sw: layout: ignore Keep-With-Next on hidden frames, part1

When a frame is hidden, don't consider it when evaluating keep-with-next
attributes - this was the case for content in hidden sections before
commit 0c96119895

~SwFrameNotify() invalidating position of hidden frame with keep
attribute causes layout loops.

Also skip hidden frames in SwFlowFrame::IsKeepFwdMoveAllowed(),
SwFlowFrame::CheckKeep(), SwFlowFrame::IsPrevObjMove(),
SwFlowFrame::MoveBwd(), CalcContent().

Change-Id: I68556ba0a8e016d962399f3ce199e5eda0378867
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/177975
Tested-by: Michael Stahl <michael.stahl@allotropia.de>
Reviewed-by: Michael Stahl <michael.stahl@allotropia.de>

sw/source/core/inc/flowfrm.hxx

@@ -184,6 +184,9 @@ public:
                 SvxFormatBreakItem const& rBreak,
                 bool bBreakCheck = false ) const;
 
+    SwFrame * FindPrevIgnoreHidden() const;
+    SwFrame * FindNextIgnoreHidden() const;
+
     bool HasLockedFollow() const;
 
     bool HasParaSpaceAtPages( bool bSct ) const;

sw/source/core/layout/flowfrm.cxx

@@ -131,7 +131,9 @@ bool SwFlowFrame::IsKeepFwdMoveAllowed( bool bIgnoreMyOwnKeepValue )
         if ( bIgnoreMyOwnKeepValue && pFrame->GetIndPrev() )
             pFrame = pFrame->GetIndPrev();
         do
-        {   if ( pFrame->GetAttrSet()->GetKeep().GetValue() )
+        {
+            if (pFrame->GetAttrSet()->GetKeep().GetValue()
+                || pFrame->IsHiddenNow())
                 pFrame = pFrame->GetIndPrev();
             else
                 return true;
@@ -150,22 +152,42 @@ void SwFlowFrame::CheckKeep()
     // it's possible for the whole troop to move back.
     SwFrame *pPre = m_rThis.GetIndPrev();
     assert(pPre);
+    while (pPre && pPre->IsHiddenNow())
+    {
+        pPre = pPre->GetIndPrev();
+    }
+    if (!pPre)
+    {
+        return;
+    }
     if( pPre->IsSctFrame() )
     {
         SwFrame *pLast = static_cast<SwSectionFrame*>(pPre)->FindLastContent();
+        while (pLast && pLast->IsHiddenNow())
+        {
+            pLast = pLast->GetIndPrev();
+        }
         if( pLast && pLast->FindSctFrame() == pPre )
             pPre = pLast;
         else
             return;
     }
-    SwFrame* pTmp;
+    SwFrame* pTmp{pPre};
     bool bKeep;
     while ( (bKeep = pPre->GetAttrSet()->GetKeep().GetValue()) &&
-            nullptr != ( pTmp = pPre->GetIndPrev() ) )
+            nullptr != (pTmp = pTmp->GetIndPrev()) )
     {
+        if (pTmp->IsHiddenNow())
+        {
+            continue;
+        }
         if( pTmp->IsSctFrame() )
         {
             SwFrame *pLast = static_cast<SwSectionFrame*>(pTmp)->FindLastContent();
+            while (pLast && pLast->IsHiddenNow())
+            {
+                pLast = pLast->GetIndPrev();
+            }
             if( pLast && pLast->FindSctFrame() == pTmp )
                 pTmp = pLast;
             else
@@ -236,6 +258,7 @@ bool SwFlowFrame::IsKeep(SvxFormatKeepItem const& rKeep,
         SvxFormatBreakItem const& rBreak,
         bool const bCheckIfLastRowShouldKeep) const
 {
+    assert(!m_rThis.IsHiddenNow()); // check it before?
     // 1. The keep attribute is ignored inside footnotes
     // 2. For compatibility reasons, the keep attribute is
     //    ignored for frames inside table cells
@@ -338,6 +361,26 @@ bool SwFlowFrame::IsKeep(SvxFormatKeepItem const& rKeep,
     return bKeep;
 }
 
+SwFrame * SwFlowFrame::FindPrevIgnoreHidden() const
+{
+    SwFrame * pRet{m_rThis.FindPrev()};
+    while (pRet && pRet->IsHiddenNow())
+    {
+        pRet = pRet->FindPrev();
+    }
+    return pRet;
+}
+
+SwFrame * SwFlowFrame::FindNextIgnoreHidden() const
+{
+    SwFrame * pRet{m_rThis.FindNext()};
+    while (pRet && pRet->IsHiddenNow())
+    {
+        pRet = pRet->FindNext();
+    }
+    return pRet;
+}
+
 sal_uInt8 SwFlowFrame::BwdMoveNecessary( const SwPageFrame *pPage, const SwRect &rRect )
 {
     // The return value helps deciding whether we need to flow back (3),
@@ -1188,7 +1231,7 @@ bool SwFlowFrame::IsPrevObjMove() const
     if( pSh && pSh->GetViewOptions()->getBrowseMode() )
         return false;
 
-    SwFrame *pPre = m_rThis.FindPrev();
+    SwFrame *const pPre{FindPrevIgnoreHidden()};
 
     if ( pPre && pPre->GetDrawObjs() )
     {
@@ -2616,7 +2659,7 @@ bool SwFlowFrame::MoveBwd( bool &rbReformat )
     // keep with next frame and next frame is locked.
     // i#38232 - If next frame is a table, do *not* check,
     // if it's locked.
-    if ( pNewUpper && !IsFollow() &&
+    if ( pNewUpper && !IsFollow() && !m_rThis.IsHiddenNow() &&
          m_rThis.GetAttrSet()->GetKeep().GetValue() && m_rThis.GetIndNext() )
     {
         SwFrame* pIndNext = m_rThis.GetIndNext();

sw/source/core/layout/fly.cxx

@@ -1705,9 +1705,10 @@ void CalcContent( SwLayoutFrame *pLay, bool bNoColl )
             // frame due to its keep-attribute, if it can't move forward.
             // #i57765# - do not consider invalid previous
             // frame, if current frame has a column/page break before attribute.
-            SwFrame* pTmpPrev = pFrame->FindPrev();
+            assert(pFrame->IsFlowFrame());
+            SwFlowFrame* pTmpFlowFrame = SwFlowFrame::CastFlowFrame(pFrame);
+            SwFrame* pTmpPrev = pTmpFlowFrame->FindPrevIgnoreHidden();
             SwFlowFrame* pTmpPrevFlowFrame = pTmpPrev && pTmpPrev->IsFlowFrame() ? SwFlowFrame::CastFlowFrame(pTmpPrev) : nullptr;
-            SwFlowFrame* pTmpFlowFrame     = pFrame->IsFlowFrame() ? SwFlowFrame::CastFlowFrame(pFrame) : nullptr;
 
             bool bPrevInvalid = pTmpPrevFlowFrame && pTmpFlowFrame &&
                                !pTmpFlowFrame->IsFollow() &&

sw/source/core/layout/frmtool.cxx

@@ -155,7 +155,7 @@ void SwFrameNotify::ImplDestroy()
             {
                 if ( mbInvaKeep )
                 {
-                    SwFrame *pPre = mpFrame->FindPrev();
+                    SwFrame *pPre = pFlow->FindPrevIgnoreHidden();
                     if ( pPre && pPre->IsFlowFrame() )
                     {
                         // 1. pPre wants to keep with me: