An initial stab at implementing annotations and dublin core for Mongo.

Instead of storing annotations in an attribute "__annotations__", we'll
store annotations directly on the object, which makes for a much nicer
Mongo document.

I changed the dublin core implementation to not even worry about
annotations and just store an attribute directly on the object.

src/mongopersist/zope/annotation.py

@@ -0,0 +1,92 @@
+##############################################################################
+#
+# Copyright (c) 2013 Zope Foundation and Contributors.
+# All Rights Reserved.
+#
+# This software is subject to the provisions of the Zope Public License,
+# Version 2.1 (ZPL).  A copy of the ZPL should accompany this distribution.
+# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
+# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
+# FOR A PARTICULAR PURPOSE.
+#
+##############################################################################
+"""Mongo Annotations Implementation."""
+from persistent.dict import PersistentDict
+from zope import component, interface
+from zope.annotation import interfaces
+
+try:
+    from UserDict import DictMixin
+except ImportError:
+    from collections import MutableMapping as DictMixin
+
+class IMongoAttributeAnnotatable(interfaces.IAnnotatable):
+    """Marker indicating that annotations can be stored on an attribute.
+
+    This is a marker interface giving permission for an `IAnnotations`
+    adapter to store data in an attribute named `__annotations__`.
+
+    """
+
+def normalize_key(key):
+    return key.replace('.', '_')
+
+@interface.implementer(interfaces.IAnnotations)
+@component.adapter(IMongoAttributeAnnotatable)
+class AttributeAnnotations(DictMixin):
+    """Store annotations on an object
+
+    Store annotations in the `__annotations__` attribute on a
+    `IAttributeAnnotatable` object.
+    """
+
+    def __init__(self, obj, context=None):
+        self.obj = obj
+
+    def __bool__(self):
+        return True
+
+    __nonzero__ = __bool__
+
+    def get(self, key, default=None):
+        """See zope.annotation.interfaces.IAnnotations"""
+        key = normalize_key(key)
+        return getattr(self.obj, key, default)
+
+    def __getitem__(self, key):
+        key = normalize_key(key)
+        try:
+            return getattr(self.obj, key)
+        except AttributeError:
+            raise KeyError(key)
+
+    def keys(self):
+        annotations = getattr(self.obj, self.ATTR_NAME, None)
+        if annotations is None:
+            return []
+
+        return annotations.keys()
+
+    def __iter__(self):
+        annotations = getattr(self.obj, self.ATTR_NAME, None)
+        if annotations is None:
+            return iter([])
+
+        return iter(annotations)
+
+    def __len__(self):
+        raise NotImplementedError
+
+    def __setitem__(self, key, value):
+        """See zope.annotation.interfaces.IAnnotations"""
+        key = normalize_key(key)
+        setattr(self.obj, key, value)
+
+    def __delitem__(self, key):
+        """See zope.app.interfaces.annotation.IAnnotations"""
+        key = normalize_key(key)
+        try:
+            delattr(self.obj, key)
+        except AttributeError:
+            raise KeyError(key)

src/mongopersist/zope/dublincore.py

@@ -0,0 +1,56 @@
+##############################################################################
+#
+# Copyright (c) 2011 Zope Foundation and Contributors.
+# All Rights Reserved.
+#
+# This software is subject to the provisions of the Zope Public License,
+# Version 2.1 (ZPL).  A copy of the ZPL should accompany this distribution.
+# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
+# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
+# FOR A PARTICULAR PURPOSE.
+#
+##############################################################################
+"""Zope Dublin Core Mongo Backend Storage"""
+from UserDict import DictMixin
+
+import zope.interface
+from zope.location import Location
+from zope.dublincore.interfaces import IWriteZopeDublinCore
+from zope.dublincore.zopedublincore import ZopeDublinCore
+from zope.security.proxy import removeSecurityProxy
+
+class DCDataWrapper(DictMixin):
+
+    def __init__(self, data):
+        self.data = data
+
+    def __getitem__(self, key):
+        return self.data[key.replace('.', '_')]
+
+    def __setitem__(self, key, value):
+        self.data[key.replace('.', '_')] = value
+
+    def __delitem__(self, key):
+        del self.data[key.replace('.', '_')]
+
+    def keys(self):
+        return [k.replace('_', '.') for k in self.data.keys()]
+
+
+@zope.interface.implementer(IWriteZopeDublinCore)
+class ZDCAnnotatableAdapter(ZopeDublinCore, Location):
+    """Adapt annotatable objects to Zope Dublin Core."""
+    DCKEY = 'dc'
+
+    def __init__(self, context):
+        self.__parent__ = context
+        self.__name__ = self.DCKEY
+        naked = removeSecurityProxy(context)
+        if not hasattr(naked, self.__name__):
+            setattr(naked, self.__name__, {})
+        dcdata = DCDataWrapper(getattr(naked, self.__name__))
+        super(ZDCAnnotatableAdapter, self).__init__(dcdata)
+
+    def _changed(self):
+        self.__parent__._p_changed = True