173 lines
4.3 KiB
Python
173 lines
4.3 KiB
Python
"""Weak reference support for Python.
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This module is an implementation of PEP 205:
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http://python.sourceforge.net/peps/pep-0205.html
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"""
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import UserDict
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from _weakref import \
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getweakrefcount, \
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getweakrefs, \
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ref, \
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proxy, \
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ReferenceError, \
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CallableProxyType, \
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ProxyType, \
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ReferenceType
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ProxyTypes = (ProxyType, CallableProxyType)
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__all__ = ["ref", "proxy", "getweakrefcount", "getweakrefs",
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"WeakKeyDictionary", "ReferenceType", "ProxyType",
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"CallableProxyType", "ProxyTypes", "WeakValueDictionary"]
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class WeakValueDictionary(UserDict.UserDict):
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# We inherit the constructor without worrying about the input
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# dictionary; since it uses our .update() method, we get the right
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# checks (if the other dictionary is a WeakValueDictionary,
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# objects are unwrapped on the way out, and we always wrap on the
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# way in).
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def __getitem__(self, key):
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o = self.data.get(key)()
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if o is None:
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raise KeyError, key
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else:
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return o
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def __repr__(self):
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return "<WeakValueDictionary at %s>" % id(self)
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def __setitem__(self, key, value):
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def remove(o, data=self.data, key=key):
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del data[key]
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self.data[key] = ref(value, remove)
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def copy(self):
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new = WeakValueDictionary()
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for key, ref in self.data.items():
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o = ref()
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if o is not None:
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new[key] = o
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return new
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def get(self, key, default):
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try:
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ref = self.data[key]
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except KeyError:
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return default
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else:
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o = ref()
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if o is None:
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# This should only happen
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return default
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else:
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return o
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def items(self):
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L = []
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for key, ref in self.data.items():
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o = ref()
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if o is not None:
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L.append((key, o))
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return L
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def popitem(self):
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while 1:
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key, ref = self.data.popitem()
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o = ref()
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if o is not None:
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return key, o
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def setdefault(self, key, default):
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try:
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ref = self.data[key]
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except KeyError:
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def remove(o, data=self.data, key=key):
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del data[key]
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ref = ref(default, remove)
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self.data[key] = ref
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return default
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else:
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return ref()
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def update(self, dict):
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d = self.data
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L = []
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for key, o in dict.items():
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def remove(o, data=d, key=key):
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del data[key]
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L.append(key, ref(o, remove))
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for key, r in L:
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d[key] = r
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def values(self):
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L = []
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for ref in self.data.values():
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o = ref()
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if o is not None:
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L.append(o)
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return L
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class WeakKeyDictionary(UserDict.UserDict):
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def __init__(self, dict=None):
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self.data = {}
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if dict is not None: self.update(dict)
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def remove(k, data=self.data):
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del data[k]
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self._remove = remove
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def __getitem__(self, key):
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return self.data[ref(key)]
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def __repr__(self):
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return "<WeakKeyDictionary at %s>" % id(self)
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def __setitem__(self, key, value):
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self.data[ref(key, self._remove)] = value
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def copy(self):
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new = WeakKeyDictionary()
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for key, value in self.data.items():
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o = key()
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if o is not None:
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new[o] = value
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return new
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def get(self, key, default):
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return self.data.get(ref(key),default)
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def items(self):
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L = []
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for key, value in self.data.items():
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o = key()
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if o is not None:
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L.append((o, value))
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return L
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def popitem(self):
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while 1:
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key, value = self.data.popitem()
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o = key()
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if o is not None:
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return o, value
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def setdefault(self, key, default):
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return self.data.setdefault(ref(key, self._remove),default)
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def update(self, dict):
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d = self.data
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L = []
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for key, value in dict.items():
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L.append(ref(key, self._remove), value)
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for key, r in L:
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d[key] = r
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# no longer needed
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del UserDict
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