# attributes.py - manages object attributes # Copyright (C) 2005, 2006, 2007 Michael Bayer mike_mp@zzzcomputing.com # # This module is part of SQLAlchemy and is released under # the MIT License: http://www.opensource.org/licenses/mit-license.php import operator, weakref, threading import UserDict from sqlalchemy import util from sqlalchemy.orm import interfaces, collections from sqlalchemy.orm.mapper import class_mapper, identity_equal from sqlalchemy import exceptions PASSIVE_NORESULT = object() ATTR_WAS_SET = object() NO_VALUE = object() class InstrumentedAttribute(interfaces.PropComparator): """public-facing instrumented attribute.""" def __init__(self, impl, comparator=None): """Construct an InstrumentedAttribute. comparator a sql.Comparator to which class-level compare/math events will be sent """ self.impl = impl self.comparator = comparator def __set__(self, obj, value): self.impl.set(obj._state, value, None) def __delete__(self, obj): self.impl.delete(obj._state) def __get__(self, obj, owner): if obj is None: return self return self.impl.get(obj._state) def get_history(self, obj, **kwargs): return self.impl.get_history(obj._state, **kwargs) def clause_element(self): return self.comparator.clause_element() def expression_element(self): return self.comparator.expression_element() def operate(self, op, *other, **kwargs): return op(self.comparator, *other, **kwargs) def reverse_operate(self, op, other, **kwargs): return op(other, self.comparator, **kwargs) def hasparent(self, instance, optimistic=False): return self.impl.hasparent(instance._state, optimistic=optimistic) property = property(lambda s: class_mapper(s.impl.class_).get_property(s.impl.key), doc="the MapperProperty object associated with this attribute") class AttributeImpl(object): """internal implementation for instrumented attributes.""" def __init__(self, class_, manager, key, callable_, trackparent=False, extension=None, compare_function=None, mutable_scalars=False, **kwargs): """Construct an AttributeImpl. class_ the class to be instrumented. manager AttributeManager managing this class key string name of the attribute callable_ optional function which generates a callable based on a parent instance, which produces the "default" values for a scalar or collection attribute when it's first accessed, if not present already. trackparent if True, attempt to track if an instance has a parent attached to it via this attribute. extension an AttributeExtension object which will receive set/delete/append/remove/etc. events. compare_function a function that compares two values which are normally assignable to this attribute. mutable_scalars if True, the values which are normally assignable to this attribute can mutate, and need to be compared against a copy of their original contents in order to detect changes on the parent instance. """ self.class_ = class_ self.manager = manager self.key = key self.callable_ = callable_ self.trackparent = trackparent self.mutable_scalars = mutable_scalars if mutable_scalars: class_._sa_has_mutable_scalars = True self.copy = None if compare_function is None: self.is_equal = operator.eq else: self.is_equal = compare_function self.extensions = util.to_list(extension or []) def commit_to_state(self, state, value=NO_VALUE): """Commits the object's current state to its 'committed' state.""" if value is NO_VALUE: if self.key in state.dict: value = state.dict[self.key] if value is not NO_VALUE: state.committed_state[self.key] = self.copy(value) def hasparent(self, state, optimistic=False): """Return the boolean value of a `hasparent` flag attached to the given item. The `optimistic` flag determines what the default return value should be if no `hasparent` flag can be located. As this function is used to determine if an instance is an *orphan*, instances that were loaded from storage should be assumed to not be orphans, until a True/False value for this flag is set. An instance attribute that is loaded by a callable function will also not have a `hasparent` flag. """ return state.parents.get(id(self), optimistic) def sethasparent(self, state, value): """Set a boolean flag on the given item corresponding to whether or not it is attached to a parent object via the attribute represented by this ``InstrumentedAttribute``. """ state.parents[id(self)] = value def get_history(self, state, passive=False): current = self.get(state, passive=passive) if current is PASSIVE_NORESULT: return None return AttributeHistory(self, state, current, passive=passive) def set_callable(self, state, callable_, clear=False): """Set a callable function for this attribute on the given object. This callable will be executed when the attribute is next accessed, and is assumed to construct part of the instances previously stored state. When its value or values are loaded, they will be established as part of the instance's *committed state*. While *trackparent* information will be assembled for these instances, attribute-level event handlers will not be fired. The callable overrides the class level