chiark / gitweb /
make sure impact of transactions is minimized
[elogind.git] / job.c
diff --git a/job.c b/job.c
index 2cf8be5330687bb8c18bbd9d03ac30269e3efa6f..d22ce19ee13490604d63fdb78e4cfb952a18061b 100644 (file)
--- a/job.c
+++ b/job.c
@@ -1,6 +1,7 @@
 /*-*- Mode: C; c-basic-offset: 8 -*-*/
 
 #include <assert.h>
+#include <errno.h>
 
 #include "macro.h"
 #include "job.h"
@@ -20,59 +21,134 @@ Job* job_new(Manager *m, JobType type, Name *name) {
         j->type = type;
         j->name = name;
 
-        /* We don't link it here, that's what job_link() is for */
+        /* We don't link it here, that's what job_dependency() is for */
 
         return j;
 }
 
-int job_link(Job *j) {
-        int r;
-
+void job_free(Job *j) {
         assert(j);
-        assert(!j->linked);
 
-        if ((r = hashmap_put(j->manager->jobs, UINT32_TO_PTR(j->id), j)) < 0)
-                return r;
+        /* Detach from next 'bigger' objects */
+
+        if (j->linked) {
+                if (j->name->meta.job == j)
+                        j->name->meta.job = NULL;
 
-        j->name->meta.job = j;
+                hashmap_remove(j->manager->jobs, UINT32_TO_PTR(j->id));
+        }
 
-        j->linked = true;
+        manager_transaction_unlink_job(j->manager, j);
 
-        return 0;
+        free(j);
 }
 
-void job_free(Job *j) {
-        assert(j);
+JobDependency* job_dependency_new(Job *subject, Job *object, bool matters) {
+        JobDependency *l;
 
-        /* Detach from next 'bigger' objects */
+        assert(object);
 
-        if (j->linked) {
-                assert(j->name);
-                assert(j->name->meta.job == j);
-                j->name->meta.job = NULL;
+        /* Adds a new job link, which encodes that the 'subject' job
+         * needs the 'object' job in some way. If 'subject' is NULL
+         * this means the 'anchor' job (i.e. the one the user
+         * explcitily asked for) is the requester. */
 
-                hashmap_remove(j->manager->jobs, UINT32_TO_PTR(j->id));
+        if (!(l = new0(JobDependency, 1)))
+                return NULL;
+
+        l->subject = subject;
+        l->object = object;
+        l->matters = matters;
+
+        if (subject) {
+                l->subject_next = subject->subject_list;
+                subject->subject_list = l;
+        } else {
+                l->subject_next = object->manager->transaction_anchor;
+                object->manager->transaction_anchor = l;
         }
 
-        hashmap_remove(j->manager->jobs_to_add, j->name);
-        set_remove(j->manager->jobs_to_remove, j);
+        if (l->subject_next)
+                l->subject_next->subject_prev = l;
+        l->subject_prev = NULL;
 
-        /* Free data and next 'smaller' objects */
-        free(j);
+        if ((l->object_next = object->object_list))
+                l->object_next->object_prev = l;
+        l->object_prev = NULL;
+        object->object_list = l;
+
+        return l;
 }
 
-void job_dump(Job *j, FILE*f) {
+void job_dependency_free(JobDependency *l) {
+        assert(l);
+
+        if (l->subject_prev)
+                l->subject_prev->subject_next = l->subject_next;
+        else if (l->subject)
+                l->subject->subject_list = l->subject_next;
+        else
+                l->object->manager->transaction_anchor = l->subject_next;
+
+        if (l->subject_next)
+                l->subject_next->subject_prev = l->subject_prev;
+
+        if (l->object_prev)
+                l->object_prev->object_next = l->object_next;
+        else
+                l->object->object_list = l->object_next;
+
+        if (l->object_next)
+                l->object_next->object_prev = l->object_prev;
+
+        free(l);
+}
+
+void job_dependency_delete(Job *subject, Job *object, bool *matters) {
+        JobDependency *l;
+
+        assert(object);
+
+        for (l = object->object_list; l; l = l->object_next) {
+                assert(l->object == object);
+
+                if (l->subject == subject)
+                        break;
+        }
+
+        if (!l) {
+                if (matters)
+                        *matters = false;
+                return;
+        }
+
+        if (matters)
+                *matters = l->matters;
+
+        job_dependency_free(l);
+}
+
+const char* job_type_to_string(JobType t) {
 
         static const char* const job_type_table[_JOB_TYPE_MAX] = {
                 [JOB_START] = "start",
                 [JOB_STOP] = "stop",
                 [JOB_VERIFY_STARTED] = "verify-started",
                 [JOB_RELOAD] = "reload",
+                [JOB_RELOAD_OR_START] = "reload-or-start",
                 [JOB_RESTART] = "restart",
                 [JOB_TRY_RESTART] = "try-restart",
-                [JOB_RESTART_FINISH] = "restart-finish"
         };
 
+
+        if (t < 0 || t >= _JOB_TYPE_MAX)
+                return "n/a";
+
+        return job_type_table[t];
+}
+
+void job_dump(Job *j, FILE*f, const char *prefix) {
+
         static const char* const job_state_table[_JOB_STATE_MAX] = {
                 [JOB_WAITING] = "waiting",
                 [JOB_RUNNING] = "running",
@@ -82,9 +158,118 @@ void job_dump(Job *j, FILE*f) {
         assert(j);
         assert(f);
 
-        fprintf(f, "Job %u (%s) →%s in state %s\n",
-                j->id,
-                name_id(j->name),
-                job_type_table[j->type],
-                job_state_table[j->state]);
+        fprintf(f,
+                "%sJob %u:\n"
+                "%s\tAction: %s → %s\n"
+                "%s\tState: %s\n",
+                prefix, j->id,
+                prefix, name_id(j->name), job_type_to_string(j->type),
+                prefix, job_state_table[j->state]);
+}
+
+bool job_is_anchor(Job *j) {
+        JobDependency *l;
+
+        assert(j);
+
+        for (l = j->object_list; l; l = l->object_next)
+                if (!l->subject)
+                        return true;
+
+        return false;
+}
+
+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;
+
+        }
+}
+
+bool job_type_is_conflicting(JobType a, JobType b) {
+
+        /* Checks whether two types are "conflicting" */
+
+        return
+                (a == JOB_STOP && b != JOB_STOP) ||
+                (b == JOB_STOP && a != JOB_STOP);
 }