core: rename (and modernize) bus_unit_check_load_state() → bus_unit_validate_load_state()

Let's use a switch() statement, cover more cases with pretty messages.
Also let's rename it to "validate", as that's more specific that
"check", as it implies checking for a "valid"/"good" state, which is
what this function does.

4 files changed, 23 insertions, 15 deletions

diff --git a/src/core/dbus-manager.c b/src/core/dbus-manager.c
index f7535e38fc..09daf268b7 100644
--- a/src/core/dbus-manager.c
+++ b/src/core/dbus-manager.c
@@ -610,7 +610,7 @@ static int method_set_unit_properties(sd_bus_message *message, void *userdata, s
         if (r < 0)
                 return r;
 
-        r = bus_unit_check_load_state(u, error);
+        r = bus_unit_validate_load_state(u, error);
         if (r < 0)
                 return r;
 
@@ -634,7 +634,7 @@ static int method_ref_unit(sd_bus_message *message, void *userdata, sd_bus_error
         if (r < 0)
                 return r;
 
-        r = bus_unit_check_load_state(u, error);
+        r = bus_unit_validate_load_state(u, error);
         if (r < 0)
                 return r;
 
@@ -658,7 +658,7 @@ static int method_unref_unit(sd_bus_message *message, void *userdata, sd_bus_err
         if (r < 0)
                 return r;
 
-        r = bus_unit_check_load_state(u, error);
+        r = bus_unit_validate_load_state(u, error);
         if (r < 0)
                 return r;
 
diff --git a/src/core/dbus-unit.c b/src/core/dbus-unit.c
index 150ccc024c..84065ac08c 100644
--- a/src/core/dbus-unit.c
+++ b/src/core/dbus-unit.c
@@ -1712,22 +1712,30 @@ int bus_unit_set_properties(
         return n;
 }
 
-int bus_unit_check_load_state(Unit *u, sd_bus_error *error) {
+int bus_unit_validate_load_state(Unit *u, sd_bus_error *error) {
         assert(u);
 
-        if (u->load_state == UNIT_LOADED)
-                return 0;
+        /* Generates a pretty error if a unit isn't properly loaded. */
 
-        /* Give a better description of the unit error when
-         * possible. Note that in the case of UNIT_MASKED, load_error
-         * is not set. */
-        if (u->load_state == UNIT_MASKED)
-                return sd_bus_error_setf(error, BUS_ERROR_UNIT_MASKED, "Unit %s is masked.", u->id);
+        switch (u->load_state) {
+
+        case UNIT_LOADED:
+                return 0;
 
-        if (u->load_state == UNIT_NOT_FOUND)
+        case UNIT_NOT_FOUND:
                 return sd_bus_error_setf(error, BUS_ERROR_NO_SUCH_UNIT, "Unit %s not found.", u->id);
 
-        return sd_bus_error_set_errnof(error, u->load_error, "Unit %s is not loaded properly: %m.", u->id);
+        case UNIT_ERROR: /* Only show .load_error in UNIT_ERROR state */
+                return sd_bus_error_set_errnof(error, u->load_error, "Unit %s failed to loaded properly: %m.", u->id);
+
+        case UNIT_MASKED:
+                return sd_bus_error_setf(error, BUS_ERROR_UNIT_MASKED, "Unit %s is masked.", u->id);
+
+        case UNIT_STUB:
+        case UNIT_MERGED:
+        default:
+                return sd_bus_error_setf(error, BUS_ERROR_NO_SUCH_UNIT, "Unexpected load state of unit %s", u->id);
+        }
 }
 
 static int bus_unit_track_handler(sd_bus_track *t, void *userdata) {
diff --git a/src/core/dbus-unit.h b/src/core/dbus-unit.h
index 8c55d7dfdf..0c1d44511d 100644
--- a/src/core/dbus-unit.h
+++ b/src/core/dbus-unit.h
@@ -31,7 +31,7 @@ int bus_unit_method_ref(sd_bus_message *message, void *userdata, sd_bus_error *e
 int bus_unit_method_unref(sd_bus_message *message, void *userdata, sd_bus_error *error);
 
 int bus_unit_queue_job(sd_bus_message *message, Unit *u, JobType type, JobMode mode, bool reload_if_possible, sd_bus_error *error);
-int bus_unit_check_load_state(Unit *u, sd_bus_error *error);
+int bus_unit_validate_load_state(Unit *u, sd_bus_error *error);
 
 int bus_unit_track_add_name(Unit *u, const char *name);
 int bus_unit_track_add_sender(Unit *u, sd_bus_message *m);
diff --git a/src/core/transaction.c b/src/core/transaction.c
index 2886a05989..516e5e9a84 100644
--- a/src/core/transaction.c
+++ b/src/core/transaction.c
@@ -910,7 +910,7 @@ int transaction_add_job_and_dependencies(
                 return sd_bus_error_setf(e, BUS_ERROR_LOAD_FAILED, "Unit %s is not loaded properly.", unit->id);
 
         if (type != JOB_STOP) {
-                r = bus_unit_check_load_state(unit, e);
+                r = bus_unit_validate_load_state(unit, e);
                 if (r < 0)
                         return r;
         }