+
+static void free_trailer_item(struct trailer_item *item)
+{
+ free(item->conf.name);
+ free(item->conf.key);
+ free(item->conf.command);
+ free((char *)item->token);
+ free((char *)item->value);
+ free(item);
+}
+
+static void update_last(struct trailer_item **last)
+{
+ if (*last)
+ while ((*last)->next != NULL)
+ *last = (*last)->next;
+}
+
+static void update_first(struct trailer_item **first)
+{
+ if (*first)
+ while ((*first)->previous != NULL)
+ *first = (*first)->previous;
+}
+
+static void add_arg_to_input_list(struct trailer_item *on_tok,
+ struct trailer_item *arg_tok,
+ struct trailer_item **first,
+ struct trailer_item **last)
+{
+ if (after_or_end(arg_tok->conf.where)) {
+ arg_tok->next = on_tok->next;
+ on_tok->next = arg_tok;
+ arg_tok->previous = on_tok;
+ if (arg_tok->next)
+ arg_tok->next->previous = arg_tok;
+ update_last(last);
+ } else {
+ arg_tok->previous = on_tok->previous;
+ on_tok->previous = arg_tok;
+ arg_tok->next = on_tok;
+ if (arg_tok->previous)
+ arg_tok->previous->next = arg_tok;
+ update_first(first);
+ }
+}
+
+static int check_if_different(struct trailer_item *in_tok,
+ struct trailer_item *arg_tok,
+ int check_all)
+{
+ enum action_where where = arg_tok->conf.where;
+ do {
+ if (!in_tok)
+ return 1;
+ if (same_trailer(in_tok, arg_tok))
+ return 0;
+ /*
+ * if we want to add a trailer after another one,
+ * we have to check those before this one
+ */
+ in_tok = after_or_end(where) ? in_tok->previous : in_tok->next;
+ } while (check_all);
+ return 1;
+}
+
+static void remove_from_list(struct trailer_item *item,
+ struct trailer_item **first,
+ struct trailer_item **last)
+{
+ struct trailer_item *next = item->next;
+ struct trailer_item *previous = item->previous;
+
+ if (next) {
+ item->next->previous = previous;
+ item->next = NULL;
+ } else if (last)
+ *last = previous;
+
+ if (previous) {
+ item->previous->next = next;
+ item->previous = NULL;
+ } else if (first)
+ *first = next;
+}
+
+static struct trailer_item *remove_first(struct trailer_item **first)
+{
+ struct trailer_item *item = *first;
+ *first = item->next;
+ if (item->next) {
+ item->next->previous = NULL;
+ item->next = NULL;
+ }
+ return item;
+}
+
+static void apply_arg_if_exists(struct trailer_item *in_tok,
+ struct trailer_item *arg_tok,
+ struct trailer_item *on_tok,
+ struct trailer_item **in_tok_first,
+ struct trailer_item **in_tok_last)
+{
+ switch (arg_tok->conf.if_exists) {
+ case EXISTS_DO_NOTHING:
+ free_trailer_item(arg_tok);
+ break;
+ case EXISTS_REPLACE:
+ add_arg_to_input_list(on_tok, arg_tok,
+ in_tok_first, in_tok_last);
+ remove_from_list(in_tok, in_tok_first, in_tok_last);
+ free_trailer_item(in_tok);
+ break;
+ case EXISTS_ADD:
+ add_arg_to_input_list(on_tok, arg_tok,
+ in_tok_first, in_tok_last);
+ break;
+ case EXISTS_ADD_IF_DIFFERENT:
+ if (check_if_different(in_tok, arg_tok, 1))
+ add_arg_to_input_list(on_tok, arg_tok,
+ in_tok_first, in_tok_last);
+ else
+ free_trailer_item(arg_tok);
+ break;
+ case EXISTS_ADD_IF_DIFFERENT_NEIGHBOR:
+ if (check_if_different(on_tok, arg_tok, 0))
+ add_arg_to_input_list(on_tok, arg_tok,
+ in_tok_first, in_tok_last);
+ else
+ free_trailer_item(arg_tok);
+ break;
+ }
+}
+
+static void apply_arg_if_missing(struct trailer_item **in_tok_first,
+ struct trailer_item **in_tok_last,
+ struct trailer_item *arg_tok)
+{
+ struct trailer_item **in_tok;
+ enum action_where where;
+
+ switch (arg_tok->conf.if_missing) {
+ case MISSING_DO_NOTHING:
+ free_trailer_item(arg_tok);
+ break;
+ case MISSING_ADD:
+ where = arg_tok->conf.where;
+ in_tok = after_or_end(where) ? in_tok_last : in_tok_first;
+ if (*in_tok) {
+ add_arg_to_input_list(*in_tok, arg_tok,
+ in_tok_first, in_tok_last);
+ } else {
+ *in_tok_first = arg_tok;
+ *in_tok_last = arg_tok;
+ }
+ break;
+ }
+}
+
+static int find_same_and_apply_arg(struct trailer_item **in_tok_first,
+ struct trailer_item **in_tok_last,
+ struct trailer_item *arg_tok)
+{
+ struct trailer_item *in_tok;
+ struct trailer_item *on_tok;
+ struct trailer_item *following_tok;
+
+ enum action_where where = arg_tok->conf.where;
+ int middle = (where == WHERE_AFTER) || (where == WHERE_BEFORE);
+ int backwards = after_or_end(where);
+ struct trailer_item *start_tok = backwards ? *in_tok_last : *in_tok_first;
+
+ for (in_tok = start_tok; in_tok; in_tok = following_tok) {
+ following_tok = backwards ? in_tok->previous : in_tok->next;
+ if (!same_token(in_tok, arg_tok))
+ continue;
+ on_tok = middle ? in_tok : start_tok;
+ apply_arg_if_exists(in_tok, arg_tok, on_tok,
+ in_tok_first, in_tok_last);
+ return 1;
+ }
+ return 0;
+}
+
+static void process_trailers_lists(struct trailer_item **in_tok_first,
+ struct trailer_item **in_tok_last,
+ struct trailer_item **arg_tok_first)
+{
+ struct trailer_item *arg_tok;
+ struct trailer_item *next_arg;
+
+ if (!*arg_tok_first)
+ return;
+
+ for (arg_tok = *arg_tok_first; arg_tok; arg_tok = next_arg) {
+ int applied = 0;
+
+ next_arg = arg_tok->next;
+ remove_from_list(arg_tok, arg_tok_first, NULL);
+
+ applied = find_same_and_apply_arg(in_tok_first,
+ in_tok_last,
+ arg_tok);
+
+ if (!applied)
+ apply_arg_if_missing(in_tok_first,
+ in_tok_last,
+ arg_tok);
+ }
+}