Add QAccessible::ActivationObserver

Makes it possible to follow changes in activation an deactivation of a11y.
Needed for WebEngine to know when to activate a11y.

Change-Id: Ia264a76974224d1baad3e88c34a4b8a9f1a3695d
Reviewed-by: Jan Arve Sæther <jan-arve.saether@digia.com>

src/gui/accessible/qaccessible.cpp

@@ -465,9 +465,11 @@ Q_GLOBAL_STATIC_WITH_ARGS(QFactoryLoader, loader,
 #endif
 #endif
 
+// FIXME turn this into one global static struct
 Q_GLOBAL_STATIC(QList<QAccessible::InterfaceFactory>, qAccessibleFactories)
 typedef QHash<QString, QAccessiblePlugin*> QAccessiblePluginsHash;
-Q_GLOBAL_STATIC(QAccessiblePluginsHash, qAccessiblePlugins);
+Q_GLOBAL_STATIC(QAccessiblePluginsHash, qAccessiblePlugins)
+Q_GLOBAL_STATIC(QList<QAccessible::ActivationObserver *>, qAccessibleActivationObservers)
 
 QAccessible::UpdateHandler QAccessible::updateHandler = 0;
 QAccessible::RootObjectHandler QAccessible::rootObjectHandler = 0;
@@ -504,6 +506,7 @@ void QAccessible::cleanup()
 
 static void qAccessibleCleanup()
 {
+    qAccessibleActivationObservers()->clear();
     qAccessibleFactories()->clear();
 }
 
@@ -603,6 +606,44 @@ QAccessible::RootObjectHandler QAccessible::installRootObjectHandler(RootObjectH
     return old;
 }
 
+/*!
+    \class QAccessible::ActivationObserver
+    \internal
+
+    Interface to listen to activation or deactivation of the accessibility framework.
+    \sa installActivationObserver()
+*/
+
+/*!
+    \internal
+
+    Install \a observer to get notified of activation or deactivation (global accessibility has been enabled or disabled).
+*/
+void QAccessible::installActivationObserver(QAccessible::ActivationObserver *observer)
+{
+    if (!observer)
+        return;
+
+    if (!cleanupAdded) {
+        qAddPostRoutine(qAccessibleCleanup);
+        cleanupAdded = true;
+    }
+    if (qAccessibleActivationObservers()->contains(observer))
+        return;
+    qAccessibleActivationObservers()->append(observer);
+}
+
+/*!
+    \internal
+
+    Remove an \a observer to no longer get notified of state changes.
+    \sa installActivationObserver()
+*/
+void QAccessible::removeActivationObserver(ActivationObserver *observer)
+{
+    qAccessibleActivationObservers()->removeAll(observer);
+}
+
 /*!
     If a QAccessibleInterface implementation exists for the given \a object,
     this function returns a pointer to the implementation; otherwise it
@@ -756,6 +797,15 @@ bool QAccessible::isActive()
     return false;
 }
 
+/*!
+    \internal
+*/
+void QAccessible::setActive(bool active)
+{
+    for (int i = 0; i < qAccessibleActivationObservers()->count() ;++i)
+        qAccessibleActivationObservers()->at(i)->accessibilityActiveChanged(active);
+}
+
 
 /*!
   Sets the root object of the accessible objects of this application

src/gui/accessible/qaccessible.h

@@ -352,6 +352,15 @@ public:
     static UpdateHandler installUpdateHandler(UpdateHandler);
     static RootObjectHandler installRootObjectHandler(RootObjectHandler);
 
+    class ActivationObserver
+    {
+    public:
+        virtual ~ActivationObserver() {}
+        virtual void accessibilityActiveChanged(bool active) = 0;
+    };
+    static void installActivationObserver(ActivationObserver *);
+    static void removeActivationObserver(ActivationObserver *);
+
     static QAccessibleInterface *queryAccessibleInterface(QObject *);
     static Id uniqueId(QAccessibleInterface *iface);
     static QAccessibleInterface *accessibleInterface(Id uniqueId);
@@ -365,6 +374,7 @@ public:
     static void updateAccessibility(QAccessibleEvent *event);
 
     static bool isActive();
+    static void setActive(bool active);
     static void setRootObject(QObject *object);
 
     static void cleanup();

src/gui/accessible/qplatformaccessibility.cpp

@@ -139,6 +139,12 @@ void QPlatformAccessibility::cleanup()
     qDeleteAll(*bridges());
 }
 
+void QPlatformAccessibility::setActive(bool active)
+{
+    m_active = active;
+    QAccessible::setActive(active);
+}
+
 #endif // QT_NO_ACCESSIBILITY
 
 QT_END_NAMESPACE

src/gui/accessible/qplatformaccessibility.h

@@ -70,7 +70,7 @@ public:
     virtual void cleanup();
 
     inline bool isActive() const { return m_active; }
-    inline void setActive(bool active) { m_active = active; }
+    void setActive(bool active);
 
 private:
     bool m_active;