core: add UNIT_GET_SLICE() helper

In a later commit we intend to move the slice logic to use proper
dependencies instead of a "UnitRef" object. This preparatory commit
drops direct use of the slice UnitRef object for a static inline
function UNIT_GET_SLICE() that is both easier to grok, and allows us to
easily replace its internal implementation later on.

1 files changed, 3 insertions, 6 deletions

diff --git a/src/core/unit-printf.c b/src/core/unit-printf.c
index ee8b0b3de8..113dd1cc8a 100644
--- a/src/core/unit-printf.c
+++ b/src/core/unit-printf.c
@@ -132,18 +132,15 @@ static int specifier_cgroup_root(char specifier, const void *data, const void *u
 }
 
 static int specifier_cgroup_slice(char specifier, const void *data, const void *userdata, char **ret) {
-        const Unit *u = userdata;
+        const Unit *u = userdata, *slice;
         char *n;
 
         assert(u);
 
         bad_specifier(u, specifier);
 
-        if (UNIT_ISSET(u->slice)) {
-                const Unit *slice;
-
-                slice = UNIT_DEREF(u->slice);
-
+        slice = UNIT_GET_SLICE(u);
+        if (slice) {
                 if (slice->cgroup_path)
                         n = strdup(slice->cgroup_path);
                 else