FDO#76013 : If original file has image whose link is broken RT gets corrupted.

- The original file contains an image which has invalid link.
- since the link is invalid the import throws an exception while loading
the image & the link is lost.
- while exporting the system used to write an empty image for an unhandled
graphic type, which is incorrect and the RT file would result in corrupt.
- Fixed this issue and added UT.

Conflicts:
sw/qa/extras/ooxmlexport/ooxmlexport.cxx
Reviewed on:
https://gerrit.libreoffice.org/8549

Change-Id: If884f154d1fba921280d63930e7fccb979ea5608

1 files changed, 6 insertions, 1 deletions

diff --git a/oox/source/export/drawingml.cxx b/oox/source/export/drawingml.cxx
index aeeff2587362..7d8ea84f3c3c 100644
--- a/oox/source/export/drawingml.cxx
+++ b/oox/source/export/drawingml.cxx
@@ -779,7 +779,12 @@ OUString DrawingML::WriteImage( const Graphic& rGraphic , bool bRelPathToMedia )
                 pExtension = ".emf";
             } else {
                 OSL_TRACE( "unhandled graphic type" );
-                break;
+                /*Earlier, even in case of unhandled graphic types we were
+                  proceeding to write the image, which would eventually
+                  write an empty image with a zero size, and return a valid
+                  relationID, which is incorrect.
+                  */
+                return sRelId;
             }
 
             aData = aStream.GetData();