gh-126384: Add tests to verify the behavior of basic COM methods.

Lib/test/test_ctypes/test_win32_com_foreign_func.py

@@ -0,0 +1,188 @@
+import ctypes
+import gc
+import sys
+import unittest
+from ctypes import POINTER, byref, c_void_p
+from ctypes.wintypes import BYTE, DWORD, WORD
+
+if sys.platform != "win32":
+    raise unittest.SkipTest("Windows-specific test")
+
+
+from _ctypes import COMError
+from ctypes import HRESULT
+
+
+COINIT_APARTMENTTHREADED = 0x2
+CLSCTX_SERVER = 5
+S_OK = 0
+OUT = 2
+TRUE = 1
+E_NOINTERFACE = -2147467262
+
+
+class GUID(ctypes.Structure):
+    # https://learn.microsoft.com/en-us/windows/win32/api/guiddef/ns-guiddef-guid
+    _fields_ = [
+        ("Data1", DWORD),
+        ("Data2", WORD),
+        ("Data3", WORD),
+        ("Data4", BYTE * 8),
+    ]
+
+
+def create_proto_com_method(name, index, restype, *argtypes):
+    proto = ctypes.WINFUNCTYPE(restype, *argtypes)
+
+    def make_method(*args):
+        foreign_func = proto(index, name, *args)
+
+        def call(self, *args, **kwargs):
+            return foreign_func(self, *args, **kwargs)
+
+        return call
+
+    return make_method
+
+
+def create_guid(name):
+    guid = GUID()
+    # https://learn.microsoft.com/en-us/windows/win32/api/combaseapi/nf-combaseapi-clsidfromstring
+    ole32.CLSIDFromString(name, byref(guid))
+    return guid
+
+
+def is_equal_guid(guid1, guid2):
+    # https://learn.microsoft.com/en-us/windows/win32/api/objbase/nf-objbase-isequalguid
+    return ole32.IsEqualGUID(byref(guid1), byref(guid2))
+
+
+ole32 = ctypes.oledll.ole32
+
+IID_IUnknown = create_guid("{00000000-0000-0000-C000-000000000046}")
+IID_IStream = create_guid("{0000000C-0000-0000-C000-000000000046}")
+IID_IPersist = create_guid("{0000010C-0000-0000-C000-000000000046}")
+CLSID_ShellLink = create_guid("{00021401-0000-0000-C000-000000000046}")
+
+# https://learn.microsoft.com/en-us/windows/win32/api/unknwn/nf-unknwn-iunknown-queryinterface(refiid_void)
+proto_query_interface = create_proto_com_method(
+    "QueryInterface", 0, HRESULT, POINTER(GUID), POINTER(c_void_p)
+)
+# https://learn.microsoft.com/en-us/windows/win32/api/unknwn/nf-unknwn-iunknown-addref
+proto_add_ref = create_proto_com_method("AddRef", 1, ctypes.c_long)
+# https://learn.microsoft.com/en-us/windows/win32/api/unknwn/nf-unknwn-iunknown-release
+proto_release = create_proto_com_method("Release", 2, ctypes.c_long)
+# https://learn.microsoft.com/en-us/windows/win32/api/objidl/nf-objidl-ipersist-getclassid
+proto_get_class_id = create_proto_com_method(
+    "GetClassID", 3, HRESULT, POINTER(GUID)
+)
+
+
+class ForeignFunctionsThatWillCallComMethodsTests(unittest.TestCase):
+    def setUp(self):
+        # https://learn.microsoft.com/en-us/windows/win32/api/combaseapi/nf-combaseapi-coinitializeex
+        ole32.CoInitializeEx(None, COINIT_APARTMENTTHREADED)
+
+    def tearDown(self):
+        # https://learn.microsoft.com/en-us/windows/win32/api/combaseapi/nf-combaseapi-couninitialize
+        ole32.CoUninitialize()
+        gc.collect()
+
+    @staticmethod
+    def create_shelllink_persist(typ):
+        ppst = typ()
+        # https://learn.microsoft.com/en-us/windows/win32/api/combaseapi/nf-combaseapi-cocreateinstance
