+
+static bool types_match(JobType a, JobType b, JobType c, JobType d) {
+ return
+ (a == c && b == d) ||
+ (a == d && b == c);
+}
+
+int job_type_merge(JobType *a, JobType b) {
+ if (*a == b)
+ return 0;
+
+ /* Merging is associative! a merged with b merged with c is
+ * the same as a merged with c merged with b. */
+
+ /* Mergeability is transitive! if a can be merged with b and b
+ * with c then a also with c */
+
+ /* Also, if a merged with b cannot be merged with c, then
+ * either a or b cannot be merged with c either */
+
+ if (types_match(*a, b, JOB_START, JOB_VERIFY_STARTED))
+ *a = JOB_START;
+ else if (types_match(*a, b, JOB_START, JOB_RELOAD) ||
+ types_match(*a, b, JOB_START, JOB_RELOAD_OR_START) ||
+ types_match(*a, b, JOB_VERIFY_STARTED, JOB_RELOAD_OR_START) ||
+ types_match(*a, b, JOB_RELOAD, JOB_RELOAD_OR_START))
+ *a = JOB_RELOAD_OR_START;
+ else if (types_match(*a, b, JOB_START, JOB_RESTART) ||
+ types_match(*a, b, JOB_START, JOB_TRY_RESTART) ||
+ types_match(*a, b, JOB_VERIFY_STARTED, JOB_RESTART) ||
+ types_match(*a, b, JOB_RELOAD, JOB_RESTART) ||
+ types_match(*a, b, JOB_RELOAD_OR_START, JOB_RESTART) ||
+ types_match(*a, b, JOB_RELOAD_OR_START, JOB_TRY_RESTART) ||
+ types_match(*a, b, JOB_RESTART, JOB_TRY_RESTART))
+ *a = JOB_RESTART;
+ else if (types_match(*a, b, JOB_VERIFY_STARTED, JOB_RELOAD))
+ *a = JOB_RELOAD;
+ else if (types_match(*a, b, JOB_VERIFY_STARTED, JOB_TRY_RESTART) ||
+ types_match(*a, b, JOB_RELOAD, JOB_TRY_RESTART))
+ *a = JOB_TRY_RESTART;
+ else
+ return -EEXIST;
+
+ return 0;
+}
+
+bool job_type_mergeable(JobType a, JobType b) {
+ return job_type_merge(&a, b) >= 0;
+}
+
+bool job_type_is_superset(JobType a, JobType b) {
+
+ /* Checks whether operation a is a "superset" of b */
+
+ if (a == b)
+ return true;
+
+ switch (a) {
+ case JOB_START:
+ return b == JOB_VERIFY_STARTED;
+
+ case JOB_RELOAD:
+ return b == JOB_VERIFY_STARTED;
+
+ case JOB_RELOAD_OR_START:
+ return
+ b == JOB_RELOAD ||
+ b == JOB_START;
+
+ case JOB_RESTART:
+ return
+ b == JOB_START ||
+ b == JOB_VERIFY_STARTED ||
+ b == JOB_RELOAD ||
+ b == JOB_RELOAD_OR_START ||
+ b == JOB_TRY_RESTART;
+
+ case JOB_TRY_RESTART:
+ return
+ b == JOB_VERIFY_STARTED ||
+ b == JOB_RELOAD;
+ default:
+ return false;
+
+ }
+}