Cache QAccessibleInterfaces.

Since there already is a one-to-one relationship
between QObject and QAccessibleInterface it makes
little sense to create and destroy the interfaces
on each call to queryAccessibleInterface.

Add a cache and keep created interfaces around for
the lifetime of the corresponding QObject.

This changes the memory management rules: accessible
interfaces must no longer be deleted. If you get an
QAccessibleIntrface pointer that pointer will stay
valid as long as the corresponding QObject is not
deleted.

This also re-enables accessibility for Mac.

We limit the range of the IDs so that they are
useable for Windows directly.
That means we can get rid of the event cache there.

This is based on: Iebf2f374916fc70a9dd29e95f45a6444b85f6cee

Change-Id: I9fe6531812c0dbc5b41101ac05830a6dd75e13a3
Reviewed-by: Morten Johan Sørvig <morten.sorvig@digia.com>

1 files changed, 17 insertions, 3 deletions

diff --git a/src/gui/accessible/qaccessible.h b/src/gui/accessible/qaccessible.h
index 09e259c1d0..8447f34154 100644
--- a/src/gui/accessible/qaccessible.h
+++ b/src/gui/accessible/qaccessible.h
@@ -45,6 +45,7 @@
 #ifndef QACCESSIBLE_H
 #define QACCESSIBLE_H
 
+#include <QtCore/qdebug.h>
 #include <QtCore/qglobal.h>
 #include <QtCore/qobject.h>
 #include <QtCore/qrect.h>
@@ -58,7 +59,6 @@
 
 QT_BEGIN_NAMESPACE
 
-
 class QAccessibleInterface;
 class QAccessibleEvent;
 class QWindow;
@@ -335,12 +335,20 @@ public:
     typedef void(*UpdateHandler)(QAccessibleEvent *event);
     typedef void(*RootObjectHandler)(QObject*);
 
+    typedef unsigned Id;
+
     static void installFactory(InterfaceFactory);
     static void removeFactory(InterfaceFactory);
     static UpdateHandler installUpdateHandler(UpdateHandler);
     static RootObjectHandler installRootObjectHandler(RootObjectHandler);
 
     static QAccessibleInterface *queryAccessibleInterface(QObject *);
+    static Id uniqueId(QAccessibleInterface *iface);
+    static QAccessibleInterface *accessibleInterface(Id uniqueId);
+    static Id registerAccessibleInterface(QAccessibleInterface *iface);
+    static void deleteAccessibleInterface(Id uniqueId);
+
+
 #if QT_DEPRECATED_SINCE(5, 0)
     QT_DEPRECATED static inline void updateAccessibility(QObject *object, int child, Event reason);
 #endif
@@ -360,6 +368,8 @@ private:
       it is not supposed to be instantiated.
     */
     QAccessible() {}
+
+    friend class QAccessibleCache;
 };
 
 Q_GUI_EXPORT bool operator==(const QAccessible::State &first, const QAccessible::State &second);
@@ -377,8 +387,10 @@ class QAccessibleTableCellInterface;
 
 class Q_GUI_EXPORT QAccessibleInterface
 {
+protected:
+    virtual ~QAccessibleInterface();
+
 public:
-    virtual ~QAccessibleInterface() {}
     // check for valid pointers
     virtual bool isValid() const = 0;
     virtual QObject *object() const = 0;
@@ -431,7 +443,9 @@ public:
 
     virtual void *interface_cast(QAccessible::InterfaceType)
     { return 0; }
-private:
+
+protected:
+    friend class QAccessibleCache;
 };
 
 class Q_GUI_EXPORT QAccessibleEvent