1 files changed, 132 insertions, 0 deletions
diff --git a/repoze/bfg/location.py b/repoze/bfg/location.py
new file mode 100644
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+++ b/repoze/bfg/location.py
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+##############################################################################
+#
+# Copyright (c) 2003 Zope Corporation 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.
+#
+##############################################################################
+
+"""Location support borrowed from ``zope.location``, but without
+``zope.security`` support, which is not used by ``repoze.bfg``
+"""
+
+import zope.interface
+from repoze.bfg.interfaces import ILocation
+from zope.proxy import ProxyBase, getProxiedObject, non_overridable
+from zope.proxy.decorator import DecoratorSpecificationDescriptor
+
+def inside(model1, model2):
+    """Is ``model1`` 'inside' ``model2``?  Return ``True`` if so, else
+    ``False``.
+
+    ``model1`` is 'inside' ``model2`` if ``model2`` is a `location
+    ancestor` of ``model1``.  It is a location ancestor if its parent
+    (or one of its parent's parents, etc.) is an ancestor.
+    """
+    while model1 is not None:
+        if model1 is model2:
+            return True
+        model1 = model1.__parent__
+
+    return False
+
+def locate(model, parent, name=None):
+    """
+    If ``model`` explicitly provides the
+    ``repoze.bfg.interfaces.ILocation`` interface, locate ``model``
+    directly set ``model`` 's ``__parent__`` attribute to the
+    ``parent`` object (also a model), and its ``__name__`` to the
+    supplied ``name`` argument.
+
+    If ``model`` does *not* explicitly provide the
+    ``repoze.bfg.interfaces.ILocation`` interface, return a
+    ``LocationProxy`` object representing ``model`` with its
+    ``__parent__`` attribute assigned to ``parent`` and a ``__name__``
+    attribute assigned to ``__name__``.  A ``LocationProxy`` object is
+    an unpickleable proxy that can 'stand in' for arbitrary object
+    instances.
+    """
+    if ILocation.providedBy(model):
+        if parent is not model.__parent__ or name != model.__name__:
+            _locate(model, parent, name)
+        return model
+    return LocationProxy(model, parent, name)
+
+def lineage(model):
+    """
+    Return a generator representing the model lineage.  The generator
+    first returns ``model`` unconditionally.  Then, if ``model``
+    supplies a ``__parent__`` attribute, return the object represented
+    by ``model.__parent__``.  If *that* object has a ``__parent__``
+    attribute, return that object's parent, and so on, until the
+    object being inspected either has no ``__parent__`` attribute or
+    which has a ``__parent__`` attribute of ``None``.  For example, if
+    the object tree is::
+
+      thing1 = Thing()
+      thing2 = Thing()
+      thing2.__parent__ = thing1
+
+    Calling ``lineage(thing2)`` will return a generator.  When we turn
+    it into a list, we will get::
+    
+      list(lineage(thing2))
+      [ <Thing object at thing2>, <Thing object at thing1> ]
+    """
+    while model is not None:
+        yield model
+        model = getattr(model, '__parent__', None)
+
+def _locate(model, parent, name=None):
+    model.__parent__ = parent
+    model.__name__ = name
+
+class ClassAndInstanceDescr(object):
+
+    def __init__(self, *args):
+        self.funcs = args
+
+    def __get__(self, inst, cls):
+        if inst is None:
+            return self.funcs[1](cls)
+        return self.funcs[0](inst)
+
+class LocationProxy(ProxyBase):
+    """Location-object proxy
+
+    This is a non-picklable proxy that can be put around objects that
+    don't implement `ILocation`.
+    """
+
+    zope.interface.implements(ILocation)
+
+    __slots__ = '__parent__', '__name__'
+    __safe_for_unpickling__ = True
+
+    def __new__(self, ob, container=None, name=None):
+        return ProxyBase.__new__(self, ob)
+
+    def __init__(self, ob, container=None, name=None):
+        ProxyBase.__init__(self, ob)
+        self.__parent__ = container
+        self.__name__ = name
+
+    @non_overridable
+    def __reduce__(self, proto=None):
+        raise TypeError("Not picklable")
+
+    __doc__ = ClassAndInstanceDescr(
+        lambda inst: getProxiedObject(inst).__doc__,
+        lambda cls, __doc__ = __doc__: __doc__,
+        )
+
+    __reduce_ex__ = __reduce__
+
+    __providedBy__ = DecoratorSpecificationDescriptor()
+