xmlsecurity: write origin.sigs when exporting OOXML signature

It's an empty file, with the only purpose to have relations, referencing
the individual signature streams. The only tricky part is that a temp
file needs closeOutput() to flush its contents, flush() is not enough.

Change-Id: I92ac61bce201c97a727ff02b1bb74599573a1807

xmlsecurity/inc/xmlsecurity/xmlsignaturehelper.hxx

@@ -184,6 +184,8 @@ public:
     bool ReadAndVerifySignatureStorageStream(const css::uno::Reference<css::io::XInputStream>& xInputStream);
     /// Adds an OOXML digital signature relation to _rels/.rels if there wasn't any before.
     void EnsureSignaturesRelation(css::uno::Reference<css::embed::XStorage> xStorage);
+    /// Given that xStorage is an OOXML _xmlsignatures storage, create origin.sigs and its relations.
+    static void ExportSignatureRelations(css::uno::Reference<css::embed::XStorage> xStorage, int nSignatureCount);
 };
 
 #endif // INCLUDED_XMLSECURITY_INC_XMLSECURITY_XMLSIGNATUREHELPER_HXX

xmlsecurity/source/dialogs/digitalsignaturesdialog.cxx

@@ -516,6 +516,16 @@ IMPL_LINK_NOARG_TYPED(DigitalSignaturesDialog, AddButtonHdl, Button*, void)
             {
                 // OOXML
                 maSignatureHelper.EnsureSignaturesRelation(mxStore);
+
+                // Old signatures + the new one.
+                int nSignatureCount = maCurrentSignatureInformations.size() + 1;
+                XMLSignatureHelper::ExportSignatureRelations(aStreamHelper.xSignatureStorage, nSignatureCount);
+
+                // Flush objects.
+                uno::Reference<embed::XTransactedObject> xTransact(aStreamHelper.xSignatureStorage, uno::UNO_QUERY);
+                xTransact->commit();
+                uno::Reference<io::XOutputStream> xOutputStream(aStreamHelper.xSignatureStream, uno::UNO_QUERY);
+                xOutputStream->closeOutput();
             }
 
             maSignatureHelper.EndMission();

xmlsecurity/source/helper/xmlsignaturehelper.cxx

@@ -465,4 +465,13 @@ void XMLSignatureHelper::EnsureSignaturesRelation(css::uno::Reference<css::embed
     xTransact->commit();
 }
 
+void XMLSignatureHelper::ExportSignatureRelations(css::uno::Reference<css::embed::XStorage> xStorage, int /*nSignatureCount*/)
+{
+    sal_Int32 nOpenMode = embed::ElementModes::READWRITE;
+    uno::Reference<io::XOutputStream> xOriginStream(xStorage->openStreamElement("origin.sigs", nOpenMode), uno::UNO_QUERY);
+    uno::Reference<io::XTruncate> xTruncate(xOriginStream, uno::UNO_QUERY);
+    xTruncate->truncate();
+    xOriginStream->closeOutput();
+}
+
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */