xopen should support filehandles

[rhpvorderman]

This is what gzip.open does for instance: https://github.com/python/cpython/blob/d7334e2c2012defaf7aae920d6a56689464509d1/Lib/gzip.py#L60

I also made sure the threaded libraries do this: https://github.com/pycompression/python-isal/blob/970c141a4976276c8254310474db1038d63000ce/src/isal/igzip_threaded.py#L78

PipedCompressionProgram can also do this for writing files. For reading files, it is not possible however.

In any case, for most of the backends, processing a filehandle rather than a file is possible. This will make it easier to chain xopen to other open methods. See: marcelm/cutadapt#761

[geertvandeweyer]

see : #150

[rhpvorderman]

Fixed by #152. Thanks again for reporting! I am planning to release 2.0.0 as soon as I have the time. I also have a use case for this feature. However, it is not critical and I do not want to rush Marcel to see my latest PR. So I cannot provide an ETA.

[rhpvorderman]

2.0.0 is released! https://pypi.org/project/xopen/2.0.0/

Xopen now supports filehandles!