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# As usual: copied form stack overflow
# https://stackoverflow.com/a/33181083
from argparse import ArgumentTypeError as err
import os
class PathType(object):
def __init__(self, exists=True, type='file', dash_ok=True):
"""exists:
True: a path that does exist
False: a path that does not exist, in a valid parent directory
None: don't care
type: file, dir, symlink, None, or a function returning True for valid paths
None: don't care
dash_ok: whether to allow "-" as stdin/stdout"""
assert exists in (True, False, None)
assert type in ('file', 'dir', 'symlink', None) or hasattr(type, '__call__')
self._exists = exists
self._type = type
self._dash_ok = dash_ok
def __call__(self, string):
if string == '-':
# the special argument "-" means sys.std{in,out}
if self._type == 'dir':
raise err('standard input/output (-) not allowed as directory path')
elif self._type == 'symlink':
raise err('standard input/output (-) not allowed as symlink path')
elif not self._dash_ok:
raise err('standard input/output (-) not allowed')
else:
e = os.path.exists(string)
if self._exists:
if not e:
raise err("path does not exist: '%s'" % string)
if self._type is None:
pass
elif self._type == 'file':
if not os.path.isfile(string):
raise err("path is not a file: '%s'" % string)
elif self._type == 'symlink':
if not os.path.symlink(string):
raise err("path is not a symlink: '%s'" % string)
elif self._type == 'dir':
if not os.path.isdir(string):
raise err("path is not a directory: '%s'" % string)
elif not self._type(string):
raise err("path not valid: '%s'" % string)
else:
if not self._exists and e:
raise err("path exists: '%s'" % string)
p = os.path.dirname(os.path.normpath(string)) or '.'
if not os.path.isdir(p):
raise err("parent path is not a directory: '%s'" % p)
elif not os.path.exists(p):
raise err("parent directory does not exist: '%s'" % p)
return string
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