tdf#106206 PDF export: fix unexpected /Im0 in page contents stream

The early return should just skip the code that's specific to pdf
images, not everything.

Change-Id: Ia9e02b05051a085a9fdf2f690c21f9ffccb7bf4d
Reviewed-on: https://gerrit.libreoffice.org/34685
Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>
Tested-by: Jenkins <ci@libreoffice.org>
(cherry picked from commit e7adffff8039175bc50b56b4c07ce0b9d8fed629)

3 files changed, 58 insertions, 1 deletions

diff --git a/vcl/qa/cppunit/pdfexport/data/tdf106206.odt b/vcl/qa/cppunit/pdfexport/data/tdf106206.odt
new file mode 100644
index 000000000000..3581157de443
--- /dev/null
+++ b/vcl/qa/cppunit/pdfexport/data/tdf106206.odt
diff --git a/vcl/qa/cppunit/pdfexport/pdfexport.cxx b/vcl/qa/cppunit/pdfexport/pdfexport.cxx
index af6e86b7d17e..edd63e6fc351 100644
--- a/vcl/qa/cppunit/pdfexport/pdfexport.cxx
+++ b/vcl/qa/cppunit/pdfexport/pdfexport.cxx
@@ -44,6 +44,8 @@ public:
     void testTdf105461();
     /// Tests that embedded video from Impress is not exported as a linked one.
     void testTdf105093();
+    /// Tests export of non-PDF images.
+    void testTdf106206();
 #endif
 
     CPPUNIT_TEST_SUITE(PdfExportTest);
@@ -51,6 +53,7 @@ public:
     CPPUNIT_TEST(testTdf106059);
     CPPUNIT_TEST(testTdf105461);
     CPPUNIT_TEST(testTdf105093);
+    CPPUNIT_TEST(testTdf106206);
 #endif
     CPPUNIT_TEST_SUITE_END();
 };
@@ -200,6 +203,57 @@ void PdfExportTest::testTdf105093()
     // This key was missing, the embedded video was handled as a linked one.
     CPPUNIT_ASSERT(pFileSpec->LookupElement("EF"));
 }
+
+void PdfExportTest::testTdf106206()
+{
+    // Import the bugdoc and export as PDF.
+    OUString aURL = m_directories.getURLFromSrc(DATA_DIRECTORY) + "tdf106206.odt";
+    mxComponent = loadFromDesktop(aURL);
+    CPPUNIT_ASSERT(mxComponent.is());
+
+    uno::Reference<frame::XStorable> xStorable(mxComponent, uno::UNO_QUERY);
+    utl::TempFile aTempFile;
+    aTempFile.EnableKillingFile();
+    utl::MediaDescriptor aMediaDescriptor;
+    aMediaDescriptor["FilterName"] <<= OUString("writer_pdf_Export");
+    xStorable->storeToURL(aTempFile.GetURL(), aMediaDescriptor.getAsConstPropertyValueList());
+
+    // Parse the export result.
+    xmlsecurity::pdfio::PDFDocument aDocument;
+    SvFileStream aStream(aTempFile.GetURL(), StreamMode::READ);
+    CPPUNIT_ASSERT(aDocument.Read(aStream));
+
+    // The document has one page.
+    std::vector<xmlsecurity::pdfio::PDFObjectElement*> aPages = aDocument.GetPages();
+    CPPUNIT_ASSERT_EQUAL(static_cast<size_t>(1), aPages.size());
+
+    // The page has a stream.
+    xmlsecurity::pdfio::PDFObjectElement* pContents = aPages[0]->LookupObject("Contents");
+    CPPUNIT_ASSERT(pContents);
+    xmlsecurity::pdfio::PDFStreamElement* pStream = pContents->GetStream();
+    CPPUNIT_ASSERT(pStream);
+    SvMemoryStream& rObjectStream = pStream->GetMemory();
+    // Uncompress it.
+    SvMemoryStream aUncompressed;
+    ZCodec aZCodec;
+    aZCodec.BeginCompression();
+    rObjectStream.Seek(0);
+    aZCodec.Decompress(rObjectStream, aUncompressed);
+    CPPUNIT_ASSERT(aZCodec.EndCompression());
+
+    // Make sure there is an image reference there.
+    OString aImage("/Im");
+    auto pStart = static_cast<const char*>(aUncompressed.GetData());
+    const char* pEnd = pStart + aUncompressed.GetSize();
+    auto it = std::search(pStart, pEnd, aImage.getStr(), aImage.getStr() + aImage.getLength());
+    CPPUNIT_ASSERT(it != pEnd);
+
+    // And also that it's not an invalid one.
+    OString aInvalidImage("/Im0");
+    it = std::search(pStart, pEnd, aInvalidImage.getStr(), aInvalidImage.getStr() + aInvalidImage.getLength());
+    // This failed, object #0 was referenced.
+    CPPUNIT_ASSERT(bool(it == pEnd));
+}
 #endif
 
 CPPUNIT_TEST_SUITE_REGISTRATION(PdfExportTest);
diff --git a/vcl/source/gdi/pdfwriter_impl.cxx b/vcl/source/gdi/pdfwriter_impl.cxx
index 69cd2e794de8..b5b371e3b577 100644
--- a/vcl/source/gdi/pdfwriter_impl.cxx
+++ b/vcl/source/gdi/pdfwriter_impl.cxx
@@ -12077,6 +12077,10 @@ bool PDFWriterImpl::writeBitmapObject( BitmapEmit& rObject, bool bMask )
 
 void PDFWriterImpl::createEmbeddedFile(const Graphic& rGraphic, ReferenceXObjectEmit& rEmit, sal_Int32 nBitmapObject)
 {
+    // The bitmap object is always a valid identifier, even if the graphic has
+    // no pdf data.
+    rEmit.m_nBitmapObject = nBitmapObject;
+
     if (!rGraphic.getPdfData().hasElements())
         return;
 
@@ -12087,7 +12091,6 @@ void PDFWriterImpl::createEmbeddedFile(const Graphic& rGraphic, ReferenceXObject
 
     rEmit.m_nFormObject = createObject();
     rEmit.m_nEmbeddedObject = m_aEmbeddedFiles.back().m_nObject;
-    rEmit.m_nBitmapObject = nBitmapObject;
     rEmit.m_aPixelSize = rGraphic.GetBitmap().GetPrefSize();
 }