[_comobject.py] Use WinDLL instead of oledll/windll

Partially fix enthought#735

comtypes/_comobject.py

@@ -5,13 +5,14 @@
     POINTER,
     FormatError,
     Structure,
+    WinDLL,
     byref,
     c_long,
     c_void_p,
-    oledll,
-    pointer,
-    windll,
+    c_wchar_p,
+    pointer
 )
+from ctypes.wintypes import INT, LONG, LPVOID, UINT, ULONG, WORD
 from typing import (
     TYPE_CHECKING,
     Any,
@@ -29,6 +30,7 @@
 
 from comtypes import GUID, IPersist, IUnknown, hresult
 from comtypes._vtbl import _MethodFinder, create_dispimpl, create_vtbl_mapping
+from comtypes.automation import DISPID, DISPPARAMS, EXCEPINFO, VARIANT
 from comtypes.errorinfo import ISupportErrorInfo
 from comtypes.typeinfo import IProvideClassInfo, IProvideClassInfo2, ITypeInfo
 
@@ -51,9 +53,10 @@
 
 ################################################################
 
+_kernel32 = WinDLL("kernel32")
 try:
-    _InterlockedIncrement = windll.kernel32.InterlockedIncrement
-    _InterlockedDecrement = windll.kernel32.InterlockedDecrement
+    _InterlockedIncrement = _kernel32.InterlockedIncrement
+    _InterlockedDecrement = _kernel32.InterlockedDecrement
 except AttributeError:
     import threading
 
@@ -82,14 +85,47 @@ def _InterlockedDecrement(ob: c_long) -> int:
     _InterlockedIncrement.restype = c_long
     _InterlockedDecrement.restype = c_long
 
+_oleaut32 = WinDLL("oleaut32")
+
+_DispGetIDsOfNames = _oleaut32.DispGetIDsOfNames
+_DispGetIDsOfNames.argtypes = [POINTER(ITypeInfo), POINTER(c_wchar_p), UINT, POINTER(DISPID)]
+_DispGetIDsOfNames.restype = LONG # technically, it is a HRESULT, but we want to avoid the OSError
+
+_DispInvoke = _oleaut32.DispInvoke
+_DispInvoke.argtypes = [LPVOID, POINTER(ITypeInfo), DISPID, WORD, POINTER(DISPPARAMS), POINTER(VARIANT), POINTER(EXCEPINFO), POINTER(UINT)]
+_DispInvoke.restype = LONG # technically, it is a HRESULT, but we want to avoid the OSError
+
+
+_ole32 = WinDLL("ole32")
+
+_CoInitialize = _ole32.CoInitialize
+_CoInitialize.argtypes = [LPVOID]
+_CoInitialize.restype = LONG # technically, it is a HRESULT, but we want to avoid the OSError
+
+_CoUninitialize = _ole32.CoUninitialize
+_CoUninitialize.argtypes = []
+_CoUninitialize.restype = None
+
+_CoAddRefServerProcess = _ole32.CoAddRefServerProcess
+_CoAddRefServerProcess.argtypes = []
+_CoAddRefServerProcess.restype = ULONG
+
+_CoReleaseServerProcess = _ole32.CoReleaseServerProcess
+_CoReleaseServerProcess.argtypes = []
+_CoReleaseServerProcess.restype = ULONG
+
+
+_user32 = WinDLL("user32")
+
+_PostQuitMessage = _user32.PostQuitMessage
+_PostQuitMessage.argtypes = [INT]
+_PostQuitMessage.restype = None
 
 class LocalServer(object):
     _queue: Optional[queue.Queue] = None
 
     def run(self, classobjects: Sequence["hints.localserver.ClassFactory"]) -> None:
-        # Use windll instead of oledll so that we don't get an
-        # exception on a FAILED hresult:
-        hr = windll.ole32.CoInitialize(None)
+        hr = _CoInitialize(None)
         if hresult.RPC_E_CHANGED_MODE == hr:
             # we're running in MTA: no message pump needed
             _debug("Server running in MTA")
@@ -100,7 +136,7 @@ def run(self, classobjects: Sequence["hints.localserver.ClassFactory"]) -> None:
             if hr >= 0:
                 # we need a matching CoUninitialize() call for a successful
                 # CoInitialize().
-                windll.ole32.CoUninitialize()
+                _CoUninitialize()
             self.run_sta()
 
         for obj in classobjects:
@@ -116,15 +152,15 @@ def run_mta(self) -> None:
         self._queue.get()
 
     def Lock(self) -> None:
-        oledll.ole32.CoAddRefServerProcess()
+        _CoAddRefServerProcess()
 
     def Unlock(self) -> None:
-        rc = oledll.ole32.CoReleaseServerProcess()
+        rc = _CoReleaseServerProcess()
         if rc == 0:
             if self._queue:
                 self._queue.put(42)
             else:
-                windll.user32.PostQuitMessage(0)
+                _PostQuitMessage(0)
 
 
 class InprocServer(object):
@@ -401,7 +437,7 @@ def IDispatch_GetIDsOfNames(self, this, riid, rgszNames, cNames, lcid, rgDispId)
             tinfo = self.__typeinfo
         except AttributeError:
             return hresult.E_NOTIMPL
-        return windll.oleaut32.DispGetIDsOfNames(tinfo, rgszNames, cNames, rgDispId)
+        return _DispGetIDsOfNames(tinfo, rgszNames, cNames, rgDispId)
 
     def IDispatch_Invoke(
         self,
@@ -432,7 +468,7 @@ def IDispatch_Invoke(
             # an error.
             interface = self._com_interfaces_[0]
             ptr = self._com_pointers_[interface._iid_]
-            return windll.oleaut32.DispInvoke(
+            return _DispInvoke(
                 ptr,
                 tinfo,
                 dispIdMember,