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      1 import unittest
      2 import ctypes
      3 import gc
      4 
      5 MyCallback = ctypes.CFUNCTYPE(ctypes.c_int, ctypes.c_int)
      6 OtherCallback = ctypes.CFUNCTYPE(ctypes.c_int, ctypes.c_int, ctypes.c_ulonglong)
      7 
      8 import _ctypes_test
      9 dll = ctypes.CDLL(_ctypes_test.__file__)
     10 
     11 class RefcountTestCase(unittest.TestCase):
     12 
     13     def test_1(self):
     14         from sys import getrefcount as grc
     15 
     16         f = dll._testfunc_callback_i_if
     17         f.restype = ctypes.c_int
     18         f.argtypes = [ctypes.c_int, MyCallback]
     19 
     20         def callback(value):
     21             #print "called back with", value
     22             return value
     23 
     24         self.assertEqual(grc(callback), 2)
     25         cb = MyCallback(callback)
     26 
     27         self.assertTrue(grc(callback) > 2)
     28         result = f(-10, cb)
     29         self.assertEqual(result, -18)
     30         cb = None
     31 
     32         gc.collect()
     33 
     34         self.assertEqual(grc(callback), 2)
     35 
     36 
     37     def test_refcount(self):
     38         from sys import getrefcount as grc
     39         def func(*args):
     40             pass
     41         # this is the standard refcount for func
     42         self.assertEqual(grc(func), 2)
     43 
     44         # the CFuncPtr instance holds atr least one refcount on func:
     45         f = OtherCallback(func)
     46         self.assertTrue(grc(func) > 2)
     47 
     48         # and may release it again
     49         del f
     50         self.assertTrue(grc(func) >= 2)
     51 
     52         # but now it must be gone
     53         gc.collect()
     54         self.assertTrue(grc(func) == 2)
     55 
     56         class X(ctypes.Structure):
     57             _fields_ = [("a", OtherCallback)]
     58         x = X()
     59         x.a = OtherCallback(func)
     60 
     61         # the CFuncPtr instance holds atr least one refcount on func:
     62         self.assertTrue(grc(func) > 2)
     63 
     64         # and may release it again
     65         del x
     66         self.assertTrue(grc(func) >= 2)
     67 
     68         # and now it must be gone again
     69         gc.collect()
     70         self.assertEqual(grc(func), 2)
     71 
     72         f = OtherCallback(func)
     73 
     74         # the CFuncPtr instance holds atr least one refcount on func:
     75         self.assertTrue(grc(func) > 2)
     76 
     77         # create a cycle
     78         f.cycle = f
     79 
     80         del f
     81         gc.collect()
     82         self.assertEqual(grc(func), 2)
     83 
     84 class AnotherLeak(unittest.TestCase):
     85     def test_callback(self):
     86         import sys
     87 
     88         proto = ctypes.CFUNCTYPE(ctypes.c_int, ctypes.c_int, ctypes.c_int)
     89         def func(a, b):
     90             return a * b * 2
     91         f = proto(func)
     92 
     93         a = sys.getrefcount(ctypes.c_int)
     94         f(1, 2)
     95         self.assertEqual(sys.getrefcount(ctypes.c_int), a)
     96 
     97 if __name__ == '__main__':
     98     unittest.main()
     99