From: W. Trevor King <wking@drexel.edu>
Date: Thu, 15 Mar 2012 02:55:45 +0000 (-0400)
Subject: Add __reduce__() method to BitwiseOperator and _NamedInt.
X-Git-Tag: 0.4~1
X-Git-Url: http://git.tremily.us/?a=commitdiff_plain;h=520f82497804b26df7624f44dfedad9303ebe6d9;p=pycomedi.git

Add __reduce__() method to BitwiseOperator and _NamedInt.

This makes it possible to successfully pickle and deepcopy instances
of these types [1,2].  This gets the

  TRIG_SRC.now == copy.deepcopy(TRIG_SRC.now)

doctest working, which I needed to successfully dump h5config
ChoiceConfig objects that use _Enum choices [3].

For example, the newly fixed pypiezo.config.ChannelConfig [4] uses the
AREF enum values as possible choices for it's `analog-reference`
setting.  h5config makes deepcopies of mutable objects to avoid
confusion if the mutable is changed externally.  It then compares the
deepcopies with uncopied values.  Now that deepcopying works for
_NamedInts, the h5config behavior will work.

[1] http://docs.python.org/library/pickle.html#pickling-and-unpickling-extension-types
[2] http://docs.python.org/library/copy.html
[3] http://pypi.python.org/pypi/h5config/
[4] http://pypi.python.org/pypi/pypiezo/
---

diff --git a/pycomedi/constant.pyx b/pycomedi/constant.pyx
index 1f89219..ae981d7 100644
--- a/pycomedi/constant.pyx
+++ b/pycomedi/constant.pyx
@@ -191,6 +191,9 @@ cdef class BitwiseOperator (object):
         else:
             raise ValueError(op)
 
+    def __reduce__(self):
+        return (BitwiseOperator, (self.value,))
+
 
 class _NamedInt (BitwiseOperator):
     "A flag or enum item."
@@ -205,6 +208,9 @@ class _NamedInt (BitwiseOperator):
     def __repr__(self):
         return '<%s %s>' % (self.__class__.__name__, self.name)
 
+    def __reduce__(self):
+        return (_NamedInt, (self.name, self.value, self.doc))
+
 
 class _Enum (list):
     "An enumerated list"
@@ -256,7 +262,6 @@ class _Enum (list):
         self._value_keys[item.value] = item
         setattr(self, item.name, item)
 
-
     def index_by_name(self, name):
         return self._name_keys[name]