bug fix for issues #293 evdns_base_load_hosts doesn't remove outdated adresses

As mentioned at https://sourceforge.net/p/levent/bugs/293/
 created a small function "evdns_base_flush_outdated_host_addresses" which removes all the previous requests of hosts , if user wants to clean up the list of hosts can call and use this function. 
Requires function declaration to be added in include/event2/dns.h
 Adding it in another patch for the same bug.

1 files changed, 13 insertions, 0 deletions

diff --git a/evdns.c b/evdns.c
index 66a3bff3..04362a32 100644
--- a/evdns.c
+++ b/evdns.c
@@ -4045,6 +4045,19 @@ evdns_base_free(struct evdns_base *base, int fail_requests)
 }
 
 void
+evdns_base_flush_outdated_host_addresses(struct evdns_base *base)
+{
+   	EVDNS_LOCK(base);
+   	struct hosts_entry *victim;
+   	while ((victim = TAILQ_FIRST(&base->hostsdb))) {
+   	TAILQ_REMOVE(&base->hostsdb, victim, next);
+        mm_free(victim);
+   	}
+   	EVDNS_UNLOCK(base);
+   	EVTHREAD_FREE_LOCK(base->lock, EVTHREAD_LOCKTYPE_RECURSIVE);
+}
+
+void
 evdns_shutdown(int fail_requests)
 {
 	if (current_base) {