms/wasm/qwasmaccessibility.h

@@ -58,6 +58,7 @@ private:
     void setHtmlElementTextName(QAccessibleInterface *iface);
     void setHtmlElementTextNameLE(QAccessibleInterface *iface);
     void setHtmlElementFocus(QAccessibleInterface *iface);
+    void setHtmlElementDisabled(QAccessibleInterface *iface);
 
     void handleStaticTextUpdate(QAccessibleEvent *event);
     void handleButtonUpdate(QAccessibleEvent *event);

src/widgets/kernel/qwidget.cpp

@@ -3377,8 +3377,25 @@ QAction *QWidget::addAction(const QIcon &icon, const QString &text, const QKeySe
 void QWidget::setEnabled(bool enable)
 {
     Q_D(QWidget);
+
+#if QT_CONFIG(accessibility)
+    const bool wasEnabled = !testAttribute(Qt::WA_ForceDisabled);
+#endif
+
     setAttribute(Qt::WA_ForceDisabled, !enable);
     d->setEnabled_helper(enable);
+
+#if QT_CONFIG(accessibility)
+    // A widget is enabled if it's parent and itself is enabled.
+    // We do not send state changed events recursively. It is up
+    // to the receiver of the events to check children if required.
+    if (QAccessible::isActive() && wasEnabled != enable) {
+        QAccessible::State states;
+        states.disabled = 1;
+        QAccessibleStateChangeEvent scEvent(this, states);
+        QAccessible::updateAccessibility(&scEvent);
+    }
+#endif
 }
 
 void QWidgetPrivate::setEnabled_helper(bool enable)