filterx: regexp_subst auto-enable 'nogroups' when no match groups are…

… present

The function now automatically checks the replacement pattern at config
parsing time. If no match group references are found in the pattern, it
will behave as if the 'nogroups' option is enabled, disabling match group
functionality for performance reasons.

Signed-off-by: shifter <[email protected]>

lib/filterx/expr-regexp-subst.c

@@ -295,6 +295,13 @@ _extract_optional_flags(FilterXFuncRegexpSubst *self, FilterXFunctionArgs *args,
   return TRUE;
 }
 
+static gboolean
+_contains_match_grp_ref(gchar *str)
+{
+  gchar *close = NULL;
+  return _next_matchgrp_ref(str, &close) != NULL;
+}
+
 static gboolean
 _extract_subst_args(FilterXFuncRegexpSubst *self, FilterXFunctionArgs *args, GError **error)
 {
@@ -366,7 +373,8 @@ filterx_function_regexp_subst_new(FilterXFunctionArgs *args, GError **error)
   self->super.super.deinit = _subst_deinit;
   self->super.super.free_fn = _subst_free;
 
-  reset_flags(&self->flags, FLAG_VAL(FILTERX_FUNC_REGEXP_SUBST_FLAG_JIT));
+  reset_flags(&self->flags, FLAG_VAL(FILTERX_FUNC_REGEXP_SUBST_FLAG_JIT) | FLAG_VAL(
+                FILTERX_FUNC_REGEXP_SUBST_FLAG_GROUPS));
   if (!_extract_subst_args(self, args, error) ||
       !filterx_function_args_check(args, error))
     goto error;