> On 08 June 2019 at 00:23 Clemens Kolbitsch <kolbit...@lastline.com> wrote:
>
> Hi list!
> ...snip...
> As before, I unfortunately cannot share the file, but after some
> tracing, I believe the problem is that PdfStream::GetFilteredCopy
> is creating "nested" output stream via
> PdfFilterFactory::CreateDecodeStream. With "nested" I mean that the
> stream contains "owned" output streams generated in this loop:
> PdfFilteredDecodeStream* pFilter = new PdfFilteredDecodeStream(
> pStream, *it, false, pDictionary );
> ++it;
>
> while( it != filters.rend() )
> {
> pFilter = new PdfFilteredDecodeStream( pFilter, *it, true,
> pDictionary );
> ++it;
> }
>
> return pFilter;
> That is, we enter the loop and create the nested pFilter. This object,
> from what I can see, is never being closed, meaning that when the
> auto_ptr calls the destructor, we hit this assert:PdfFilter::~PdfFilter()
> {
> // Whoops! Didn't call EndEncode() before destroying the filter!
> // Note that we can't do this for the user, since EndEncode() might
> // throw and we can't safely have that in a dtor. That also means
> // we can't throw here, but must abort.
> assert( !m_pOutputStream );
thanks for your analysis, this seems to be correct (IMHO, I've also looked at
this code only recently, at since some years). I've attached a proposed patch,
please test.
> Without a full understanding of the code, this may be more guessing than a
> good pointer, but it seems we may not be calling EndDecode when writing
> fails (of if it is never triggered on the nested output stream).
When writing fails, PdfFilter::FailEncodeDecode() is called, which does close
and NULL it. When it hasn't, the destructor of PdfFilteredDecodeStream doesn't
close the underlying stream before deleting it, thereby causing the assertion
failure AFAICS w/o test file.
> I'm happy to do any debugging you need, but hopefully the stack-trace above
> helps identify the issue.
> ...snip...
Please test with the attached patch, I hope it fixes the issue (for decoding,
on the encoding side it'd be a different issue, right?).
> Thanks!
> -Clemens
P.S. @Clemens: I don't know if you're subscribed to the list, so I've sent this
e-mail to you also directly.
Index: src/podofo/base/PdfFilter.cpp
===================================================================
--- src/podofo/base/PdfFilter.cpp (revision 1993)
+++ src/podofo/base/PdfFilter.cpp (working copy)
@@ -174,6 +174,9 @@
virtual ~PdfFilteredDecodeStream()
{
+ if ( NULL != m_pOutputStream )
+ m_pOutputStream->Close();
+
delete m_pOutputStream;
}
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