Make QAxBase/QAxWidget QDataStream operators hidden friends

Prompted by 4664acf185 adding QAxWidget
operators as non-member non-friends, make both QAxBase and QAxWidget
operator hidden friends, as we want all our operators to be these days.

This change is BC, but it's not 100% SC, because streaming of objects
that merely implicitly convert to QAxWidget/QAxBase, but are not
derived from them, now fails.

Also move the QAxWidget operators out-of-line, so we have some chance
of adding something to them, though the pre-existing QAxBase operators
mean adding anything there will change the serialization format
vis-a-vis 6.8 (nothing a QDataStream version upgrade can't solve,
though).

[ChangeLog][Potentially Source-Incompatiable Changes][QAxBase] The
QDataStream operators are now hidden friends, so they will only match
types which are QAxBase, or derived from it, not those that merely
implicitly convert to them. A backwards-compatible fix is to make the
conversion explicit and only call these operators on actual QAxBase
subclass objects.

Amends the start of the public history and
4664acf185.

Pick-to: 6.9
Change-Id: I60fe1ba10f7478c2dfedf33cc45bbc257f297a4b
Reviewed-by: Oliver Wolff <oliver.wolff@qt.io>
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/activeqt/container/qaxbase.h

@@ -116,6 +116,31 @@ private:
     int internalInvoke(QMetaObject::Call, int index, void **v);
     bool dynamicCallHelper(const char *name, void *out, QList<QVariant> &var,
                            QByteArray &type, unsigned flags = 0);
+
+private:
+#ifndef QT_NO_DATASTREAM
+    friend QDataStream &operator>>(QDataStream &s, QAxBase &c)
+    {
+        QAxBase::PropertyBag bag;
+        const QSignalBlocker blocker(c.qObject());
+        QString control;
+        s >> control;
+        c.setControl(control);
+        s >> bag;
+        c.setPropertyBag(bag);
+
+        return s;
+    }
+
+    friend QDataStream &operator<<(QDataStream &s, const QAxBase &c)
+    {
+        QAxBase::PropertyBag bag = c.propertyBag();
+        s << c.control();
+        s << bag;
+
+        return s;
+    }
+#endif // QT_NO_DATASTREAM
 };
 
 template <> inline QAxBase *qobject_cast<QAxBase*>(const QObject *o)
@@ -137,30 +162,6 @@ inline QString QAxBase::generateDocumentation()
     return qax_generateDocumentation(this);
 }
 
-#ifndef QT_NO_DATASTREAM
-inline QDataStream &operator >>(QDataStream &s, QAxBase &c)
-{
-    QAxBase::PropertyBag bag;
-    const QSignalBlocker blocker(c.qObject());
-    QString control;
-    s >> control;
-    c.setControl(control);
-    s >> bag;
-    c.setPropertyBag(bag);
-
-    return s;
-}
-
-inline QDataStream &operator <<(QDataStream &s, const QAxBase &c)
-{
-    QAxBase::PropertyBag bag = c.propertyBag();
-    s << c.control();
-    s << bag;
-
-    return s;
-}
-#endif // QT_NO_DATASTREAM
-
 QT_END_NAMESPACE
 
 #ifndef Q_COM_METATYPE_DECLARED

src/activeqt/container/qaxwidget.cpp

@@ -2410,4 +2410,24 @@ bool QAxWidget::translateKeyEvent(int message, int keycode) const
     return translate;
 }
 
+#ifndef QT_NO_DATASTREAM
+/*!
+    \internal
+*/
+// friend
+QDataStream &operator>>(QDataStream &s, QAxWidget &w)
+{
+    return s >> static_cast<QAxBase &>(w);
+}
+
+/*!
+    \internal
+*/
+// friend
+QDataStream &operator<<(QDataStream &s, const QAxWidget &w)
+{
+    return s << static_cast<const QAxBase &>(w);
+}
+#endif // QT_NO_DATASTREAM
+
 QT_END_NAMESPACE

src/activeqt/container/qaxwidget.h

@@ -74,6 +74,11 @@ private:
     Q_DECLARE_PRIVATE(QAxWidget)
 
     friend class QAxClientSite;
+
+#ifndef QT_NO_DATASTREAM
+    friend QDataStream &operator>>(QDataStream &s, QAxWidget &w);
+    friend QDataStream &operator<<(QDataStream &s, const QAxWidget &w);
+#endif
 };
 
 template <> inline QAxWidget *qobject_cast<QAxWidget*>(const QObject *o)
@@ -88,18 +93,6 @@ template <> inline QAxWidget *qobject_cast<QAxWidget*>(QObject *o)
     return static_cast<QAxWidget *>(result);
 }
 
-#ifndef QT_NO_DATASTREAM
-inline QDataStream &operator>>(QDataStream &s, QAxWidget &w)
-{
-    return s >> static_cast<QAxBase &>(w);
-}
-
-inline QDataStream &operator<<(QDataStream &s, const QAxWidget &w)
-{
-    return s << static_cast<const QAxBase &>(w);
-}
-#endif
-
 QT_END_NAMESPACE
 
 #endif // QAXWIDGET_H