Issues #276, #1163 - introduce class IncomingParam

src/plugin/COM_Value.cpp

 /**
  * \file COM_Value.cpp Support for the values used in COM and Automation.
  */
 #include "COM_Value.h"
 #include <stdexcept>
 
 using namespace AdblockPlus::COM;
 
 /*
  * MSDN SysAllocStringLen function http://msdn.microsoft.com/en-us/library/windows/desktop/ms221639%28v=vs.85%29.aspx
@@ skipping 44 matching lines @@
 }
 
 BSTR_Argument::operator std::wstring() const
 {
   if (!bstr)
   {
     return std::wstring();
   }
   return std::wstring(bstr, SysStringLen(bstr));
 }
+
+
+bool IncomingParam::wstringConvertible() const
+{
+  /*
+   * Initial support is for BSTR only.
+   * We've got one case later where we'll need to support VT_I4.
+   */
+  return var.vt == VT_BSTR;
+}
+
+std::wstring IncomingParam::wstringValueNoexcept() const
+{
+  return L"";
+}