Merge pull request #78 from NextThought/eid-persistent-allowed

Make ExternalizableInstanceDict subclassable along with Persistent.

CHANGES.rst

@@ -8,6 +8,9 @@
 
 - Nothing changed yet.
 
+- ``ExternalizableInstanceDict`` no longer inherits from
+  ``AbstractDynamicIO``, it just implements the same interface (with
+  the exception of many of the ``_ext`` methods). This class is deprecated.
 
 1.0.0a4 (2018-07-30)
 ====================

docs/conf.py

@@ -192,12 +192,14 @@
     'http://zopecontainer.readthedocs.io/en/latest': None,
     'http://zopedatetime.readthedocs.io/en/latest': None,
     'http://zopedublincore.readthedocs.io/en/latest': None,
+    'http://zopeevent.readthedocs.io/en/latest': None,
     'http://zopehookable.readthedocs.io/en/latest': None,
     'http://zopeinterface.readthedocs.io/en/latest': None,
     'http://zopeintid.readthedocs.io/en/latest/': None,
     'http://zopemimetype.readthedocs.io/en/latest/': None,
     'http://zopeproxy.readthedocs.io/en/latest': None,
     'http://zopeschema.readthedocs.io/en/latest/': None,
+    'http://zopelifecycleevent.readthedocs.io/en/latest/': None,
 }
 
 extlinks = {

src/nti/externalization/_datastructures.pxd

@@ -56,9 +56,15 @@ cdef class AbstractDynamicObjectIO(ExternalizableDictionaryMixin):
     cpdef find_factory_for_named_value(self, key, value, registry)
     cdef _updateFromExternalObject(self, parsed)
 
+# cdef class _ExternalizableInstanceDict(AbstractDynamicObjectIO):
+#     cdef dict __dict__
 
-cdef class ExternalizableInstanceDict(AbstractDynamicObjectIO):
-    pass
+
+# This class is sometimes subclassed while also subclassing persistent.Persistent,
+# which doesn't work if it's an extension class, so we can't do that. It's rarely used,
+# so performance doesn't matter as much.
+#cdef class ExternalizableInstanceDict(AbstractDynamicObjectIO):
+#    pass
 
 cdef class InterfaceObjectIO(AbstractDynamicObjectIO):
     cdef readonly _ext_self

src/nti/externalization/datastructures.py

@@ -11,7 +11,7 @@
 # There are a *lot* of fixme (XXX and the like) in this file.
 # Turn those off in general so we can see through the noise.
 # pylint:disable=fixme
-
+# pylint:disable=keyword-arg-before-vararg
 
 # stdlib imports
 import numbers
@@ -26,6 +26,7 @@
 
 from nti.schema.interfaces import find_most_derived_interface
 
+from .interfaces import IInternalObjectIO
 from .interfaces import IInternalObjectIOFinder
 from .interfaces import IAnonymousObjectFactory
 from .interfaces import StandardInternalFields
@@ -90,6 +91,11 @@ def _ext_standard_external_dictionary(self, replacement, mergeFrom=None, **kwarg
             decorate_callback=kwargs.get('decorate_callback', NotGiven))
 
     def toExternalDictionary(self, mergeFrom=None, *unused_args, **kwargs):
+        """
+        Produce the standard external dictionary for this object.
+
+        Uses `_ext_replacement`.
+        """
         return self._ext_standard_external_dictionary(self._ext_replacement(),
                                                       mergeFrom=mergeFrom,
                                                       **kwargs)
@@ -317,21 +323,34 @@ def _updateFromExternalObject(self, parsed):
 interface.classImplements(AbstractDynamicObjectIO, IInternalObjectIOFinder)
 
 
-class ExternalizableInstanceDict(AbstractDynamicObjectIO):
-    """
-    Externalizes to a dictionary containing the members of ``__dict__``
-    that do not start with an underscore.
-
-    Meant to be used as a super class; also can be used as an external object superclass.
-    """
+class _ExternalizableInstanceDict(AbstractDynamicObjectIO):
 
