138 lines
5.4 KiB
Python
138 lines
5.4 KiB
Python
##
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# Transcribed from http://code.activestate.com/recipes/523034/ on May 1, 2009
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# by Jef Spaleta This code provides an emulation for the defaultdict
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# functionality introduced in python 2.5's collection module
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#
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# Changes from the original:
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# * Change the return value from __reduce__ to use iteritems() to prevent
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# a segfault when pickling. (Jef Spaleta)
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# * Change how we setup the module to use collections.defaultdict by default
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# (Toshio Kuratomi)
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#
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# Copyright (c) 2007 Justin Kirtland
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#
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# PYTHON SOFTWARE FOUNDATION LICENSE VERSION 2
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# --------------------------------------------
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#
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# 1. This LICENSE AGREEMENT is between the Python Software Foundation ("PSF"),
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# and the Individual or Organization ("Licensee") accessing and otherwise
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# using this software ("Python") in source or binary form and its
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# associated documentation.
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#
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# 2. Subject to the terms and conditions of this License Agreement, PSF hereby
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# grants Licensee a nonexclusive, royalty-free, world-wide license to
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# reproduce, analyze, test, perform and/or display publicly, prepare
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# derivative works, distribute, and otherwise use Python alone or in any
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# derivative version, provided, however, that PSF's License Agreement and
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# PSF's notice of copyright, i.e., "Copyright (c) 2001, 2002, 2003, 2004,
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# 2005, 2006 Python Software Foundation; All Rights Reserved" are retained
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# in Python alone or in any derivative version prepared by Licensee.
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#
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# 3. In the event Licensee prepares a derivative work that is based on or
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# incorporates Python or any part thereof, and wants to make the derivative
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# work available to others as provided herein, then Licensee hereby agrees
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# to include in any such work a brief summary of the changes made to
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# Python.
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#
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# 4. PSF is making Python available to Licensee on an "AS IS" basis. PSF
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# MAKES NO REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED. BY WAY OF
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# EXAMPLE, BUT NOT LIMITATION, PSF MAKES NO AND DISCLAIMS ANY
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# REPRESENTATION OR WARRANTY OF MERCHANTABILITY OR FITNESS FOR ANY
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# PARTICULAR PURPOSE OR THAT THE USE OF PYTHON WILL NOT INFRINGE ANY THIRD
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# PARTY RIGHTS.
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#
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# 5. PSF SHALL NOT BE LIABLE TO LICENSEE OR ANY OTHER USERS OF PYTHON FOR ANY
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# INCIDENTAL, SPECIAL, OR CONSEQUENTIAL DAMAGES OR LOSS AS A RESULT OF
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# MODIFYING, DISTRIBUTING, OR OTHERWISE USING PYTHON, OR ANY DERIVATIVE
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# THEREOF, EVEN IF ADVISED OF THE POSSIBILITY THEREOF.
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#
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# 6. This License Agreement will automatically terminate upon a material
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# breach of its terms and conditions.
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#
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# 7. Nothing in this License Agreement shall be deemed to create any
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# relationship of agency, partnership, or joint venture between PSF and
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# Licensee. This License Agreement does not grant permission to use PSF
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# trademarks or trade name in a trademark sense to endorse or promote
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# products or services of Licensee, or any third party.
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#
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# 8. By copying, installing or otherwise using Python, Licensee agrees to be
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# bound by the terms and conditions of this License Agreement.
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'''
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-----------
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defaultdict
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-----------
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This is a pure python implementation of defaultdict that is compatible with
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the defaultdict class provided by python-2.5 and above.
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.. seealso::
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:class:`collections.defaultdict`
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for documentation on this module
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'''
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# Pylint disabled messages
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#
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# :C0103: We're defnining a compatible class name therefore we need to match
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# the format of that name.
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import types
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from kitchen import b_
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# :C0103, W0613: We're implementing the python-2.5 defaultdict API so
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# we have to use the same names as python.
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# :C0111: We point people at the stdlib API docs for defaultdict rather than
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# reproduce it here.
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#pylint:disable-msg=C0103,W0613,C0111
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class defaultdict(dict):
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def __init__(self, default_factory=None, *args, **kwargs):
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if (default_factory is not None and
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not hasattr(default_factory, '__call__')):
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raise TypeError(b_('First argument must be callable'))
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dict.__init__(self, *args, **kwargs)
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self.default_factory = default_factory
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def __getitem__(self, key):
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try:
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return dict.__getitem__(self, key)
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except KeyError:
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return self.__missing__(key)
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def __missing__(self, key):
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if self.default_factory is None:
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raise KeyError(key)
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self[key] = value = self.default_factory()
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return value
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def __reduce__(self):
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if self.default_factory is None:
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args = tuple()
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else:
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args = self.default_factory,
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return type(self), args, None, None, self.iteritems()
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def copy(self):
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return self.__copy__()
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def __copy__(self):
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return type(self)(self.default_factory, self)
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def __deepcopy__(self, memo):
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import copy
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return type(self)(self.default_factory,
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copy.deepcopy(self.items()))
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def __repr__(self):
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# Note: Have to use "is not None" otherwise we get an infinite
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# recursion
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if isinstance(self.default_factory, types.MethodType) \
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and self.default_factory.im_self is not None \
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and issubclass(self.default_factory.im_class, defaultdict):
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defrepr = '<bound method sub._factory of defaultdict(...'
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else:
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defrepr = repr(self.default_factory)
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return 'defaultdict(%s, %s)' % (defrepr, dict.__repr__(self))
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__all__ = ('defaultdict',)
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