You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
919 lines
24 KiB
Python
919 lines
24 KiB
Python
# util/_collections.py
|
|
# Copyright (C) 2005-2013 the SQLAlchemy authors and contributors <see AUTHORS file>
|
|
#
|
|
# This module is part of SQLAlchemy and is released under
|
|
# the MIT License: http://www.opensource.org/licenses/mit-license.php
|
|
|
|
"""Collection classes and helpers."""
|
|
|
|
import itertools
|
|
import weakref
|
|
import operator
|
|
from .compat import threading
|
|
|
|
EMPTY_SET = frozenset()
|
|
|
|
|
|
class KeyedTuple(tuple):
|
|
"""``tuple`` subclass that adds labeled names.
|
|
|
|
E.g.::
|
|
|
|
>>> k = KeyedTuple([1, 2, 3], labels=["one", "two", "three"])
|
|
>>> k.one
|
|
1
|
|
>>> k.two
|
|
2
|
|
|
|
Result rows returned by :class:`.Query` that contain multiple
|
|
ORM entities and/or column expressions make use of this
|
|
class to return rows.
|
|
|
|
The :class:`.KeyedTuple` exhibits similar behavior to the
|
|
``collections.namedtuple()`` construct provided in the Python
|
|
standard library, however is architected very differently.
|
|
Unlike ``collections.namedtuple()``, :class:`.KeyedTuple` is
|
|
does not rely on creation of custom subtypes in order to represent
|
|
a new series of keys, instead each :class:`.KeyedTuple` instance
|
|
receives its list of keys in place. The subtype approach
|
|
of ``collections.namedtuple()`` introduces significant complexity
|
|
and performance overhead, which is not necessary for the
|
|
:class:`.Query` object's use case.
|
|
|
|
.. versionchanged:: 0.8
|
|
Compatibility methods with ``collections.namedtuple()`` have been
|
|
added including :attr:`.KeyedTuple._fields` and
|
|
:meth:`.KeyedTuple._asdict`.
|
|
|
|
.. seealso::
|
|
|
|
:ref:`ormtutorial_querying`
|
|
|
|
"""
|
|
|
|
def __new__(cls, vals, labels=None):
|
|
t = tuple.__new__(cls, vals)
|
|
t._labels = []
|
|
if labels:
|
|
t.__dict__.update(zip(labels, vals))
|
|
t._labels = labels
|
|
return t
|
|
|
|
def keys(self):
|
|
"""Return a list of string key names for this :class:`.KeyedTuple`.
|
|
|
|
.. seealso::
|
|
|
|
:attr:`.KeyedTuple._fields`
|
|
|
|
"""
|
|
|
|
return [l for l in self._labels if l is not None]
|
|
|
|
@property
|
|
def _fields(self):
|
|
"""Return a tuple of string key names for this :class:`.KeyedTuple`.
|
|
|
|
This method provides compatibility with ``collections.namedtuple()``.
|
|
|
|
.. versionadded:: 0.8
|
|
|
|
.. seealso::
|
|
|
|
:meth:`.KeyedTuple.keys`
|
|
|
|
"""
|
|
return tuple(self.keys())
|
|
|
|
def _asdict(self):
|
|
"""Return the contents of this :class:`.KeyedTuple` as a dictionary.
|
|
|
|
This method provides compatibility with ``collections.namedtuple()``,
|
|
with the exception that the dictionary returned is **not** ordered.
|
|
|
|
.. versionadded:: 0.8
|
|
|
|
"""
|
|
return dict((key, self.__dict__[key]) for key in self.keys())
|
|
|
|
|
|
class ImmutableContainer(object):
|
|
def _immutable(self, *arg, **kw):
|
|
raise TypeError("%s object is immutable" % self.__class__.__name__)
|
|
|
|
__delitem__ = __setitem__ = __setattr__ = _immutable
|
|
|
|
|
|
class immutabledict(ImmutableContainer, dict):
|
|
|
|
clear = pop = popitem = setdefault = \
|
|
update = ImmutableContainer._immutable
|
|
|
|
def __new__(cls, *args):
|
|
new = dict.__new__(cls)
|
|
dict.__init__(new, *args)
|
|
return new
|
|
|
|
def __init__(self, *args):
|
|
pass
|
|
|
|
def __reduce__(self):
|
|
return immutabledict, (dict(self), )
|
|
|
|
def union(self, d):
|
|
if not self:
|
|
return immutabledict(d)
|
|
else:
|
|
d2 = immutabledict(self)
|
|
dict.update(d2, d)
|
|
return d2
|
|
|
|
def __repr__(self):
|
|
return "immutabledict(%s)" % dict.__repr__(self)
|
|
|
|
|
|
class Properties(object):
|
|
"""Provide a __getattr__/__setattr__ interface over a dict."""
