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# copyright 2003-2010 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
# contact http://www.logilab.fr/ -- mailto:contact@logilab.fr
#
# This file is part of logilab-common.
#
# logilab-common is free software: you can redistribute it and/or modify it under
# the terms of the GNU Lesser General Public License as published by the Free
# Software Foundation, either version 2.1 of the License, or (at your option) any
# later version.
#
# logilab-common is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
# details.
#
# You should have received a copy of the GNU Lesser General Public License along
# with logilab-common. If not, see <http://www.gnu.org/licenses/>.
"""Deprecation utilities."""
__docformat__ = "restructuredtext en"
import sys
from warnings import warn
class class_deprecated(type):
"""metaclass to print a warning on instantiation of a deprecated class"""
def __call__(cls, *args, **kwargs):
msg = getattr(cls, "__deprecation_warning__",
"%(cls)s is deprecated") % {'cls': cls.__name__}
warn(msg, DeprecationWarning, stacklevel=2)
return type.__call__(cls, *args, **kwargs)
def class_renamed(old_name, new_class, message=None):
"""automatically creates a class which fires a DeprecationWarning
when instantiated.
>>> Set = class_renamed('Set', set, 'Set is now replaced by set')
>>> s = Set()
sample.py:57: DeprecationWarning: Set is now replaced by set
s = Set()
>>>
"""
clsdict = {}
if message is None:
message = '%s is deprecated, use %s' % (old_name, new_class.__name__)
clsdict['__deprecation_warning__'] = message
try:
# new-style class
return class_deprecated(old_name, (new_class,), clsdict)
except (NameError, TypeError):
# old-style class
class DeprecatedClass(new_class):
"""FIXME: There might be a better way to handle old/new-style class
"""
def __init__(self, *args, **kwargs):
warn(message, DeprecationWarning, stacklevel=2)
new_class.__init__(self, *args, **kwargs)
return DeprecatedClass
def class_moved(new_class, old_name=None, message=None):
"""nice wrapper around class_renamed when a class has been moved into
another module
"""
if old_name is None:
old_name = new_class.__name__
if message is None:
message = 'class %s is now available as %s.%s' % (
old_name, new_class.__module__, new_class.__name__)
return class_renamed(old_name, new_class, message)
def deprecated(reason=None, stacklevel=2):
"""Decorator that raises a DeprecationWarning to print a message
when the decorated function is called.
"""
def deprecated_decorator(func):
message = reason or 'The function "%s" is deprecated'
if '%s' in message:
message = message % func.func_name
def wrapped(*args, **kwargs):
warn(message, DeprecationWarning, stacklevel=stacklevel)
return func(*args, **kwargs)
try:
wrapped.__name__ = func.__name__
except TypeError: # readonly attribute in 2.3
pass
wrapped.__doc__ = func.__doc__
return wrapped
return deprecated_decorator
def moved(modpath, objname):
"""use to tell that a callable has been moved to a new module.
It returns a callable wrapper, so that when its called a warning is printed
telling where the object can be found, import is done (and not before) and
the actual object is called.
NOTE: the usage is somewhat limited on classes since it will fail if the
wrapper is use in a class ancestors list, use the `class_moved` function
instead (which has no lazy import feature though).
"""
def callnew(*args, **kwargs):
from logilab.common.modutils import load_module_from_name
message = "object %s has been moved to module %s" % (objname, modpath)
warn(message, DeprecationWarning, stacklevel=2)
m = load_module_from_name(modpath)
return getattr(m, objname)(*args, **kwargs)
return callnew
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