diff options
Diffstat (limited to 'lib/sqlalchemy/orm/identity.py')
| -rw-r--r-- | lib/sqlalchemy/orm/identity.py | 89 |
1 files changed, 28 insertions, 61 deletions
diff --git a/lib/sqlalchemy/orm/identity.py b/lib/sqlalchemy/orm/identity.py index 0753ea991..aa041a585 100644 --- a/lib/sqlalchemy/orm/identity.py +++ b/lib/sqlalchemy/orm/identity.py @@ -15,6 +15,9 @@ class IdentityMap(dict): self._mutable_attrs = {} self.modified = False self._wr = weakref.ref(self) + + def replace(self, state): + raise NotImplementedError() def add(self, state): raise NotImplementedError() @@ -102,6 +105,17 @@ class WeakInstanceDict(IdentityMap): def contains_state(self, state): return dict.get(self, state.key) is state + def replace(self, state): + if dict.__contains__(self, state.key): + existing = dict.__getitem__(self, state.key) + if existing is not state: + self._manage_removed_state(existing) + else: + return + + dict.__setitem__(self, state.key, state) + self._manage_incoming_state(state) + def add(self, state): if state.key in self: if dict.__getitem__(self, state.key) is not state: @@ -161,12 +175,24 @@ class StrongInstanceDict(IdentityMap): def contains_state(self, state): return state.key in self and attributes.instance_state(self[state.key]) is state + def replace(self, state): + if dict.__contains__(self, state.key): + existing = dict.__getitem__(self, state.key) + existing = attributes.instance_state(existing) + if existing is not state: + self._manage_removed_state(existing) + else: + return + + dict.__setitem__(self, state.key, state.obj()) + self._manage_incoming_state(state) + def add(self, state): dict.__setitem__(self, state.key, state.obj()) self._manage_incoming_state(state) def remove(self, state): - if dict.pop(self, state.key) is not state: + if attributes.instance_state(dict.pop(self, state.key)) is not state: raise AssertionError("State %s is not present in this identity map" % state) self._manage_removed_state(state) @@ -176,7 +202,7 @@ class StrongInstanceDict(IdentityMap): self._manage_removed_state(state) def remove_key(self, key): - state = dict.__getitem__(self, key) + state = attributes.instance_state(dict.__getitem__(self, key)) self.remove(state) def prune(self): @@ -190,62 +216,3 @@ class StrongInstanceDict(IdentityMap): self.modified = bool(dirty) return ref_count - len(self) -class IdentityManagedState(attributes.InstanceState): - def _instance_dict(self): - return None - - def modified_event(self, attr, should_copy, previous, passive=False): - attributes.InstanceState.modified_event(self, attr, should_copy, previous, passive) - - instance_dict = self._instance_dict() - if instance_dict: - instance_dict.modified = True - - def _is_really_none(self): - """do a check modified/resurrect. - - This would be called in the extremely rare - race condition that the weakref returned None but - the cleanup handler had not yet established the - __resurrect callable as its replacement. - - """ - if self.check_modified(): - self.obj = self.__resurrect - return self.obj() - else: - return None - - def _cleanup(self, ref): - """weakref callback. - - This method may be called by an asynchronous - gc. - - If the state shows pending changes, the weakref - is replaced by the __resurrect callable which will - re-establish an object reference on next access, - else removes this InstanceState from the owning - identity map, if any. - - """ - if self.check_modified(): - self.obj = self.__resurrect - else: - instance_dict = self._instance_dict() - if instance_dict: - instance_dict.remove(self) - self.dispose() - - def __resurrect(self): - """A substitute for the obj() weakref function which resurrects.""" - - # store strong ref'ed version of the object; will revert - # to weakref when changes are persisted - obj = self.manager.new_instance(state=self) - self.obj = weakref.ref(obj, self._cleanup) - self._strong_obj = obj - obj.__dict__.update(self.dict) - self.dict = obj.__dict__ - self._run_on_load(obj) - return obj |