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.
We need to know whether pushInheritedAttributesToPage or getAllPages
have been called when generating JSON output. When reading the JSON
back in, we have to call the same methods so that object numbers will
line up properly.
Where not possible, use "auto" to get the iterator type.
Editorial note: I have avoid this change for a long time because of
not wanting to make gratuitous changes to version history, which can
obscure when certain changes were made, but with having recently
touched every single file to apply automatic code formatting and with
making several broad changes to the API, I decided it was time to take
the plunge and get rid of the older (pre-C++11) verbose iterator
syntax. The new code is just easier to read and understand, and in
many cases, it will be more effecient as fewer temporary copies are
being made.
m-holger, if you're reading, you can see that I've finally come
around. :-)
The executables that libtool built invoked the underlying binary with
an "lt-" prefix. The code contained numerous workarounds for testing,
which can now be removed.
