Add pickle support to ctypes types.

Lib/ctypes/test/test_pickling.py

@@ -0,0 +1,78 @@
+import unittest
+import pickle
+from ctypes import *
+import _ctypes_test
+dll = CDLL(_ctypes_test.__file__)
+
+class X(Structure):
+    _fields_ = [("a", c_int), ("b", c_double)]
+    init_called = 0
+    def __init__(self, *args, **kw):
+        X.init_called += 1
+        self.x = 42
+
+class Y(X):
+    _fields_ = [("str", c_char_p)]
+
+class PickleTest(unittest.TestCase):
+    def dumps(self, item):
+        return pickle.dumps(item)
+
+    def loads(self, item):
+        return pickle.loads(item)
+
+    def test_simple(self):
+        for src in [
+            c_int(42),
+            c_double(3.14),
+            ]:
+            dst = self.loads(self.dumps(src))
+            self.failUnlessEqual(src.__dict__, dst.__dict__)
+            self.failUnlessEqual(buffer(src),
+                                 buffer(dst))
+
+    def test_struct(self):
+        X.init_called = 0
+
+        x = X()
+        x.a = 42
+        self.failUnlessEqual(X.init_called, 1)
+
+        y = self.loads(self.dumps(x))
+
+        # loads must NOT call __init__
+        self.failUnlessEqual(X.init_called, 1)
+
+        # ctypes instances are identical when the instance __dict__
+        # and the memory buffer are identical
+        self.failUnlessEqual(y.__dict__, x.__dict__)
+        self.failUnlessEqual(buffer(y),
+                             buffer(x))
+
+    def test_unpickable(self):
+        # ctypes objects that are pointers or contain pointers are
+        # unpickable.
+        self.assertRaises(ValueError, lambda: self.dumps(Y()))
+
+        prototype = CFUNCTYPE(c_int)
+
+        for item in [
+            c_char_p(),
+            c_wchar_p(),
+            c_void_p(),
+            pointer(c_int(42)),
+            dll._testfunc_p_p,
+            prototype(lambda: 42),
+            ]:
+            self.assertRaises(ValueError, lambda: self.dumps(item))
+
+class PickleTest_1(PickleTest):
+    def dumps(self, item):
+        return pickle.dumps(item, 1)
+
+class PickleTest_2(PickleTest):
+    def dumps(self, item):
+        return pickle.dumps(item, 2)
+
+if __name__ == "__main__":
+    unittest.main()