+        ole32.CoCreateInstance(
+            byref(CLSID_ShellLink),
+            None,
+            CLSCTX_SERVER,
+            byref(IID_IPersist),
+            byref(ppst),
+        )
+        return ppst
+
+    def test_without_paramflags_and_iid(self):
+        class IUnknown(c_void_p):
+            QueryInterface = proto_query_interface()
+            AddRef = proto_add_ref()
+            Release = proto_release()
+
+        class IPersist(IUnknown):
+            GetClassID = proto_get_class_id()
+
+        ppst = self.create_shelllink_persist(IPersist)
+
+        clsid = GUID()
+        hr_getclsid = ppst.GetClassID(byref(clsid))
+        self.assertEqual(S_OK, hr_getclsid)
+        self.assertEqual(TRUE, is_equal_guid(CLSID_ShellLink, clsid))
+
+        self.assertEqual(2, ppst.AddRef())
+        self.assertEqual(3, ppst.AddRef())
+
+        punk = IUnknown()
+        hr_qi = ppst.QueryInterface(IID_IUnknown, punk)
+        self.assertEqual(S_OK, hr_qi)
+        self.assertEqual(3, punk.Release())
+
+        with self.assertRaises(OSError) as e:
+            punk.QueryInterface(IID_IStream, IUnknown())
+        self.assertEqual(E_NOINTERFACE, e.exception.winerror)
+
+        self.assertEqual(2, ppst.Release())
+        self.assertEqual(1, ppst.Release())
+        self.assertEqual(0, ppst.Release())
+
+    def test_with_paramflags_and_without_iid(self):
+        class IUnknown(c_void_p):
+            QueryInterface = proto_query_interface(None)
+            AddRef = proto_add_ref()
+            Release = proto_release()
+
+        class IPersist(IUnknown):
+            GetClassID = proto_get_class_id(((OUT, "pClassID"),))
+
+        ppst = self.create_shelllink_persist(IPersist)
+
+        clsid = ppst.GetClassID()
+        self.assertEqual(TRUE, is_equal_guid(CLSID_ShellLink, clsid))
+
+        punk = IUnknown()
+        hr_qi = ppst.QueryInterface(IID_IUnknown, punk)
+        self.assertEqual(S_OK, hr_qi)
+        self.assertEqual(1, punk.Release())
+
+        with self.assertRaises(OSError) as e:
+            ppst.QueryInterface(IID_IStream, IUnknown())
+        self.assertEqual(E_NOINTERFACE, e.exception.winerror)
+
+        self.assertEqual(0, ppst.Release())
+
+    def test_with_paramflags_and_iid(self):
+        class IUnknown(c_void_p):
+            QueryInterface = proto_query_interface(None, IID_IUnknown)
+            AddRef = proto_add_ref()
+            Release = proto_release()
+
+        class IPersist(IUnknown):
+            GetClassID = proto_get_class_id(((OUT, "pClassID"),), IID_IPersist)
+
+        ppst = self.create_shelllink_persist(IPersist)
+
+        clsid = ppst.GetClassID()
+        self.assertEqual(TRUE, is_equal_guid(CLSID_ShellLink, clsid))
+
+        punk = IUnknown()
+        hr_qi = ppst.QueryInterface(IID_IUnknown, punk)
+        self.assertEqual(S_OK, hr_qi)
+        self.assertEqual(1, punk.Release())
+
+        with self.assertRaises(COMError) as e:
+            ppst.QueryInterface(IID_IStream, IUnknown())
+        self.assertEqual(E_NOINTERFACE, e.exception.hresult)
+
+        self.assertEqual(0, ppst.Release())
+
+
+if __name__ == '__main__':
+    unittest.main()