tdf#46738 Fix exporting .xlsx of coloured empty cells

When spreadsheet contains more that 84 cells, and these
cells are empty, but contains additional data (border color,
text color, specific formatting), the remaining rows are
ignored during export to .xlsx and .xls
As a result such empty rows are not saved during export.
This patch is fixing most cases and make sure that at least
first 84 empty cells will be preserved.
It is not impacting the performance as it is still notchecking
next columns when the visible cells are more that 84 characters.
This patch improve exporting empty cells, but not impacts
performance.

Change-Id: Ia7027e2c8a2fd48ab4a0e840f970d57167454451
Reviewed-on: https://gerrit.libreoffice.org/29899
Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Markus Mohrhard <markus.mohrhard@googlemail.com>

3 files changed, 35 insertions, 4 deletions

diff --git a/sc/qa/unit/data/ods/empty_cells_with_background.ods b/sc/qa/unit/data/ods/empty_cells_with_background.ods
new file mode 100644
index 000000000000..1301bca84489
--- /dev/null
+++ b/sc/qa/unit/data/ods/empty_cells_with_background.ods
diff --git a/sc/qa/unit/subsequent_export-test.cxx b/sc/qa/unit/subsequent_export-test.cxx
index 9c451752d3cb..693990dafd69 100644
--- a/sc/qa/unit/subsequent_export-test.cxx
+++ b/sc/qa/unit/subsequent_export-test.cxx
@@ -111,6 +111,7 @@ public:
     void testXfDefaultValuesXLSX();
     void testOutlineExportXLSX();
     void testHiddenEmptyRowsXLSX();
+    void testEmptyRowsWithBackgroundColorXLSX();
     void testLandscapeOrientationXLSX();
 
     void testInlineArrayXLS();
@@ -202,6 +203,7 @@ public:
     CPPUNIT_TEST(testXfDefaultValuesXLSX);
     CPPUNIT_TEST(testOutlineExportXLSX);
     CPPUNIT_TEST(testHiddenEmptyRowsXLSX);
+    CPPUNIT_TEST(testEmptyRowsWithBackgroundColorXLSX);
     CPPUNIT_TEST(testLandscapeOrientationXLSX);
     CPPUNIT_TEST(testInlineArrayXLS);
     CPPUNIT_TEST(testEmbeddedChartXLS);
@@ -753,6 +755,32 @@ void ScExportTest::testOutlineExportXLSX()
     assertXPath(pSheet, "/x:worksheet/x:sheetData/x:row", 30);
 }
 
+void ScExportTest::testEmptyRowsWithBackgroundColorXLSX()
+{
+    // tdf#46738 FILESAVE:  Cell background and border color formatting information of empty cells
+    // lost in particular document after FILESAVE as xls and xlsx
+    ScDocShellRef xShell = loadDoc("empty_cells_with_background.", FORMAT_ODS);
+    CPPUNIT_ASSERT(xShell.Is());
+
+    std::shared_ptr<utl::TempFile> pXPathFile = ScBootstrapFixture::exportTo(&(*xShell), FORMAT_XLSX);
+    xmlDocPtr pSheet = XPathHelper::parseExport(pXPathFile, m_xSFactory, "xl/worksheets/sheet1.xml");
+    CPPUNIT_ASSERT(pSheet);
+
+    // Check if all 100 rows are saved into .xlsx file,
+    // as it contains information about background color information (style)
+    assertXPath(pSheet, "/x:worksheet/x:sheetData/x:row[1]", "r", "1");
+    assertXPath(pSheet, "/x:worksheet/x:sheetData/x:row[2]", "r", "2");
+    assertXPath(pSheet, "/x:worksheet/x:sheetData/x:row[3]", "r", "3");
+    assertXPath(pSheet, "/x:worksheet/x:sheetData/x:row[100]", "r", "100");
+    assertXPath(pSheet, "/x:worksheet/x:sheetData/x:row", 100);
+
+    // Check if all 4 column were created
+    assertXPath(pSheet, "/x:worksheet/x:sheetData/x:row[100]/x:c[1]", "r", "A100");
+    assertXPath(pSheet, "/x:worksheet/x:sheetData/x:row[100]/x:c[2]", "r", "B100");
+    assertXPath(pSheet, "/x:worksheet/x:sheetData/x:row[100]/x:c[3]", "r", "C100");
+    assertXPath(pSheet, "/x:worksheet/x:sheetData/x:row[100]/x:c[4]", "r", "D100");
+    assertXPath(pSheet, "/x:worksheet/x:sheetData/x:row[100]/x:c", 4);
+}
 
 void ScExportTest::testHiddenEmptyRowsXLSX()
 {
diff --git a/sc/source/core/data/attarray.cxx b/sc/source/core/data/attarray.cxx
index fb90fb435cb4..cf5426266de2 100644
--- a/sc/source/core/data/attarray.cxx
+++ b/sc/source/core/data/attarray.cxx
@@ -1815,7 +1815,7 @@ bool ScAttrArray::GetFirstVisibleAttr( SCROW& rFirstRow ) const
     return bFound;
 }
 
-// size (rows) of a range of attributes after cell content where the search is stopped
+// Number of rows after the search will be stopped
 // (more than a default page size, 2*42 because it's as good as any number)
 
 const SCROW SC_VISATTR_STOP = 84;
@@ -1860,13 +1860,16 @@ bool ScAttrArray::GetLastVisibleAttr( SCROW& rLastRow, SCROW nLastData ) const
         if ( nAttrStartRow <= nLastData )
             nAttrStartRow = nLastData + 1;
         SCROW nAttrSize = pData[nEndPos].nRow + 1 - nAttrStartRow;
-        if ( nAttrSize >= SC_VISATTR_STOP )
-            break;  // while, ignore this range and below
-        else if ( pData[nEndPos].pPattern->IsVisible() )
+        if ( pData[nEndPos].pPattern->IsVisible() )
         {
             rLastRow = pData[nEndPos].nRow;
             bFound = true;
         }
+        // We are not ignoring range for current column,
+        // if it is larger than SC_VISATTR_STOP, because it is still in default page size range.
+        // We are not checking next columns, due to performance reasons.
+        if ( nAttrSize >= SC_VISATTR_STOP )
+            break;
         nPos = nEndPos + 1;
     }