swapon: control column header tooltips with --annotation

Whether column header names should be annotated can be specified
with the --annotation option which takes the following three
arguments: 'auto', 'never' and 'always', where the former is the
default and makes it so that annotations are only added when the
output device is a terminal. If the option is omitted the 'auto'
behavior should be expected.

Signed-off-by: Christian Goeschel Ndjomouo <cgoesc2@wgu.edu>

diff --git a/sys-utils/swapon.c b/sys-utils/swapon.c
index 9ef10c153c8d8086d83766d5ad4d18fd83474fb2..1cf8fda2c3df54be1bc28c4d8f45912233350f31 100644 (file)
--- a/sys-utils/swapon.c
+++ b/sys-utils/swapon.c
@@ -141,6 +141,7 @@ struct swapon_ctl {
        struct swap_prop props;         /* global settings for all devices */
 
        bool    all,            /* turn on all swap devices */
+               annotation,     /* annotate columns with a tooltip (always|never|auto)*/
                bytes,          /* display --show in bytes */
                fix_page_size,  /* reinitialize page size */
                no_heading,     /* toggle --show headers */
@@ -320,7 +321,8 @@ static int show_table(struct swapon_ctl *ctl)
                cl = scols_table_new_column(table, col->name, col->whint, col->flags);
                if (!cl)
                        err(EXIT_FAILURE, _("failed to allocate output column"));
-               scols_column_refer_annotation(cl, col->help);
+               if (ctl->annotation && col->help)
+                       scols_column_refer_annotation(cl, col->help);
        }
 
        while (mnt_table_next_fs(st, itr, &fs) == 0)
@@ -828,19 +830,21 @@ static void __attribute__((__noreturn__)) usage(void)
        fputs(_("Enable devices and files for paging and swapping.\n"), out);
 
        fputs(USAGE_OPTIONS, out);
-       fputs(_(" -a, --all                enable all swaps from /etc/fstab\n"), out);
-       fputs(_(" -d, --discard[=<policy>] enable swap discards, if supported by device\n"), out);
-       fputs(_(" -e, --ifexists           silently skip devices that do not exist\n"), out);
-       fputs(_(" -f, --fixpgsz            reinitialize the swap space if necessary\n"), out);
-       fputs(_(" -o, --options <list>     comma-separated list of swap options\n"), out);
-       fputs(_(" -p, --priority <prio>    specify the priority of the swap device\n"), out);
-       fputs(_(" -s, --summary            display summary about used swap devices (DEPRECATED)\n"), out);
-       fputs(_(" -T, --fstab <path>       alternative file to /etc/fstab\n"), out);
-       fputs(_("     --show[=<columns>]   display summary in definable table\n"), out);
-       fputs(_("     --noheadings         don't print table heading (with --show)\n"), out);
-       fputs(_("     --raw                use the raw output format (with --show)\n"), out);
-       fputs(_("     --bytes              display swap size in bytes in --show output\n"), out);
-       fputs(_(" -v, --verbose            verbose mode\n"), out);
+       fputs(_(" -a, --all                     enable all swaps from /etc/fstab\n"), out);
+       fputs(_(" -d, --discard[=<policy>]      enable swap discards, if supported by device\n"), out);
+       fputs(_(" -e, --ifexists                silently skip devices that do not exist\n"), out);
+       fputs(_(" -f, --fixpgsz                 reinitialize the swap space if necessary\n"), out);
+       fputs(_(" -o, --options <list>          comma-separated list of swap options\n"), out);
+       fputs(_(" -p, --priority <prio>         specify the priority of the swap device\n"), out);
+       fputs(_(" -s, --summary                 display summary about used swap devices (DEPRECATED)\n"), out);
+       fputs(_(" -T, --fstab <path>            alternative file to /etc/fstab\n"), out);
+       fputs(_("     --show[=<columns>]        display summary in definable table\n"), out);
+       fputs(_("     --output-all              output all available columns\n"), out);
+       fputs(_("     --annotation=[<when>]     annotate columns with a tooltip (always|never|auto)\n"), out);
+       fputs(_("     --noheadings              don't print table heading (with --show)\n"), out);
+       fputs(_("     --raw                     use the raw output format (with --show)\n"), out);
+       fputs(_("     --bytes                   display swap size in bytes in --show output\n"), out);
+       fputs(_(" -v, --verbose                 verbose mode\n"), out);
 
        fputs(USAGE_SEPARATOR, out);
        fprintf(out, USAGE_HELP_OPTIONS(26));
@@ -872,10 +876,11 @@ int main(int argc, char *argv[])
 {
        int status = 0, c;
        size_t i;
-       char *options = NULL, *fstab_filename = NULL;
+       char *options = NULL, *fstab_filename = NULL, *annotation_opt_arg = NULL;
 
        enum {
                BYTES_OPTION = CHAR_MAX + 1,
+               ANNOTATION_OPTION,
                NOHEADINGS_OPTION,
                RAW_OPTION,
                SHOW_OPTION,
@@ -895,6 +900,7 @@ int main(int argc, char *argv[])
                { "version",      no_argument,       NULL, 'V'                 },
                { "show",         optional_argument, NULL, SHOW_OPTION         },
                { "output-all",   no_argument,       NULL, OPT_LIST_TYPES      },
+               { "annotation",   optional_argument, NULL, ANNOTATION_OPTION   },
                { "noheadings",   no_argument,       NULL, NOHEADINGS_OPTION   },
                { "raw",          no_argument,       NULL, RAW_OPTION          },
                { "bytes",        no_argument,       NULL, BYTES_OPTION        },
@@ -990,6 +996,9 @@ int main(int argc, char *argv[])
                        for (ctl.ncolumns = 0; (size_t)ctl.ncolumns < ARRAY_SIZE(infos); ctl.ncolumns++)
                                ctl.columns[ctl.ncolumns] = ctl.ncolumns;
                        break;
+               case ANNOTATION_OPTION:
+                       annotation_opt_arg = optarg;
+                       break;
                case NOHEADINGS_OPTION:
                        ctl.no_heading = 1;
                        break;
@@ -1012,6 +1021,9 @@ int main(int argc, char *argv[])
        }
        argv += optind;
 
+       if (annotationwanted(annotation_opt_arg))
+               ctl.annotation = 1;
+
        if (ctl.summarize)
                return display_summary();