From f60c64d528c84395ec1ce4bdd7be878006d864af Mon Sep 17 00:00:00 2001
From: Mark Hammond <mhammond@skippinet.com.au>
Date: Tue, 14 Mar 2006 12:12:44 +0000
Subject: [PATCH] pythoncom.Empty now does what it implies - a Variant with
 VT_EMPTY.  The new pythoncom.ArgNotFound supports the old behaviour (of
 VT_ERROR with DISP_E_PARAMNOTFOUND)

---
 com/win32com/client/genpy.py         |  2 +-
 com/win32com/src/MiscTypes.cpp       | 31 ++++++++++++++++++++++++++++
 com/win32com/src/PythonCOM.cpp       |  4 ++++
 com/win32com/src/include/PythonCOM.h |  7 +++++++
 com/win32com/src/oleargs.cpp         |  8 +++++--
 5 files changed, 49 insertions(+), 3 deletions(-)

diff --git a/com/win32com/client/genpy.py b/com/win32com/client/genpy.py
index 347f61432..d2b64a07e 100644
--- a/com/win32com/client/genpy.py
+++ b/com/win32com/client/genpy.py
@@ -805,7 +805,7 @@ def do_gen_file_header(self):
     print >> self.file, 'from win32com.client import Dispatch'
     print >> self.file
     print >> self.file, '# The following 3 lines may need tweaking for the particular server'
-    print >> self.file, '# Candidates are pythoncom.Missing and pythoncom.Empty'
+    print >> self.file, '# Candidates are pythoncom.Missing, .Empty and .ArgNotFound'
     print >> self.file, 'defaultNamedOptArg=pythoncom.Empty'
     print >> self.file, 'defaultNamedNotOptArg=pythoncom.Empty'
     print >> self.file, 'defaultUnnamedArg=pythoncom.Empty'
diff --git a/com/win32com/src/MiscTypes.cpp b/com/win32com/src/MiscTypes.cpp
index 68088cfb0..f5b3fb469 100644
--- a/com/win32com/src/MiscTypes.cpp
+++ b/com/win32com/src/MiscTypes.cpp
@@ -261,4 +261,35 @@ PYCOM_EXPORT PyTypeObject PyOleMissingType =
 	0,                      /*tp_as_sequence*/
 	0,                      /*tp_as_mapping*/
 };
+/////////////////////////////////////////////////////////////////////////////
+// class PyOleArgNotFound
+PyOleArgNotFound::PyOleArgNotFound()
+{
+	ob_type = &PyOleArgNotFoundType;
+	_Py_NewReference(this);
+}
+
+static void notfound_dealloc(PyOleArgNotFound *o)
+{
+	delete o;
+}
+
+PyTypeObject PyOleArgNotFoundType =
+{
+	PyObject_HEAD_INIT(&PyType_Type)
+	0,
+	"ArgNotFound",
+	sizeof(PyOleArgNotFound),
+	0,
+	(destructor)notfound_dealloc,  /*tp_dealloc*/
+	0,                      /*tp_print*/
+	0,                      /*tp_getattr*/
+	0,                      /*tp_setattr*/
+	0,                      /*tp_compare*/
+	0,                      /*tp_repr*/
+	0,                      /*tp_as_number*/
+	0,                      /*tp_as_sequence*/
+	0,                      /*tp_as_mapping*/
+};
+
 ////////////////////////////////
diff --git a/com/win32com/src/PythonCOM.cpp b/com/win32com/src/PythonCOM.cpp
index 03508da86..be2ad2929 100644
--- a/com/win32com/src/PythonCOM.cpp
+++ b/com/win32com/src/PythonCOM.cpp
@@ -30,6 +30,7 @@ extern PyObject *g_obPyCom_MapInterfaceNameToIID;
 
 static PyObject *g_obEmpty = NULL;
 static PyObject *g_obMissing = NULL;
+static PyObject *g_obArgNotFound = NULL;
 
 PyObject *PyCom_InternalError = NULL;
 
@@ -1818,6 +1819,9 @@ extern "C" __declspec(dllexport) void initpythoncom()
 	g_obMissing = new PyOleMissing;
 	PyDict_SetItemString(dict, "Missing", g_obMissing);
 
+	g_obArgNotFound = new PyOleArgNotFound;
+	PyDict_SetItemString(dict, "ArgNotFound", g_obArgNotFound);
+
 	// Add some symbolic constants to the module   
 	// pycom_Error = PyString_FromString("pythoncom.error");
 	PyObject *pycom_Error = PyWinExc_COMError;
diff --git a/com/win32com/src/include/PythonCOM.h b/com/win32com/src/include/PythonCOM.h
index 29ab4c91e..c5fd3a1a9 100644
--- a/com/win32com/src/include/PythonCOM.h
+++ b/com/win32com/src/include/PythonCOM.h
@@ -221,6 +221,7 @@ class PYCOM_EXPORT PyIBase :
 /* Special Type objects */
 extern PYCOM_EXPORT PyTypeObject PyOleEmptyType;     // equivalent to VT_EMPTY
 extern PYCOM_EXPORT PyTypeObject PyOleMissingType;     // special Python handling.
+extern PYCOM_EXPORT PyTypeObject PyOleArgNotFoundType;     // special VT_ERROR value
 
 // ALL of these set an appropriate Python error on bad return.
 
@@ -395,6 +396,12 @@ class PYCOM_EXPORT PyOleMissing : public PyObject
 	PyOleMissing();
 };
 
+class PYCOM_EXPORT PyOleArgNotFound : public PyObject
+{
+public:
+	PyOleArgNotFound();
+};
+
 // We need to dynamically create C++ Python objects
 // These helpers allow each type object to create it.
 #define MAKE_PYCOM_CTOR(classname) static PyIUnknown * classname::PyObConstruct(IUnknown *pInitObj) {return new classname(pInitObj);}
diff --git a/com/win32com/src/oleargs.cpp b/com/win32com/src/oleargs.cpp
index dac6bfa9c..a8c3679da 100644
--- a/com/win32com/src/oleargs.cpp
+++ b/com/win32com/src/oleargs.cpp
@@ -53,6 +53,7 @@ static PyObject* OleSetTypeErrorW(TCHAR *msg)
 // you need to use the complicated ArgHelpers class for that!
 BOOL PyCom_VariantFromPyObject(PyObject *obj, VARIANT *var)
 {
+	BOOL bGoodEmpty = FALSE; // Set if VT_EMPTY should really be used.
 	V_VT(var) = VT_EMPTY;
 	if ( PyString_Check(obj) || PyUnicode_Check(obj) )
 	{
@@ -131,7 +132,10 @@ BOOL PyCom_VariantFromPyObject(PyObject *obj, VARIANT *var)
 		V_UNKNOWN(var) = PyIUnknown::GetI(obj);
 		V_UNKNOWN(var)->AddRef();
 	}
-	else if (obj->ob_type == &PyOleEmptyType)
+	else if (obj->ob_type == &PyOleEmptyType) {
+		bGoodEmpty = TRUE;
+	}
+	else if (obj->ob_type == &PyOleArgNotFoundType)
 	{
 		// use default parameter
 		// Note the SDK documentation for FUNCDESC describes this behaviour
@@ -185,7 +189,7 @@ BOOL PyCom_VariantFromPyObject(PyObject *obj, VARIANT *var)
 	{
 	}
 	*/
-	if (V_VT(var) == VT_EMPTY) {
+	if (V_VT(var) == VT_EMPTY && !bGoodEmpty) {
 		// Must ensure we have a Python error set if we fail!
 		if (!PyErr_Occurred()) {
 			char *extraMessage = "";