guard against styles based on themselves

which leads to stack exhaustion when queries,

make m_BasedOnStyle private and replace it with
a call to GetBasedOnStyle which checks that
the base style is not itself

(cherry picked from commit da5e8ba3)
Reviewed-on: https://gerrit.libreoffice.org/20531Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>
(cherry picked from commit 7e5b93bf)

Change-Id: I093546793755f8a3a6e8a3c23fb8565ad27b75da
Reviewed-on: https://gerrit.libreoffice.org/20532Reviewed-by: David Tardon <dtardon@redhat.com>
Tested-by: David Tardon <dtardon@redhat.com>

lotuswordpro/source/filter/lwpcelllayout.cxx

@@ -269,7 +269,7 @@ void LwpCellLayout::ApplyFmtStyle(XFCellStyle *pCellStyle)
     if (!pLayoutNumerics)
     {
         // if current layout doesn't have format, go to based on layout
-        LwpCellLayout* pCellLayout = dynamic_cast<LwpCellLayout*>(m_BasedOnStyle.obj().get());
+        LwpCellLayout* pCellLayout = dynamic_cast<LwpCellLayout*>(GetBasedOnStyle().get());
         if (pCellLayout)
         {
             pLayoutNumerics = dynamic_cast<LwpLayoutNumerics*>(pCellLayout->GetNumericsObject().obj().get());
@@ -656,7 +656,7 @@ void LwpCellLayout::ApplyProtect(XFCell * pCell, LwpObjectID aTableID)
     else
     {
         // judge base on
-        LwpCellLayout * pBase = dynamic_cast<LwpCellLayout *>(m_BasedOnStyle.obj().get());
+        LwpCellLayout * pBase = dynamic_cast<LwpCellLayout *>(GetBasedOnStyle().get());
         if (pBase && pBase->IsProtected())
         {
             bProtected = true;

lotuswordpro/source/filter/lwplayout.hxx

@@ -328,6 +328,8 @@ public:
 
 protected:
     void Read() SAL_OVERRIDE;
+private:
+    LwpObjectID m_BasedOnStyle;
 protected:
     enum
     {
@@ -336,8 +338,7 @@ protected:
     };
 
     LwpObjectID m_Content;
-    LwpObjectID m_BasedOnStyle;
-
+    rtl::Reference<LwpObject> GetBasedOnStyle();
     LwpObjectID     m_TabPiece;
     LwpLayoutStyle* m_pStyleStuff;
     LwpLayoutMisc*  m_pMiscStuff;

lotuswordpro/source/filter/lwpobjid.cxx

@@ -187,12 +187,12 @@ sal_uInt32 LwpObjectID::DiskSizeIndexed() const
 */
 rtl::Reference<LwpObject> LwpObjectID::obj(VO_TYPE tag) const
 {
-    LwpGlobalMgr* pGlobal = LwpGlobalMgr::GetInstance();
-    LwpObjectFactory* pObjMgr = pGlobal->GetLwpObjFactory();
-    if(IsNull())
+    if (IsNull())
     {
         return NULL;
     }
+    LwpGlobalMgr* pGlobal = LwpGlobalMgr::GetInstance();
+    LwpObjectFactory* pObjMgr = pGlobal->GetLwpObjFactory();
     rtl::Reference<LwpObject> pObj = pObjMgr->QueryObject(*this);
     if( tag!=VO_INVALID &&  (pObj.is()) )
     {