|
|
|
|
def __init__(self, data):
|
|
self.__dict__['_data'] = data
|
|
|
|
def __len__(self):
|
|
return len(self._data)
|
|
|
|
def __iter__(self):
|
|
return self._data.itervalues()
|
|
|
|
def __add__(self, other):
|
|
return list(self) + list(other)
|
|
|
|
def __setitem__(self, key, object):
|
|
self._data[key] = object
|
|
|
|
def __getitem__(self, key):
|
|
return self._data[key]
|
|
|
|
def __delitem__(self, key):
|
|
del self._data[key]
|
|
|
|
def __setattr__(self, key, object):
|
|
self._data[key] = object
|
|
|
|
def __getstate__(self):
|
|
return {'_data': self.__dict__['_data']}
|
|
|
|
def __setstate__(self, state):
|
|
self.__dict__['_data'] = state['_data']
|
|
|
|
def __getattr__(self, key):
|
|
try:
|
|
return self._data[key]
|
|
except KeyError:
|
|
raise AttributeError(key)
|
|
|
|
def __contains__(self, key):
|
|
return key in self._data
|
|
|
|
def as_immutable(self):
|
|
"""Return an immutable proxy for this :class:`.Properties`."""
|
|
|
|
return ImmutableProperties(self._data)
|
|
|
|
def update(self, value):
|
|
self._data.update(value)
|
|
|
|
def get(self, key, default=None):
|
|
if key in self:
|
|
return self[key]
|
|
else:
|
|
return default
|
|
|
|
def keys(self):
|
|
return self._data.keys()
|
|
|
|
def values(self):
|
|
return self._data.values()
|
|
|
|
def items(self):
|
|
return self._data.items()
|
|
|
|
def has_key(self, key):
|
|
return key in self._data
|
|
|
|
def clear(self):
|
|
self._data.clear()
|
|
|
|
|
|
class OrderedProperties(Properties):
|
|
"""Provide a __getattr__/__setattr__ interface with an OrderedDict
|
|
as backing store."""
|
|
def __init__(self):
|
|
Properties.__init__(self, OrderedDict())
|
|
|
|
|
|
class ImmutableProperties(ImmutableContainer, Properties):
|
|
"""Provide immutable dict/object attribute to an underlying dictionary."""
|
|
|
|
|
|
class OrderedDict(dict):
|
|
"""A dict that returns keys/values/items in the order they were added."""
|
|
|
|
def __init__(self, ____sequence=None, **kwargs):
|
|
self._list = []
|
|
if ____sequence is None:
|
|
if kwargs:
|
|
self.update(**kwargs)
|
|
else:
|
|
self.update(____sequence, **kwargs)
|
|
|
|
def clear(self):
|
|
self._list = []
|
|
dict.clear(self)
|
|
|
|
def copy(self):
|
|
return self.__copy__()
|
|
|
|
def __copy__(self):
|
|
return OrderedDict(self)
|
|
|
|
def sort(self, *arg, **kw):
|
|
self._list.sort(*arg, **kw)
|
|
|
|
def update(self, ____sequence=None, **kwargs):
|
|
if ____sequence is not None:
|
|
if hasattr(____sequence, 'keys'):
|
|
for key in ____sequence.keys():
|
|
self.__setitem__(key, ____sequence[key])
|
|
else:
|
|
for key, value in ____sequence:
|
|
self[key] = value
|
|
if kwargs:
|
|
self.update(kwargs)
|
|
|
|
def setdefault(self, key, value):
|
|
if key not in self:
|
|
self.__setitem__(key, value)
|
|
return value
|
|
else:
|
|
return self.__getitem__(key)
|
|
|
|
def __iter__(self):
|
|
return iter(self._list)
|
|
|
|
def values(self):
|
|
return [self[key] for key in self._list]
|
|
|
|
def itervalues(self):
|
|
return iter([self[key] for key in self._list])
|
|
|
|
def keys(self):
|
|
return list(self._list)
|
|
|
|
def iterkeys(self):
|
|
return iter(self.keys())
|
|
|
|
def items(self):
|
|
return [(key, self[key]) for key in self.keys()]
|
|
|
|
def iteritems(self):
|
|
return iter(self.items())
|
|
|
|
def __setitem__(self, key, object):
|
|
if key not in self:
|
|
try:
|
|
self._list.append(key)
|
|
except AttributeError:
