Make reference counting for QAxClientSite multi-processor safe

It is not safe to use ++long/--long to implement reference counting for
COM object in multi-processor environment. We use InterlockedIncrement()
and InterlockedDecrement() to implement reference counting.

Change-Id: Ibfc5f3456cbaefb9267feb378483c5c60c305f00
Reviewed-by: Bradley T. Hughes <bradley.hughes@nokia.com>
Reviewed-by: Joerg Bornemann <joerg.bornemann@nokia.com>

1 files changed, 6 insertions, 6 deletions

diff --git a/src/activeqt/container/qaxwidget.cpp b/src/activeqt/container/qaxwidget.cpp
index 92a1e11729..a11ac7a61b 100644
--- a/src/activeqt/container/qaxwidget.cpp
+++ b/src/activeqt/container/qaxwidget.cpp
@@ -408,7 +408,7 @@ private:
     CONTROLINFO control_info;
 
     QSize sizehint;
-    unsigned long ref;
+    LONG ref;
     QAxWidget *widget;
     QAxHostWidget *host;
 #if !defined(Q_WS_WINCE)
@@ -774,16 +774,16 @@ void QAxClientSite::deactivate()
 //**** IUnknown
 unsigned long WINAPI QAxClientSite::AddRef()
 {
-    return ++ref;
+    return InterlockedIncrement(&ref);
 }
 
 unsigned long WINAPI QAxClientSite::Release()
 {
-    if (!--ref) {
+    LONG refCount = InterlockedDecrement(&ref);
+    if (!refCount)
         delete this;
-        return 0;
-    }
-    return ref;
+
+    return refCount;
 }
 
 HRESULT WINAPI QAxClientSite::QueryInterface(REFIID iid, void **iface)