Files
deb-python-cassandra-driver/cassandra/util.py
2015-01-26 15:10:26 -06:00

656 lines
20 KiB
Python

from __future__ import with_statement
try:
from collections import OrderedDict
except ImportError:
# OrderedDict from Python 2.7+
# 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.
from UserDict import DictMixin
class OrderedDict(dict, DictMixin): # noqa
""" A dictionary which maintains the insertion order of keys. """
def __init__(self, *args, **kwds):
""" A dictionary which maintains the insertion order of keys. """
if len(args) > 1:
raise TypeError('expected at most 1 arguments, got %d' % len(args))
try:
self.__end
except AttributeError:
self.clear()
self.update(*args, **kwds)
def clear(self):
self.__end = end = []
end += [None, end, end] # sentinel node for doubly linked list
self.__map = {} # key --> [key, prev, next]
dict.clear(self)
def __setitem__(self, key, value):
if key not in self:
end = self.__end
curr = end[1]
curr[2] = end[1] = self.__map[key] = [key, curr, end]
dict.__setitem__(self, key, value)
def __delitem__(self, key):
dict.__delitem__(self, key)
key, prev, next = self.__map.pop(key)
prev[2] = next
next[1] = prev
def __iter__(self):
end = self.__end
curr = end[2]
while curr is not end:
yield curr[0]
curr = curr[2]
def __reversed__(self):
end = self.__end
curr = end[1]
while curr is not end:
yield curr[0]
curr = curr[1]
def popitem(self, last=True):
if not self:
raise KeyError('dictionary is empty')
if last:
key = next(reversed(self))
else:
key = next(iter(self))
value = self.pop(key)
return key, value
def __reduce__(self):
items = [[k, self[k]] for k in self]
tmp = self.__map, self.__end
del self.__map, self.__end
inst_dict = vars(self).copy()
self.__map, self.__end = tmp
if inst_dict:
return (self.__class__, (items,), inst_dict)
return self.__class__, (items,)
def keys(self):
return list(self)
setdefault = DictMixin.setdefault
update = DictMixin.update
pop = DictMixin.pop
values = DictMixin.values
items = DictMixin.items
iterkeys = DictMixin.iterkeys
itervalues = DictMixin.itervalues
iteritems = DictMixin.iteritems
def __repr__(self):
if not self:
return '%s()' % (self.__class__.__name__,)
return '%s(%r)' % (self.__class__.__name__, self.items())
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
def __eq__(self, other):
if isinstance(other, OrderedDict):
if len(self) != len(other):
return False
for p, q in zip(self.items(), other.items()):
if p != q:
return False
return True
return dict.__eq__(self, other)
def __ne__(self, other):
return not self == other
# WeakSet from Python 2.7+ (https://code.google.com/p/weakrefset)
from _weakref import ref
class _IterationGuard(object):
# This context manager registers itself in the current iterators of the
# weak container, such as to delay all removals until the context manager
# exits.
# This technique should be relatively thread-safe (since sets are).
def __init__(self, weakcontainer):
# Don't create cycles
self.weakcontainer = ref(weakcontainer)
def __enter__(self):
w = self.weakcontainer()
if w is not None:
w._iterating.add(self)
return self
def __exit__(self, e, t, b):
w = self.weakcontainer()
if w is not None:
s = w._iterating
s.remove(self)
if not s:
w._commit_removals()
class WeakSet(object):
def __init__(self, data=None):
self.data = set()
def _remove(item, selfref=ref(self)):
self = selfref()
if self is not None:
if self._iterating:
self._pending_removals.append(item)
else:
self.data.discard(item)
self._remove = _remove
# A list of keys to be removed
self._pending_removals = []
self._iterating = set()
if data is not None:
self.update(data)
def _commit_removals(self):
l = self._pending_removals
discard = self.data.discard
while l:
discard(l.pop())
def __iter__(self):
with _IterationGuard(self):
for itemref in self.data:
item = itemref()
if item is not None:
yield item
def __len__(self):
return sum(x() is not None for x in self.data)
def __contains__(self, item):
return ref(item) in self.data
def __reduce__(self):
return (self.__class__, (list(self),),
getattr(self, '__dict__', None))
__hash__ = None
def add(self, item):
if self._pending_removals:
self._commit_removals()
self.data.add(ref(item, self._remove))
def clear(self):
if self._pending_removals:
self._commit_removals()
self.data.clear()
def copy(self):
return self.__class__(self)
def pop(self):
if self._pending_removals:
self._commit_removals()
while True:
try:
itemref = self.data.pop()
except KeyError:
raise KeyError('pop from empty WeakSet')
item = itemref()
if item is not None:
return item
def remove(self, item):
if self._pending_removals:
self._commit_removals()
self.data.remove(ref(item))
def discard(self, item):
if self._pending_removals:
self._commit_removals()
self.data.discard(ref(item))
def update(self, other):
if self._pending_removals:
self._commit_removals()
if isinstance(other, self.__class__):
self.data.update(other.data)
else:
for element in other:
self.add(element)
def __ior__(self, other):
self.update(other)
