discard cached cell values if the cell changes

FormulaGroupContext is actually a cache of cell results for OpenCL,
but the cached values are not always properly discarded. Happens e.g.
with testFormulaDepTracking in sc_ucalc fails if OpenCL is forced for
it (i.e. with mnOpenCLMinimumFormulaGroupSize disabled), because
a SetString() call for a cell doesn't invalidate the cache.

This obviously reduces the cache hit rate a bit, but according to my
tests it's not that bad (in fact the cache doesn't seem to get used
that often, so I even wonder if it's worth it).

Change-Id: Ia7ef2214956861d26ca3a42b84f9fecbff8316d0
Reviewed-on: https://gerrit.libreoffice.org/56087
Tested-by: Jenkins
Reviewed-by: Michael Meeks <michael.meeks@collabora.com>

1 files changed, 6 insertions, 1 deletions

diff --git a/sc/inc/document.hxx b/sc/inc/document.hxx
index fcd09a1214de..ad371bd73cd8 100644
--- a/sc/inc/document.hxx
+++ b/sc/inc/document.hxx
@@ -353,9 +353,11 @@ private:
     rtl::Reference<ScPoolHelper> mxPoolHelper;
 
     std::shared_ptr<svl::SharedStringPool> mpCellStringPool;
-    std::shared_ptr<sc::FormulaGroupContext> mpFormulaGroupCxt;
     std::unique_ptr<sc::DocumentLinkManager> mpDocLinkMgr;
 
+    std::shared_ptr<sc::FormulaGroupContext> mpFormulaGroupCxt;
+    bool                mbFormulaGroupCxtBlockDiscard;
+
     ScCalcConfig        maCalcConfig;
 
     SfxUndoManager*     mpUndoManager;
@@ -1118,6 +1120,9 @@ public:
     svl::SharedString                         GetSharedString( const ScAddress& rPos ) const;
 
     std::shared_ptr<sc::FormulaGroupContext>& GetFormulaGroupContext();
+    void                                      DiscardFormulaGroupContext();
+    void                                      BlockFormulaGroupContextDiscard( bool block )
+                                                  { mbFormulaGroupCxtBlockDiscard = block; }
 
     SC_DLLPUBLIC void                         GetInputString( SCCOL nCol, SCROW nRow, SCTAB nTab, OUString& rString );
     FormulaError                              GetStringForFormula( const ScAddress& rPos, OUString& rString );