diff options
Diffstat (limited to 'Lib/weakref.py')
| -rw-r--r-- | Lib/weakref.py | 120 |
1 files changed, 92 insertions, 28 deletions
diff --git a/Lib/weakref.py b/Lib/weakref.py index 88c60e7..787c885 100644 --- a/Lib/weakref.py +++ b/Lib/weakref.py @@ -20,7 +20,7 @@ from _weakref import ( ProxyType, ReferenceType) -from _weakrefset import WeakSet +from _weakrefset import WeakSet, _IterationGuard from exceptions import ReferenceError @@ -48,10 +48,24 @@ class WeakValueDictionary(UserDict.UserDict): def remove(wr, selfref=ref(self)): self = selfref() if self is not None: - del self.data[wr.key] + if self._iterating: + self._pending_removals.append(wr.key) + else: + del self.data[wr.key] self._remove = remove + # A list of keys to be removed + self._pending_removals = [] + self._iterating = set() UserDict.UserDict.__init__(self, *args, **kw) + def _commit_removals(self): + l = self._pending_removals + d = self.data + # We shouldn't encounter any KeyError, because this method should + # always be called *before* mutating the dict. + while l: + del d[l.pop()] + def __getitem__(self, key): o = self.data[key]() if o is None: @@ -59,6 +73,11 @@ class WeakValueDictionary(UserDict.UserDict): else: return o + def __delitem__(self, key): + if self._pending_removals: + self._commit_removals() + del self.data[key] + def __contains__(self, key): try: o = self.data[key]() @@ -77,8 +96,15 @@ class WeakValueDictionary(UserDict.UserDict): return "<WeakValueDictionary at %s>" % id(self) def __setitem__(self, key, value): + if self._pending_removals: + self._commit_removals() self.data[key] = KeyedRef(value, self._remove, key) + def clear(self): + if self._pending_removals: + self._commit_removals() + self.data.clear() + def copy(self): new = WeakValueDictionary() for key, wr in self.data.items(): @@ -120,16 +146,18 @@ class WeakValueDictionary(UserDict.UserDict): return L def iteritems(self): - for wr in self.data.itervalues(): - value = wr() - if value is not None: - yield wr.key, value + with _IterationGuard(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() + with _IterationGuard(self): + for k in self.data.iterkeys(): + yield k - def __iter__(self): - return self.data.iterkeys() + __iter__ = iterkeys def itervaluerefs(self): """Return an iterator that yields the weak references to the values. @@ -141,15 +169,20 @@ class WeakValueDictionary(UserDict.UserDict): keep the values around longer than needed. """ - return self.data.itervalues() + with _IterationGuard(self): + for wr in self.data.itervalues(): + yield wr def itervalues(self): - for wr in self.data.itervalues(): - obj = wr() - if obj is not None: - yield obj + with _IterationGuard(self): + for wr in self.data.itervalues(): + obj = wr() + if obj is not None: + yield obj def popitem(self): + if self._pending_removals: + self._commit_removals() while 1: key, wr = self.data.popitem() o = wr() @@ -157,6 +190,8 @@ class WeakValueDictionary(UserDict.UserDict): return key, o def pop(self, key, *args): + if self._pending_removals: + self._commit_removals() try: o = self.data.pop(key)() except KeyError: @@ -172,12 +207,16 @@ class WeakValueDictionary(UserDict.UserDict): try: wr = self.data[key] except KeyError: + if self._pending_removals: + self._commit_removals() self.data[key] = KeyedRef(default, self._remove, key) return default else: return wr() def update(self, dict=None, **kwargs): + if self._pending_removals: + self._commit_removals() d = self.data if dict is not None: if not hasattr(dict, "items"): @@ -245,9 +284,29 @@ class WeakKeyDictionary(UserDict.UserDict): def remove(k, selfref=ref(self)): self = selfref() if self is not None: - del self.data[k] + if self._iterating: + self._pending_removals.append(k) + else: + del self.data[k] self._remove = remove - if dict is not None: self.update(dict) + # A list of dead weakrefs (keys to be removed) + self._pending_removals = [] + self._iterating = set() + if dict is not None: + self.update(dict) + + def _commit_removals(self): + # NOTE: We don't need to call this method before mutating the dict, + # because a dead weakref never compares equal to a live weakref, + # even if they happened to refer to equal objects. + # However, it means keys may already have been removed. + l = self._pending_removals + d = self.data + while l: + try: + del d[l.pop()] + except KeyError: + pass def __delitem__(self, key): del self.data[ref(key)] @@ -306,10 +365,11 @@ class WeakKeyDictionary(UserDict.UserDict): return L def iteritems(self): - for wr, value in self.data.iteritems(): - key = wr() - if key is not None: - yield key, value + with _IterationGuard(self): + for wr, value in self.data.iteritems(): + key = wr() + if key is not None: + yield key, value def iterkeyrefs(self): """Return an iterator that yields the weak references to the keys. @@ -321,19 +381,23 @@ class WeakKeyDictionary(UserDict.UserDict): keep the keys around longer than needed. """ - return self.data.iterkeys() + with _IterationGuard(self): + for wr in self.data.iterkeys(): + yield wr def iterkeys(self): - for wr in self.data.iterkeys(): - obj = wr() - if obj is not None: - yield obj + with _IterationGuard(self): + for wr in self.data.iterkeys(): + obj = wr() + if obj is not None: + yield obj - def __iter__(self): - return self.iterkeys() + __iter__ = iterkeys def itervalues(self): - return self.data.itervalues() + with _IterationGuard(self): + for value in self.data.itervalues(): + yield value def keyrefs(self): """Return a list of weak references to the keys. |