a11y atspi: Forward new QAccessibleAnnouncementEvent to AT-SPI

Forward the newly added QAccessibleAnnouncementEvent
to the AT-SPI level as a corresponding AT-SPI Announcement
event.

The AtspiLive enum to specify the priority/politeness
level was added in at-spi2-core/libatspi commit [1] which is
contained in libatspi versions >= 2.50, so define
the relevant values ATSPI_LIVE_ASSERTIVE and ATSPI_LIVE_POLITE
manually for older libatspi versions.

(Note that the mention of binary compatibility in above-mentioned
at-spi2-core commit only applies for ATK, not AT-SPI, so is not
relevant here.)

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

[1] https://gitlab.gnome.org/GNOME/at-spi2-core/-/commit/32c9420ec82f07da8033c675a2bbf25e535f0509

Task-number: QTBUG-75003
Change-Id: I752aadca2abdda58b3869e17e74fcd9d7572f915
Reviewed-by: Axel Spoerl <axel.spoerl@qt.io>
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>

2 files changed, 41 insertions, 0 deletions

diff --git a/src/gui/accessible/linux/atspiadaptor.cpp b/src/gui/accessible/linux/atspiadaptor.cpp
index b3269a2a95..2cebad1453 100644
--- a/src/gui/accessible/linux/atspiadaptor.cpp
+++ b/src/gui/accessible/linux/atspiadaptor.cpp
@@ -35,6 +35,13 @@
 #define ATSPI_COORD_TYPE_PARENT 2
 #endif
 
+// ATSPI_*_VERSION defines were added in libatspi 2.50,
+// as was the AtspiLive enum; define values here for older versions
+#if !defined(ATSPI_MAJOR_VERSION) || !defined(ATSPI_MINOR_VERSION) || ATSPI_MAJOR_VERSION < 2 || ATSPI_MINOR_VERSION < 50
+#define ATSPI_LIVE_POLITE 1
+#define ATSPI_LIVE_ASSERTIVE 2
+#endif
+
 QT_BEGIN_NAMESPACE
 
 using namespace Qt::StringLiterals;
@@ -47,6 +54,7 @@ AtSpiAdaptor::AtSpiAdaptor(DBusConnection *connection, QObject *parent)
     , sendFocus(0)
     , sendObject(0)
     , sendObject_active_descendant_changed(0)
+    , sendObject_announcement(0)
     , sendObject_attributes_changed(0)
     , sendObject_bounds_changed(0)
     , sendObject_children_changed(0)
@@ -678,6 +686,8 @@ void AtSpiAdaptor::setBitFlag(const QString &flag)
             if (false) {
             } else if (right.startsWith("ActiveDescendantChanged"_L1)) {
                 sendObject_active_descendant_changed = 1;
+            } else if (right.startsWith("Announcement"_L1)) {
+                sendObject_announcement = 1;
             } else if (right.startsWith("AttributesChanged"_L1)) {
                 sendObject_attributes_changed = 1;
             } else if (right.startsWith("BoundsChanged"_L1)) {
@@ -929,6 +939,26 @@ void AtSpiAdaptor::notifyStateChange(QAccessibleInterface *interface, const QStr
     sendDBusSignal(path, ATSPI_DBUS_INTERFACE_EVENT_OBJECT ""_L1, "StateChanged"_L1, stateArgs);
 }
 
+void AtSpiAdaptor::sendAnnouncement(QAccessibleAnnouncementEvent *event)
+{
+    QAccessibleInterface *iface = event->accessibleInterface();
+    if (!iface) {
+        qCWarning(lcAccessibilityAtspi, "Announcement event has no accessible set.");
+        return;
+    }
+    if (!iface->isValid()) {
+        qCWarning(lcAccessibilityAtspi) << "Announcement event with invalid accessible: " << iface;
+        return;
+    }
+
+    const QString path = pathForInterface(iface);
+    const QString message = event->message();
+    const QAccessible::AnnouncementPriority prio = event->priority();
+    const int politeness = (prio == QAccessible::AnnouncementPriority::Assertive) ? ATSPI_LIVE_ASSERTIVE : ATSPI_LIVE_POLITE;
+
+    const QVariantList args = packDBusSignalArguments(QString(), politeness, 0, QVariant::fromValue(QDBusVariant(message)));
+    sendDBusSignal(path, ATSPI_DBUS_INTERFACE_EVENT_OBJECT ""_L1, "Announcement"_L1, args);
+}
 
 /*!
     This function gets called when Qt notifies about accessibility updates.
@@ -1003,6 +1033,14 @@ void AtSpiAdaptor::notify(QAccessibleEvent *event)
             sendFocusChanged(event->accessibleInterface());
         break;
     }
+
+    case QAccessible::Announcement: {
+        if (sendObject || sendObject_announcement) {
+            QAccessibleAnnouncementEvent *announcementEvent = static_cast<QAccessibleAnnouncementEvent*>(event);
+            sendAnnouncement(announcementEvent);
+        }
+        break;
+    }
     case QAccessible::TextInserted:
     case QAccessible::TextRemoved:
     case QAccessible::TextUpdated: {
diff --git a/src/gui/accessible/linux/atspiadaptor_p.h b/src/gui/accessible/linux/atspiadaptor_p.h
index c2f9b60ebf..aab15d4501 100644
--- a/src/gui/accessible/linux/atspiadaptor_p.h
+++ b/src/gui/accessible/linux/atspiadaptor_p.h
@@ -85,6 +85,8 @@ private:
 
     void notifyStateChange(QAccessibleInterface *interface, const QString& state, int value);
 
+    void sendAnnouncement(QAccessibleAnnouncementEvent *event);
+
     // accessible helper functions
     AtspiRole getRole(QAccessibleInterface *interface) const;
     QSpiRelationArray relationSet(QAccessibleInterface *interface, const QDBusConnection &connection) const;
@@ -130,6 +132,7 @@ private:
     // all of object
     uint sendObject : 1;
     uint sendObject_active_descendant_changed : 1;
+    uint sendObject_announcement : 1;
     uint sendObject_attributes_changed : 1;
     uint sendObject_bounds_changed : 1;
     uint sendObject_children_changed : 1;