Function pdf_cache_object 

pub unsafe extern "C" fn pdf_cache_object(
    ctx: *mut fz_context,
    doc: *mut pdf_document,
    num: c_int,
) -> *mut pdf_xref_entry

Retrieve the pdf_xref_entry for a given object.

This can cause xref reorganisations (solidifications etc) due to
repairs, so all held pdf_xref_entries should be considered
invalid after this call (other than the returned one).