callable set in the ``InstrumentedAttribute` constructor. """ if clear: self.clear(state) if callable_ is None: self.initialize(state) else: state.callables[self.key] = callable_ def _get_callable(self, state): if self.key in state.callables: return state.callables[self.key] elif self.callable_ is not None: return self.callable_(state.obj()) else: return None def check_mutable_modified(self, state): return False def initialize(self, state): """Initialize this attribute on the given object instance with an empty value.""" state.dict[self.key] = None return None def get(self, state, passive=False): """Retrieve a value from the given object. If a callable is assembled on this object's attribute, and passive is False, the callable will be executed and the resulting value will be set as the new value for this attribute. """ try: return state.dict[self.key] except KeyError: callable_ = self._get_callable(state) if callable_ is not None: if passive: return PASSIVE_NORESULT value = callable_() if value is not ATTR_WAS_SET: return self.set_committed_value(state, value) else: if self.key not in state.dict: return self.get(state, passive=passive) return state.dict[self.key] else: # Return a new, empty value return self.initialize(state) def append(self, state, value, initiator): self.set(state, value, initiator) def remove(self, state, value, initiator): self.set(state, None, initiator) def set(self, state, value, initiator): raise NotImplementedError() def set_committed_value(self, state, value): """set an attribute value on the given instance and 'commit' it. this indicates that the given value is the "persisted" value, and history will be logged only if a newly set value is not equal to this value. this is typically used by deferred/lazy attribute loaders to set object attributes after the initial load. """ if state.committed_state is not None: self.commit_to_state(state, value) # remove per-instance callable, if any state.callables.pop(self, None) state.dict[self.key] = value return value def fire_append_event(self, state, value, initiator): state.modified = True if self.trackparent and value is not None: self.sethasparent(value._state, True) obj = state.obj() for ext in self.extensions: ext.append(obj, value, initiator or self) def fire_remove_event(self, state, value, initiator): state.modified = True if self.trackparent and value is not None: self.sethasparent(value._state, False) obj = state.obj() for ext in self.extensions: ext.remove(obj, value, initiator or self) def fire_replace_event(self, state, value, previous, initiator): state.modified = True if self.trackparent: if value is not None: self.sethasparent(value._state, True) if previous is not None: self.sethasparent(previous._state, False) obj = state.obj() for ext in self.extensions: ext.set(obj, value, previous, initiator or self) class ScalarAttributeImpl(AttributeImpl): """represents a scalar value-holding InstrumentedAttribute.""" def __init__(self, class_, manager, key, callable_, copy_function=None, compare_function=None, mutable_scalars=False, **kwargs): super(ScalarAttributeImpl, self).__init__(class_, manager, key, callable_, compare_function=compare_function, mutable_scalars=mutable_scalars, **kwargs) if copy_function is None: copy_function = self.__copy self.copy = copy_function self.accepts_global_callable = True def __copy(self, item): # scalar values are assumed to be immutable unless a copy function # is passed return item def delete(self, state): del state.dict[self.key] state.modified=True def check_mutable_modified(self, state): if self.mutable_scalars: h = self.get_history(state, passive=True) if h is not None and h.is_modified(): state.modified = True return True else: return False else: return False def set(self, state, value, initiator): """Set a value on the given object. `initiator` is the ``InstrumentedAttribute`` that initiated the ``set()` operation and is used to control the depth of a circular setter operation. """ if initiator is self: return state.dict[self.key] = value state.modified=True type = property(lambda self: self.property.columns[0].type) class ScalarObjectAttributeImpl(ScalarAttributeImpl): """represents a scalar class-instance holding InstrumentedAttribute. Adds events to delete/set operations. """ def __init__(self, class_, manager, key, callable_, trackparent=False, extension=None, copy_function=None, compare_function=None, mutable_scalars=False, **kwargs): super(ScalarObjectAttributeImpl, self).