PDF Viewing Support (poppler-qt4)

[Adam Batkin]

I've had a lot of trouble getting everything just right. I put some debugging code in my 
PdfDocument and PdfPage destructors to notify me when they are called, so I can tell when 
the C++ objects are actually destructed.

The interesting bit is the typesystem file for the PdfDocument class:

         <object-type name="PdfDocument">
                 <modify-function signature="page(int)const" access="private" 
rename="page_helper">
                         <modify-argument index="return">
                                 <reference-count action="ignore"/>
                                 <define-ownership class="java" owner="java"/>
                         </modify-argument>
                 </modify-function>
                 <inject-code class="java">
                         public PdfPage page(int num) {
                                 PdfPage page = page_helper(num);
                                 page.theDocument = this;
                                 return page;
                         }
                 </inject-code>
         </object-type>

Does that look reasonable? It seems to work. That's basically letting Java keep ownership 
of everything, which should work since the PdfPage class now has a Java reference back to 
its PdfDocument.

I did some testing with a giant List of every PdfPage ever obtained, and made sure that no 
PdfDocuments were ever garbage collected (without the <modify-argument bits the 
PdfDocuments would often be GCed too early).

Thanks,

-Adam Batkin