First steps to round-trip xlExternalLinkPath/xlPathMissing things

Links to broken or missing external workbooks in .xlsx have the
relationship type
http://schemas.microsoft.com/office/2006/relationships/xlExternalLinkPath/xlPathMissing
. Ideally we should round-trip those (save identically back to .xlsx).
Currently we don't save them at all, and Excel doesn't like formulas
that refer to such external (but not mentioned in externalLinks)
workbooks.

Just a start, does not actually produce anything useful yet.

Change-Id: Ic5a481c91864134f1caf66c56a4aef685d3018a7

2 files changed, 30 insertions, 3 deletions

diff --git a/sc/source/filter/inc/externallinkbuffer.hxx b/sc/source/filter/inc/externallinkbuffer.hxx
index 7114daa4eddf..8d52c4216604 100644
--- a/sc/source/filter/inc/externallinkbuffer.hxx
+++ b/sc/source/filter/inc/externallinkbuffer.hxx
@@ -20,6 +20,8 @@
 #ifndef INCLUDED_SC_SOURCE_FILTER_INC_EXTERNALLINKBUFFER_HXX
 #define INCLUDED_SC_SOURCE_FILTER_INC_EXTERNALLINKBUFFER_HXX
 
+#include <ostream>
+
 #include <com/sun/star/sheet/ExternalLinkInfo.hpp>
 #include <oox/helper/containerhelper.hxx>
 #include "defnamesbuffer.hxx"
@@ -160,12 +162,32 @@ enum class ExternalLinkType
     Self,          /// Link refers to the current workbook.
     Same,          /// Link refers to the current sheet.
     External,      /// Link refers to an external spreadsheet document.
+    // let's ignore xlStartup and xlAlternateStartup for now
+    PathMissing,   /// Just for round-tripping
     Library,       /// Link refers to an external add-in.
     DDE,           /// DDE link.
     OLE,           /// OLE link.
     Unknown        /// Unknown or unsupported link type.
 };
 
+template< typename charT, typename traits >
+inline std::basic_ostream<charT, traits> & operator <<(
+    std::basic_ostream<charT, traits> & stream, const ExternalLinkType& type )
+{
+    switch (type)
+    {
+    case ExternalLinkType::Self: return stream << "self";
+    case ExternalLinkType::Same: return stream << "same";
+    case ExternalLinkType::External: return stream << "external";
+    case ExternalLinkType::PathMissing: return stream << "pathmissing";
+    case ExternalLinkType::Library: return stream << "library";
+    case ExternalLinkType::DDE: return stream << "dde";
+    case ExternalLinkType::OLE: return stream << "ole";
+    case ExternalLinkType::Unknown: return stream << "unknown";
+    default: return stream << static_cast<int>(type);
+    }
+}
+
 class ExternalLink : public WorkbookHelper
 {
 public:
diff --git a/sc/source/filter/oox/externallinkbuffer.cxx b/sc/source/filter/oox/externallinkbuffer.cxx
index 73e65081a418..eb6d5fad6356 100644
--- a/sc/source/filter/oox/externallinkbuffer.cxx
+++ b/sc/source/filter/oox/externallinkbuffer.cxx
@@ -360,8 +360,9 @@ void ExternalLink::importExternalBook( const Relations& rRelations, SequenceInpu
 void ExternalLink::importExtSheetNames( SequenceInputStream& rStrm )
 {
     // load external sheet names and create the sheet caches in the Calc document
-    OSL_ENSURE( (meLinkType == ExternalLinkType::External) || (meLinkType == ExternalLinkType::Library),
-        "ExternalLink::importExtSheetNames - invalid link type" );
+    SAL_WARN_IF( (meLinkType != ExternalLinkType::External) && (meLinkType != ExternalLinkType::Library),
+        "sc.filter",
+        "Invalid link type: " << meLinkType );
     if( meLinkType == ExternalLinkType::External )   // ignore sheets of external libraries
         for( sal_Int32 nSheet = 0, nCount = rStrm.readInt32(); !rStrm.isEof() && (nSheet < nCount); ++nSheet )
             insertExternalSheet( BiffHelper::readString( rStrm ) );
@@ -487,12 +488,16 @@ void ExternalLink::setExternalTargetUrl( const OUString& rTargetUrl, const OUStr
         if( !maTargetUrl.isEmpty() )
             meLinkType = ExternalLinkType::External;
     }
+    else if( rTargetType == CREATE_MSOFFICE_RELATION_TYPE( "xlExternalLinkPath/xlPathMissing" ) )
+    {
+        meLinkType = ExternalLinkType::PathMissing;
+    }
     else if( rTargetType == CREATE_MSOFFICE_RELATION_TYPE( "xlExternalLinkPath/xlLibrary" ) )
     {
         meLinkType = ExternalLinkType::Library;
         meFuncLibType = FunctionProvider::getFuncLibTypeFromLibraryName( rTargetUrl );
     }
-    OSL_ENSURE( meLinkType != ExternalLinkType::Unknown, "ExternalLink::setExternalTargetUrl - empty target URL or unknown target type" );
+    SAL_WARN_IF( meLinkType == ExternalLinkType::Unknown, "sc.filter", "Empty target URL or unknown target type, URL='" << rTargetUrl << "', type='" << rTargetType << "'" );
 
     // create the external document link API object that will contain the sheet caches
     if( meLinkType == ExternalLinkType::External ) try