OpenSystemsDevelopment / qpdf

Increase to POINTERHOLDER_TRANSITION=3

patrepl s/PointerHolder/std::shared_ptr/g **/*.cc **/*.hh
patrepl s/make_pointer_holder/std::make_shared/g **/*.cc
patrepl s/make_array_pointer_holder/QUtil::make_shared_array/g **/*.cc
patrepl s,qpdf/std::shared_ptr,qpdf/PointerHolder, **/*.cc **/*.hh
git restore include/qpdf/PointerHolder.hh
git restore libtests/pointer_holder.cc
cleanpatch
./format-code

Run this:

for i in  **/*.cc **/*.c **/*.h **/*.hh; do
  clang-format < $i >| $i.new && mv $i.new $i
done

It's better to just make it a .hh file to reduce confusion.

The PDF spec only allows UTF-16BE, but most readers seem to accept
UTF-16LE as well, so now qpdf does too.

There are codepoints in PDFDoc that are not valid UTF-8 but map to
valid UTF-8. We were handling those correctly with bidirectional
mapping.

However, if those same code points appeared in UTF-8, where they have
no meaning, they were left as fixed points when converting to PDFDoc,
where they do have meaning. This change recognizes them as errors.

This comment expands all tabs using an 8-character tab-width. You
should ignore this commit when using git blame or use git blame -w.

In the early days, I used to use tabs where possible for indentation,
since emacs did this automatically. In recent years, I have switched
to only using spaces, which means qpdf source code has been a mixture
of spaces and tabs. I have avoided cleaning this up because of not
wanting gratuitous whitespaces change to cloud the output of git
blame, but I changed my mind after discussing with users who view qpdf
source code in editors/IDEs that have other tab widths by default and
in light of the fact that I am planning to start applying automatic
code formatting soon.

* Don't surprise people with deprecation warnings
* Provide detailed instructions and support for the transition

* Use unique_ptr in place of shared_ptr in some cases
* unique_ptr for arrays does not require a custom deleter
* use std::make_unique (c++14) where possible

Use get() and use_count() instead. Add #define
NO_POINTERHOLDER_DEPRECATION to remove deprecation markers for these
only.

This commit also removes all deprecated PointerHolder API calls from
qpdf's code except in PointerHolder's test suite, which must continue
to test the deprecated APIs.

PointerHolder will be replaced with shared_ptr, so let people start
moving.

This makes it much more convention to use the initializeFromArgv
functions since you can use string literals.

If some keys depend on others, we have to check up front since there
is no control of what order key handlers will be called. Anyway, keys
are unordered in json, so we don't want to depend on ordering.

This was used, but it no longer is, so let's not keep the extra
complexity around.

Replace most of the calls to QUtil::copy_string with this instead.

This is a massive rewrite of the help text and cli.rst section of the
manual. All command-line flags now have their own help and are
specifically index. qpdf --help is completely redone.

Handle optional choices in addition to required choices. Refactor the
way help options are added to completion to make it work with optional
help choices.