|
|
# work around Python pickle loads() with
|
|
# dict subclass (seems to ignore __setstate__?)
|
|
self._list = [key]
|
|
dict.__setitem__(self, key, object)
|
|
|
|
def __delitem__(self, key):
|
|
dict.__delitem__(self, key)
|
|
self._list.remove(key)
|
|
|
|
def pop(self, key, *default):
|
|
present = key in self
|
|
value = dict.pop(self, key, *default)
|
|
if present:
|
|
self._list.remove(key)
|
|
return value
|
|
|
|
def popitem(self):
|
|
item = dict.popitem(self)
|
|
self._list.remove(item[0])
|
|
return item
|
|
|
|
|
|
class OrderedSet(set):
|
|
def __init__(self, d=None):
|
|
set.__init__(self)
|
|
self._list = []
|
|
if d is not None:
|
|
self.update(d)
|
|
|
|
def add(self, element):
|
|
if element not in self:
|
|
self._list.append(element)
|
|
set.add(self, element)
|
|
|
|
def remove(self, element):
|
|
set.remove(self, element)
|
|
self._list.remove(element)
|
|
|
|
def insert(self, pos, element):
|
|
if element not in self:
|
|
self._list.insert(pos, element)
|
|
set.add(self, element)
|
|
|
|
def discard(self, element):
|
|
if element in self:
|
|
self._list.remove(element)
|
|
set.remove(self, element)
|
|
|
|
def clear(self):
|
|
set.clear(self)
|
|
self._list = []
|
|
|
|
def __getitem__(self, key):
|
|
return self._list[key]
|
|
|
|
def __iter__(self):
|
|
return iter(self._list)
|
|
|
|
def __add__(self, other):
|
|
return self.union(other)
|
|
|
|
def __repr__(self):
|
|
return '%s(%r)' % (self.__class__.__name__, self._list)
|
|
|
|
__str__ = __repr__
|
|
|
|
def update(self, iterable):
|
|
for e in iterable:
|
|
if e not in self:
|
|
self._list.append(e)
|
|
set.add(self, e)
|
|
return self
|
|
|
|
__ior__ = update
|
|
|
|
def union(self, other):
|
|
result = self.__class__(self)
|
|
result.update(other)
|
|
return result
|
|
|
|
__or__ = union
|
|
|
|
def intersection(self, other):
|
|
other = set(other)
|
|
return self.__class__(a for a in self if a in other)
|
|
|
|
__and__ = intersection
|
|
|
|
def symmetric_difference(self, other):
|
|
other = set(other)
|
|
result = self.__class__(a for a in self if a not in other)
|
|
result.update(a for a in other if a not in self)
|
|
return result
|
|
|
|
__xor__ = symmetric_difference
|
|
|
|
def difference(self, other):
|
|
other = set(other)
|
|
return self.__class__(a for a in self if a not in other)
|
|
|
|
__sub__ = difference
|
|
|
|
def intersection_update(self, other):
|
|
other = set(other)
|
|
set.intersection_update(self, other)
|
|
self._list = [a for a in self._list if a in other]
|
|
return self
|
|
|
|
__iand__ = intersection_update
|
|
|
|
def symmetric_difference_update(self, other):
|
|
set.symmetric_difference_update(self, other)
|
|
self._list = [a for a in self._list if a in self]
|
|
self._list += [a for a in other._list if a in self]
|
|
return self
|
|
|
|
__ixor__ = symmetric_difference_update
|
|
|
|
def difference_update(self, other):
|
|
set.difference_update(self, other)
|
|
self._list = [a for a in self._list if a in self]
|
|
return self
|
|
|
|
__isub__ = difference_update
|
|
|
|
|
|
class IdentitySet(object):
|
|
"""A set that considers only object id() for uniqueness.