__init__(class_, manager, key, callable_, trackparent=trackparent, extension=extension, compare_function=compare_function, mutable_scalars=mutable_scalars, **kwargs) if compare_function is None: self.is_equal = identity_equal self.accepts_global_callable = False def delete(self, state): old = self.get(state) del state.dict[self.key] self.fire_remove_event(state, old, self) def set(self, state, value, initiator): """Set a value on the given object. `initiator` is the ``InstrumentedAttribute`` that initiated the ``set()` operation and is used to control the depth of a circular setter operation. """ if initiator is self: return old = self.get(state) state.dict[self.key] = value self.fire_replace_event(state, value, old, initiator) class CollectionAttributeImpl(AttributeImpl): """A collection-holding attribute that instruments changes in membership. InstrumentedCollectionAttribute holds an arbitrary, user-specified container object (defaulting to a list) and brokers access to the CollectionAdapter, a "view" onto that object that presents consistent bag semantics to the orm layer independent of the user data implementation. """ def __init__(self, class_, manager, key, callable_, typecallable=None, trackparent=False, extension=None, copy_function=None, compare_function=None, **kwargs): super(CollectionAttributeImpl, self).__init__(class_, manager, key, callable_, trackparent=trackparent, extension=extension, compare_function=compare_function, **kwargs) if copy_function is None: copy_function = self.__copy self.copy = copy_function self.accepts_global_callable = False if typecallable is None: typecallable = list self.collection_factory = \ collections._prepare_instrumentation(typecallable) self.collection_interface = \ util.duck_type_collection(self.collection_factory()) def __copy(self, item): return [y for y in list(collections.collection_adapter(item))] def delete(self, state): if self.key not in state.dict: return state.modified = True collection = self.get_collection(state) collection.clear_with_event() del state.dict[self.key] def initialize(self, state): """Initialize this attribute on the given object instance with an empty collection.""" _, user_data = self._build_collection(state) state.dict[self.key] = user_data return user_data def append(self, state, value, initiator): if initiator is self: return collection = self.get_collection(state) collection.append_with_event(value, initiator) def remove(self, state, value, initiator): if initiator is self: return collection = self.get_collection(state) collection.remove_with_event(value, initiator) def set(self, state, value, initiator): """Set a value on the given object. `initiator` is the ``InstrumentedAttribute`` that initiated the ``set()` operation and is used to control the depth of a circular setter operation. """ if initiator is self: return setting_type = util.duck_type_collection(value) if value is None or setting_type != self.collection_interface: raise exceptions.ArgumentError( "Incompatible collection type on assignment: %s is not %s-like" % (type(value).__name__, self.collection_interface.__name__)) if hasattr(value, '_sa_adapter'): value = list(getattr(value, '_sa_adapter')) elif setting_type == dict: value = value.values() old = self.get(state) old_collection = self.get_collection(state, old) new_collection, user_data = self._build_collection(state) idset = util.IdentitySet constants = idset(old_collection or []).intersection(value or []) additions = idset(value or []).difference(constants) removals = idset(old_collection or []).difference(constants) for member in value or []: if member in additions: new_collection.append_with_event(member) elif member in constants: new_collection.append_without_event(member) state.dict[self.key] = user_data state.modified = True # mark all the orphaned elements as detached from the parent if old_collection: for member in removals: old_collection.remove_with_event(member) old_collection.unlink(old) def set_committed_value(self, state, value): """Set an attribute value on the given instance and 'commit' it.""" collection, user_data = self._build_collection(state) self._load_collection(state, value or [], emit_events=False, collection=collection) value = user_data if state.committed_state is not None: self.commit_to_state(state, value) # remove per-instance callable, if any state.callables.pop(self, None) state.dict[self.key] = value return value def _build_collection(self, state): user_data = self.collection_factory() collection = collections.CollectionAdapter(self, state, user_data) return collection, user_data def _load_collection(self, state, values, emit_events=True, collection=None): collection = collection or self.get_collection(state) if values is None: return elif emit_events: for item in values: collection.append_with_event(item) else: for item in values: collection.append_without_event(item) def get_collection(self, state, user_data=None): if user_data is None: user_data = self.get(state) try: return getattr(user_data, '_sa_adapter') except AttributeError: collections.CollectionAdapter(self, state, user_data) return getattr(user_data, '_sa_adapter') class GenericBackrefExtension(interfaces.AttributeExtension): """An extension which synchronizes a two-way relationship. A typical two-way relationship is a parent object containing a list of child objects, where each child object references the parent. The other are two objects which contain scalar references to each other. """ def __init__(self, key): self.key = key def set(self, obj, child, oldchild, initiator): if oldchild is child: return if oldchild is not None: # With lazy=None, there's no guarantee that the full collection is # present when updating via a backref. impl = getattr(oldchild.