ole: Join the MTA if necessary when executing an RPC call.

dlls/ole32/compobj.c

@@ -422,6 +422,12 @@ static LRESULT CALLBACK apartment_wndproc(HWND hWnd, UINT msg, WPARAM wParam, LP
     }
 }
 
+void apartment_joinmta(void)
+{
+    apartment_addref(MTA);
+    COM_CurrentInfo()->apt = MTA;
+}
+
 /*****************************************************************************
  * This section contains OpenDllList implemantation
  */

dlls/ole32/compobj_private.h

@@ -228,6 +228,7 @@ static inline HRESULT apartment_getoxid(struct apartment *apt, OXID *oxid)
     *oxid = apt->oxid;
     return S_OK;
 }
+void apartment_joinmta(void);
 
 
 /* DCOM messages used by the apartment window (not compatible with native) */

dlls/ole32/rpc.c

@@ -503,7 +503,20 @@ static void __RPC_STUB dispatch_rpc(RPC_MESSAGE *msg)
         CloseHandle(params->handle);
     }
     else
+    {
+        BOOL joined = FALSE;
+        if (!COM_CurrentInfo()->apt)
+        {
+            apartment_joinmta();
+            joined = TRUE;
+        }
         RPC_ExecuteCall(params);
+        if (joined)
+        {
+            apartment_release(COM_CurrentInfo()->apt);
+            COM_CurrentInfo()->apt = NULL;
+        }
+    }
 
     HeapFree(GetProcessHeap(), 0, params);