tdf#148665 Fix crash while loading SmartArt graphics

The regression introduced by c79fa460fe6220051bbda2d3c0cb67fbf765e2ac
causes LibreOffice to crash while loading certain files that contain
SmartArt graphics.

By loading sample documents from tdf#148665 (docx) and also tdf#148735
(pptx) in a debug session, it became obvious that the problem happens
in these statements from TextBody::toString() in textbody.cxx:

if (!isEmpty())
return maParagraphs.front()->getRuns().front()->getText();

It is guaranteed that maParagraphs is not empty when trying to call
getRuns(), but it is not checked that there are no runs in the first
paragraph before trying to call getText(). The isEmpty() function
returns false upon finding out that there is at least 1 paragraph.

A check is added to TextBody::toString() to prevent a crash.

This is the backtrace generated from loading documents from tdf#148735
in a Qt Creator debug session:

1   __GI_raise  raise.c   50   0x7ffff79ec03b
2   __GI_abort  abort.c   79   0x7ffff79cb859
3   ??   0x7ffff7846109
4   std::vector<std::shared_ptr<oox::drawingml::TextRun>>::front  vector  443  0x7fffd23d1fa6
5   oox::drawingml::TextBody::toString  textbody.cxx  92   0x7fffd23d0f85
6   oox::drawingml::DiagramData::secureDataFromShapeToModelAfterDiagramImport datamodel.cxx   295  0x7fffd22d3047
7   oox::drawingml::AdvancedDiagramHelper::doAnchor   diagramhelper.cxx   213  0x7fffd22fb92d
8   oox::drawingml::Shape::propagateDiagramHelper   shape.cxx   229  0x7fffd2372a27
9   oox::ppt::PPTShape::addShape  pptshape.cxx  574  0x7fffd25b2bd4
10  oox::ppt::SlidePersist::createXShapes   slidepersist.cxx  150  0x7fffd25d81ea
11  oox::ppt::PresentationFragmentHandler::importSlide  presentationfragmenthandler.cxx 404  0x7fffd25c1a78
12  oox::ppt::PresentationFragmentHandler::finalizeImport   presentationfragmenthandler.cxx 550  0x7fffd25c3331
13  oox::core::FragmentHandler2::endDocument  fragmenthandler2.cxx  53   0x7fffd22364ab
14  sax_fastparser::FastSaxParserImpl::parseStream  fastparser.cxx  907  0x7fffe18b2d2b
15  sax_fastparser::FastSaxParser::parseStream  fastparser.cxx  1480 0x7fffe18b71d2
16  oox::core::FastParser::parseStream  fastparser.cxx  121  0x7fffd221d85b
17  oox::core::FastParser::parseStream  fastparser.cxx  129  0x7fffd221d930
18  oox::core::XmlFilterBase::importFragment  xmlfilterbase.cxx   413  0x7fffd2248ba5
19  oox::core::XmlFilterBase::importFragment  xmlfilterbase.cxx   343  0x7fffd2248687
20  oox::ppt::PowerPointImport::importDocument  pptimport.cxx   109  0x7fffd25a89e2
... <More>

Change-Id: I3a40be33061008b93455a5926259ef5b92e4ffe6
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/133341
Tested-by: Jenkins
Tested-by: Julien Nabet <serval2412@yahoo.fr>
Reviewed-by: Thorsten Behrens <thorsten.behrens@allotropia.de>

0 files changed, 0 insertions, 0 deletions