__class__, self.key).impl try: impl.remove(oldchild._state, obj, initiator) except (ValueError, KeyError, IndexError): pass if child is not None: getattr(child.__class__, self.key).impl.append(child._state, obj, initiator) def append(self, obj, child, initiator): getattr(child.__class__, self.key).impl.append(child._state, obj, initiator) def remove(self, obj, child, initiator): getattr(child.__class__, self.key).impl.remove(child._state, obj, initiator) class InstanceState(object): """tracks state information at the instance level.""" __slots__ = 'class_', 'obj', 'dict', 'committed_state', 'modified', 'trigger', 'callables', 'parents', 'instance_dict', '_strong_obj', 'expired_attributes' def __init__(self, obj): self.class_ = obj.__class__ self.obj = weakref.ref(obj, self.__cleanup) self.dict = obj.__dict__ self.committed_state = {} self.modified = False self.trigger = None self.callables = {} self.parents = {} self.instance_dict = None def __cleanup(self, ref): # tiptoe around Python GC unpredictableness instance_dict = self.instance_dict if instance_dict is None: return instance_dict = instance_dict() if instance_dict is None: return # the mutexing here is based on the assumption that gc.collect() # may be firing off cleanup handlers in a different thread than that # which is normally operating upon the instance dict. instance_dict._mutex.acquire() try: # if instance_dict de-refed us, or it called our # _resurrect, return. again setting local copy # to avoid the rug being pulled in between id2 = self.instance_dict if id2 is None or id2() is None or self.obj() is not None: return self.__resurrect(instance_dict) finally: instance_dict._mutex.release() def _check_resurrect(self, instance_dict): instance_dict._mutex.acquire() try: return self.obj() or self.__resurrect(instance_dict) finally: instance_dict._mutex.release() def __resurrect(self, instance_dict): if self.modified or self.class_._sa_attribute_manager._is_modified(self): # store strong ref'ed version of the object; will revert # to weakref when changes are persisted obj = self.class_._sa_attribute_manager.new_instance(self.class_, state=self) self.obj = weakref.ref(obj, self.__cleanup) self._strong_obj = obj obj.__dict__.update(self.dict) self.dict = obj.__dict__ return obj else: del instance_dict[self.dict['_instance_key']] return None def __getstate__(self): return {'committed_state':self.committed_state, 'parents':self.parents, 'modified':self.modified, 'instance':self.obj()} def __setstate__(self, state): self.committed_state = state['committed_state'] self.parents = state['parents'] self.modified = state['modified'] self.obj = weakref.ref(state['instance']) self.class_ = self.obj().__class__ self.dict = self.obj().__dict__ self.callables = {} self.trigger = None def initialize(self, key): getattr(self.class_, key).impl.initialize(self) def set_callable(self, key, callable_): self.dict.pop(key, None) self.callables[key] = callable_ def __fire_trigger(self): instance = self.obj() self.trigger(instance, [k for k in self.expired_attributes if k not in self.dict]) for k in self.expired_attributes: self.callables.pop(k, None) self.expired_attributes.clear() return ATTR_WAS_SET def expire_attributes(self, attribute_names): if not hasattr(self, 'expired_attributes'): self.expired_attributes = util.Set() if attribute_names is None: for attr in self.class_._sa_attribute_manager.managed_attributes(self.class_): self.dict.pop(attr.impl.key, None) self.callables[attr.impl.key] = self.__fire_trigger self.expired_attributes.add(attr.impl.key) else: for key in attribute_names: self.dict.pop(key, None) if not getattr(self.class_, key).impl.accepts_global_callable: continue self.callables[key] = self.__fire_trigger self.expired_attributes.add(key) def reset(self, key): """remove the given attribute and any callables associated with it.""" self.dict.pop(key, None) self.callables.pop(key, None) def clear(self): """clear all attributes from the instance.""" for attr in self.class_._sa_attribute_manager.managed_attributes(self.class_): self.dict.pop(attr.impl.key, None) def commit(self, keys): """commit all attributes named in the given list of key names. This is used by a partial-attribute load operation to mark committed those attributes which were refreshed from the database. """ for key in keys: getattr(self.class_, key).impl.commit_to_state(self) def commit_all(self): """commit all attributes unconditionally. This is used after a flush() or a regular instance load or refresh operation to mark committed all populated attributes. """ self.committed_state = {} self.modified = False for attr in self.class_._sa_attribute_manager.managed_attributes(self.class_): attr.impl.commit_to_state(self) # remove strong ref self._strong_obj = None class InstanceDict(UserDict.UserDict): """similar to WeakValueDictionary, but wired towards 'state' objects.""" def __init__(self, *args, **kw): self._wr = weakref.ref(self) # RLock because the mutex is used by a cleanup # handler, which can be called at any time (including within an already mutexed block) self._mutex = threading.RLock() UserDict.UserDict.