embeddedobj: fix lost native data when updating it via OLE fails, take 2

How to reproduce the problem:

1) Create an ODT file which has an OLE object, where the native data is
an OLE2 container, containing a Package stream, containing a DOCX file

2) Install some external application on Windows which registers itself
as a handler for the DOCX CSLID [ this is where writing a testcase for
this bug is challenging ].

3) Open this document via Java, using URP. Load the document with
Hidden=true and OnMainThread=true.

4) Save the document using XStorable.store().

Expected result: the native data is there.

Actual result: the native data is sometimes missing (0 bytes).

The root cause is that GetUserClassID() Win32 API call in
OleComponent::StoreOwnTmpIfNecessary() fails in some cases, and
re-trying a few times after a small sleep doesn't help.

Handle this error better by doing what
OleEmbeddedObject::SwitchOwnPersistence(XStorage, OUString) already
does: discard the old native data only if we have non-empty new native
data.

A result of the above was that an export to reqif-xhtml (sw HTML export
with FilterOptions set to xhtmlns=reqif-xhtml) wrote empty \objdata.

Change-Id: I59611601cf09597e9f7727db5bd6d7426fe17b75
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/114537
Reviewed-by: Miklos Vajna <vmiklos@collabora.com>
Tested-by: Jenkins

1 files changed, 16 insertions, 0 deletions

diff --git a/embeddedobj/source/msole/olepersist.cxx b/embeddedobj/source/msole/olepersist.cxx
index fddf46d6e658..c4d80bb404fd 100644
--- a/embeddedobj/source/msole/olepersist.cxx
+++ b/embeddedobj/source/msole/olepersist.cxx
@@ -743,6 +743,22 @@ void OleEmbeddedObject::SwitchOwnPersistence( const uno::Reference< embed::XStor
         return;
     }
 
+    uno::Reference<io::XSeekable> xNewSeekable(xNewObjectStream, uno::UNO_QUERY);
+    if (xNewSeekable.is() && xNewSeekable->getLength() == 0)
+    {
+        uno::Reference<io::XSeekable> xOldSeekable(m_xObjectStream, uno::UNO_QUERY);
+        if (xOldSeekable.is() && xOldSeekable->getLength() > 0)
+        {
+            SAL_WARN("embeddedobj.ole", "OleEmbeddedObject::SwitchOwnPersistence(stream version): "
+                                        "empty new stream, reusing old one");
+            uno::Reference<io::XInputStream> xInput = m_xObjectStream->getInputStream();
+            uno::Reference<io::XOutputStream> xOutput = xNewObjectStream->getOutputStream();
+            xOldSeekable->seek(0);
+            comphelper::OStorageHelper::CopyInputToOutput(xInput, xOutput);
+            xNewSeekable->seek(0);
+        }
+    }
+
     try {
         uno::Reference< lang::XComponent > xComponent( m_xObjectStream, uno::UNO_QUERY );
         OSL_ENSURE( !m_xObjectStream.is() || xComponent.is(), "Wrong stream implementation!" );