resolved: optionally, allocate DnsResourceKey objects on the stack

Sometimes when looking up entries in hashmaps indexed by a
DnsResourceKey it is helpful not having to allocate a full
DnsResourceKey dynamically just to use it as search key. Instead,
optionally allow allocation of a DnsResourceKey on the stack. Resource
keys allocated like that of course are subject to other lifetime cycles
than the usual Resource keys, hence initialize the reference counter to
to (unsigned) -1.

While we are at it, remove the prototype for
dns_resource_key_new_dname() which was never implemented.

1 files changed, 5 insertions, 6 deletions

diff --git a/src/resolve/resolved-dns-rr.c b/src/resolve/resolved-dns-rr.c
index 281e228b12..b109934d3a 100644
--- a/src/resolve/resolved-dns-rr.c
+++ b/src/resolve/resolved-dns-rr.c
@@ -51,12 +51,6 @@ DnsResourceKey* dns_resource_key_new(uint16_t class, uint16_t type, const char *
         return k;
 }
 
-DnsResourceKey* dns_resource_key_new_cname(const DnsResourceKey *key) {
-        assert(key);
-
-        return dns_resource_key_new(key->class, DNS_TYPE_CNAME, DNS_RESOURCE_KEY_NAME(key));
-}
-
 DnsResourceKey* dns_resource_key_new_redirect(const DnsResourceKey *key, const DnsResourceRecord *cname) {
         int r;
 
@@ -137,6 +131,10 @@ DnsResourceKey* dns_resource_key_ref(DnsResourceKey *k) {
         if (!k)
                 return NULL;
 
+        /* Static/const keys created with DNS_RESOURCE_KEY_CONST will
+         * set this to -1, they should not be reffed/unreffed */
+        assert(k->n_ref != (unsigned) -1);
+
         assert(k->n_ref > 0);
         k->n_ref++;
 
@@ -147,6 +145,7 @@ DnsResourceKey* dns_resource_key_unref(DnsResourceKey *k) {
         if (!k)
                 return NULL;
 
+        assert(k->n_ref != (unsigned) -1);
         assert(k->n_ref > 0);
 
         if (k->n_ref == 1) {