hashmap: introduce hash_ops to make struct Hashmap smaller

It is redundant to store 'hash' and 'compare' function pointers in
struct Hashmap separately. The functions always comprise a pair.
Store a single pointer to struct hash_ops instead.

systemd keeps hundreds of hashmaps, so this saves a little bit of
memory.

6 files changed, 15 insertions, 10 deletions

diff --git a/src/libsystemd/sd-bus/bus-match.c b/src/libsystemd/sd-bus/bus-match.c
index 88b61a75be..18afe0f12a 100644
--- a/src/libsystemd/sd-bus/bus-match.c
+++ b/src/libsystemd/sd-bus/bus-match.c
@@ -450,13 +450,13 @@ static int bus_match_add_compare_value(
                 where->child = c;
 
                 if (t == BUS_MATCH_MESSAGE_TYPE) {
-                        c->compare.children = hashmap_new(trivial_hash_func, trivial_compare_func);
+                        c->compare.children = hashmap_new(NULL);
                         if (!c->compare.children) {
                                 r = -ENOMEM;
                                 goto fail;
                         }
                 } else if (BUS_MATCH_CAN_HASH(t)) {
-                        c->compare.children = hashmap_new(string_hash_func, string_compare_func);
+                        c->compare.children = hashmap_new(&string_hash_ops);
                         if (!c->compare.children) {
                                 r = -ENOMEM;
                                 goto fail;
diff --git a/src/libsystemd/sd-bus/bus-objects.c b/src/libsystemd/sd-bus/bus-objects.c
index 3a2de6520e..81c840f129 100644
--- a/src/libsystemd/sd-bus/bus-objects.c
+++ b/src/libsystemd/sd-bus/bus-objects.c
@@ -225,7 +225,7 @@ static int get_child_nodes(
         assert(n);
         assert(_s);
 
-        s = set_new(string_hash_func, string_compare_func);
+        s = set_new(&string_hash_ops);
         if (!s)
                 return -ENOMEM;
 
@@ -1420,7 +1420,7 @@ static struct node *bus_node_allocate(sd_bus *bus, const char *path) {
         if (n)
                 return n;
 
-        r = hashmap_ensure_allocated(&bus->nodes, string_hash_func, string_compare_func);
+        r = hashmap_ensure_allocated(&bus->nodes, &string_hash_ops);
         if (r < 0)
                 return NULL;
 
@@ -1590,6 +1590,11 @@ static int vtable_member_compare_func(const void *a, const void *b) {
         return strcmp(x->member, y->member);
 }
 
+static const struct hash_ops vtable_member_hash_ops = {
+        .hash = vtable_member_hash_func,
+        .compare = vtable_member_compare_func
+};
+
 static int add_object_vtable_internal(
                 sd_bus *bus,
                 sd_bus_slot **slot,
@@ -1618,11 +1623,11 @@ static int add_object_vtable_internal(
                       !streq(interface, "org.freedesktop.DBus.Peer") &&
                       !streq(interface, "org.freedesktop.DBus.ObjectManager"), -EINVAL);
 
-        r = hashmap_ensure_allocated(&bus->vtable_methods, vtable_member_hash_func, vtable_member_compare_func);
+        r = hashmap_ensure_allocated(&bus->vtable_methods, &vtable_member_hash_ops);
         if (r < 0)
                 return r;
 
-        r = hashmap_ensure_allocated(&bus->vtable_properties, vtable_member_hash_func, vtable_member_compare_func);
+        r = hashmap_ensure_allocated(&bus->vtable_properties, &vtable_member_hash_ops);
         if (r < 0)
                 return r;
 
diff --git a/src/libsystemd/sd-bus/bus-track.c b/src/libsystemd/sd-bus/bus-track.c
index ffa2cf3d75..0a3322a4ee 100644
--- a/src/libsystemd/sd-bus/bus-track.c
+++ b/src/libsystemd/sd-bus/bus-track.c
@@ -166,7 +166,7 @@ _public_ int sd_bus_track_add_name(sd_bus_track *track, const char *name) {
         assert_return(track, -EINVAL);
         assert_return(service_name_is_valid(name), -EINVAL);
 
-        r = hashmap_ensure_allocated(&track->names, string_hash_func, string_compare_func);
+        r = hashmap_ensure_allocated(&track->names, &string_hash_ops);
         if (r < 0)
                 return r;
 
diff --git a/src/libsystemd/sd-bus/bus-util.c b/src/libsystemd/sd-bus/bus-util.c
index a85d36180e..7c6da60cca 100644
--- a/src/libsystemd/sd-bus/bus-util.c
+++ b/src/libsystemd/sd-bus/bus-util.c
@@ -399,7 +399,7 @@ int bus_verify_polkit_async(
         if (!sender)
                 return -EBADMSG;
 
-        r = hashmap_ensure_allocated(registry, trivial_hash_func, trivial_compare_func);
+        r = hashmap_ensure_allocated(registry, NULL);
         if (r < 0)
                 return r;
 
diff --git a/src/libsystemd/sd-bus/busctl.c b/src/libsystemd/sd-bus/busctl.c
index af71804410..f06b74505b 100644
--- a/src/libsystemd/sd-bus/busctl.c
+++ b/src/libsystemd/sd-bus/busctl.c
@@ -76,7 +76,7 @@ static int list_bus_names(sd_bus *bus, char **argv) {
 
         pager_open_if_enabled();
 
-        names = hashmap_new(string_hash_func, string_compare_func);
+        names = hashmap_new(&string_hash_ops);
         if (!names)
                 return log_oom();
 
diff --git a/src/libsystemd/sd-bus/sd-bus.c b/src/libsystemd/sd-bus/sd-bus.c
index 83b3aa1c3c..33b65aba72 100644
--- a/src/libsystemd/sd-bus/sd-bus.c
+++ b/src/libsystemd/sd-bus/sd-bus.c
@@ -1756,7 +1756,7 @@ _public_ int sd_bus_call_async(
         if (!BUS_IS_OPEN(bus->state))
                 return -ENOTCONN;
 
-        r = hashmap_ensure_allocated(&bus->reply_callbacks, uint64_hash_func, uint64_compare_func);
+        r = hashmap_ensure_allocated(&bus->reply_callbacks, &uint64_hash_ops);
         if (r < 0)
                 return r;