__init__(self, *args, **kw) def __getitem__(self, key): state = self.data[key] o = state.obj() if o is None: o = state._check_resurrect(self) if o is None: raise KeyError, key return o def __contains__(self, key): try: state = self.data[key] o = state.obj() if o is None: o = state._check_resurrect(self) except KeyError: return False return o is not None def has_key(self, key): return key in self def __repr__(self): return "" % id(self) def __setitem__(self, key, value): if key in self.data: self._mutex.acquire() try: if key in self.data: self.data[key].instance_dict = None finally: self._mutex.release() self.data[key] = value._state value._state.instance_dict = self._wr def __delitem__(self, key): state = self.data[key] state.instance_dict = None del self.data[key] def get(self, key, default=None): try: state = self.data[key] except KeyError: return default else: o = state.obj() if o is None: # This should only happen return default else: return o def items(self): L = [] for key, state in self.data.items(): o = state.obj() if o is not None: L.append((key, o)) return L def iteritems(self): for state in self.data.itervalues(): value = state.obj() if value is not None: yield value._instance_key, value def iterkeys(self): return self.data.iterkeys() def __iter__(self): return self.data.iterkeys() def __len__(self): return len(self.values()) def itervalues(self): for state in self.data.itervalues(): obj = state.obj() if obj is not None: yield obj def values(self): L = [] for state in self.data.values(): o = state.obj() if o is not None: L.append(o) return L def popitem(self): raise NotImplementedError() def pop(self, key, *args): raise NotImplementedError() def setdefault(self, key, default=None): raise NotImplementedError() def update(self, dict=None, **kwargs): raise NotImplementedError() def copy(self): raise NotImplementedError() class AttributeHistory(object): """Calculate the *history* of a particular attribute on a particular instance. """ NO_VALUE = object() def __init__(self, attr, state, current, passive=False): self.attr = attr # get the "original" value. if a lazy load was fired when we got # the 'current' value, this "original" was also populated just # now as well (therefore we have to get it second) if state.committed_state: original = state.committed_state.get(attr.key, NO_VALUE) else: original = NO_VALUE if hasattr(attr, 'get_collection'): self._current = current if original is NO_VALUE: s = util.IdentitySet([]) else: s = util.IdentitySet(original) # FIXME: the tests have an assumption on the collection's ordering self._added_items = util.OrderedIdentitySet() self._unchanged_items = util.OrderedIdentitySet() self._deleted_items = util.OrderedIdentitySet() if current: collection = attr.get_collection(state, current) for a in collection: if a in s: self._unchanged_items.add(a) else: self._added_items.add(a) for a in s: if a not in self._unchanged_items: self._deleted_items.add(a) else: self._current = [current] if attr.is_equal(current, original) is True: self._unchanged_items = [current] self._added_items = [] self._deleted_items = [] else: self._added_items = [current] if original is not NO_VALUE and original is not None: self._deleted_items = [original] else: self._deleted_items = [] self._unchanged_items = [] def __iter__(self): return iter(self._current) def is_modified(self): return len(self._deleted_items) > 0 or len(self._added_items) > 0 def added_items(self): return list(self._added_items) def unchanged_items(self): return list(self._unchanged_items) def deleted_items(self): return list(self._deleted_items) class AttributeManager(object): """Allow the instrumentation of object attributes.""" def __init__(self): # will cache attributes, indexed by class objects self._inherited_attribute_cache = weakref.WeakKeyDictionary() self._noninherited_attribute_cache = weakref.WeakKeyDictionary() def clear_attribute_cache(self): self._attribute_cache.clear() def managed_attributes(self, class_): """Return a list of all ``InstrumentedAttribute`` objects associated with the given class. """ try: # TODO: move this collection onto the class itself? return self._inherited_attribute_cache[class_] except KeyError: if not isinstance(class_, type): raise TypeError(repr(class_) + " is not a type") inherited = [v for v in [getattr(class_, key, None) for key in dir(class_)] if isinstance(v, InstrumentedAttribute)] self._inherited_attribute_cache[class_] = inherited return inherited def noninherited_managed_attributes(self, class_): try: # TODO: move this collection onto the class itself? return self._noninherited_attribute_cache[class_] except KeyError: if not isinstance(class_, type): raise TypeError(repr(class_) + " is not a type") noninherited = [v for v in [getattr(class_, key, None) for key in list(class_.