Final, full protocol 2 support

[marcintustin]

This adds full pickle protocol 2 support:

• __reduce__ and __reduce_ex__ may redirect to another object
• Will use __reduce__ or __reduce_ex__ if provided, in preference to object __dict__ or __slots__; will not use __reduce__ or __reduce_ex__ for special-cased classes, and will not use the default object implementations of those methods.
• Adds support for pickling iterators (and adds optional parameter max_iter to avoid livelocking on infinite iterators).
• Adds support for __getinitargs__ and unpickling classic classes which take __init__ parameters, even if __getinitargs__ is not provided.

@davvid

[davvid]

This looks good. Please run git diff --check before committing; you can cleanup trailing whitespace by using git rebase --whitespace=fix ... which helps keeps things tidy. There's a few print statements in the tests that would be good to rebase squash out too.

Enable travis notifications on your repo; the tests seem to be failing under python3. ImportError: No module named __builtin__

There's also an isinstance(basestring, ...) part which might be better written as from jsonpickle.compat import unicode ... isinstance(x, (str, unicode)) to make it compatible across all python versions.

[marcintustin]

@davvid All done, but I still have tests failing for 3.3. I'll figure that out and update you when it's ready.

[marcintustin]

@davvid All done, all tests pass: https://travis-ci.org/marcintustin/jsonpickle/builds/34202884

[marcintustin]

And here's the latest CI results for that last commit, which cleans up some comments: https://travis-ci.org/marcintustin/jsonpickle/builds/34204325

[marcintustin]

This should close out #78

[davvid]

Thanks Marcin, it's all merged now.

I rebased your branch so you might need to git reset --merge jsonpickle/master (assuming you've done git remote add jsonpickle git://github.com/jsonpickle/jsonpickle.git && git fetch jsonpickle) to get your repo in sync. I reworded a few of the commit messages so that they stay within 78 columns and did the --whitespace=fix thing to kill the trailing whitespace... these were small nits and were not worth holding up the merge ;-)

I also added a commit that eliminates the need for MAX_ITER since it looks like islice() does the right thing when None is passed in. That allowed us to get rid of that variable.

max_iter is still a generally useful feature so I exposed it in the encode() public API. That way users can specify a max_iter if needed.

Thanks a ton for making this happen! 👏

[marcintustin]

@davvid Awesome, thanks for collaborating on that. I'm very pleased to be working on the project. I'm fairly certain this is now the most-pickling pickler for python 2 (in that it supports a proper superset of what python 2 ships with). With the Protocol 4 stuff I plan to add, it will be the most pickling pickler for python in general.

As to max_iter, I coded it to always be a finite limit, because infinite iterators are a normal case in python; that said, I understand the reasons why you'd want to leave it to the user to deal with that when it happens.