From 7de404bb4af2744a64c13e31a780fc0229b8f9e5 Mon Sep 17 00:00:00 2001
From: Chris McDonough <chrism@agendaless.com>
Date: Mon, 7 Jul 2008 04:44:57 +0000
Subject: Look up a view after traversal; adapt it to IWSGIApplication.

---
 repoze/bfg/location.py | 118 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 118 insertions(+)
 create mode 100644 repoze/bfg/location.py

(limited to 'repoze/bfg/location.py')

diff --git a/repoze/bfg/location.py b/repoze/bfg/location.py
new file mode 100644
index 000000000..37e5386b3
--- /dev/null
+++ b/repoze/bfg/location.py
@@ -0,0 +1,118 @@
+##############################################################################
+#
+# 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.
+#
+##############################################################################
+
+import zope.interface
+from zope.proxy import ProxyBase
+from zope.proxy import getProxiedObject
+from zope.proxy import non_overridable
+from zope.proxy.decorator import DecoratorSpecificationDescriptor
+from repoze.bfg.interfaces import ILocation
+
+class Location(object):
+    """Stupid mix-in that defines `__parent__` and `__name__` attributes."""
+
+    zope.interface.implements(ILocation)
+
+    __parent__ = __name__ = None
+
+def locate(object, parent, name=None):
+    """Locate an object in another
+
+    This method should only be called from trusted code, because it
+    sets attributes that are normally unsettable.
+    """
+
+    object.__parent__ = parent
+    object.__name__ = name
+
+
+def located(object, parent, name=None):
+    """Locate an object in another and return it.
+
+    If the object does not provide ILocation a LocationProxy is returned.
+
+    """
+    if ILocation.providedBy(object):
+        if parent is not object.__parent__ or name != object.__name__:
+            locate(object, parent, name)
+        return object
+    return LocationProxy(object, parent, name)
+
+
+def LocationIterator(object):
+    while object is not None:
+        yield object
+        object = getattr(object, '__parent__', None)
+
+
+def inside(l1, l2):
+    """Is l1 inside l2
+
+    L1 is inside l2 if l2 is an ancestor of l1.
+
+    """
+    while l1 is not None:
+        if l1 is l2:
+            return True
+        l1 = l1.__parent__
+
+    return False
+
+
+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()
+
-- 
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