     # TODO: there should be some better way to customize this if desired (an explicit list)
     # TODO: Play well with __slots__? ZODB supports slots, but doesn't recommend them
     # TODO: This won't evolve well. Need something more sophisticated,
     # probably a meta class.
-
     _update_accepts_type_attrs = False
 
+    def __init__(self, context):
+        self.context = context
+        for name in (
+                '_update_accepts_type_attrs',
+                '__external_use_minimal_base__',
+                '_excluded_in_ivars_',
+                '_excluded_out_ivars_',
+                '_ext_primitive_out_ivars_',
+                '_prefer_oid_'
+        ):
+            try:
+                v = getattr(context, name)
+            except AttributeError:
+                continue
+            else:
+                setattr(self, name, v)
+
+    def _ext_replacement(self):
+        return self.context
+
     def _ext_all_possible_keys(self):
         return frozenset(self._ext_replacement().__dict__.keys())
 
@@ -345,13 +364,58 @@ def _ext_setattr(self, ext_self, k, value):
 
     def _ext_accept_update_key(self, k, ext_self, ext_keys):
         return (
-            super(ExternalizableInstanceDict, self)._ext_accept_update_key(k, ext_self, ext_keys)
+            super(_ExternalizableInstanceDict, self)._ext_accept_update_key(k, ext_self, ext_keys)
             or (self._update_accepts_type_attrs and hasattr(ext_self, k))
         )
 
     __repr__ = make_repr()
 
 
+class ExternalizableInstanceDict(object):
+    """
+    Externalizes to a dictionary containing the members of
+    ``__dict__`` that do not start with an underscore.
+
+    Meant to be used as a super class; also can be used as an external
+    object superclass.
+
+    .. versionchanged:: 1.0a5
+       No longer extends `AbstractDynamicObjectIO`, just delegates to it.
+    .. deprecated:: 1.0a5
+       Prefer interfaces.
+    """
+    # pylint:disable=protected-access
+    _update_accepts_type_attrs = _ExternalizableInstanceDict._update_accepts_type_attrs
+    __external_use_minimal_base__ = _ExternalizableInstanceDict.__external_use_minimal_base__
+    _excluded_out_ivars_ = AbstractDynamicObjectIO._excluded_out_ivars_
+    _excluded_in_ivars_ = AbstractDynamicObjectIO._excluded_in_ivars_
+    _ext_primitive_out_ivars_ = AbstractDynamicObjectIO._ext_primitive_out_ivars_
+    _prefer_oid_ = AbstractDynamicObjectIO._prefer_oid_
+
+    def _ext_replacement(self):
+        "See `ExternalizableDictionaryMixin._ext_replacement`."
+        return self
+
+    def __make_io(self):
+        return _ExternalizableInstanceDict(self._ext_replacement())
+
+    def __getattr__(self, name):
+        # here if we didn't have the attribute. Does our IO?
+        return getattr(self.__make_io(), name)
+
+    def updateFromExternalObject(self, parsed, *unused_args, **unused_kwargs):
+        "See `~.IInternalObjectIO.updateFromExternalObject`"
+        self.__make_io().updateFromExternalObject(parsed)
+
+    def toExternalObject(self, mergeFrom=None, *args, **kwargs):
+        "See `~.IInternalObjectIO.toExternalObject`. Calls `toExternalDictionary`."
+        return self.toExternalDictionary(mergeFrom, *args, **kwargs)
+
+    def toExternalDictionary(self, mergeFrom=None, *unused_args, **kwargs):
+        "See `ExternalizableDictionaryMixin.toExternalDictionary`"
+        return self.__make_io().toExternalDictionary(mergeFrom)
+
+interface.classImplements(ExternalizableInstanceDict, IInternalObjectIO)
 
