Include module for desktop build

libs/pyutil/weakutil.py

@@ -0,0 +1,42 @@
+# Copyright (c) 2005-2010 Zooko Wilcox-O'Hearn
+#  This file is part of pyutil; see README.rst for licensing terms.
+
+import warnings
+
+# from the Python Standard Library
+from weakref import ref
+
+# from the pyutil library
+from assertutil import precondition
+
+# Thanks to Thomas Wouters, JP Calderone and the authors from the Python Cookbook.
+
+# class WeakMethod copied from The Python Cookbook and simplified.
+
+class WeakMethod:
+    """ Wraps a function or, more importantly, a bound method, in
+    a way that allows a bound method's object to be GC'd """
+    def __init__(self, fn, callback=None):
+        warnings.warn("deprecated", DeprecationWarning)
+        precondition(hasattr(fn, 'im_self'), "fn is required to be a bound method.")
+        self._cleanupcallback = callback
+        self._obj = ref(fn.im_self, self.call_cleanup_cb)
+        self._meth = fn.im_func
+
+    def __call__(self, *args, **kws):
+        s = self._obj()
+        if s:
+            return self._meth(s, *args,**kws)
+
+    def __repr__(self):
+        return "<%s %s %s>" % (self.__class__.__name__, self._obj, self._meth,)
+
+    def call_cleanup_cb(self, thedeadweakref):
+        if self._cleanupcallback is not None:
+            self._cleanupcallback(self, thedeadweakref)
+
+def factory_function_name_here(o):
+    if hasattr(o, 'im_self'):
+        return WeakMethod(o)
+    else:
+        return o