Hi,
I think you have discovered a major problem in PoDoFo.
Only indirect objects have an owner set. Destinations are often direct objects
though, so there is no guarantee that GetOwner() will return something.
Therefore, I changed PdfDestination::GetPage() and added a parameter where you
can pass the owner as a PdfDocument or a PdfVecObjects. This should make the
usage more obvious and will hopefully solve your problem.
Sorry, for the troubles.
Best regards,
Dominik
On Wednesday, January 12, 2011 12:21:03 pm Matias wrote:
> Hi there
>
> Thought I'd keep you posted regarding the issue I had with reading PDF
> destinations from the names tree last week. I managed to fix the issue
> after realising that the issue is that the object returned with
> GetKey(PdfName("D")) from the destination object of interest in the Dests
> names tree had an uninitialised pointer to the owner. If I set the owner
> of the destination object's dictionary like this, the crash ended:
> destObjDict.GetKey(PdfName("D"))->SetOwner(&doc->GetObjects());
>
> Is this a bug, or have I missed something? Still don't know how I'd write
> the same code without crashing using the GetDestination() method of
> PdfAnnotation, instead of finding out the destination object by hand using
> the names tree.
>
>
> PdfDictionary dict = ann->GetObject()->GetDictionary();
>
> PdfObject *indirKey = ann->GetObject()->GetIndirectKey("Dest");
>
> PdfString str = indirKey->GetString();
>
> NSUInteger pageNumber = NSNotFound;
> if (namesTree->GetValue(PdfName("Dests"),str)) {
> PdfObject *destObj = namesTree->GetValue(PdfName("Dests"), str);
>
> if (destObj) {
> if (destObj->GetDataType() == ePdfDataType_Dictionary) {
> PdfDictionary destObjDict = destObj->GetDictionary();
>
> if (destObjDict.GetKey(PdfName("D")) != NULL) {
> destObjDict.GetKey(PdfName("D"))->SetOwner(&doc-
>GetObjects()); //this
> fixes the crash
>
> PdfDestination destination =
> PdfDestination(destObjDict.GetKey(PdfName("D"))); PdfPage *page =
> destination.GetPage();
>
> pageNumber = page->GetPageNumber();
> }
> }
> }
> } else {
> cerr << "Destination is null";
> }
>
> On 6 Jan 2011, at 17:54, Dominik Seichter wrote:
> > Hi Matias,
> >
> > You are obviously right! I fixed the implementation of
> > PdfNamesTree::HasValue. Does this change fix the first problem you
> > reported?
> >
> > Cheers,
> >
> > Dominik
> >
> > On Thursday, January 06, 2011 04:54:48 pm Matias wrote:
> >> I found a seeming bug in PdfNamesTree::HasValue whilst trying to debug
> >> this issue. As Leonard helpfully pointed out, I should drop the / from
> >> in front of the name. I put it there in confusion because HasValue
> >> returned false if I queried for the key name without the slash. Well,
> >> as it turns out, the definition of PdfNamesTree::HasValue is as
> >> follows:
> >>
> >> bool PdfNamesTree::HasValue( const PdfName & tree, const PdfString & key
> >> ) const {
> >>
> >> return ( this->GetValue( tree, key) == NULL );
> >>
> >> }
> >>
> >> Surely it should be != NULL ?
> >>
> >>> I have a PdfAnnotation* stored in a variable named ann. The destination
> >>> of this PDF annotation is a named object in the document (a page
> >>> object). I've checked that ann->HasDestination() returns true for it.
> >>> However, if I try the following, I get an EXC_BAD_ACCESS:
> >>> PdfDestination destination = ann->GetDestination();
> >>>
> >>> Furthermore, if I try and resolve the destination of the object in the
> >>> following way through the /Dests names tree of the document, I get a
> >>> NULL back:
> >>>
> >>> PdfDictionary dict = ann->GetObject()->GetDictionary();
> >>> PdfObject *indirKey = ann->GetObject()->GetIndirectKey("Dest");
> >>> cerr << indirKey->GetString().GetStringUtf8(); //returns the name of
> >>> the named object correctly
> >>>
> >>> PdfNamesTree *namesTree = doc->GetNamesTree();
> >>> PdfObject *dests = namesTree->GetDestsNode();
> >>> PdfString str = indirKey->GetString();
> >>> PdfObject *indirObj = dests->GetIndirectKey(str.GetStringUtf8());
> >>>
> >>> if (namesTree->HasValue(PdfName("/Dests"),str)) {
> >>>
> >>> PdfObject *destObj = namesTree->GetValue(PdfName("/Dests"),
> >>> indirKey->GetString());
> >>>
> >>> if (!destObj) {
> >>>
> >>> cerr << "Value is NULL!"; //this code is reached, and it
shouldn't?
> >>>
> >>> }
> >>>
> >>> }
> >>>
> >>> Any ideas of what I am doing wrong? Does this have something to do with
> >>> lazy loading and accessing an indirect key perhaps?
> >>> -----------------------------------------------------------------------
> >>> - ------ Learn how Oracle Real Application Clusters (RAC) One Node
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> >>
> >> ------------------------------------------------------------------------
> >> --- --- Learn how Oracle Real Application Clusters (RAC) One Node allows
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> >> environment, and, should the need arise, upgrade to a full multi-node
> >> Oracle RAC database without downtime or disruption
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