1"""
2A testcase which accesses *values* in a dll.
3"""
4
5import unittest
6import sys
7from ctypes import *
8
9import _ctypes_test
10
11class ValuesTestCase(unittest.TestCase):
12
13    def test_an_integer(self):
14        # This test checks and changes an integer stored inside the
15        # _ctypes_test dll/shared lib.
16        ctdll = CDLL(_ctypes_test.__file__)
17        an_integer = c_int.in_dll(ctdll, "an_integer")
18        x = an_integer.value
19        self.assertEqual(x, ctdll.get_an_integer())
20        an_integer.value *= 2
21        self.assertEqual(x*2, ctdll.get_an_integer())
22        # To avoid test failures when this test is repeated several
23        # times the original value must be restored
24        an_integer.value = x
25        self.assertEqual(x, ctdll.get_an_integer())
26
27    def test_undefined(self):
28        ctdll = CDLL(_ctypes_test.__file__)
29        self.assertRaises(ValueError, c_int.in_dll, ctdll, "Undefined_Symbol")
30
31class PythonValuesTestCase(unittest.TestCase):
32    """This test only works when python itself is a dll/shared library"""
33
34    def test_optimizeflag(self):
35        # This test accesses the Py_OptimizeFlag integer, which is
36        # exported by the Python dll and should match the sys.flags value
37
38        opt = c_int.in_dll(pythonapi, "Py_OptimizeFlag").value
39        self.assertEqual(opt, sys.flags.optimize)
40
41    def test_frozentable(self):
42        # Python exports a PyImport_FrozenModules symbol. This is a
43        # pointer to an array of struct _frozen entries.  The end of the
44        # array is marked by an entry containing a NULL name and zero
45        # size.
46
47        # In standard Python, this table contains a __hello__
48        # module, and a __phello__ package containing a spam
49        # module.
50        class struct_frozen(Structure):
51            _fields_ = [("name", c_char_p),
52                        ("code", POINTER(c_ubyte)),
53                        ("size", c_int)]
54        FrozenTable = POINTER(struct_frozen)
55
56        ft = FrozenTable.in_dll(pythonapi, "PyImport_FrozenModules")
57        # ft is a pointer to the struct_frozen entries:
58        items = []
59        # _frozen_importlib changes size whenever importlib._bootstrap
60        # changes, so it gets a special case.  We should make sure it's
61        # found, but don't worry about its size too much.  The same
62        # applies to _frozen_importlib_external.
63        bootstrap_seen = []
64        bootstrap_expected = [
65                b'_frozen_importlib',
66                b'_frozen_importlib_external',
67                ]
68        for entry in ft:
69            # This is dangerous. We *can* iterate over a pointer, but
70            # the loop will not terminate (maybe with an access
71            # violation;-) because the pointer instance has no size.
72            if entry.name is None:
73                break
74
75            if entry.name in bootstrap_expected:
76                bootstrap_seen.append(entry.name)
77                self.assertTrue(entry.size,
78                    "{!r} was reported as having no size".format(entry.name))
79                continue
80            items.append((entry.name.decode("ascii"), entry.size))
81
82        expected = [("__hello__", 139),
83                    ("__phello__", -139),
84                    ("__phello__.spam", 139),
85                    ]
86        self.assertEqual(items, expected, "PyImport_FrozenModules example "
87            "in Doc/library/ctypes.rst may be out of date")
88
89        self.assertEqual(sorted(bootstrap_seen), bootstrap_expected,
90            "frozen bootstrap modules did not match PyImport_FrozenModules")
91
92        from ctypes import _pointer_type_cache
93        del _pointer_type_cache[struct_frozen]
94
95    def test_undefined(self):
96        self.assertRaises(ValueError, c_int.in_dll, pythonapi,
97                          "Undefined_Symbol")
98
99if __name__ == '__main__':
100    unittest.main()
101