+static int dns_cache_init(DnsCache *c) {
+ int r;
+
+ assert(c);
+
+ r = prioq_ensure_allocated(&c->by_expiry, dns_cache_item_prioq_compare_func);
+ if (r < 0)
+ return r;
+
+ r = hashmap_ensure_allocated(&c->by_key, &dns_resource_key_hash_ops);
+ if (r < 0)
+ return r;
+
+ return r;
+}
+
+static int dns_cache_link_item(DnsCache *c, DnsCacheItem *i) {
+ DnsCacheItem *first;
+ int r;
+
+ assert(c);
+ assert(i);
+
+ r = prioq_put(c->by_expiry, i, &i->prioq_idx);
+ if (r < 0)
+ return r;
+
+ first = hashmap_get(c->by_key, i->key);
+ if (first) {
+ LIST_PREPEND(by_key, first, i);
+ assert_se(hashmap_replace(c->by_key, first->key, first) >= 0);
+ } else {
+ r = hashmap_put(c->by_key, i->key, i);
+ if (r < 0) {
+ prioq_remove(c->by_expiry, i, &i->prioq_idx);
+ return r;
+ }
+ }
+
+ return 0;
+}
+
+static DnsCacheItem* dns_cache_get(DnsCache *c, DnsResourceRecord *rr) {
+ DnsCacheItem *i;
+
+ assert(c);
+ assert(rr);
+
+ LIST_FOREACH(by_key, i, hashmap_get(c->by_key, rr->key))
+ if (i->rr && dns_resource_record_equal(i->rr, rr) > 0)
+ return i;
+
+ return NULL;
+}
+
+static void dns_cache_item_update_positive(DnsCache *c, DnsCacheItem *i, DnsResourceRecord *rr, usec_t timestamp) {