add 'explicit operator bool' to our reference classes

Change-Id: I91cfbe2646dcc55b98d2b809c49c9ea073f54f58
Reviewed-on: https://gerrit.libreoffice.org/33517Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>

include/com/sun/star/uno/Reference.h

@@ -93,6 +93,15 @@ public:
     inline bool SAL_CALL is() const
         { return (NULL != _pInterface); }
 
+#if defined LIBO_INTERNAL_ONLY
+    /** Checks if reference is null.
+
+        @return true if reference acquires an interface, i.e. true if it is not null
+    */
+    inline explicit operator bool() const
+        { return is(); }
+#endif
+
     /** Equality operator: compares two interfaces
         Checks if both references are null or refer to the same object.
 

include/rtl/ref.hxx

@@ -195,6 +195,14 @@ public:
         return (m_pBody != NULL);
     }
 
+#if defined LIBO_INTERNAL_ONLY
+    /** Returns True if the handle does point to a valid body.
+     */
+    inline explicit operator bool() const
+    {
+        return is();
+    }
+#endif
 
     /** Returns True if this points to pBody.
      */

include/tools/ref.hxx

@@ -90,6 +90,8 @@ public:
 
     bool Is()         const { return pObj != nullptr; }
 
+    explicit operator bool() const { return Is(); }
+
     T * get()         const { return pObj; }
 
     T * operator ->() const { assert(pObj != nullptr); return pObj; }