Prune old hostcache entries with each call...

This can be optimized a tidbit, but this is a start.

lib/hash.c

@@ -249,6 +249,26 @@ curl_hash_clean(curl_hash *h)
 }
 /* }}} */
 
+/* {{{ void curl_hash_clean_with_criterium (curl_hash *, void *, int (*)(void *, void *))
+ */
+void
+curl_hash_clean_with_criterium(curl_hash *h, void *user, int (*comp)(void *, void *))
+{
+  curl_llist_element *le;
+  int i;
+
+  for (i = 0; i < h->slots; ++i) {
+    for (le = CURL_LLIST_HEAD(h->table[i]);
+         le != NULL;
+         le = CURL_LLIST_NEXT(le)) {
+      if (comp(user, ((curl_hash_element *) CURL_LLIST_VALP(le))->ptr)) {
+        curl_llist_remove(h->table[i], le, (void *) h);
+        --h->size;
+      }
+    }
+  }
+}
+
 /* {{{ int curl_hash_count (curl_hash *)
  */
 int 

lib/hash.h

@@ -53,6 +53,7 @@ int curl_hash_find(curl_hash *, char *, size_t, void **p);
 void curl_hash_apply(curl_hash *h, void *user, void (*cb)(void *, curl_hash_element *));
 int curl_hash_count(curl_hash *h);
 void curl_hash_clean(curl_hash *h);
+void curl_hash_clean_with_criterium(curl_hash *h, void *user, int (*comp)(void *, void *));
 void curl_hash_destroy(curl_hash *h);
 
 #define curl_hash_update curl_hash_add

lib/hostip.c

@@ -152,6 +152,38 @@ _create_hostcache_id(char *server, int port, ssize_t *entry_len)
   return id;
 }
 
+struct _curl_hostcache_prune_data {
+  int cache_timeout;
+  int now;
+};
+
+static int
+_curl_hostcache_timestamp_remove(void *datap, void *hc)
+{
+  struct _curl_hostcache_prune_data *data = 
+    (struct _curl_hostcache_prune_data *) datap;
+  struct curl_dns_cache_entry *c = (struct curl_dns_cache_entry *) hc;
+  
+  if (data->now - c->timestamp < data->cache_timeout) {
+    return 0;
+  }
+  
+  return 1;
+}
+
+static void
+_curl_hostcache_prune(curl_hash *hostcache, int cache_timeout, int now)
+{
+  struct _curl_hostcache_prune_data user;
+
+  user.cache_timeout = cache_timeout;
+  user.now = now;
+  
+  curl_hash_clean_with_criterium(hostcache, 
+                                 (void *) &user, 
+                                 _curl_hostcache_timestamp_remove);
+}
+
 /* Macro to save redundant free'ing of entry_id */
 #define _hostcache_return(__v) \
 { \
@@ -175,6 +207,13 @@ Curl_addrinfo *Curl_resolv(struct SessionHandle *data,
     return Curl_getaddrinfo(data, hostname, port, bufp);
   }
 
+  time(&now);
+
+  /* Remove outdated entries from the hostcache */
+  _curl_hostcache_prune(data->hostcache, 
+                        data->set.dns_cache_timeout, 
+                        now);
+
   /* Create an entry id, based upon the hostname and port */
   entry_len = strlen(hostname);
   entry_id = _create_hostcache_id(hostname, port, &entry_len);
@@ -184,20 +223,10 @@ Curl_addrinfo *Curl_resolv(struct SessionHandle *data,
     return Curl_getaddrinfo(data, hostname, port, bufp);
   }
   
-  time(&now);
   /* See if its already in our dns cache */
   if (entry_id && curl_hash_find(data->hostcache, entry_id, entry_len+1, (void **) &p)) {
-    /* Do we need to check for a cache timeout? */
-    if (data->set.dns_cache_timeout != -1) {
-      /* Return if the entry has not timed out */
-      if ((now - p->timestamp) < data->set.dns_cache_timeout) {
     _hostcache_return(p->addr);
   }
-    }
-    else {
-      _hostcache_return(p->addr);
-    }
-  }
 
   /* Create a new cache entry */
   p = (struct curl_dns_cache_entry *) malloc(sizeof(struct curl_dns_cache_entry));