tdf#136238 Speedup deleting a very very large cross page table

We have a very large nested/list action here, which means
that RemoveOldestUndoAction() cannot do anything, and we spin
in the loop in sw::UndoManager::AddUndoAction

So we need to break out of that loop in this situation, which
makes the delete almost instantaneous.

Change-Id: Ia2bd9c0fd00c6551e99ae09154ecf0f680b9fcea
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/182748
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>
Tested-by: Jenkins

include/svl/undo.hxx

@@ -302,8 +302,10 @@ public:
     bool            HasTopUndoActionMark( UndoStackMark const i_mark );
 
     /** removes the oldest Undo actions from the stack
+    * @returns false if it could not do anything (can happen when the action is very large)
     */
-    void            RemoveOldestUndoAction();
+    [[nodiscard]]
+    bool            RemoveOldestUndoAction();
 
     void dumpAsXml(xmlTextWriterPtr pWriter) const;
 

svl/source/undo/undo.cxx

@@ -1173,19 +1173,21 @@ void SfxUndoManager::UndoMark(UndoStackMark i_mark)
 }
 
 
-void SfxUndoManager::RemoveOldestUndoAction()
+bool SfxUndoManager::RemoveOldestUndoAction()
 {
     UndoManagerGuard aGuard( *m_xData );
 
     if ( IsInListAction() && ( m_xData->maUndoArray.nCurUndoAction == 1 ) )
     {
-        assert(!"SfxUndoManager::RemoveOldestUndoActions: cannot remove a not-yet-closed list action!");
-        return;
+        // this can happen if we are performing a very large writer edit (e.g. removing a very large table)
+        SAL_WARN("svl", "SfxUndoManager::RemoveOldestUndoActions: cannot remove a not-yet-closed list action!");
+        return false;
     }
 
     aGuard.markForDeletion( m_xData->maUndoArray.Remove( 0 ) );
     --m_xData->maUndoArray.nCurUndoAction;
     ImplCheckEmptyActions();
+    return true;
 }
 
 void SfxUndoManager::dumpAsXml(xmlTextWriterPtr pWriter) const

sw/source/core/undo/docundo.cxx

@@ -629,7 +629,8 @@ void UndoManager::AddUndoAction(std::unique_ptr<SfxUndoAction> pAction, bool bTr
     // if the undo nodes array is too large, delete some actions
     while (UNDO_ACTION_LIMIT < sal_Int32(GetUndoNodes().Count()))
     {
-        RemoveOldestUndoAction();
+        if (!RemoveOldestUndoAction())
+            break;
     }
 }