* Updated pygtkmvc to 1.2.2.

src/gtkmvc/support/noconflict.py

@@ -0,0 +1,65 @@
+# Author: Michele Simionato <michelesimionato@libero.it>
+# Copyright (C) 2004 by Michele Simionato
+# License: Python License (version not specified)
+# Last Updated: 2nd of March 2007, 10:23 GMT
+#
+# Any serious user of metaclasses has been bitten at least once by
+# the infamous metaclass/metatype conflict. This script contains a
+# general recipe to solve the problem, as well as some theory and
+# some examples.
+
+
+import inspect, types, __builtin__
+
+############## preliminary: two utility functions #####################
+
+def skip_redundant(iterable, skipset=None):
+   "Redundant items are repeated items or items in the original skipset."
+   if skipset is None: skipset = set()
+   for item in iterable:
+      if item not in skipset:
+         skipset.add(item)
+         yield item
+
+
+def remove_redundant(metaclasses):
+   skipset = set([types.ClassType])
+   for meta in metaclasses: # determines the metaclasses to be skipped
+      skipset.update(inspect.getmro(meta)[1:])
+   return tuple(skip_redundant(metaclasses, skipset))
+
+##################################################################
+## now the core of the module: two mutually recursive functions ##
+##################################################################
+
+memoized_metaclasses_map = {}
+
+def get_noconflict_metaclass(bases, left_metas, right_metas):
+   """Not intended to be used outside of this module, unless you know
+   what you are doing."""
+   # make tuple of needed metaclasses in specified priority order
+   metas = left_metas + tuple(map(type, bases)) + right_metas
+   needed_metas = remove_redundant(metas)
+
+   # return existing confict-solving meta, if any
+   if needed_metas in memoized_metaclasses_map:
+      return memoized_metaclasses_map[needed_metas]
+   # nope: compute, memoize and return needed conflict-solving meta
+   elif not needed_metas:         # wee, a trivial case, happy us
+      meta = type
+   elif len(needed_metas) == 1: # another trivial case
+      meta = needed_metas[0]
+   # check for recursion, can happen i.e. for Zope ExtensionClasses
+   elif needed_metas == bases: 
+      raise TypeError("Incompatible root metatypes", needed_metas)
+   else: # gotta work ...
+      metaname = '_' + ''.join([m.__name__ for m in needed_metas])
+      meta = classmaker()(metaname, needed_metas, {})
+   memoized_metaclasses_map[needed_metas] = meta
+   return meta
+
+def classmaker(left_metas=(), right_metas=()):
+   def make_class(name, bases, adict):
+      metaclass = get_noconflict_metaclass(bases, left_metas, right_metas)
+      return metaclass(name, bases, adict)
+   return make_class