Introduce menubar plugin system

Merge-request: 916
Reviewed-by: Thierry Bastian <thierry.bastian@nokia.com>
(cherry picked from commit be0d346052d69693c2780e62401f3c0d4b0d89d4)

src/gui/widgets/qabstractmenubarimpl_p.h

@@ -41,7 +41,9 @@
 #ifndef QABSTRACTMENUBARIMPL_P_H
 #define QABSTRACTMENUBARIMPL_P_H
 
+#include <qfactoryinterface.h>
 #include <qglobal.h>
+#include <qplugin.h>
 
 #ifndef QT_NO_MENUBAR
 
@@ -54,6 +56,16 @@ class QMenuBar;
 class QObject;
 class QWidget;
 
+class QAbstractMenuBarImpl;
+
+struct QMenuBarImplFactoryInterface : public QFactoryInterface
+{
+    virtual QAbstractMenuBarImpl* createImpl() = 0;
+};
+
+#define QMenuBarImplFactoryInterface_iid "com.nokia.qt.QMenuBarImplFactoryInterface"
+Q_DECLARE_INTERFACE(QMenuBarImplFactoryInterface, QMenuBarImplFactoryInterface_iid)
+
 /**
  * The platform-specific implementation of a menubar
  */

src/gui/widgets/qmenubar.cpp

@@ -55,6 +55,7 @@
 #include <qtoolbar.h>
 #include <qtoolbutton.h>
 #include <qwhatsthis.h>
+#include <qpluginloader.h>
 
 #ifndef QT_NO_MENUBAR
 
@@ -728,7 +729,8 @@ void QMenuBarPrivate::init()
     Q_Q(QMenuBar);
     q->setSizePolicy(QSizePolicy::MinimumExpanding, QSizePolicy::Minimum);
     q->setAttribute(Qt::WA_CustomWhatsThis);
-    impl = new QMenuBarImpl;
+
+    impl = qt_guiMenuBarImplFactory()->createImpl();
     impl->init(q);
 
     q->setBackgroundRole(QPalette::Button);

src/gui/widgets/qmenubarimpl.cpp

@@ -48,6 +48,8 @@
 #include "qmenu.h"
 #include "qmenubar.h"
 
+#include <private/qfactoryloader_p.h>
+
 QT_BEGIN_NAMESPACE
 
 QMenuBarImpl::~QMenuBarImpl()
@@ -239,6 +241,28 @@ bool QMenuBarImpl::menuBarEventFilter(QObject *, QEvent *)
     return false;
 }
 
+struct QMenuBarImplFactory : public QMenuBarImplFactoryInterface
+{
+    QAbstractMenuBarImpl* createImpl() { return new QMenuBarImpl; }
+    virtual QStringList keys() const { return QStringList(); }
+};
+
+QMenuBarImplFactoryInterface *qt_guiMenuBarImplFactory()
+{
+    static QMenuBarImplFactoryInterface *factory = 0;
+    if (!factory) {
+#ifndef QT_NO_LIBRARY
+        QFactoryLoader loader(QMenuBarImplFactoryInterface_iid, QLatin1String("/menubar"));
+        factory = qobject_cast<QMenuBarImplFactoryInterface *>(loader.instance(QLatin1String("default")));
+#endif // QT_NO_LIBRARY
+        if(!factory) {
+            static QMenuBarImplFactory def;
+            factory = &def;
+        }
+    }
+    return factory;
+}
+
 QT_END_NAMESPACE
 
 #endif // QT_NO_MENUBAR

src/gui/widgets/qmenubarimpl_p.h

@@ -175,6 +175,8 @@ private:
 #endif
 };
 
+QMenuBarImplFactoryInterface *qt_guiMenuBarImplFactory();
+
 QT_END_NAMESPACE
 
 #endif // QT_NO_MENUBAR