An indirect object reference to 0, 0 is invalid. If it appears in the
file or is parsed from a string, the parser catches it. This check
would only be useful for someone explicitly calling getObject with 0,
0, and that would trigger an error during resolve().
Replace operator== and operator!=, which were testing for the same
underlying object, with isSameObjectAs. This change was motivated by
the fact that pikepdf internally had its own operator== method for
QPDFObjectHandle that did structural comparison. I backed out qpdf's
operator== as a courtesy to pikepdf (in my own testing) but also
because I think people might naturally assume that operator== does a
structural comparison, and isSameObjectAs is clearer in its intent.
I decided that it's actually fine to copy a direct object to another
QPDF. Even if we eventually prevent a QPDFObject from having multiple
parents, this could happen if an object is moved.
When a QPDF is destroyed, changing indirect objects to direct nulls
makes them effectively disappear silently when they sneak into other
places. Instead, we should treat this as an error. Adding a destroyed
object type makes this possible.
The qpdf member was already sufficient. Removing this actually fixed a
few pre-existing issues around detecting foreign ownership and
allowing certain conditions to be warnings rather than exceptions.
* Just removing a header file would cause build errors with no hint as
to what happened. This way, people get a warning rather than error
for the life of qpdf 11, and the warning tells them what to do.
* This avoids build surprises resulting from having two versions of
QPDF headers installed at once. If you were building code out of a
checkout of qpdf but had an older version installed on your system,
if your code included <qpdf/QPDFObject.hh>, everything would work,
but then your code would break without QPDFObject.hh later.
A bug was fixed between qpdf 8.4.2 and 9.0.0 regarding this type of
file (see #305 and #311), but it was necessary to retest after some
major refactoring work at the lexical and parsing layers. This lays
the groundwork for including this in performance benchmarks and in the
qpdf test suite rather than having to keep a large,
non-redistributable file around.
20 arrays of 20K nulls is plenty for performance memory testing and
doesn't take too long to run. Compared to qpdf 8.4.2, in qpdf 11.0.0,
the file generated here uses 3% of the RAM and runs over 4 times
faster.
