systemctl: ellipsize job list only when necessary, highlight running

I was debugging systemd waiting on a missing disk, and noticed
that the job listing could use some polishing. Jobs that are
actually running are highlighted, so it's easier to see what
very actually waiting for.

Also, the needed widths are precalculated, to use available columns
more ecomically.

src/shared/util.h

@@ -647,4 +647,11 @@ static inline bool logind_running(void) {
         return access("/run/systemd/seats/", F_OK) >= 0;
 }
 
+static inline unsigned decimal_str_max(unsigned x) {
+        unsigned ans = 1;
+        while (x /= 10)
+                ans ++;
+        return ans;
+}
+
 int unlink_noerrno(const char *path);

src/systemctl/systemctl.c

@@ -895,13 +895,84 @@ static int list_dependencies(DBusConnection *bus, char **args) {
         return list_dependencies_one(bus, u, 0, NULL, 0);
 }
 
+struct job_info {
+        uint32_t id;
+        char *name, *type, *state;
+};
+
+static void list_jobs_print(struct job_info* jobs, size_t n) {
+        size_t i;
+        struct job_info *j;
+        const char *on, *off;
+        bool shorten = false;
+
+        assert(n == 0 || jobs);
+
+        if (n == 0) {
+                on = ansi_highlight_green(true);
+                off = ansi_highlight_green(false);
+
+                printf("%sNo jobs running.%s\n", on, off);
+                return;
+        }
+
+        pager_open_if_enabled();
+
+        {
+                /* JOB UNIT TYPE STATE */
+                unsigned l0 = 3, l1 = 4, l2 = 4, l3 = 5;
+
+                for (i = 0, j = jobs; i < n; i++, j++) {
+                        assert(j->name && j->type && j->state);
+                        l0 = MAX(l0, decimal_str_max(j->id));
+                        l1 = MAX(l1, strlen(j->name));
+                        l2 = MAX(l2, strlen(j->type));
+                        l3 = MAX(l3, strlen(j->state));
+                }
+
+                if (!arg_full && l0 + 1 + l1 + l2 + 1 + l3 > columns()) {
+                        l1 = MAX(33u, columns() - l0 - l2 - l3 - 3);
+                        shorten = true;
+                }
+
+                if (on_tty())
+                        printf("%*s %-*s %-*s %-*s\n",
+                               l0, "JOB",
+                               l1, "UNIT",
+                               l2, "TYPE",
+                               l3, "STATE");
+
+                for (i = 0, j = jobs; i < n; i++, j++) {
+                        char _cleanup_free_ *e = NULL;
+
+                        if (streq(j->state, "running")) {
+                                on = ansi_highlight(true);
+                                off = ansi_highlight(false);
+                        } else
+                                on = off = "";
+
+                        e = shorten ? ellipsize(j->name, l1, 33) : NULL;
+                        printf("%*u %s%-*s%s %-*s %s%-*s%s\n",
+                               l0, j->id,
+                               on, l1, e ? e : j->name, off,
+                               l2, j->type,
+                               on, l3, j->state, off);
+                }
+        }
+
+        on = ansi_highlight(true);
+        off = ansi_highlight(false);
+
+        if (on_tty())
+                printf("\n%s%zu jobs listed%s.\n", on, n, off);
+}
+
 static int list_jobs(DBusConnection *bus, char **args) {
         _cleanup_dbus_message_unref_ DBusMessage *reply = NULL;
         DBusMessageIter iter, sub, sub2;
-        unsigned k = 0;
         int r;
-
-        pager_open_if_enabled();
+        struct job_info *jobs = NULL;
+        size_t size = 0, used = 0;
 
         r = bus_method_call_with_reply(
                         bus,
@@ -924,13 +995,9 @@ static int list_jobs(DBusConnection *bus, char **args) {
 
         dbus_message_iter_recurse(&iter, &sub);
 
-        if (on_tty())
-                printf("%4s %-25s %-15s %-7s\n", "JOB", "UNIT", "TYPE", "STATE");
-
         while (dbus_message_iter_get_arg_type(&sub) != DBUS_TYPE_INVALID) {
                 const char *name, *type, *state, *job_path, *unit_path;
                 uint32_t id;
-                char _cleanup_free_ *e = NULL;
 
                 if (dbus_message_iter_get_arg_type(&sub) != DBUS_TYPE_STRUCT) {
                         log_error("Failed to parse reply.");
@@ -946,19 +1013,37 @@ static int list_jobs(DBusConnection *bus, char **args) {
                     bus_iter_get_basic_and_next(&sub2, DBUS_TYPE_OBJECT_PATH, &job_path, true) < 0 ||
                     bus_iter_get_basic_and_next(&sub2, DBUS_TYPE_OBJECT_PATH, &unit_path, false) < 0) {
                         log_error("Failed to parse reply.");
-                        return -EIO;
+                        r = -EIO;
+                        goto finish;
                 }
 
-                e = arg_full ? NULL : ellipsize(name, 25, 33);
-                printf("%4u %-25s %-15s %-7s\n", id, e ? e : name, type, state);
+                if (!greedy_realloc((void**) &jobs, &size,
+                                    sizeof(struct job_info) * (used + 1))) {
+                        r = log_oom();
+                        goto finish;
+                }
 
-                k++;
+                jobs[used++] = (struct job_info) { id,
+                                                   strdup(name),
+                                                   strdup(type),
+                                                   strdup(state) };
+                if (!jobs[used-1].name || !jobs[used-1].type || !jobs[used-1].state) {
+                        r = log_oom();
+                        goto finish;
+                }
 
                 dbus_message_iter_next(&sub);
         }
 
-        if (on_tty())
-                printf("\n%u jobs listed.\n", k);
+        list_jobs_print(jobs, used);
+
+ finish:
+        while (used--) {
+                free(jobs[used].name);
+                free(jobs[used].type);
+                free(jobs[used].state);
+        }
+        free(jobs);
 
         return 0;
 }