|
|
|
|
This strategy has edge cases for builtin types- it's possible to have
|
|
two 'foo' strings in one of these sets, for example. Use sparingly.
|
|
|
|
"""
|
|
|
|
_working_set = set
|
|
|
|
def __init__(self, iterable=None):
|
|
self._members = dict()
|
|
if iterable:
|
|
for o in iterable:
|
|
self.add(o)
|
|
|
|
def add(self, value):
|
|
self._members[id(value)] = value
|
|
|
|
def __contains__(self, value):
|
|
return id(value) in self._members
|
|
|
|
def remove(self, value):
|
|
del self._members[id(value)]
|
|
|
|
def discard(self, value):
|
|
try:
|
|
self.remove(value)
|
|
except KeyError:
|
|
pass
|
|
|
|
def pop(self):
|
|
try:
|
|
pair = self._members.popitem()
|
|
return pair[1]
|
|
except KeyError:
|
|
raise KeyError('pop from an empty set')
|
|
|
|
def clear(self):
|
|
self._members.clear()
|
|
|
|
def __cmp__(self, other):
|
|
raise TypeError('cannot compare sets using cmp()')
|
|
|
|
def __eq__(self, other):
|
|
if isinstance(other, IdentitySet):
|
|
return self._members == other._members
|
|
else:
|
|
return False
|
|
|
|
def __ne__(self, other):
|
|
if isinstance(other, IdentitySet):
|
|
return self._members != other._members
|
|
else:
|
|
return True
|
|
|
|
def issubset(self, iterable):
|
|
other = type(self)(iterable)
|
|
|
|
if len(self) > len(other):
|
|
return False
|
|
for m in itertools.ifilterfalse(other._members.__contains__,
|
|
self._members.iterkeys()):
|
|
return False
|
|
return True
|
|
|
|
def __le__(self, other):
|
|
if not isinstance(other, IdentitySet):
|
|
return NotImplemented
|
|
return self.issubset(other)
|
|
|
|
def __lt__(self, other):
|
|
if not isinstance(other, IdentitySet):
|
|
return NotImplemented
|
|
return len(self) < len(other) and self.issubset(other)
|
|
|
|
def issuperset(self, iterable):
|
|
other = type(self)(iterable)
|
|
|
|
if len(self) < len(other):
|
|
return False
|
|
|
|
for m in itertools.ifilterfalse(self._members.__contains__,
|
|
other._members.iterkeys()):
|
|
return False
|
|
return True
|
|
|
|
def __ge__(self, other):
|
|
if not isinstance(other, IdentitySet):
|
|
return NotImplemented
|
|
return self.issuperset(other)
|
|
|
|
def __gt__(self, other):
|
|
if not isinstance(other, IdentitySet):
|
|
return NotImplemented
|
|
return len(self) > len(other) and self.issuperset(other)
|
|
|
|
def union(self, iterable):
|
|
result = type(self)()
|
|
# testlib.pragma exempt:__hash__
|
|
members = self._member_id_tuples()
|
|
other = _iter_id(iterable)
|
|
result._members.update(self._working_set(members).union(other))
|
|
return result
|
|
|
|
def __or__(self, other):
|
|
if not isinstance(other, IdentitySet):
|
|
return NotImplemented
|
|
return self.union(other)
|
|
|
|
def update(self, iterable):
|
|
self._members = self.union(iterable)._members
|
|
|
|
def __ior__(self, other):
|
|
if not isinstance(other, IdentitySet):
|
|
return NotImplemented
|
|
self.update(other)
|
|
return self
|
|
|
|
def difference(self, iterable):
|
|
result = type(self)()
|
|
# testlib.pragma exempt:__hash__
|
|
members = self._member_id_tuples()
|
|
other = _iter_id(iterable)
|
|
result._members.update(self._working_set(members).difference(other))
|
|
return result
|
|
|
|
def __sub__(self, other):
|
|
if not isinstance(other, IdentitySet):
|
|
return NotImplemented
|
|
return self.difference(other)
|
|
|
|
def difference_update(self, iterable):
|
|
