Christian Couder <chriscool@xxxxxxxxxxxxx> writes:
> This patch implements the logic that process trailers
> from file and arguments.
>
> At the beginning trailers from file are in their own
> infile_tok doubly linked list, and trailers from
> arguments are in their own arg_tok doubly linked list.
>
> The lists are traversed and when an arg_tok should be
> "applied", it is removed from its list and inserted
> into the infile_tok list.
>
> Signed-off-by: Christian Couder <chriscool@xxxxxxxxxxxxx>
> ---
> trailer.c | 187 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 187 insertions(+)
>
> diff --git a/trailer.c b/trailer.c
> index f129b5a..ba0cfe0 100644
> --- a/trailer.c
> +++ b/trailer.c
> @@ -46,3 +46,190 @@ static inline size_t alnum_len(const char *buf, int len)
> while (--len >= 0 && !isalnum(buf[len]));
> return (size_t) len + 1;
> }
> +
> +static void add_arg_to_infile(struct trailer_item *infile_tok,
> + struct trailer_item *arg_tok)
> +{
> + if (arg_tok->conf->where == WHERE_AFTER) {
> + arg_tok->next = infile_tok->next;
> + infile_tok->next = arg_tok;
> + arg_tok->previous = infile_tok;
> + if (arg_tok->next)
> + arg_tok->next->previous = arg_tok;
> + } else {
> + arg_tok->previous = infile_tok->previous;
> + infile_tok->previous = arg_tok;
> + arg_tok->next = infile_tok;
> + if (arg_tok->previous)
> + arg_tok->previous->next = arg_tok;
> + }
> +}
> +
> +static int check_if_different(struct trailer_item *infile_tok,
> + struct trailer_item *arg_tok,
> + int alnum_len, int check_all)
> +{
> + enum action_where where = arg_tok->conf->where;
> + do {
> + if (!infile_tok)
> + return 1;
> + if (same_trailer(infile_tok, arg_tok, alnum_len))
> + return 0;
> + /*
> + * if we want to add a trailer after another one,
> + * we have to check those before this one
> + */
> + infile_tok = (where == WHERE_AFTER) ? infile_tok->previous : infile_tok->next;
> + } while (check_all);
> + return 1;
> +}
> +
> +static void apply_arg_if_exist(struct trailer_item *infile_tok,
> + struct trailer_item *arg_tok,
> + int alnum_len)
> +{
> + switch (arg_tok->conf->if_exist) {
> + case EXIST_DO_NOTHING:
> + free(arg_tok);
> + break;
> + case EXIST_OVERWRITE:
> + free((char *)infile_tok->value);
> + infile_tok->value = xstrdup(arg_tok->value);
> + free(arg_tok);
> + break;
> + case EXIST_ADD:
> + add_arg_to_infile(infile_tok, arg_tok);
> + break;
> + case EXIST_ADD_IF_DIFFERENT:
> + if (check_if_different(infile_tok, arg_tok, alnum_len, 1))
> + add_arg_to_infile(infile_tok, arg_tok);
> + else
> + free(arg_tok);
> + break;
> + case EXIST_ADD_IF_DIFFERENT_NEIGHBOR:
> + if (check_if_different(infile_tok, arg_tok, alnum_len, 0))
> + add_arg_to_infile(infile_tok, arg_tok);
> + else
> + free(arg_tok);
> + break;
Makes me wonder if people want a rule to say "if the same key
already exists, regardless of the value".
> + }
> +}
> +
> +static void remove_from_list(struct trailer_item *item,
> + struct trailer_item **first)
> +{
> + if (item->next)
> + item->next->previous = item->previous;
> + if (item->previous)
> + item->previous->next = item->next;
> + else
> + *first = item->next;
> +}
Will callers free the item that now is not on the list?
> +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 process_infile_tok(struct trailer_item *infile_tok,
> + struct trailer_item **arg_tok_first,
> + enum action_where where)
> +{
> + struct trailer_item *arg_tok;
> + struct trailer_item *next_arg;
> +
> + int tok_alnum_len = alnum_len(infile_tok->token, strlen(infile_tok->token));
> + for (arg_tok = *arg_tok_first; arg_tok; arg_tok = next_arg) {
> + next_arg = arg_tok->next;
> + if (same_token(infile_tok, arg_tok, tok_alnum_len) &&
> + arg_tok->conf->where == where) {
> + remove_from_list(arg_tok, arg_tok_first);
> + apply_arg_if_exist(infile_tok, arg_tok, tok_alnum_len);
> + /*
> + * If arg has been added to infile,
> + * then we need to process it too now.
> + */
> + if ((where == WHERE_AFTER ? infile_tok->next : infile_tok->previous) == arg_tok)
> + infile_tok = arg_tok;
> + }
> + }
> +}
> +
> +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 apply_arg_if_missing(struct trailer_item **infile_tok_first,
> + struct trailer_item **infile_tok_last,
> + struct trailer_item *arg_tok)
> +{
Makes me wonder if it would make the code simpler to keep an anchor
item "struct trailer_item" that is off heap, and pass that single
anchor item around, using its next/prev fields as the first and the
last. Wouldn't it let you remove the special cases for the first
and last item?
> + struct trailer_item **infile_tok;
> + enum action_where where;
> +
> + switch (arg_tok->conf->if_missing) {
> + case MISSING_DO_NOTHING:
> + free(arg_tok);
> + break;
> + case MISSING_ADD:
> + where = arg_tok->conf->where;
> + infile_tok = (where == WHERE_AFTER) ? infile_tok_last : infile_tok_first;
> + if (*infile_tok) {
> + add_arg_to_infile(*infile_tok, arg_tok);
> + *infile_tok = arg_tok;
> + } else {
> + *infile_tok_first = arg_tok;
> + *infile_tok_last = arg_tok;
> + }
> + break;
This piece makes me wonder if "after" is a good name. prepend and
append, perhaps?
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