Moved classinstance into util

1 files changed, 39 insertions, 0 deletions

diff --git a/paste/util/classinit.py b/paste/util/classinit.py
new file mode 100644
index 0000000..05156d5
--- /dev/null
+++ b/paste/util/classinit.py
@@ -0,0 +1,39 @@
+class ClassInitMeta(type):
+
+    def __new__(meta, class_name, bases, new_attrs):
+        cls = type.__new__(meta, class_name, bases, new_attrs)
+        if (new_attrs.has_key('__classinit__')
+            and not isinstance(cls.__classinit__, staticmethod)):
+            setattr(cls, '__classinit__',
+                    staticmethod(cls.__classinit__.im_func))
+        if hasattr(cls, '__classinit__'):
+            cls.__classinit__(cls, new_attrs)
+        return cls
+
+def build_properties(cls, new_attrs):
+    """
+    Given a class and a new set of attributes (as passed in by
+    __classinit__), create or modify properties based on functions
+    with special names ending in __get, __set, and __del.
+    """
+    for name, value in new_attrs.items():
+        if (name.endswith('__get') or name.endswith('__set')
+            or name.endswith('__del')):
+            base = name[:-5]
+            if hasattr(cls, base):
+                old_prop = getattr(cls, base)
+                if not isinstance(old_prop, property):
+                    raise ValueError(
+                        "Attribute %s is a %s, not a property; function %s is named like a property"
+                        % (base, type(old_prop), name))
+                attrs = {'fget': old_prop.fget,
+                         'fset': old_prop.fset,
+                         'fdel': old_prop.fdel,
+                         'doc': old_prop.__doc__}
+            else:
+                attrs = {}
+            attrs['f' + name[-3:]] = value
+            if name.endswith('__get') and value.__doc__:
+                attrs['doc'] = value.__doc__
+            new_prop = property(**attrs)
+            setattr(cls, base, new_prop)