[poppler] Properly using(and freeing) PopplerPage objects

[Reza Hasanzadeh]

Hey there,

I have got a few questions about memory bhaviour of Poppler objects:

- I hold a list of all PopplerPage objects of a document in
memory(obtained with "poppler_document_get_page"). I noticed my
program consumes 10x memory amount compared to Evince fed the same
file. Are there any best practices for dealing with PopplerPage
objects?

- What is the proper way of freeing PopplerDocument? since I retain a
single PopplerDocument object will "g_object_unref(doc)" suffice?

- How should I free a PopplerPage obtained with
"poppler_document_get_page"? I currently "use g_object_unref" and I
doubt if it is enough since in Poppler's source code when I ask a
PopplerPage object it seems that each returned page refs the document
that the page belongs to:

PopplerPage *
_poppler_page_new (PopplerDocument *document, Page *page, int index)
{
  PopplerPage *poppler_page;

  g_return_val_if_fail (POPPLER_IS_DOCUMENT (document), NULL);

  poppler_page = (PopplerPage *) g_object_new (POPPLER_TYPE_PAGE,
nullptr, NULL);
  poppler_page->document = (PopplerDocument *) g_object_ref (document);
  poppler_page->page = page;
  poppler_page->index = index;

  return poppler_page;
}

I am developing a book reading system.

Reza