fix memory leak in array xls import

The ScMatrix instances are leaked because there is no DecRef called on
them when we Reset the TokenPool.

Change-Id: Ie5e1a10c6be94b45df784c04f6db744928f213ff
Reviewed-on: https://gerrit.libreoffice.org/23194
Reviewed-by: Kohei Yoshida <libreoffice@kohei.us>
Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Markus Mohrhard <markus.mohrhard@googlemail.com>

sc/source/filter/excel/tokstack.cxx

@@ -126,11 +126,7 @@ TokenPool::~TokenPool()
         delete ppP_Nlf[ n ];
     delete[] ppP_Nlf;
 
-    for( n = 0 ; n < nP_Matrix ; n++ )
-    {
-        if( ppP_Matrix[ n ] )
-            ppP_Matrix[ n ]->DecRef( );
-    }
+    ClearMatrix();
     delete[] ppP_Matrix;
 
     delete pScToken;
@@ -879,6 +875,7 @@ void TokenPool::Reset()
     maExtNames.clear();
     maExtCellRefs.clear();
     maExtAreaRefs.clear();
+    ClearMatrix();
 }
 
 bool TokenPool::IsSingleOp( const TokenId& rId, const DefTokenId eId ) const
@@ -934,4 +931,16 @@ ScMatrix* TokenPool::GetMatrix( unsigned int n ) const
     return nullptr;
 }
 
+void TokenPool::ClearMatrix()
+{
+    for(sal_uInt16 n = 0 ; n < nP_Matrix ; n++ )
+    {
+        if( ppP_Matrix[ n ] )
+        {
+            ppP_Matrix[ n ]->DecRef( );
+            ppP_Matrix[n] = nullptr;
+        }
+    }
+}
+
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */

sc/source/filter/inc/tokstack.hxx

@@ -182,6 +182,7 @@ private:
         bool                        GrowMatrix();
         bool                        GetElement( const sal_uInt16 nId );
         bool                        GetElementRek( const sal_uInt16 nId );
+        void                        ClearMatrix();
 public:
     TokenPool( svl::SharedStringPool& rSPool );
                                     ~TokenPool();