 _primitives = six.string_types + (numbers.Number, bool)
 

src/nti/externalization/interfaces.py

@@ -398,12 +398,15 @@ class IObjectModifiedFromExternalEvent(IObjectModifiedEvent):
     """
     An object has been updated from an external value.
     """
-    kwargs = interface.Attribute("The key word arguments")
+    kwargs = interface.Attribute("The keyword arguments")
     external_value = interface.Attribute("The external value")
 
 
 @interface.implementer(IObjectModifiedFromExternalEvent)
 class ObjectModifiedFromExternalEvent(ObjectModifiedEvent):
+    """
+    Default implementation of `IObjectModifiedFromExternalEvent`.
+    """
 
     kwargs = None
     external_value = None

src/nti/externalization/internalization/__init__.py

@@ -9,6 +9,8 @@
 from __future__ import division
 from __future__ import print_function
 
+import warnings
+
 from zope.interface.interfaces import ComponentLookupError
 
 __all__ = [
@@ -20,7 +22,7 @@
     'default_externalized_object_factory_finder_factory',
     'find_factory_for_class_name',
     'find_factory_for',
-    'notifyModified',
+    'notify_modified',
     'validate_field_value',
     'validate_named_field_value',
 ]
@@ -37,7 +39,7 @@
 from .factories import find_factory_for_class_name
 from .factories import find_factory_for
 
-from .events import notifyModified
+from .events import notifyModified as notify_modified
 
 from .updater import update_from_external_object
 
@@ -64,3 +66,13 @@ def new_from_external_object(external_object, *args, **kwargs):
     if factory is None:
         raise ComponentLookupError("No factory for object", external_object)
     return update_from_external_object(factory(), external_object, *args, **kwargs)
+
+
+def notifyModified(*args, **kwargs):
+    """
+    A deprecated alias of `notify_modified`.
+
+    .. deprecated:: 1.0a5
+    """
+    warnings.warn("Use notify_modified instead", FutureWarning, stacklevel=2)
+    return notify_modified(*args, **kwargs)

src/nti/externalization/internalization/events.py

@@ -133,6 +133,31 @@ def _notifyModified(containedObject, externalObject, updater, external_keys,
 
 def notifyModified(containedObject, externalObject, updater=None, external_keys=None,
                    **kwargs):
+    """
+    Create and send an `~.ObjectModifiedFromExternalEvent` for
+    *containedObject* using `zope.event.notify`.
+
+    The *containedObject* is the subject of the event. The
+    *externalObject* is the dictionary of data that was used to update
+    the *containedObject*.
+
+    *external_keys* is list of keys from *externalObject* that
+    actually changed *containedObject*. If this is not given, we
+    assume that all keys in *externalObject* were changed. Note that
+    these should to correspond to the interface fields of interfaces
+    that the *containedObject* implements in order to properly be able
+    to create and populate the `zope.lifecycleevent` `~zope.lifecycleevent.IAttributes`.
+
+    *updater*, if given, is the `~nti.externalization.interfaces.IInternalObjectUpdater`
+    instance that was used to handle the updates. If this object implements
+    an ``_ext_adjust_modified_event`` method, it will be called to adjust (and return)
+    the event object that will be notified.
+
+    *kwargs* are the keyword arguments passed to the event constructor.
+
+    :return: The event object that was notified.
+    """
+
     return _notifyModified(containedObject, externalObject, updater, external_keys,
                            kwargs)
 

src/nti/externalization/tests/test_datastructures.py

@@ -514,3 +514,16 @@ def _ext_replacement(self):
                 return context
 
         return FUT()
+
+
+    def test_can_also_subclass_persistent(self):
+        from nti.externalization.datastructures import ExternalizableInstanceDict
+        from persistent import Persistent
+
+        class Base(ExternalizableInstanceDict):
+            pass
+
+        class P(Base, Persistent):
+            pass
+
+        self.assertIsNotNone(P)