tdf#119126 forcepoint#76 avoid deleting footnote that would delete ...

... undeletable page

(cherry picked from commit 0005b330)

Conflicts:
	sw/qa/extras/layout/layout.cxx

Reviewed-on: https://gerrit.libreoffice.org/66393Tested-by: Xisco Faulí <xiscofauli@libreoffice.org>
Reviewed-by: Miklos Vajna <vmiklos@collabora.com>
(cherry picked from commit 558f01a2)

Change-Id: I4622569eb9c757c6dcbdda32081ddc94e53db919

sw/source/core/inc/frame.hxx

@@ -841,7 +841,7 @@ public:
     bool IsProtected() const;
 
     bool IsColLocked()  const { return mbColLocked; }
-    bool IsDeleteForbidden()  const { return mbForbidDelete; }
+    virtual bool IsDeleteForbidden() const { return mbForbidDelete; }
 
     /// this is the only way to delete a SwFrame instance
     static void DestroyFrame(SwFrame *const pFrame);

sw/source/core/inc/ftnfrm.hxx

@@ -68,6 +68,7 @@ class SwFootnoteFrame: public SwLayoutFrame
 public:
     SwFootnoteFrame( SwFrameFormat*, SwFrame*, SwContentFrame*, SwTextFootnote* );
 
+    virtual bool IsDeleteForbidden() const override;
     virtual void Cut() override;
     virtual void Paste( SwFrame* pParent, SwFrame* pSibling = nullptr ) override;
 

sw/source/core/layout/calcmove.cxx

@@ -245,6 +245,7 @@ void SwFrame::PrepareMake(vcl::RenderContext* pRenderContext)
     StackHack aHack;
     if ( GetUpper() )
     {
+        SwFrameDeleteGuard aDeleteGuard(this);
         if ( lcl_IsCalcUpperAllowed( *this ) )
             GetUpper()->Calc(pRenderContext);
         OSL_ENSURE( GetUpper(), ":-( Layout unstable (Upper gone)." );

sw/source/core/layout/ftnfrm.cxx

@@ -471,6 +471,27 @@ void SwFootnoteFrame::InvalidateNxtFootnoteCnts( SwPageFrame const *pPage )
     }
 }
 
+bool SwFootnoteFrame::IsDeleteForbidden() const
+{
+    if (SwLayoutFrame::IsDeleteForbidden())
+        return true;
+    // needs to be in sync with the ::Cut logic
+    const SwLayoutFrame *pUp = GetUpper();
+    if (pUp)
+    {
+        if (GetPrev())
+            return false;
+
+        // The last footnote takes its container along if it
+        // is deleted. Cut would put pUp->Lower() to the value
+        // of GetNext(), so if there is no GetNext then
+        // Cut would delete pUp. If that condition is true
+        // here then check if the container is delete-forbidden
+        return !GetNext() && pUp->IsDeleteForbidden();
+    }
+    return false;
+}
+
 void SwFootnoteFrame::Cut()
 {
     if ( GetNext() )
@@ -496,7 +517,7 @@ void SwFootnoteFrame::Cut()
     if ( pUp )
     {
         // The last footnote takes its container along
-        if ( !pUp->Lower() )
+        if (!pUp->Lower())
         {
             SwPageFrame *pPage = pUp->FindPageFrame();
             if ( pPage )
@@ -1587,7 +1608,8 @@ void SwFootnoteBossFrame::AppendFootnote( SwContentFrame *pRef, SwTextFootnote *
             pNew->Calc(getRootFrame()->GetCurrShell()->GetOut());
             // #i57914# - adjust fix #i49383#
             if ( !bOldFootnoteFrameLocked && !pNew->GetLower() &&
-                 !pNew->IsColLocked() && !pNew->IsBackMoveLocked() )
+                 !pNew->IsColLocked() && !pNew->IsBackMoveLocked() &&
+                 !pNew->IsDeleteForbidden() )
             {
                 pNew->Cut();
                 SwFrame::DestroyFrame(pNew);
@@ -2192,7 +2214,8 @@ void SwFootnoteBossFrame::RearrangeFootnotes( const SwTwips nDeadLine, const boo
                         if ( !bLock && bUnlockLastFootnoteFrame &&
                              !pLastFootnoteFrame->GetLower() &&
                              !pLastFootnoteFrame->IsColLocked() &&
-                             !pLastFootnoteFrame->IsBackMoveLocked() )
+                             !pLastFootnoteFrame->IsBackMoveLocked() &&
+                             !pLastFootnoteFrame->IsDeleteForbidden() )
                         {
                             pLastFootnoteFrame->Cut();
                             SwFrame::DestroyFrame(pLastFootnoteFrame);

sw/source/core/layout/tabfrm.cxx

@@ -861,6 +861,11 @@ bool SwTabFrame::RemoveFollowFlowLine()
     // #140081# Make code robust.
     if ( !pFollowFlowLine || !pLastLine )
         return true;
+    if (pFollowFlowLine->IsDeleteForbidden())
+    {
+        SAL_WARN("sw.layout", "Cannot remove in-use Follow Flow Line");
+        return true;
+    }
 
     // Move content
     lcl_MoveRowContent( *pFollowFlowLine, *static_cast<SwRowFrame*>(pLastLine) );