replace remaining FlowFrmJoinLockGuard with SwFrmDeleteGuard

Given both tdf#91695 and the remaining crash on novell622972-2.html
it seems now safer to replace the remaining FlowFrmJoinLockGuard with
SwFrmDeleteGuard and rely on IsDeleteForbidden instead of IsJoinLocked
for the crashing layout edge-cases

and bundle the IsDeleteForbidden other IsDeleteForbidden users together
under SwFrmDeleteGuard

Change-Id: I017b6155daa3a6e49c5bee5b21ca4eddcfd5b5c0

sw/source/core/inc/flowfrm.hxx

@@ -62,7 +62,6 @@ class SwFlowFrm
     friend inline void TableSplitRecalcUnlock( SwFlowFrm * );
     // #i44049#
     friend class SwObjectFormatterTextFrm;
-    friend class FlowFrmJoinLockGuard;
 
     // TableSel is allowed to reset the follow-bit
     friend inline void UnsetFollow( SwFlowFrm *pFlow );
@@ -236,38 +235,6 @@ inline bool SwFlowFrm::IsFwdMoveAllowed()
     return m_rThis.GetIndPrev() != 0;
 }
 
-//use this to protect a SwLayoutFrm for a given scope from getting merged with
-//its neighbour and thus deleted
-class FlowFrmJoinLockGuard
-{
-private:
-    SwFlowFrm *m_pFlow;
-    bool m_bOldJoinLocked;
-public:
-    //JoinLock pParent for the lifetime of the Cut/Paste call, etc. to avoid
-    //SwSectionFrm::MergeNext removing the pParent we're trying to reparent
-    //into
-    FlowFrmJoinLockGuard(SwLayoutFrm* pFrm)
-    {
-        m_pFlow = SwFlowFrm::CastFlowFrm(pFrm);
-        if (m_pFlow)
-        {
-            m_bOldJoinLocked = m_pFlow->IsJoinLocked();
-            m_pFlow->LockJoin();
-        }
-        else
-        {
-            m_bOldJoinLocked = false;
-        }
-    }
-
-    ~FlowFrmJoinLockGuard()
-    {
-        if (m_pFlow && !m_bOldJoinLocked)
-            m_pFlow->UnlockJoin();
-    }
-};
-
 #endif
 
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */

sw/source/core/inc/frame.hxx

@@ -1150,6 +1150,32 @@ inline bool SwFrm::IsAccessibleFrm() const
 {
     return (GetType() & FRM_ACCESSIBLE) != 0;
 }
+
+//use this to protect a SwFrm for a given scope from getting deleted
+class SwFrmDeleteGuard
+{
+private:
+    SwFrm *m_pFrm;
+    bool m_bOldDeleteAllowed;
+public:
+    //Flag pFrm for SwFrmDeleteGuard lifetime that we shouldn't delete
+    //it in e.g. SwSectionFrm::MergeNext etc because we will need it
+    //again after the SwFrmDeleteGuard dtor
+    SwFrmDeleteGuard(SwFrm* pFrm)
+        : m_pFrm(pFrm)
+    {
+        m_bOldDeleteAllowed = m_pFrm && !m_pFrm->IsDeleteForbidden();
+        if (m_bOldDeleteAllowed)
+            m_pFrm->ForbidDelete();
+    }
+
+    ~SwFrmDeleteGuard()
+    {
+        if (m_bOldDeleteAllowed)
+            m_pFrm->AllowDelete();
+    }
+};
+
 #endif
 
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */

sw/source/core/layout/calcmove.cxx

@@ -346,9 +346,10 @@ void SwFrm::OptPrepareMake()
     if ( GetUpper() && !GetUpper()->IsFooterFrm() &&
          !GetUpper()->IsFlyFrm() )
     {
-        ForbidDelete();
-        GetUpper()->Calc(getRootFrm()->GetCurrShell() ? getRootFrm()->GetCurrShell()->GetOut() : 0);
-        AllowDelete();
+        {
+            SwFrmDeleteGuard aDeleteGuard(this);
+            GetUpper()->Calc(getRootFrm()->GetCurrShell() ? getRootFrm()->GetCurrShell()->GetOut() : 0);
+        }
         OSL_ENSURE( GetUpper(), ":-( Layout unstable (Upper gone)." );
         if ( !GetUpper() )
             return;

sw/source/core/layout/flowfrm.cxx

@@ -577,10 +577,10 @@ void SwFlowFrm::MoveSubTree( SwLayoutFrm* pParent, SwFrm* pSibling )
     bool bInvaLay;
 
     {
-        //JoinLock pParent for the lifetime of the Cut/Paste call to avoid
-        //SwSectionFrm::MergeNext removing the pParent we're trying to reparent
-        //into
-        FlowFrmJoinLockGuard aJoinGuard(pParent);
+        //Ensure pParent persists for the lifetime of the Cut/Paste call to
+        //avoid SwSectionFrm::MergeNext removing the pParent we're trying to
+        //reparent into
+        SwFrmDeleteGuard aDeleteGuard(pParent);
         pOldParent = CutTree( &m_rThis );
         bInvaLay = PasteTree( &m_rThis, pParent, pSibling, pOldParent );
     }

sw/source/core/layout/fly.cxx

@@ -1463,14 +1463,10 @@ void CalcContent( SwLayoutFrm *pLay,
             if ( bNoCalcFollow && pFrm->IsTextFrm() )
                 static_cast<SwTextFrm*>(pFrm)->ForbidFollowFormat();
 
-            const bool bDeleteForbidden(pSect && pSect->IsDeleteForbidden());
-            if (pSect && !bDeleteForbidden)
-                pSect->ForbidDelete();
-
-            pFrm->Calc(pRenderContext);
-
-            if (pSect && !bDeleteForbidden)
-                pSect->AllowDelete();
+            {
+                SwFrmDeleteGuard aDeleteGuard(pSect);
+                pFrm->Calc(pRenderContext);
+            }
 
             // OD 14.03.2003 #i11760# - reset control flag for follow format.
             if ( pFrm->IsTextFrm() )

sw/source/core/layout/layact.cxx

@@ -1223,11 +1223,10 @@ bool SwLayAction::FormatLayout( OutputDevice *pRenderContext, SwLayoutFrm *pLay,
             aOldRect = static_cast<SwPageFrm*>(pLay)->GetBoundRect(pRenderContext);
         }
 
-        bool const bDeleteForbidden(pLay->IsDeleteForbidden());
-        pLay->ForbidDelete();
-        pLay->Calc(pRenderContext);
-        if (!bDeleteForbidden)
-            pLay->AllowDelete();
+        {
+            SwFrmDeleteGuard aDeleteGuard(pLay);
+            pLay->Calc(pRenderContext);
+        }
 
         if ( aOldFrame != pLay->Frm() )
             bChanged = true;
@@ -1375,7 +1374,7 @@ bool SwLayAction::FormatLayout( OutputDevice *pRenderContext, SwLayoutFrm *pLay,
     if ( pLay->IsFootnoteFrm() ) // no LayFrms as Lower
         return bChanged;
 
-    FlowFrmJoinLockGuard aJoinGuard(pLay);
+    SwFrmDeleteGuard aDeleteGuard(pLay);
     SwFrm *pLow = pLay->Lower();
     bool bTabChanged = false;
     while ( pLow && pLow->GetUpper() == pLay )