rhbz#876742 speed up table manipulation in Impress

It turns out this is not actually a performance problem but an oversight
in implementation (or a bug, if you want .-)

Every manipulation with a table (e.g., move, resize; actually even a
selection of the table) leads to creation of a full copy of the table
(SdrObject::getFullDragClone()). One of the actions the table copy impl.
does is to call sdr::CellProperties::SetStyleSheet() on every cell of
the new table. CellProperties is derived from
sdr::properties::TextProperties and CellProperties::SetStyleSheet() just
passes the call to TextProperties::SetStyleSheet(). This is where the
trouble begins :-)

The SDR representation of a table, SdrTableObj, is derived from
SdrTextObj. Because of that, SdrTextObj needs to be able to contain more
than one SdrText (because a table needs one for every cell). This is
handled correctly by TextProperties. But, because there is no SDR
representation of a single cell, CellProperties uses the SdrTableObj as
the SDR object it works on. Therefore TextProperties::SetStyleSheet()
processes all SdrText objects of the _whole table_, not just a single
cell. And this is repeated for every other cell...

Change-Id: Iab2e2d0e1e8038710645c0bd24666e6032b0a003

1 files changed, 52 insertions, 0 deletions

diff --git a/svx/source/table/cell.cxx b/svx/source/table/cell.cxx
index e46b4865fb50..3a33a282b9ec 100644
--- a/svx/source/table/cell.cxx
+++ b/svx/source/table/cell.cxx
@@ -99,6 +99,46 @@ static const SvxItemPropertySet* ImplGetSvxCellPropertySet()
     return &aSvxCellPropertySet;
 }
 
+namespace
+{
+
+class CellTextProvider : public svx::ITextProvider
+{
+public:
+    explicit CellTextProvider(const sdr::table::CellRef xCell);
+    virtual ~CellTextProvider();
+
+private:
+    virtual sal_Int32 getTextCount() const;
+    virtual SdrText* getText(sal_Int32 nIndex) const;
+
+private:
+    const sdr::table::CellRef m_xCell;
+};
+
+CellTextProvider::CellTextProvider(const sdr::table::CellRef xCell)
+    : m_xCell(xCell)
+{
+}
+
+CellTextProvider::~CellTextProvider()
+{
+}
+
+sal_Int32 CellTextProvider::getTextCount() const
+{
+    return 1;
+}
+
+SdrText* CellTextProvider::getText(sal_Int32 nIndex) const
+{
+    (void) nIndex;
+    assert(nIndex == 0);
+    return m_xCell.get();
+}
+
+}
+
 namespace sdr
 {
     namespace properties
@@ -109,6 +149,8 @@ namespace sdr
             // create a new itemset
             SfxItemSet& CreateObjectSpecificItemSet(SfxItemPool& rPool);
 
+            const svx::ITextProvider& getTextProvider() const;
+
         public:
             // basic constructor
             CellProperties(SdrObject& rObj, sdr::table::Cell* pCell );
@@ -131,6 +173,9 @@ namespace sdr
             void SetStyleSheet(SfxStyleSheet* pNewStyleSheet, sal_Bool bDontRemoveHardAttr);
 
             sdr::table::CellRef mxCell;
+
+        private:
+            const CellTextProvider maTextProvider;
         };
 
         // create a new itemset
@@ -153,15 +198,22 @@ namespace sdr
                 0, 0));
         }
 
+        const svx::ITextProvider& CellProperties::getTextProvider() const
+        {
+            return maTextProvider;
+        }
+
         CellProperties::CellProperties(SdrObject& rObj, sdr::table::Cell* pCell)
         :   TextProperties(rObj)
         ,   mxCell(pCell)
+        ,   maTextProvider(mxCell)
         {
         }
 
         CellProperties::CellProperties(const CellProperties& rProps, SdrObject& rObj, sdr::table::Cell* pCell)
         :   TextProperties(rProps, rObj)
         ,   mxCell( pCell )
+        ,   maTextProvider(mxCell)
         {
         }