[poppler] libpdfjs

[Nedim Srndic]

Hello, 

On Thu, 2011-10-13 at 07:00 -0300, jose.aliste at gmail.com wrote:
> Hi,
> 
> On Thu, Oct 13, 2011 at 4:04 AM, Nedim Srndic <nedim.sh at gmail.com> wrote:
> > Hi,
> >
> > On Wed, 2011-10-12 at 17:08 -0300, jose.aliste at gmail.com wrote:
> >> Hi,
> >>
> >> On Wed, Oct 12, 2011 at 10:26 AM, Albert Astals Cid <aacid at kde.org> wrote:
> >> > A Dimecres, 12 d'octubre de 2011, Nedim Srndic vàreu escriure:
> >> >> Dear list,
> >> >>
> >> >> Poppler's Catalog class has a getJS() method that returns JavaScript
> >> >> scripts from the PDF document.
> >> >> http://www.google.com/codesearch#F0okAQSJLc0/poppler/Catalog.h&q=javascript%
> >> >> 20package:poppler&type=cs&l=187
> >> >>
> >> >> It currently only scans the Name tree for JavaScript scripts, but they
> >> >> can also be found in many other places in a PDF document. It is not so
> >> >> straightforward to find this in the PDF reference. I had to, though, so
> >> >> I wrote a very compact C++ library called libpdfjs that looks for
> >> >> JavaScript strings in those locations where the PDF reference says they
> >> >> might be found (except for attachments, need to implement that). The
> >> >> library home page is here:
> >> >> https://sourceforge.net/p/libpdfjs/home/Home/
> >> >>
> >> >> Do you (Poppler developers) plan to support something like this in the
> >> >> future? If you do, then maybe the libpdfjs functionality can be moved to
> >> >> Poppler and libpdfjs obsoleted.
> >> >
> >>
> >> > As far as I know there is noone working on it. We will gladfully accept your
> >> > patches though.
> >> I have some wip patches in my branch that add this functionality to
> >> poppler. I'll take a look into your lib but as Albert says, if you
> >> feel like providing a patch for poppler, that would be great.
> >>
> >
> > It would be very useful if one of the developers could review the code,
> 
> well, your code is not going to be reviewed unless you provide patches
> for poppler ;)
> I took a quick look about it and some of the internal methods you are
> using are things we want.

Yeah, my concern is that I may be doing something wrong, i.e., not
according to the Poppler coding standards. Want to avoid that.

> 
> > so that we know if it's acceptable/desirable. Also, the JavaScript is
> > spread across the document in many places, and currently the library
> > does not differentiate between them. Is that OK?
> 
> I think you are missing a point by doing it like this. In popppler
> there are already many  objects that have actions and what you need to
> do it is to support a javascript action on them, and add the api so
> you can query that. In general you need to know where the action came
> from so you can execute the code in the runtime whenever is
> appropriate.

OK, what I made was code that finds all the JavaScript in a PDF
document. What you are suggesting is, if I understand, to create a new
action type for JavaScript and patch all PDF object classes in Poppler
(such as Annotations and Name trees) that support JS actions to have
something like a getJSAction() method. 

That might be worth doing if somebody is going to make use of this
(except for myself, obviously). AFAIK, none of the PDF readers using
Poppler have a JS engine. Maybe they would consider having one if they
had easy access to the underlying JS scripts. That's up to them to
decide I guess. 

> 
> I will try to upload the finished part of my patches soon so we can
> get a review from core devs.

Does that mean that you already created some patches based on libpdfjs?

Best regards, 
Nedim Srndic
> 
> >
> > I would be glad to provide a patch. Would it be OK to put the code in
> > the getJS() method?
> >
> >> José
> >>
> >> >
> >> > Albert
> >> >
> >> >
> >> >>
> >> >> Greetings,
> >> >> Nedim Srndic
> >> >>
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> >
> >
> >