hostip: fix unintended destruction of hash table

.. and added unit1602 for hash.c

lib/conncache.c

@@ -126,7 +126,7 @@ int Curl_conncache_init(struct conncache *connc, int size)
 void Curl_conncache_destroy(struct conncache *connc)
 {
   if(connc)
-    Curl_hash_clean(&connc->hash);
+    Curl_hash_destroy(&connc->hash);
 }
 
 /* returns an allocated key to find a bundle for this connection */

lib/hash.c

@@ -212,8 +212,11 @@ Curl_hash_apply(curl_hash *h, void *user,
 }
 #endif
 
+/* Destroys all the entries in the given hash and resets its attributes,
+ * prepping the given hash for [static|dynamic] deallocation.
+ */
 void
-Curl_hash_clean(struct curl_hash *h)
+Curl_hash_destroy(struct curl_hash *h)
 {
   int i;
 
@@ -227,6 +230,17 @@ Curl_hash_clean(struct curl_hash *h)
   h->slots = 0;
 }
 
+/* Removes all the entries in the given hash.
+ *
+ * @unittest: 1602
+ */
+void
+Curl_hash_clean(struct curl_hash *h)
+{
+  Curl_hash_clean_with_criterium(h, NULL, NULL);
+}
+
+/* Cleans all entries that pass the comp function criteria. */
 void
 Curl_hash_clean_with_criterium(struct curl_hash *h, void *user,
                                int (*comp)(void *, void *))
@@ -246,7 +260,7 @@ Curl_hash_clean_with_criterium(struct curl_hash *h, void *user,
       struct curl_hash_element *he = le->ptr;
       lnext = le->next;
       /* ask the callback function if we shall remove this entry or not */
-      if(comp(user, he->ptr)) {
+      if(comp == NULL || comp(user, he->ptr)) {
         Curl_llist_remove(list, le, (void *) h);
         --h->size; /* one less entry in the hash now */
       }

lib/hash.h

@@ -80,6 +80,7 @@ void *Curl_hash_pick(struct curl_hash *, void * key, size_t key_len);
 void Curl_hash_apply(struct curl_hash *h, void *user,
                      void (*cb)(void *user, void *ptr));
 int Curl_hash_count(struct curl_hash *h);
+void Curl_hash_destroy(struct curl_hash *h);
 void Curl_hash_clean(struct curl_hash *h);
 void Curl_hash_clean_with_criterium(struct curl_hash *h, void *user,
                                     int (*comp)(void *, void *));

lib/hostip.c

@@ -137,7 +137,7 @@ struct curl_hash *Curl_global_host_cache_init(void)
 void Curl_global_host_cache_dtor(void)
 {
   if(host_cache_initialized) {
-    Curl_hash_clean(&hostname_cache);
+    Curl_hash_destroy(&hostname_cache);
     host_cache_initialized = 0;
   }
 }

lib/multi.c

@@ -324,8 +324,8 @@ struct Curl_multi *Curl_multi_handle(int hashsize, /* socket hash */
 
   error:
 
-  Curl_hash_clean(&multi->sockhash);
-  Curl_hash_clean(&multi->hostcache);
+  Curl_hash_destroy(&multi->sockhash);
+  Curl_hash_destroy(&multi->hostcache);
   Curl_conncache_destroy(&multi->conn_cache);
   Curl_close(multi->closure_handle);
   multi->closure_handle = NULL;
@@ -1874,7 +1874,7 @@ CURLMcode curl_multi_cleanup(CURLM *multi_handle)
       Curl_close(multi->closure_handle);
     }
 
-    Curl_hash_clean(&multi->sockhash);
+    Curl_hash_destroy(&multi->sockhash);
     Curl_conncache_destroy(&multi->conn_cache);
     Curl_llist_destroy(multi->msglist, NULL);
     Curl_llist_destroy(multi->pending, NULL);
@@ -1897,7 +1897,7 @@ CURLMcode curl_multi_cleanup(CURLM *multi_handle)
       data = nextdata;
     }
 
-    Curl_hash_clean(&multi->hostcache);
+    Curl_hash_destroy(&multi->hostcache);
 
     /* Free the blacklists by setting them to NULL */
     Curl_pipeline_set_site_blacklist(NULL, &multi->pipelining_site_bl);

lib/share.c

@@ -188,7 +188,7 @@ curl_share_cleanup(CURLSH *sh)
     return CURLSHE_IN_USE;
   }
 
-  Curl_hash_clean(&share->hostcache);
+  Curl_hash_destroy(&share->hostcache);
 
 #if !defined(CURL_DISABLE_HTTP) && !defined(CURL_DISABLE_COOKIES)
   Curl_cookie_cleanup(share->cookies);