Function bind_variable

gpcontrib/orafce/dbms_sql.c:500–570

* Calling procedure can be slow, so there is a function alternative */

 * Calling procedure can be slow, so there is a function alternative
 */
static Datum
bind_variable(PG_FUNCTION_ARGS)
{
	CursorData *c;
	VariableData *var;
	char *varname, *varname_downcase;
	Oid			valtype;
	bool		is_unknown = false;

	c = get_cursor(fcinfo, true);

	if (PG_ARGISNULL(1))
		ereport(ERROR,
			    (errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
			     errmsg("name of bind variable is NULL")));

	varname = text_to_cstring(PG_GETARG_TEXT_P(1));
	if (*varname == ':')
		varname += 1;

	varname_downcase = downcase_identifier(varname, (int) strlen(varname), false, true);
	var = get_var(c, varname_downcase, -1, false);

	valtype = get_fn_expr_argtype(fcinfo->flinfo, 2);
	if (valtype == RECORDOID)
		ereport(ERROR,
			    (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
			     errmsg("cannot to bind a value of record type")));

	valtype = getBaseType(valtype);
	if (valtype == UNKNOWNOID)
	{
		is_unknown = true;
		valtype = TEXTOID;
	}

	if (var->typoid != InvalidOid)
	{
		if (!var->typbyval && !var->isnull)
		{
			pfree(DatumGetPointer(var->value));
			var->value = (Datum) 0;
		}

		var->isnull = true;
	}

	var->typoid = valtype;

	if (!PG_ARGISNULL(2))
	{
		MemoryContext	oldcxt;

		get_typlenbyval(var->typoid, &var->typlen, &var->typbyval);

		oldcxt = MemoryContextSwitchTo(c->cursor_cxt);

		if (is_unknown)