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from distutils.version import LooseVersion
from platform import python_version
import functools
import re
import sys
def ensure_python_version(min_version):
if not isinstance(min_version, tuple):
min_version = (min_version, )
if sys.version_info < min_version:
raise ImportError("""
You are running scikit-image on an unsupported version of Python.
Unfortunately, scikit-image 0.15 and above no longer work with your installed
version of Python (%s). You therefore have two options: either upgrade to
Python %s, or install an older version of scikit-image.
For Python 2.7 or Python 3.4, use
$ pip install 'scikit-image<0.15'
Please also consider updating `pip` and `setuptools`:
$ pip install pip setuptools --upgrade
Newer versions of these tools avoid installing packages incompatible
with your version of Python.
""" % (python_version(), '.'.join([str(v) for v in min_version])))
def _check_version(actver, version, cmp_op):
"""
Check version string of an active module against a required version.
If dev/prerelease tags result in TypeError for string-number comparison,
it is assumed that the dependency is satisfied.
Users on dev branches are responsible for keeping their own packages up to
date.
Copyright (C) 2013 The IPython Development Team
Distributed under the terms of the BSD License.
"""
try:
if cmp_op == '>':
return LooseVersion(actver) > LooseVersion(version)
elif cmp_op == '>=':
return LooseVersion(actver) >= LooseVersion(version)
elif cmp_op == '=':
return LooseVersion(actver) == LooseVersion(version)
elif cmp_op == '<':
return LooseVersion(actver) < LooseVersion(version)
else:
return False
except TypeError:
return True
def get_module_version(module_name):
"""Return module version or None if version can't be retrieved."""
mod = __import__(module_name,
fromlist=[module_name.rpartition('.')[-1]])
return getattr(mod, '__version__', getattr(mod, 'VERSION', None))
def is_installed(name, version=None):
"""Test if *name* is installed.
Parameters
----------
name : str
Name of module or "python"
version : str, optional
Version string to test against.
If version is not None, checking version
(must have an attribute named '__version__' or 'VERSION')
Version may start with =, >=, > or < to specify the exact requirement
Returns
-------
out : bool
True if `name` is installed matching the optional version.
Notes
-----
Original Copyright (C) 2009-2011 Pierre Raybaut
Licensed under the terms of the MIT License.
"""
if name.lower() == 'python':
actver = sys.version[:6]
else:
try:
actver = get_module_version(name)
except ImportError:
return False
if version is None:
return True
else:
match = re.search('[0-9]', version)
assert match is not None, "Invalid version number"
symb = version[:match.start()]
if not symb:
symb = '='
assert symb in ('>=', '>', '=', '<'),\
"Invalid version condition '%s'" % symb
version = version[match.start():]
return _check_version(actver, version, symb)
def require(name, version=None):
"""Return decorator that forces a requirement for a function or class.
Parameters
----------
name : str
Name of module or "python".
version : str, optional
Version string to test against.
If version is not None, checking version
(must have an attribute named '__version__' or 'VERSION')
Version may start with =, >=, > or < to specify the exact requirement
Returns
-------
func : function
A decorator that raises an ImportError if a function is run
in the absence of the input dependency.
"""
def decorator(obj):
@functools.wraps(obj)
def func_wrapped(*args, **kwargs):
if is_installed(name, version):
return obj(*args, **kwargs)
else:
msg = '"%s" in "%s" requires "%s'
msg = msg % (obj, obj.__module__, name)
if not version is None:
msg += " %s" % version
raise ImportError(msg + '"')
return func_wrapped
return decorator
def get_module(module_name, version=None):
"""Return a module object of name *module_name* if installed.
Parameters
----------
module_name : str
Name of module.
version : str, optional
Version string to test against.
If version is not None, checking version
(must have an attribute named '__version__' or 'VERSION')
Version may start with =, >=, > or < to specify the exact requirement
Returns
-------
mod : module or None
Module if *module_name* is installed matching the optional version
or None otherwise.
"""
if not is_installed(module_name, version):
return None
return __import__(module_name,
fromlist=[module_name.rpartition('.')[-1]])