Mass Deface
" % id(self)
def __setitem__(self, key, value):
self.data[key] = KeyedRef(value, self._remove, key)
def copy(self):
new = WeakValueDictionary()
for key, wr in self.data.items():
o = wr()
if o is not None:
new[key] = o
return new
__copy__ = copy
def __deepcopy__(self, memo):
from copy import deepcopy
new = self.__class__()
for key, wr in self.data.items():
o = wr()
if o is not None:
new[deepcopy(key, memo)] = o
return new
def get(self, key, default=None):
try:
wr = self.data[key]
except KeyError:
return default
else:
o = wr()
if o is None:
# This should only happen
return default
else:
return o
def items(self):
L = []
for key, wr in self.data.items():
o = wr()
if o is not None:
L.append((key, o))
return L
def iteritems(self):
for wr in self.data.itervalues():
value = wr()
if value is not None:
yield wr.key, value
def iterkeys(self):
return self.data.iterkeys()
def __iter__(self):
return self.data.iterkeys()
def itervaluerefs(self):
"""Return an iterator that yields the weak references to the values.
The references are not guaranteed to be 'live' at the time
they are used, so the result of calling the references needs
to be checked before being used. This can be used to avoid
creating references that will cause the garbage collector to
keep the values around longer than needed.
"""
return self.data.itervalues()
def itervalues(self):
for wr in self.data.itervalues():
obj = wr()
if obj is not None:
yield obj
def popitem(self):
while 1:
key, wr = self.data.popitem()
o = wr()
if o is not None:
return key, o
def pop(self, key, *args):
try:
o = self.data.pop(key)()
except KeyError:
if args:
return args[0]
raise
if o is None:
raise KeyError, key
else:
return o
def setdefault(self, key, default=None):
try:
wr = self.data[key]
except KeyError:
self.data[key] = KeyedRef(default, self._remove, key)
return default
else:
return wr()
def update(self, dict=None, **kwargs):
d = self.data
if dict is not None:
if not hasattr(dict, "items"):
dict = type({})(dict)
for key, o in dict.items():
d[key] = KeyedRef(o, self._remove, key)
if len(kwargs):
self.update(kwargs)
def valuerefs(self):
"""Return a list of weak references to the values.
The references are not guaranteed to be 'live' at the time
they are used, so the result of calling the references needs
to be checked before being used. This can be used to avoid
creating references that will cause the garbage collector to
keep the values around longer than needed.
"""
return self.data.values()
def values(self):
L = []
for wr in self.data.values():
o = wr()
if o is not None:
L.append(o)
return L
class KeyedRef(ref):
"""Specialized reference that includes a key corresponding to the value.
This is used in the WeakValueDictionary to avoid having to create
a function object for each key stored in the mapping. A shared
callback object can use the 'key' attribute of a KeyedRef instead
of getting a reference to the key from an enclosing scope.
"""
__slots__ = "key",
def __new__(type, ob, callback, key):
self = ref.__new__(type, ob, callback)
self.key = key
return self
def __init__(self, ob, callback, key):
super(KeyedRef, self).__init__(ob, callback)
class WeakKeyDictionary(UserDict.UserDict):
""" Mapping class that references keys weakly.
Entries in the dictionary will be discarded when there is no
longer a strong reference to the key. This can be used to
associate additional data with an object owned by other parts of
an application without adding attributes to those objects. This
can be especially useful with objects that override attribute
accesses.
"""
def __init__(self, dict=None):
self.data = {}
def remove(k, selfref=ref(self)):
self = selfref()
if self is not None:
del self.data[k]
self._remove = remove
if dict is not None: self.update(dict)
def __delitem__(self, key):
del self.data[ref(key)]
def __getitem__(self, key):
return self.data[ref(key)]
def __repr__(self):
return "