return self
# Helper functions for simple delegating methods.
def _apply(self, other, method):
if not isinstance(other, self.__class__):
other = self.__class__(other)
newdata = method(other.data)
newset = self.__class__()
newset.data = newdata
return newset
def difference(self, other):
return self._apply(other, self.data.difference)
__sub__ = difference
def difference_update(self, other):
if self._pending_removals:
self._commit_removals()
if self is other:
self.data.clear()
else:
self.data.difference_update(ref(item) for item in other)
def __isub__(self, other):
if self._pending_removals:
self._commit_removals()
if self is other:
self.data.clear()
else:
self.data.difference_update(ref(item) for item in other)
return self
def intersection(self, other):
return self._apply(other, self.data.intersection)
__and__ = intersection
def intersection_update(self, other):
if self._pending_removals:
self._commit_removals()
self.data.intersection_update(ref(item) for item in other)
def __iand__(self, other):
if self._pending_removals:
self._commit_removals()
self.data.intersection_update(ref(item) for item in other)
return self
def issubset(self, other):
return self.data.issubset(ref(item) for item in other)
__lt__ = issubset
def __le__(self, other):
return self.data <= set(ref(item) for item in other)
def issuperset(self, other):
return self.data.issuperset(ref(item) for item in other)
__gt__ = issuperset
def __ge__(self, other):
return self.data >= set(ref(item) for item in other)
def __eq__(self, other):
if not isinstance(other, self.__class__):
return NotImplemented
return self.data == set(ref(item) for item in other)
def symmetric_difference(self, other):
return self._apply(other, self.data.symmetric_difference)
__xor__ = symmetric_difference
def symmetric_difference_update(self, other):
if self._pending_removals:
self._commit_removals()
if self is other:
self.data.clear()
else:
self.data.symmetric_difference_update(ref(item) for item in other)
def __ixor__(self, other):
if self._pending_removals:
self._commit_removals()
if self is other:
self.data.clear()
else:
self.data.symmetric_difference_update(ref(item) for item in other)
return self
def union(self, other):
return self._apply(other, self.data.union)
__or__ = union
def isdisjoint(self, other):
return len(self.intersection(other)) == 0
try:
from blist import sortedset
except ImportError:
import warnings
warnings.warn(
"The blist library is not available, so a pure python list-based set will "
"be used in place of blist.sortedset for set collection values. "
"You can find the blist library here: https://pypi.python.org/pypi/blist/")
from bisect import bisect_left
class sortedset(object):
'''
A sorted set based on sorted list
This set is used in place of blist.sortedset in Python environments
where blist module/extension is not available.
A sorted set implementation is used in this case because it does not
require its elements to be immutable/hashable.
#Not implemented: update functions, inplace operators
'''
def __init__(self, iterable=()):
self._items = []
for i in iterable:
self.add(i)
def __len__(self):
return len(self._items)
def __iter__(self):
return iter(self._items)
def __reversed__(self):
return reversed(self._items)
def __repr__(self):
return '%s(%r)' % (
self.__class__.__name__,
self._items)
def __reduce__(self):
return self.__class__, (self._items,)
def __eq__(self, other):
if isinstance(other, self.__class__):
return self._items == other._items
else:
if not isinstance(other, set):
return False
return len(other) == len(self._items) and all(item in other for item in self._items)
def __ne__(self, other):
if isinstance(other, self.__class__):
return self._items != other._items
else:
if not isinstance(other, set):
return True
return len(other) != len(self._items) or any(item not in other for item in self._items)
def __le__(self, other):
return self.issubset(other)
def __lt__(self, other):
return len(other) > len(self._items) and self.issubset(other)
def __ge__(self, other):
return self.issuperset(other)
def __gt__(self, other):
return len(self._items) > len(other) and self.issuperset(other)
def __and__(self, other):
return self._intersect(other)
def __or__(self, other):
return self.union(other)
def __sub__(self, other):
return self._diff(other)
def __xor__(self, other):
return self.symmetric_difference(other)
def __contains__(self, item):
i = bisect_left(self._items, item)
return i < len(self._items) and self._items[i] == item
def add(self, item):
i = bisect_left(self._items, item)
if i < len(self._items):
if self._items[i] != item:
