weakref.py revision 1d9e4b7de3d15007d5b9e7ac4b38f5e158d3c840
141deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake"""Weak reference support for Python. 241deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake 341deb1efc2f969b58e49af669cc20d15ccdb04c6Fred DrakeThis module is an implementation of PEP 205: 441deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake 541deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drakehttp://python.sourceforge.net/peps/pep-0205.html 641deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake""" 741deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake 841deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drakeimport UserDict 941deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake 1041deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drakefrom _weakref import \ 1141deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake getweakrefcount, \ 1241deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake getweakrefs, \ 1341deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake ref, \ 1441deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake proxy, \ 1541deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake ReferenceError, \ 1641deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake CallableProxyType, \ 1741deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake ProxyType, \ 1841deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake ReferenceType 1941deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake 2041deb1efc2f969b58e49af669cc20d15ccdb04c6Fred DrakeProxyTypes = (ProxyType, CallableProxyType) 2141deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake 229a9d219f07656a9f1eb6f8beb2a9e2ee462b77f8Fred Drake__all__ = ["ref", "proxy", "getweakrefcount", "getweakrefs", 2340fc16059f04ee8fda0b5956cc4883eb21ca8f8cSkip Montanaro "WeakKeyDictionary", "ReferenceType", "ProxyType", 2440fc16059f04ee8fda0b5956cc4883eb21ca8f8cSkip Montanaro "CallableProxyType", "ProxyTypes", "WeakValueDictionary"] 2541deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake 265e1633365d8a48e96dd4f42c4e7c8729bc62c26dMartin v. Löwisclass WeakValueDictionary(UserDict.UserDict): 2741deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake 2841deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake # We inherit the constructor without worrying about the input 2941deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake # dictionary; since it uses our .update() method, we get the right 309d2c85dec7262475b83d45fdb53651c9c069e1cbFred Drake # checks (if the other dictionary is a WeakValueDictionary, 319d2c85dec7262475b83d45fdb53651c9c069e1cbFred Drake # objects are unwrapped on the way out, and we always wrap on the 329d2c85dec7262475b83d45fdb53651c9c069e1cbFred Drake # way in). 3341deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake 3441deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake def __getitem__(self, key): 3541deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake o = self.data.get(key)() 3641deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake if o is None: 3741deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake raise KeyError, key 3841deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake else: 3941deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake return o 4041deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake 4141deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake def __repr__(self): 429d2c85dec7262475b83d45fdb53651c9c069e1cbFred Drake return "<WeakValueDictionary at %s>" % id(self) 4341deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake 4441deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake def __setitem__(self, key, value): 4541deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake def remove(o, data=self.data, key=key): 4641deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake del data[key] 4741deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake self.data[key] = ref(value, remove) 4841deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake 4941deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake def copy(self): 509d2c85dec7262475b83d45fdb53651c9c069e1cbFred Drake new = WeakValueDictionary() 5141deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake for key, ref in self.data.items(): 5241deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake o = ref() 5341deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake if o is not None: 5441deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake new[key] = o 559d2c85dec7262475b83d45fdb53651c9c069e1cbFred Drake return new 5641deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake 571d9e4b7de3d15007d5b9e7ac4b38f5e158d3c840Fred Drake def get(self, key, default=None): 