sw_redlinehide_4b: fix CanSkipOverRedline() using wrong start position

It must use the start position that GetNextRedln() returned, not the
start of the end redline that GetNextRedln() returned, obviously.

This triggers an assert in CanSkipOverRedline() in ooo31961-27.odt.

Change-Id: I40b9647e0b8be9768e49047d309dd22470e658bd

sw/source/core/text/itratr.cxx

@@ -450,13 +450,14 @@ static void InsertCharAttrs(SfxPoolItem const** pAttrs, SfxItemSet const& rItems
 
 // if return false: portion ends at start of redline, indexes unchanged
 // if return true: portion end not known (past end of redline), indexes point to first hint past end of redline
-static bool CanSkipOverRedline(SwRangeRedline const& rRedline,
+static bool CanSkipOverRedline(
+        SwTextNode const& rStartNode, sal_Int32 const nStartRedline,
+        SwRangeRedline const& rRedline,
         size_t & rStartIndex, size_t & rEndIndex,
         bool const isTheAnswerYes)
 {
     size_t nStartIndex(rStartIndex);
     size_t nEndIndex(rEndIndex);
-    SwPosition const*const pRLStart(rRedline.Start());
     SwPosition const*const pRLEnd(rRedline.End());
     if (!pRLEnd->nNode.GetNode().IsTextNode() // if fully deleted...
         || pRLEnd->nContent == pRLEnd->nNode.GetNode().GetTextNode()->Len())
@@ -469,17 +470,16 @@ static bool CanSkipOverRedline(SwRangeRedline const& rRedline,
     // can't compare the SwFont that's stored somewhere, it doesn't have compare
     // operator, so try to recreate the situation with some temp arrays here
     SfxPoolItem const* activeCharAttrsStart[RES_CHRATR_END - RES_CHRATR_BEGIN + 1] = { nullptr, };
-    if (pRLStart->nNode != pRLEnd->nNode)
+    if (&rStartNode != &pRLEnd->nNode.GetNode())
     {   // nodes' attributes are only needed if there are different nodes
-        InsertCharAttrs(activeCharAttrsStart,
-                pRLStart->nNode.GetNode().GetTextNode()->GetSwAttrSet());
+        InsertCharAttrs(activeCharAttrsStart, rStartNode.GetSwAttrSet());
     }
-    if (SwpHints *const pStartHints = pRLStart->nNode.GetNode().GetTextNode()->GetpSwpHints())
+    if (SwpHints const*const pStartHints = rStartNode.GetpSwpHints())
     {
         // check hint ends of hints that start before and end within
-        sal_Int32 const nRedlineEnd(pRLStart->nNode == pRLEnd->nNode
+        sal_Int32 const nRedlineEnd(&rStartNode == &pRLEnd->nNode.GetNode()
                 ? pRLEnd->nContent.GetIndex()
-                : pRLStart->nNode.GetNode().GetTextNode()->Len());
+                : rStartNode.Len());
         for ( ; nEndIndex < pStartHints->Count(); ++nEndIndex)
         {
             SwTextAttr *const pAttr(pStartHints->GetSortedByEnd(nEndIndex));
@@ -491,7 +491,7 @@ static bool CanSkipOverRedline(SwRangeRedline const& rRedline,
             {
                 break;
             }
-            if (pRLStart->nContent.GetIndex() <= pAttr->GetStart())
+            if (nStartRedline <= pAttr->GetStart())
             {
                 continue;
             }
@@ -542,7 +542,7 @@ static bool CanSkipOverRedline(SwRangeRedline const& rRedline,
             pRLEnd->nContent.GetIndex() < *pStartHints->GetSortedByEnd(nEndIndex)->GetAnyEnd());
     }
 
-    if (pRLStart->nNode != pRLEnd->nNode)
+    if (&rStartNode != &pRLEnd->nNode.GetNode())
     {
         nStartIndex = 0;
         nEndIndex = 0;
@@ -554,7 +554,7 @@ static bool CanSkipOverRedline(SwRangeRedline const& rRedline,
         // ... and the charfmt must be *nominally* the same
 
     SfxPoolItem const* activeCharAttrsEnd[RES_CHRATR_END - RES_CHRATR_BEGIN + 1] = { nullptr, };
-    if (pRLStart->nNode != pRLEnd->nNode)
+    if (&rStartNode != &pRLEnd->nNode.GetNode())
     {   // nodes' attributes are only needed if there are different nodes
         InsertCharAttrs(activeCharAttrsEnd,
                 pRLEnd->nNode.GetNode().GetTextNode()->GetSwAttrSet());
@@ -564,8 +564,8 @@ static bool CanSkipOverRedline(SwRangeRedline const& rRedline,
     {
         // check hint starts of hints that start within and end after
 #ifndef NDEBUG
-        sal_Int32 const nRedlineStart(pRLStart->nNode == pRLEnd->nNode
-                ? pRLStart->nContent.GetIndex()
+        sal_Int32 const nRedlineStart(&rStartNode == &pRLEnd->nNode.GetNode()
+                ? nStartRedline
                 : 0);
 #endif
         for ( ; nStartIndex < pEndHints->Count(); ++nStartIndex)
@@ -629,7 +629,7 @@ static bool CanSkipOverRedline(SwRangeRedline const& rRedline,
                 default: assert(false);
             }
         }
-        if (pRLStart->nNode != pRLEnd->nNode)
+        if (&rStartNode != &pRLEnd->nNode.GetNode())
         {
             // need to iterate the nEndIndex forward too so the loop in the
             // caller can look for the right ends in the next iteration
@@ -743,7 +743,7 @@ TextFrameIndex SwAttrIter::GetNextAttr() const
                 assert(m_pMergedPara);
                 assert(redline.second.first->End()->nNode.GetIndex() <= m_pMergedPara->pLastNode->GetIndex()
                     || !redline.second.first->End()->nNode.GetNode().IsTextNode());
-                if (CanSkipOverRedline(*redline.second.first,
+                if (CanSkipOverRedline(*pTextNode, redline.first, *redline.second.first,
                         nStartIndex, nEndIndex, m_nPosition == redline.first))
                 {   // if current position is start of the redline, must skip!
                     nActRedline += redline.second.second;