Implement record pointers as [in, out] method parameters of a Dispatch Interface (#2310)

* Implement record pointers as method parameters of a Dispatch Interface
to get server side modifications of a record marshaled back to the client.

* Added a untitest for record pointers as [ in, out ] method parameters.

Author: geppi

com/TestSources/PyCOMTest/PyCOMImpl.cpp

@@ -618,6 +618,14 @@ HRESULT CPyCOMTest::GetStruct(TestStruct1 *ret)
     *ret = r;
     return S_OK;
 }
+
+HRESULT CPyCOMTest::ModifyStruct(TestStruct1 *prec)
+{
+    prec->int_value = 100;
+    prec->str_value = SysAllocString(L"Nothing is as constant as change");
+    return S_OK;
+}
+
 HRESULT CPyCOMTest::DoubleString(BSTR in, BSTR *out)
 {
     *out = SysAllocStringLen(NULL, SysStringLen(in) * 2);

com/TestSources/PyCOMTest/PyCOMImpl.h

@@ -119,6 +119,8 @@ class CPyCOMTest : public IDispatchImpl<IPyCOMTest, &IID_IPyCOMTest, &LIBID_PyCO
     STDMETHOD(None)();
     STDMETHOD(def)();
 
+    STDMETHOD(ModifyStruct)(TestStruct1 *prec);
+
     // info associated to each session
     struct PyCOMTestSessionData {
         IStream *pStream;  // Stream for marshalling the data to the new thread.

com/TestSources/PyCOMTest/PyCOMTest.idl

@@ -293,6 +293,8 @@ library PyCOMTestLib
 		// reserved words etc
 		HRESULT None();
 		HRESULT def();
+        // Test struct byref as [ in, out ] parameter.
+        HRESULT ModifyStruct([ in, out ] TestStruct1 * prec);
 	};
 
 	// Define a new class to test how Python handles derived interfaces!

com/win32com/client/build.py

@@ -548,7 +548,6 @@ def _ResolveType(typerepr, itypeinfo):
             if was_user and subrepr in [
                 pythoncom.VT_DISPATCH,
                 pythoncom.VT_UNKNOWN,
-                pythoncom.VT_RECORD,
             ]:
                 # Drop the VT_PTR indirection
                 return subrepr, sub_clsid, sub_doc

com/win32com/src/oleargs.cpp

@@ -1572,6 +1572,7 @@ BOOL PythonOleArgHelper::MakeObjToVariant(PyObject *obj, VARIANT *var, PyObject
             // Nothing else to do - the code below sets the VT up correctly.
             break;
         case VT_RECORD:
+		case VT_RECORD | VT_BYREF:
             rc = PyObject_AsVARIANTRecordInfo(obj, var);
             break;
         case VT_CY:

com/win32com/test/testPyComTest.py

@@ -198,6 +198,18 @@ def TestCommon(o, is_generated):
     progress("Checking structs")
     r = o.GetStruct()
     assert r.int_value == 99 and str(r.str_value) == "Hello from C++"
+    # Dynamic does not support struct byref as [ in, out ] parameters
+    if hasattr(o, "CLSID"):
+        progress("Checking struct byref as [ in, out ] parameter")
+        mod_r = o.ModifyStruct(r)
+        # We expect the input value to stay unchanged
+        assert r.int_value == 99 and str(r.str_value) == "Hello from C++"
+        # and the return value to reflect the modifications performed on the COM server side
+        assert (
+            mod_r.int_value == 100
+            and str(mod_r.str_value) == "Nothing is as constant as change"
+        )
+
     assert o.DoubleString("foo") == "foofoo"
 
     progress("Checking var args")