Copy two trivial classes from zope.cachedescriptors into this package, which...

Copy two trivial classes from zope.cachedescriptors into this package, which allows us to remove that dependency. We didn't actually use any caching properties as the dependency suggested.

CHANGES.txt

@@ -2,9 +2,12 @@
 CHANGES
 =======
 
-3.10.2 (unreleased)
+3.11.0 (unreleased)
 -------------------
 
+- Copy two trivial classes from zope.cachedescriptors into this package, which
+  allows us to remove that dependency. We didn't actually use any caching
+  properties as the dependency suggested.
 
 3.10.1 (2009-12-29)
 -------------------

setup.py

@@ -27,7 +27,7 @@ def read(*rnames):
     return open(os.path.join(os.path.dirname(__file__), *rnames)).read()
 
 setup(name='zope.container',
-      version = '3.10.2dev',
+      version = '3.11.0dev',
       author='Zope Corporation and Contributors',
       author_email='zope-dev@zope.org',
       description='Zope Container',
@@ -68,7 +68,6 @@ setup(name='zope.container',
                 ]),
       install_requires=['setuptools',
                         'zope.interface',
-                        'zope.cachedescriptors',
                         'zope.dottedname',
                         'zope.schema',
                         'zope.component',

src/zope/container/btree.py

@@ -23,10 +23,29 @@ from BTrees.Length import Length
 
 from zope.container.interfaces import IBTreeContainer
 from zope.container.contained import Contained, setitem, uncontained
-from zope.cachedescriptors.property import Lazy
 from zope.interface import implements
 
 
+class Lazy(object):
+    """Lazy Attributes.
+    """
+
+    def __init__(self, func, name=None):
+        if name is None:
+            name = func.__name__
+        self.data = (func, name)
+
+    def __get__(self, inst, class_):
+        if inst is None:
+            return self
+
+        func, name = self.data
+        value = func(inst)
+        inst.__dict__[name] = value
+
+        return value
+
+
 class BTreeContainer(Contained, Persistent):
 
     implements(IBTreeContainer)

src/zope/container/constraints.py

@@ -153,7 +153,6 @@ __docformat__ = 'restructuredtext'
 
 import sys
 
-from zope.cachedescriptors.property import readproperty
 from zope.dottedname.resolve import resolve
 import zope.schema
 from zope.interface import providedBy
@@ -220,6 +219,20 @@ def checkFactory(container, name, factory):
 
     return True
 
+
+class readproperty(object):
+
+    def __init__(self, func):
+        self.func = func
+
+    def __get__(self, inst, class_):
+        if inst is None:
+            return self
+
+        func = self.func
+        return func(inst)
+
+
 class IItemTypePrecondition(zope.interface.Interface):
 
     def __call__(container, name, object):