5841deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake try: 5941deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake ref = self.data[key] 6041deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake except KeyError: 6141deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake return default 6241deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake else: 6341deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake o = ref() 6441deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake if o is None: 6541deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake # This should only happen 6641deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake return default 6741deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake else: 6841deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake return o 6941deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake 7041deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake def items(self): 71312a5dc539b583abcbbf006942a4ceead9b9172bFred Drake L = [] 72312a5dc539b583abcbbf006942a4ceead9b9172bFred Drake for key, ref in self.data.items(): 7341deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake o = ref() 7441deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake if o is not None: 75312a5dc539b583abcbbf006942a4ceead9b9172bFred Drake L.append((key, o)) 7641deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake return L 7741deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake 7841deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake def popitem(self): 7941deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake while 1: 8041deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake key, ref = self.data.popitem() 8141deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake o = ref() 8241deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake if o is not None: 8341deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake return key, o 8441deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake 8541deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake def setdefault(self, key, default): 8641deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake try: 8741deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake ref = self.data[key] 8841deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake except KeyError: 8941deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake def remove(o, data=self.data, key=key): 9041deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake del data[key] 9141deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake ref = ref(default, remove) 9241deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake self.data[key] = ref 9341deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake return default 9441deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake else: 9541deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake return ref() 9641deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake 9741deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake def update(self, dict): 9841deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake d = self.data 9941deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake L = [] 10041deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake for key, o in dict.items(): 10141deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake def remove(o, data=d, key=key): 10241deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake del data[key] 1031d9e4b7de3d15007d5b9e7ac4b38f5e158d3c840Fred Drake L.append((key, ref(o, remove))) 10441deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake for key, r in L: 10541deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake d[key] = r 10641deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake 10741deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake def values(self): 10841deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake L = [] 10941deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake for ref in self.data.values(): 11041deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake o = ref() 11141deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake if o is not None: 11241deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake L.append(o) 11341deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake return L 11441deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake 11541deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake 1165e1633365d8a48e96dd4f42c4e7c8729bc62c26dMartin v. Löwisclass WeakKeyDictionary(UserDict.UserDict): 1175e1633365d8a48e96dd4f42c4e7c8729bc62c26dMartin v. Löwis 1185e1633365d8a48e96dd4f42c4e7c8729bc62c26dMartin v. Löwis def __init__(self, dict=None): 1195e1633365d8a48e96dd4f42c4e7c8729bc62c26dMartin v. Löwis self.data = {} 1205e1633365d8a48e96dd4f42c4e7c8729bc62c26dMartin