self._members = self.difference(iterable)._members
|
|
|
|
def __isub__(self, other):
|
|
if not isinstance(other, IdentitySet):
|
|
return NotImplemented
|
|
self.difference_update(other)
|
|
return self
|
|
|
|
def intersection(self, iterable):
|
|
result = type(self)()
|
|
# testlib.pragma exempt:__hash__
|
|
members = self._member_id_tuples()
|
|
other = _iter_id(iterable)
|
|
result._members.update(self._working_set(members).intersection(other))
|
|
return result
|
|
|
|
def __and__(self, other):
|
|
if not isinstance(other, IdentitySet):
|
|
return NotImplemented
|
|
return self.intersection(other)
|
|
|
|
def intersection_update(self, iterable):
|
|
self._members = self.intersection(iterable)._members
|
|
|
|
def __iand__(self, other):
|
|
if not isinstance(other, IdentitySet):
|
|
return NotImplemented
|
|
self.intersection_update(other)
|
|
return self
|
|
|
|
def symmetric_difference(self, iterable):
|
|
result = type(self)()
|
|
# testlib.pragma exempt:__hash__
|
|
members = self._member_id_tuples()
|
|
other = _iter_id(iterable)
|
|
result._members.update(
|
|
self._working_set(members).symmetric_difference(other))
|
|
return result
|
|
|
|
def _member_id_tuples(self):
|
|
return ((id(v), v) for v in self._members.itervalues())
|
|
|
|
def __xor__(self, other):
|
|
if not isinstance(other, IdentitySet):
|
|
return NotImplemented
|
|
return self.symmetric_difference(other)
|
|
|
|
def symmetric_difference_update(self, iterable):
|
|
self._members = self.symmetric_difference(iterable)._members
|
|
|
|
def __ixor__(self, other):
|
|
if not isinstance(other, IdentitySet):
|
|
return NotImplemented
|
|
self.symmetric_difference(other)
|
|
return self
|
|
|
|
def copy(self):
|
|
return type(self)(self._members.itervalues())
|
|
|
|
__copy__ = copy
|
|
|
|
def __len__(self):
|
|
return len(self._members)
|
|
|
|
def __iter__(self):
|
|
return self._members.itervalues()
|
|
|
|
def __hash__(self):
|
|
raise TypeError('set objects are unhashable')
|
|
|
|
def __repr__(self):
|
|
return '%s(%r)' % (type(self).__name__, self._members.values())
|
|
|
|
|
|
class WeakSequence(object):
|
|
def __init__(self, __elements=()):
|
|
self._storage = [
|
|
weakref.ref(element, self._remove) for element in __elements
|
|
]
|
|
|
|
def append(self, item):
|
|
self._storage.append(weakref.ref(item, self._remove))
|
|
|
|
def _remove(self, ref):
|
|
self._storage.remove(ref)
|
|
|
|
def __len__(self):
|
|
return len(self._storage)
|
|
|
|
def __iter__(self):
|
|
return (obj for obj in
|
|
(ref() for ref in self._storage) if obj is not None)
|
|
|
|
def __getitem__(self, index):
|
|
try:
|
|
obj = self._storage[index]
|
|
except KeyError:
|
|
raise IndexError("Index %s out of range" % index)
|
|
else:
|
|
return obj()
|
|
|
|
|
|
class OrderedIdentitySet(IdentitySet):
|
|
class _working_set(OrderedSet):
|
|
# a testing pragma: exempt the OIDS working set from the test suite's
|
|
# "never call the user's __hash__" assertions. this is a big hammer,
|
|
# but it's safe here: IDS operates on (id, instance) tuples in the
|
|
# working set.
|
|
__sa_hash_exempt__ = True
|
|
|
|
def __init__(self, iterable=None):
|
|
IdentitySet.__init__(self)
|
|
self._members = OrderedDict()
|
|
if iterable:
|
|
for o in iterable:
|
|
self.add(o)
|
|
|
|
|
|
class PopulateDict(dict):
|
|
"""A dict which populates missing values via a creation function.