__dict__)] if isinstance(v, InstrumentedAttribute)] self._noninherited_attribute_cache[class_] = noninherited return noninherited def is_modified(self, obj): return self._is_modified(obj._state) def _is_modified(self, state): if state.modified: return True elif getattr(state.class_, '_sa_has_mutable_scalars', False): for attr in self.managed_attributes(state.class_): if getattr(attr.impl, 'mutable_scalars', False) and attr.impl.check_mutable_modified(state): return True else: return False else: return False def get_history(self, obj, key, **kwargs): """Return a new ``AttributeHistory`` object for the given attribute on the given object. """ return getattr(obj.__class__, key).impl.get_history(obj._state, **kwargs) def get_as_list(self, obj, key, passive=False): """Return an attribute of the given name from the given object. If the attribute is a scalar, return it as a single-item list, otherwise return a collection based attribute. If the attribute's value is to be produced by an unexecuted callable, the callable will only be executed if the given `passive` flag is False. """ attr = getattr(obj.__class__, key).impl state = obj._state x = attr.get(state, passive=passive) if x is PASSIVE_NORESULT: return [] elif hasattr(attr, 'get_collection'): return list(attr.get_collection(state, x)) elif isinstance(x, list): return x else: return [x] def has_parent(self, class_, obj, key, optimistic=False): return getattr(class_, key).impl.hasparent(obj._state, optimistic=optimistic) def _create_prop(self, class_, key, uselist, callable_, typecallable, useobject, **kwargs): """Create a scalar property object, defaulting to ``InstrumentedAttribute``, which will communicate change events back to this ``AttributeManager``. """ if kwargs.pop('dynamic', False): from sqlalchemy.orm import dynamic return dynamic.DynamicAttributeImpl(class_, self, key, typecallable, **kwargs) elif uselist: return CollectionAttributeImpl(class_, self, key, callable_, typecallable, **kwargs) elif useobject: return ScalarObjectAttributeImpl(class_, self, key, callable_, **kwargs) else: return ScalarAttributeImpl(class_, self, key, callable_, **kwargs) def manage(self, obj): if not hasattr(obj, '_state'): obj._state = InstanceState(obj) def new_instance(self, class_, state=None): """create a new instance of class_ without its __init__() method being called.""" s = class_.__new__(class_) if state: s._state = state else: s._state = InstanceState(s) return s def register_class(self, class_, extra_init=None, on_exception=None): """decorate the constructor of the given class to establish attribute management on new instances.""" # do a sweep first, this also helps some attribute extensions # (like associationproxy) become aware of themselves at the # class level self.unregister_class(class_) oldinit = None doinit = False class_._sa_attribute_manager = self def init(instance, *args, **kwargs): instance._state = InstanceState(instance) if extra_init: extra_init(class_, oldinit, instance, args, kwargs) if doinit: try: oldinit(instance, *args, **kwargs) except: if on_exception: on_exception(class_, oldinit, instance, args, kwargs) raise # override oldinit oldinit = class_.__init__ if oldinit is None or not hasattr(oldinit, '_oldinit'): init._oldinit = oldinit class_.__init__ = init # if oldinit is already one of our 'init' methods, replace it elif hasattr(oldinit, '_oldinit'): init._oldinit = oldinit._oldinit class_.__init = init oldinit = oldinit._oldinit if oldinit is not None: doinit = oldinit is not object.__init__ try: init.__name__ = oldinit.__name__ init.__doc__ = oldinit.__doc__ except: # cant set __name__ in py 2.3 ! pass def unregister_class(self, class_): if hasattr(class_, '__init__') and hasattr(class_.__init__, '_oldinit'): if class_.__init__._oldinit is not None: class_.__init__ = class_.__init__._oldinit else: delattr(class_, '__init__') for attr in self.noninherited_managed_attributes(class_): delattr(class_, attr.impl.key) self._inherited_attribute_cache.pop(class_,None) self._noninherited_attribute_cache.pop(class_,None) def register_attribute(self, class_, key, uselist, useobject, callable_=None, **kwargs): """Register an attribute at the class level to be instrumented for all instances of the class. """ # firt invalidate the cache for the given class # (will be reconstituted as needed, while getting managed attributes) self._inherited_attribute_cache.pop(class_, None) self._noninherited_attribute_cache.pop(class_, None) typecallable = kwargs.pop('typecallable', None) if isinstance(typecallable, InstrumentedAttribute): typecallable = None comparator = kwargs.pop('comparator', None) setattr(class_, key, InstrumentedAttribute(self._create_prop(class_, key, uselist, callable_, useobject=useobject, typecallable=typecallable, **kwargs), comparator=comparator)) def init_collection(self, instance, key): """Initialize a collection attribute and return the collection adapter.""" attr = getattr(instance.__class__, key).impl state = instance._state user_data = attr.initialize(state) return attr.get_collection(state, user_data)