from __future__ import unicode_literals
from __future__ import absolute_import
from . import util
from copy import deepcopy
class OrderedDict(dict):
"""
A dictionary that keeps its keys in the order in which they're inserted.
Copied from Django's SortedDict with some modifications.
"""
def __new__(cls, *args, **kwargs):
instance = super(OrderedDict, cls).__new__(cls, *args, **kwargs)
instance.keyOrder = []
return instance
def __init__(self, data=None):
if data is None or isinstance(data, dict):
data = data or []
super(OrderedDict, self).__init__(data)
self.keyOrder = list(data) if data else []
else:
super(OrderedDict, self).__init__()
super_set = super(OrderedDict, self).__setitem__
for key, value in data:
# Take the ordering from first key
if key not in self:
self.keyOrder.append(key)
# But override with last value in data (dict() does this)
super_set(key, value)
def __deepcopy__(self, memo):
return self.__class__([(key, deepcopy(value, memo))
for key, value in self.items()])
def __copy__(self):
# The Python's default copy implementation will alter the state
# of self. The reason for this seems complex but is likely related to
# subclassing dict.
return self.copy()
def __setitem__(self, key, value):
if key not in self:
self.keyOrder.append(key)
super(OrderedDict, self).__setitem__(key, value)
def __delitem__(self, key):
super(OrderedDict, self).__delitem__(key)
self.keyOrder.remove(key)
def __iter__(self):
return iter(self.keyOrder)
def __reversed__(self):
return reversed(self.keyOrder)
def pop(self, k, *args):
result = super(OrderedDict, self).pop(k, *args)
try:
self.keyOrder.remove(k)
except ValueError:
# Key wasn't in the dictionary in the first place. No problem.
pass
return result
def popitem(self):
result = super(OrderedDict, self).popitem()
self.keyOrder.remove(result[0])
return result
def _iteritems(self):
for key in self.keyOrder:
yield key, self[key]
def _iterkeys(self):
for key in self.keyOrder:
yield key
def _itervalues(self):
for key in self.keyOrder:
yield self[key]
if util.PY3: # pragma: no cover
items = _iteritems
keys = _iterkeys
values = _itervalues
else: # pragma: no cover
iteritems = _iteritems
iterkeys = _iterkeys
itervalues = _itervalues
def items(self):
return [(k, self[k]) for k in self.keyOrder]
def keys(self):
return self.keyOrder[:]
def values(self):
return [self[k] for k in self.keyOrder]
def update(self, dict_):
for k in dict_:
self[k] = dict_[k]
def setdefault(self, key, default):
if key not in self:
self.keyOrder.append(key)
return super(OrderedDict, self).setdefault(key, default)
def value_for_index(self, index):
"""Returns the value of the item at the given zero-based index."""
return self[self.keyOrder[index]]
def insert(self, index, key, value):
"""Inserts the key, value pair before the item with the given index."""
if key in self.keyOrder:
n = self.keyOrder.index(key)
del self.keyOrder[n]
if n < index:
index -= 1
self.keyOrder.insert(index, key)
super(OrderedDict, self).__setitem__(key, value)
def copy(self):
"""Returns a copy of this object."""
# This way of initializing the copy means it works for subclasses, too.
return self.__class__(self)
def __repr__(self):
"""
Replaces the normal dict.__repr__ with a version that returns the keys
in their Ordered order.
"""
return '{%s}' % ', '.join(
['%r: %r' % (k, v) for k, v in self._iteritems()]
)
def clear(self):
super(OrderedDict, self).clear()
self.keyOrder = []
def index(self, key):
""" Return the index of a given key. """
try:
return self.keyOrder.index(key)
except ValueError:
raise ValueError("Element '%s' was not found in OrderedDict" % key)
def index_for_location(self, location):
""" Return index or None for a given location. """
if location == '_begin':
i = 0
elif location == '_end':
i = None
elif location.startswith('<') or location.startswith('>'):
i = self.index(location[1:])
if location.startswith('>'):
if i >= len(self):
# last item
i = None
else:
i += 1
else:
raise ValueError('Not a valid location: "%s". Location key '
'must start with a ">" or "<".' % location)
return i
def add(self, key, value, location):
""" Insert by key location. """
i = self.index_for_location(location)
if i is not None:
self.insert(i, key, value)
else:
self.__setitem__(key, value)
def link(self, key, location):
""" Change location of an existing item. """
n = self.keyOrder.index(key)
del self.keyOrder[n]
try:
i = self.index_for_location(location)
if i is not None:
self.keyOrder.insert(i, key)
else:
self.keyOrder.append(key)
except Exception as e:
# restore to prevent data loss and reraise
self.keyOrder.insert(n, key)
raise e