|
|
|
|
Note the creation function takes a key, unlike
|
|
collections.defaultdict.
|
|
|
|
"""
|
|
|
|
def __init__(self, creator):
|
|
self.creator = creator
|
|
|
|
def __missing__(self, key):
|
|
self[key] = val = self.creator(key)
|
|
return val
|
|
|
|
# Define collections that are capable of storing
|
|
# ColumnElement objects as hashable keys/elements.
|
|
# At this point, these are mostly historical, things
|
|
# used to be more complicated.
|
|
column_set = set
|
|
column_dict = dict
|
|
ordered_column_set = OrderedSet
|
|
populate_column_dict = PopulateDict
|
|
|
|
def unique_list(seq, hashfunc=None):
|
|
seen = {}
|
|
if not hashfunc:
|
|
return [x for x in seq
|
|
if x not in seen
|
|
and not seen.__setitem__(x, True)]
|
|
else:
|
|
return [x for x in seq
|
|
if hashfunc(x) not in seen
|
|
and not seen.__setitem__(hashfunc(x), True)]
|
|
|
|
|
|
class UniqueAppender(object):
|
|
"""Appends items to a collection ensuring uniqueness.
|
|
|
|
Additional appends() of the same object are ignored. Membership is
|
|
determined by identity (``is a``) not equality (``==``).
|
|
"""
|
|
|
|
def __init__(self, data, via=None):
|
|
self.data = data
|
|
self._unique = {}
|
|
if via:
|
|
self._data_appender = getattr(data, via)
|
|
elif hasattr(data, 'append'):
|
|
self._data_appender = data.append
|
|
elif hasattr(data, 'add'):
|
|
self._data_appender = data.add
|
|
|
|
def append(self, item):
|
|
id_ = id(item)
|
|
if id_ not in self._unique:
|
|
self._data_appender(item)
|
|
self._unique[id_] = True
|
|
|
|
def __iter__(self):
|
|
return iter(self.data)
|
|
|
|
|
|
def to_list(x, default=None):
|
|
if x is None:
|
|
return default
|
|
if not isinstance(x, (list, tuple)):
|
|
return [x]
|
|
else:
|
|
return x
|
|
|
|
|
|
def to_set(x):
|
|
if x is None:
|
|
return set()
|
|
if not isinstance(x, set):
|
|
return set(to_list(x))
|
|
else:
|
|
return x
|
|
|
|
|
|
def to_column_set(x):
|
|
if x is None:
|
|
return column_set()
|
|
if not isinstance(x, column_set):
|
|
return column_set(to_list(x))
|
|
else:
|
|
return x
|
|
|
|
|
|
def update_copy(d, _new=None, **kw):
|
|
"""Copy the given dict and update with the given values."""
|
|
|
|
d = d.copy()
|
|
if _new:
|
|
d.update(_new)
|
|
d.update(**kw)
|
|
return d
|
|
|
|
|
|
def flatten_iterator(x):
|
|
"""Given an iterator of which further sub-elements may also be
|
|
iterators, flatten the sub-elements into a single iterator.
|
|
|
|
"""
|
|
for elem in x:
|
|
if not isinstance(elem, basestring) and hasattr(elem, '__iter__'):
|
|
for y in flatten_iterator(elem):
|
|
yield y
|
|
else:
|
|
yield elem
|
|
|
|
|
|
class LRUCache(dict):
|
|
"""Dictionary with 'squishy' removal of least
|
|
recently used items.
