alpm_list_add always returns the provided list making it impossible for callers to check whether or not the operation actually succeeded without manually comparing the list length before and after. alpm_list_append instead returns a pointer to the newly created list item so that success can be checked. Signed-off-by: Andrew Gregory <andrew.gregory.8@gmail.com> --- lib/libalpm/alpm_list.c | 34 ++++++++++++++++++++++++---------- lib/libalpm/alpm_list.h | 1 + 2 files changed, 25 insertions(+), 10 deletions(-) diff --git a/lib/libalpm/alpm_list.c b/lib/libalpm/alpm_list.c index 62b2843..f3effc7 100644 --- a/lib/libalpm/alpm_list.c +++ b/lib/libalpm/alpm_list.c @@ -93,28 +93,42 @@ void SYMEXPORT alpm_list_free_inner(alpm_list_t *list, alpm_list_fn_free fn) */ alpm_list_t SYMEXPORT *alpm_list_add(alpm_list_t *list, void *data) { - alpm_list_t *ptr, *lp; + alpm_list_append(&list, data); + return list; +} + +/** + * @brief Add a new item to the end of the list. + * + * @param list the list to add to + * @param data the new item to be added to the list + * + * @return the newly added item + */ +alpm_list_t SYMEXPORT *alpm_list_append(alpm_list_t **list, void *data) +{ + alpm_list_t *ptr; ptr = malloc(sizeof(alpm_list_t)); if(ptr == NULL) { - return list; + return NULL; } ptr->data = data; ptr->next = NULL; /* Special case: the input list is empty */ - if(list == NULL) { + if(*list == NULL) { + *list = ptr; ptr->prev = ptr; - return ptr; + } else { + alpm_list_t *lp = alpm_list_last(*list); + lp->next = ptr; + ptr->prev = lp; + (*list)->prev = ptr; } - lp = alpm_list_last(list); - lp->next = ptr; - ptr->prev = lp; - list->prev = ptr; - - return list; + return ptr; } /** diff --git a/lib/libalpm/alpm_list.h b/lib/libalpm/alpm_list.h index 801f4a0..5af84e1 100644 --- a/lib/libalpm/alpm_list.h +++ b/lib/libalpm/alpm_list.h @@ -57,6 +57,7 @@ void alpm_list_free_inner(alpm_list_t *list, alpm_list_fn_free fn); /* item mutators */ alpm_list_t *alpm_list_add(alpm_list_t *list, void *data); +alpm_list_t *alpm_list_append(alpm_list_t **list, void *data); alpm_list_t *alpm_list_add_sorted(alpm_list_t *list, void *data, alpm_list_fn_cmp fn); alpm_list_t *alpm_list_join(alpm_list_t *first, alpm_list_t *second); alpm_list_t *alpm_list_mmerge(alpm_list_t *left, alpm_list_t *right, alpm_list_fn_cmp fn); -- 2.7.0