On Wed, 2013-08-07 at 13:56 +0200, Lukas Slebodnik wrote:
[..]
nitpicking some more given Lucas nacked.
>+static errno_t ad_sort_servers(struct ares_srv_reply **list,
void *pvt)
>+{
>+ struct ad_srv_plugin_state *state = NULL;
>+ struct ares_srv_reply dummy[3] = {{NULL, NULL, 0, 0, 0}};
I think this can be done by simply writing:
struct ares_srv_reply dummy[3] = { 0 };
>+ struct ares_srv_reply *head = &dummy[0];
>+ struct ares_srv_reply *tail = &dummy[0];
>+ struct ares_srv_reply *in_head = &dummy[1];
>+ struct ares_srv_reply *in_tail = &dummy[1];
>+ struct ares_srv_reply *out_head = &dummy[2];
>+ struct ares_srv_reply *out_tail = &dummy[2];
>+ struct ares_srv_reply *cur = NULL;
>+ struct ares_srv_reply *next = NULL;
>+ const char *domain = NULL;
>+ errno_t ret;
>+
>+ if (list == NULL) {
>+ ret = EINVAL;
>+ goto done;
>+ }
>+
>+ if (*list == NULL || (*list)->next == NULL) {
>+ ret = EOK;
>+ goto done;
>+ }
>+
>+ state = talloc_get_type(pvt, struct ad_srv_plugin_state);
>+ domain = state->discovery_domain;
>+
>+ /* first sort by rfc2782 */
>+ ret = resolv_sort_srv_reply(list);
>+ if (ret != EOK) {
>+ DEBUG(SSSDBG_CRIT_FAILURE, ("resolv_sort_srv_reply() failed "
>+ "[%d]: %s\n", ret, strerror(ret)));
>+ goto done;
>+ }
>+
>+ /* when several servers share priority, prefer the one that is located
>+ * in the same domain as client (e.g. child domain instead of forest
>+ * root) */
>+
>+ next = *list;
>+ do {
>+ cur = next;
>+ next = cur->next;
>+
>+ if (is_host_in_domain(cur->host, domain)) {
>+ in_tail->next = cur;
>+ in_tail = in_tail->next;
>+ in_tail->next = NULL;
>+ } else {
>+ out_tail->next = cur;
>+ out_tail = out_tail->next;
>+ out_tail->next = NULL;
>+ }
>+
>+ if (next == NULL || cur->priority != next->priority) {
>+ /* priority has changed or we have reached the end of the srv list,
>+ * we will merge the lists */
>+ APPEND_ARES_LIST(tail, in_head, in_tail);
>+ APPEND_ARES_LIST(tail, out_head, out_tail);
>+ }
>+ } while (next != NULL);
>+
>+ *list = head->next;
>+
>+ ret = EOK;
>+
>+done:
>+ return ret;
>+}
I am sorry, but this linked list sorting is not very readable.
There is a lot of "struct ares_srv_reply" pointers:
head, tail, in_head, in_tail, out_head, out_tail, cur, next
I tried to visualize this sorting with pencil and paper, but
it was a real mess.
I would prefer to:
either: use similar approach like in reply_priority_sort
from file src/resolv/async_resolv.c (merger-sort)
or: don't change this function, but unit test should be written for this
function
Why not simply make this a doubly linked list and use the functions in
src/util/dlinklist.h ?
Or if you really have to use single linked, maybe add a slinklist.h file
in util/ that does things as much as possible like dlinklist.h so that
we use the same style.
Simo.
--
Simo Sorce * Red Hat, Inc * New York