a11y uia: Forward new QAccessibleAnnouncementEvent to UIA

Bridge the newly added QAccessibleAnnouncementEvent to UIA
on Windows, by calling UiaRaiseNotificationEvent [1].

This makes the announcement from the example app attached
to QTBUG-75003 work when using the NVDA screen reader on Windows.

As described in commit d25d9f2c26,
implement the UiaRaiseNotificationEvent function for MingW
in qwindowsuiautomation as MingW doesn't provide that
itself yet (see the earlier MingW build failure without
that "kludge" in place: [2]).

[1] https://learn.microsoft.com/en-us/windows/win32/api/uiautomationcoreapi/nf-uiautomationcoreapi-uiaraisenotificationevent
[2] a2e63edda6/build_1714142084/log.txt.gz

Fixes: QTBUG-75003
Change-Id: Ia32d49276e0dd33cff5113b4169ee317869390e7
Reviewed-by: Oliver Wolff <oliver.wolff@qt.io>

src/plugins/platforms/windows/uiautomation/qwindowsuiaaccessibility.cpp

@@ -127,6 +127,9 @@ void QWindowsUiaAccessibility::notifyAccessibilityUpdate(QAccessibleEvent *event
         return;
 
     switch (event->type()) {
+    case QAccessible::Announcement:
+        QWindowsUiaMainProvider::raiseNotification(static_cast<QAccessibleAnnouncementEvent *>(event));
+        break;
     case QAccessible::Focus:
         QWindowsUiaMainProvider::notifyFocusChange(event);
         break;

src/plugins/platforms/windows/uiautomation/qwindowsuiamainprovider.cpp

@@ -204,6 +204,24 @@ void QWindowsUiaMainProvider::notifyTextChange(QAccessibleEvent *event)
     }
 }
 
+void QWindowsUiaMainProvider::raiseNotification(QAccessibleAnnouncementEvent *event)
+{
+    if (QAccessibleInterface *accessible = event->accessibleInterface()) {
+        if (QWindowsUiaMainProvider *provider = providerForAccessible(accessible)) {
+            BSTR message = bStrFromQString(event->message());
+            QAccessible::AnnouncementPriority prio = event->priority();
+            NotificationProcessing processing = (prio == QAccessible::AnnouncementPriority::Assertive)
+                    ? NotificationProcessing_ImportantAll
+                    : NotificationProcessing_All;
+            BSTR activityId = bStrFromQString(QString::fromLatin1(""));
+            UiaRaiseNotificationEvent(provider, NotificationKind_Other, processing, message, activityId);
+
+            ::SysFreeString(message);
+            ::SysFreeString(activityId);
+        }
+    }
+}
+
 HRESULT STDMETHODCALLTYPE QWindowsUiaMainProvider::QueryInterface(REFIID iid, LPVOID *iface)
 {
     HRESULT result = QComObject::QueryInterface(iid, iface);

src/plugins/platforms/windows/uiautomation/qwindowsuiamainprovider.h

@@ -34,6 +34,7 @@ public:
     static void notifyNameChange(QAccessibleEvent *event);
     static void notifySelectionChange(QAccessibleEvent *event);
     static void notifyTextChange(QAccessibleEvent *event);
+    static void raiseNotification(QAccessibleAnnouncementEvent *event);
 
     // IUnknown
     HRESULT STDMETHODCALLTYPE QueryInterface(REFIID id, LPVOID *iface) override;

src/plugins/platforms/windows/uiautomation/qwindowsuiautomation.cpp

@@ -69,6 +69,14 @@ HRESULT WINAPI UiaRaiseAutomationEvent(IRawElementProviderSimple *pProvider, EVE
     return func.invoke(pProvider, id);
 }
 
+HRESULT WINAPI UiaRaiseNotificationEvent(
+    IRawElementProviderSimple *pProvider, NotificationKind notificationKind,
+    NotificationProcessing notificationProcessing, BSTR displayString, BSTR activityId)
+{
+    static auto func = winapi_func("uiautomationcore", FN(UiaRaiseNotificationEvent));
+    return func.invoke(pProvider, notificationKind, notificationProcessing, displayString, activityId);
+}
+
 #endif // defined(__MINGW32__) || defined(__MINGW64__)
 
 #endif // QT_CONFIG(accessibility)