self._items.insert(i, item)
else:
self._items.append(item)
def clear(self):
del self._items[:]
def copy(self):
new = sortedset()
new._items = list(self._items)
return new
def isdisjoint(self, other):
return len(self._intersect(other)) == 0
def issubset(self, other):
return len(self._intersect(other)) == len(self._items)
def issuperset(self, other):
return len(self._intersect(other)) == len(other)
def pop(self):
if not self._items:
raise KeyError("pop from empty set")
return self._items.pop()
def remove(self, item):
i = bisect_left(self._items, item)
if i < len(self._items):
if self._items[i] == item:
self._items.pop(i)
return
raise KeyError('%r' % item)
def union(self, *others):
union = sortedset()
union._items = list(self._items)
for other in others:
if isinstance(other, self.__class__):
i = 0
for item in other._items:
i = bisect_left(union._items, item, i)
if i < len(union._items):
if item != union._items[i]:
union._items.insert(i, item)
else:
union._items.append(item)
else:
for item in other:
union.add(item)
return union
def intersection(self, *others):
isect = self.copy()
for other in others:
isect = isect._intersect(other)
if not isect:
break
return isect
def difference(self, *others):
diff = self.copy()
for other in others:
diff = diff._diff(other)
if not diff:
break
return diff
def symmetric_difference(self, other):
diff_self_other = self._diff(other)
diff_other_self = other.difference(self)
return diff_self_other.union(diff_other_self)
def _diff(self, other):
diff = sortedset()
if isinstance(other, self.__class__):
i = 0
for item in self._items:
i = bisect_left(other._items, item, i)
if i < len(other._items):
if item != other._items[i]:
diff._items.append(item)
else:
diff._items.append(item)
else:
for item in self._items:
if item not in other:
diff.add(item)
return diff
def _intersect(self, other):
isect = sortedset()
if isinstance(other, self.__class__):
i = 0
for item in self._items:
i = bisect_left(other._items, item, i)
if i < len(other._items):
if item == other._items[i]:
isect._items.append(item)
else:
break
else:
for item in self._items:
if item in other:
isect.add(item)
return isect
from collections import Mapping
import six
from six.moves import cPickle
class OrderedMap(Mapping):
'''
An ordered map that accepts non-hashable types for keys. It also maintains the
insertion order of items, behaving as OrderedDict in that regard. These maps
are constructed and read just as normal mapping types, exept that they may
contain arbitrary collections and other non-hashable items as keys::
>>> od = OrderedMap([({'one': 1, 'two': 2}, 'value'),
... ({'three': 3, 'four': 4}, 'value2')])
>>> list(od.keys())
[{'two': 2, 'one': 1}, {'three': 3, 'four': 4}]
>>> list(od.values())
['value', 'value2']
These constructs are needed to support nested collections in Cassandra 2.1.3+,
where frozen collections can be specified as parameters to others\*::
CREATE TABLE example (
...
value map<frozen<map<int, int>>, double>
...
)
This class dervies from the (immutable) Mapping API. Objects in these maps
are not intended be modified.
\* Note: Because of the way Cassandra encodes nested types, when using the
driver with nested collections, :attr:`~.Cluster.protocol_version` must be 3
or higher.
'''
def __init__(self, *args, **kwargs):
if len(args) > 1:
raise TypeError('expected at most 1 arguments, got %d' % len(args))
self._items = []
self._index = {}
if args:
e = args[0]
if callable(getattr(e, 'keys', None)):
for k in e.keys():
self._items.append((k, e[k]))
else:
for k, v in e:
self._insert(k, v)
for k, v in six.iteritems(kwargs):
self._insert(k, v)
def _insert(self, key, value):
flat_key = self._serialize_key(key)
i = self._index.get(flat_key, -1)
if i >= 0:
self._items[i] = (key, value)
else:
self._items.append((key, value))
self._index[flat_key] = len(self._items) - 1
def __getitem__(self, key):
index = self._index[self._serialize_key(key)]
return self._items[index][1]
def __iter__(self):
for i in self._items:
yield i[0]
def __len__(self):
return len(self._items)
def __eq__(self, other):
if isinstance(other, OrderedMap):
return self._items == other._items
try:
d = dict(other)
return len(d) == len(self._items) and all(i[1] == d[i[0]] for i in self._items)
except KeyError:
return False
except TypeError:
pass
return NotImplemented
def __repr__(self):
return '%s([%s])' % (
self.__class__.__name__,
', '.join("(%r, %r)" % (k, v) for k, v in self._items))
def __str__(self):
return '{%s}' % ', '.join("%s: %s" % (k, v) for k, v in self._items)
@staticmethod
def _serialize_key(key):
return cPickle.dumps(key)