v. Löwis if dict is not None: self.update(dict) 1215e1633365d8a48e96dd4f42c4e7c8729bc62c26dMartin v. Löwis def remove(k, data=self.data): 1225e1633365d8a48e96dd4f42c4e7c8729bc62c26dMartin v. Löwis del data[k] 1235e1633365d8a48e96dd4f42c4e7c8729bc62c26dMartin v. Löwis self._remove = remove 1245e1633365d8a48e96dd4f42c4e7c8729bc62c26dMartin v. Löwis 1255e1633365d8a48e96dd4f42c4e7c8729bc62c26dMartin v. Löwis def __getitem__(self, key): 1265e1633365d8a48e96dd4f42c4e7c8729bc62c26dMartin v. Löwis return self.data[ref(key)] 1275e1633365d8a48e96dd4f42c4e7c8729bc62c26dMartin v. Löwis 1285e1633365d8a48e96dd4f42c4e7c8729bc62c26dMartin v. Löwis def __repr__(self): 1295e1633365d8a48e96dd4f42c4e7c8729bc62c26dMartin v. Löwis return "<WeakKeyDictionary at %s>" % id(self) 1305e1633365d8a48e96dd4f42c4e7c8729bc62c26dMartin v. Löwis 1315e1633365d8a48e96dd4f42c4e7c8729bc62c26dMartin v. Löwis def __setitem__(self, key, value): 1325e1633365d8a48e96dd4f42c4e7c8729bc62c26dMartin v. Löwis self.data[ref(key, self._remove)] = value 1335e1633365d8a48e96dd4f42c4e7c8729bc62c26dMartin v. Löwis 1345e1633365d8a48e96dd4f42c4e7c8729bc62c26dMartin v. Löwis def copy(self): 1355e1633365d8a48e96dd4f42c4e7c8729bc62c26dMartin v. Löwis new = WeakKeyDictionary() 1365e1633365d8a48e96dd4f42c4e7c8729bc62c26dMartin v. Löwis for key, value in self.data.items(): 1375e1633365d8a48e96dd4f42c4e7c8729bc62c26dMartin v. Löwis o = key() 1385e1633365d8a48e96dd4f42c4e7c8729bc62c26dMartin v. Löwis if o is not None: 1395e1633365d8a48e96dd4f42c4e7c8729bc62c26dMartin v. Löwis new[o] = value 1409d2c85dec7262475b83d45fdb53651c9c069e1cbFred Drake return new 1415e1633365d8a48e96dd4f42c4e7c8729bc62c26dMartin v. Löwis 1421d9e4b7de3d15007d5b9e7ac4b38f5e158d3c840Fred Drake def get(self, key, default=None): 1435e1633365d8a48e96dd4f42c4e7c8729bc62c26dMartin v. Löwis return self.data.get(ref(key),default) 1445e1633365d8a48e96dd4f42c4e7c8729bc62c26dMartin v. Löwis 1451d9e4b7de3d15007d5b9e7ac4b38f5e158d3c840Fred Drake def has_key(self, key): 1461d9e4b7de3d15007d5b9e7ac4b38f5e158d3c840Fred Drake return self.data.has_key(ref(key)) 1471d9e4b7de3d15007d5b9e7ac4b38f5e158d3c840Fred Drake 1485e1633365d8a48e96dd4f42c4e7c8729bc62c26dMartin v. Löwis def items(self): 1495e1633365d8a48e96dd4f42c4e7c8729bc62c26dMartin v. Löwis L = [] 1505e1633365d8a48e96dd4f42c4e7c8729bc62c26dMartin v. Löwis for key, value in self.data.items(): 1515e1633365d8a48e96dd4f42c4e7c8729bc62c26dMartin v. Löwis o = key() 1525e1633365d8a48e96dd4f42c4e7c8729bc62c26dMartin v. Löwis if o is not None: 1535e1633365d8a48e96dd4f42c4e7c8729bc62c26dMartin v. Löwis L.append((o, value)) 1545e1633365d8a48e96dd4f42c4e7c8729bc62c26dMartin v. Löwis return L 1555e1633365d8a48e96dd4f42c4e7c8729bc62c26dMartin v. Löwis 1561d9e4b7de3d15007d5b9e7ac4b38f5e158d3c840Fred Drake def keys(self): 1571d9e4b7de3d15007d5b9e7ac4b38f5e158d3c840Fred Drake L = [] 1581d9e4b7de3d15007d5b9e7ac4b38f5e158d3c840Fred Drake for ref in self.data.keys(): 1591d9e4b7de3d15007d5b9e7ac4b38f5e158d3c840Fred Drake o = ref() 1601d9e4b7de3d15007d5b9e7ac4b38f5e158d3c840Fred Drake if o is not None: 1611d9e4b7de3d15007d5b9e7ac4b38f5e158d3c840Fred Drake L.append(o) 1621d9e4b7de3d15007d5b9e7ac4b38f5e158d3c840Fred Drake return L 1631d9e4b7de3d15007d5b9e7ac4b38f5e158d3c840Fred Drake 1645e1633365d8a48e96dd4f42c4e7c8729bc62c26dMartin v. Löwis def popitem(self): 1655e1633365d8a48e96dd4f42c4e7c8729bc62c26dMartin v. Löwis while 1: 1665e1633365d8a48e96dd4f42c4e7c8729bc62c26dMartin v. Löwis key, value = self.data.popitem() 1675e1633365d8a48e96dd4f42c4e7c8729bc62c26dMartin v. Löwis o = key() 1685e1633365d8a48e96dd4f42c4e7c8729bc62c26dMartin v. Löwis if o is not None: 1695e1633365d8a48e96dd4f42c4e7c8729bc62c26dMartin v. Löwis return o, value 1705e1633365d8a48e96dd4f42c4e7c8729bc62c26dMartin v. Löwis 1715e1633365d8a48e96dd4f42c4e7c8729bc62c26dMartin v. Löwis def setdefault(self, key, default): 1725e1633365d8a48e96dd4f42c4e7c8729bc62c26dMartin v. Löwis return self.data.setdefault(ref(key, self._remove),default) 1735e1633365d8a48e96dd4f42c4e7c8729bc62c26dMartin v. Löwis 1745e1633365d8a48e96dd4f42c4e7c8729bc62c26dMartin v. Löwis def update(self, dict): 1755e1633365d8a48e96dd4f42c4e7c8729bc62c26dMartin v. Löwis d = self.data 1765e1633365d8a48e96dd4f42c4e7c8729bc62c26dMartin v. Löwis L = [] 1775e1633365d8a48e96dd4f42c4e7c8729bc62c26dMartin v. Löwis for key, value in dict.items(): 1781d9e4b7de3d15007d5b9e7ac4b38f5e158d3c840Fred Drake L.append((ref(key, self._remove), value)) 1795e1633365d8a48e96dd4f42c4e7c8729bc62c26dMartin v. Löwis for key, r in L: 1805e1633365d8a48e96dd4f42c4e7c8729bc62c26dMartin v. Löwis d[key] = r 1815e1633365d8a48e96dd4f42c4e7c8729bc62c26dMartin v. Löwis 18241deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drake# no longer needed 18341deb1efc2f969b58e49af669cc20d15ccdb04c6Fred Drakedel UserDict 184