"""
A testcase which accesses *values* in a dll.
"""
import _imp
import importlib.util
import sys
import unittest
from ctypes import (Structure, CDLL, POINTER, pythonapi,
_pointer_type_cache,
c_ubyte, c_char_p, c_int)
from test.support import import_helper
class ValuesTestCase(unittest.TestCase):
def setUp(self):
_ctypes_test = import_helper.import_module("_ctypes_test")
self.ctdll = CDLL(_ctypes_test.__file__)
def test_an_integer(self):
# This test checks and changes an integer stored inside the
# _ctypes_test dll/shared lib.
ctdll = self.ctdll
an_integer = c_int.in_dll(ctdll, "an_integer")
x = an_integer.value
self.assertEqual(x, ctdll.get_an_integer())
an_integer.value *= 2
self.assertEqual(x*2, ctdll.get_an_integer())
# To avoid test failures when this test is repeated several
# times the original value must be restored
an_integer.value = x
self.assertEqual(x, ctdll.get_an_integer())
def test_undefined(self):
self.assertRaises(ValueError, c_int.in_dll, self.ctdll, "Undefined_Symbol")
class PythonValuesTestCase(unittest.TestCase):
"""This test only works when python itself is a dll/shared library"""
def test_optimizeflag(self):
# This test accesses the Py_OptimizeFlag integer, which is
# exported by the Python dll and should match the sys.flags value
opt = c_int.in_dll(pythonapi, "Py_OptimizeFlag").value
self.assertEqual(opt, sys.flags.optimize)
def test_frozentable(self):
# Python exports a PyImport_FrozenModules symbol. This is a
# pointer to an array of struct _frozen entries. The end of the
# array is marked by an entry containing a NULL name and zero
# size.
# In standard Python, this table contains a __hello__
# module, and a __phello__ package containing a spam
# module.
class struct_frozen(Structure):
_fields_ = [("name", c_char_p),
("code", POINTER(c_ubyte)),
("size", c_int),
("is_package", c_int),
]
FrozenTable = POINTER(struct_frozen)
modules = []
for group in ["Bootstrap", "Stdlib", "Test"]:
ft = FrozenTable.in_dll(pythonapi, f"_PyImport_Frozen{group}")
# ft is a pointer to the struct_frozen entries:
for entry in ft:
# This is dangerous. We *can* iterate over a pointer, but
# the loop will not terminate (maybe with an access
# violation;-) because the pointer instance has no size.
if entry.name is None:
break
modname = entry.name.decode("ascii")
modules.append(modname)
with self.subTest(modname):
if entry.size != 0:
# Do a sanity check on entry.size and entry.code.
self.assertGreater(abs(entry.size), 10)
self.assertTrue([entry.code[i] for i in range(abs(entry.size))])
# Check the module's package-ness.
with import_helper.frozen_modules():
spec = importlib.util.find_spec(modname)
if entry.is_package:
# It's a package.
self.assertIsNotNone(spec.submodule_search_locations)
else:
self.assertIsNone(spec.submodule_search_locations)
with import_helper.frozen_modules():
expected = _imp._frozen_module_names()
self.maxDiff = None
self.assertEqual(modules, expected,
"_PyImport_FrozenBootstrap example "
"in Doc/library/ctypes.rst may be out of date")
del _pointer_type_cache[struct_frozen]
def test_undefined(self):
self.assertRaises(ValueError, c_int.in_dll, pythonapi,
"Undefined_Symbol")
if __name__ == '__main__':
unittest.main()
Codebase Browser
cpython