Tools/Scripts/webkitpy/thirdparty/ordered_dict.py

# Copyright (c) 2009 Raymond Hettinger.
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.

# This code is obtained from http://code.activestate.com/recipes/576669/

from collections import MutableMapping

class OrderedDict(dict, MutableMapping):

    # Methods with direct access to underlying attributes

    def __init__(self, *args, **kwds):
        if len(args) > 1:
            raise TypeError('expected at 1 argument, got %d', len(args))
        if not hasattr(self, '_keys'):
            self._keys = []
        self.update(*args, **kwds)

    def clear(self):
        del self._keys[:]
        dict.clear(self)

    def __setitem__(self, key, value):
        if key not in self:
            self._keys.append(key)
        dict.__setitem__(self, key, value)

    def __delitem__(self, key):
        dict.__delitem__(self, key)
        self._keys.remove(key)

    def __iter__(self):
        return iter(self._keys)

    def __reversed__(self):
        return reversed(self._keys)

    def popitem(self):
        if not self:
            raise KeyError
        key = self._keys.pop()
        value = dict.pop(self, key)
        return key, value

    def __reduce__(self):
        items = [[k, self[k]] for k in self]
        inst_dict = vars(self).copy()
        inst_dict.pop('_keys', None)
        return (self.__class__, (items,), inst_dict)

    # Methods with indirect access via the above methods

    setdefault = MutableMapping.setdefault
    update = MutableMapping.update
    pop = MutableMapping.pop
    keys = MutableMapping.keys
    values = MutableMapping.values
    items = MutableMapping.items

    def __repr__(self):
        pairs = ', '.join(map('%r: %r'.__mod__, self.items()))
        return '%s({%s})' % (self.__class__.__name__, pairs)

    def copy(self):
        return self.__class__(self)

    @classmethod
    def fromkeys(cls, iterable, value=None):
        d = cls()
        for key in iterable:
            d[key] = value
        return d