|
|
|
|
"""
|
|
def __init__(self, capacity=100, threshold=.5):
|
|
self.capacity = capacity
|
|
self.threshold = threshold
|
|
self._counter = 0
|
|
|
|
def _inc_counter(self):
|
|
self._counter += 1
|
|
return self._counter
|
|
|
|
def __getitem__(self, key):
|
|
item = dict.__getitem__(self, key)
|
|
item[2] = self._inc_counter()
|
|
return item[1]
|
|
|
|
def values(self):
|
|
return [i[1] for i in dict.values(self)]
|
|
|
|
def setdefault(self, key, value):
|
|
if key in self:
|
|
return self[key]
|
|
else:
|
|
self[key] = value
|
|
return value
|
|
|
|
def __setitem__(self, key, value):
|
|
item = dict.get(self, key)
|
|
if item is None:
|
|
item = [key, value, self._inc_counter()]
|
|
dict.__setitem__(self, key, item)
|
|
else:
|
|
item[1] = value
|
|
self._manage_size()
|
|
|
|
def _manage_size(self):
|
|
while len(self) > self.capacity + self.capacity * self.threshold:
|
|
by_counter = sorted(dict.values(self),
|
|
key=operator.itemgetter(2),
|
|
reverse=True)
|
|
for item in by_counter[self.capacity:]:
|
|
try:
|
|
del self[item[0]]
|
|
except KeyError:
|
|
# if we couldnt find a key, most
|
|
# likely some other thread broke in
|
|
# on us. loop around and try again
|
|
break
|
|
|
|
|
|
class ScopedRegistry(object):
|
|
"""A Registry that can store one or multiple instances of a single
|
|
class on the basis of a "scope" function.
|
|
|
|
The object implements ``__call__`` as the "getter", so by
|
|
calling ``myregistry()`` the contained object is returned
|
|
for the current scope.
|
|
|
|
:param createfunc:
|
|
a callable that returns a new object to be placed in the registry
|
|
|
|
:param scopefunc:
|
|
a callable that will return a key to store/retrieve an object.
|
|
"""
|
|
|
|
def __init__(self, createfunc, scopefunc):
|
|
"""Construct a new :class:`.ScopedRegistry`.
|
|
|
|
:param createfunc: A creation function that will generate
|
|
a new value for the current scope, if none is present.
|
|
|
|
:param scopefunc: A function that returns a hashable
|
|
token representing the current scope (such as, current
|
|
thread identifier).
|
|
|
|
"""
|
|
self.createfunc = createfunc
|
|
self.scopefunc = scopefunc
|
|
self.registry = {}
|
|
|
|
def __call__(self):
|
|
key = self.scopefunc()
|
|
try:
|
|
return self.registry[key]
|
|
except KeyError:
|
|
return self.registry.setdefault(key, self.createfunc())
|
|
|
|
def has(self):
|
|
"""Return True if an object is present in the current scope."""
|
|
|
|
return self.scopefunc() in self.registry
|
|
|
|
def set(self, obj):
|
|
"""Set the value forthe current scope."""
|
|
|
|
self.registry[self.scopefunc()] = obj
|
|
|
|
def clear(self):
|
|
"""Clear the current scope, if any."""
|
|
|
|
try:
|
|
del self.registry[self.scopefunc()]
|
|
except KeyError:
|
|
pass
|
|
|
|
|
|
class ThreadLocalRegistry(ScopedRegistry):
|
|
"""A :class:`.ScopedRegistry` that uses a ``threading.local()``
|
|
variable for storage.
|
|
|
|
"""
|
|
def __init__(self, createfunc):
|
|
self.createfunc = createfunc
|
|
self.registry = threading.local()
|
|
|
|
def __call__(self):
|
|
try:
|
|
return self.registry.value
|
|
except AttributeError:
|
|
val = self.registry.value = self.createfunc()
|
|
return val
|
|
|
|
def has(self):
|
|
return hasattr(self.registry, "value")
|
|
|
|
def set(self, obj):
|
|
self.registry.value = obj
|
|
|
|
def clear(self):
|
|
try:
|
|
del self.registry.value
|
|
except AttributeError:
|
|
pass
|
|
|
|
|
|
def _iter_id(iterable):
|
|
"""Generator: ((id(o), o) for o in iterable)."""
|
|
|
|
for item in iterable:
|
|
yield id(item), item
|