lscpu: add --list-columns option and declutter --help output

This moves the list of available columns from the --help output
to the '--list-columns' option and makes the usage information
more readable.

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

diff --git a/sys-utils/lscpu.c b/sys-utils/lscpu.c
index fe0eac9e7e9bffbbb6d53376593f50970ffbcaf4..fe996ebf93a1b1cbc1131885f162696df41fe0e3 100644 (file)
--- a/sys-utils/lscpu.c
+++ b/sys-utils/lscpu.c
@@ -34,6 +34,7 @@
 #include "optutils.h"
 #include "c_strtod.h"
 #include "sysfs.h"
+#include "column-list-table.h"
 
 #include "lscpu.h"
 
@@ -1182,7 +1183,6 @@ static void print_summary(struct lscpu_cxt *cxt)
 static void __attribute__((__noreturn__)) usage(void)
 {
        FILE *out = stdout;
-       size_t i;
 
        fputs(USAGE_HEADER, out);
        fprintf(out, _(" %s [options]\n"), program_invocation_short_name);
@@ -1206,17 +1206,34 @@ static void __attribute__((__noreturn__)) usage(void)
        fputs(_("     --hierarchic[=when] use subsections in summary (auto, never, always)\n"), out);
        fputs(_("     --output-all        print all available columns for -e, -p or -C\n"), out);
        fputs(USAGE_SEPARATOR, out);
+       fputs(_(" -H, --list-columns      list the available columns\n"), out);
        fprintf(out, USAGE_HELP_OPTIONS(25));
 
-       fputs(_("\nAvailable output columns for -e or -p:\n"), out);
-       for (i = 0; i < ARRAY_SIZE(coldescs_cpu); i++)
-               fprintf(out, " %13s  %s\n", coldescs_cpu[i].name, _(coldescs_cpu[i].help));
+       fprintf(out, USAGE_MAN_TAIL("lscpu(1)"));
 
-       fputs(_("\nAvailable output columns for -C:\n"), out);
-       for (i = 0; i < ARRAY_SIZE(coldescs_cache); i++)
-               fprintf(out, " %13s  %s\n", coldescs_cache[i].name, _(coldescs_cache[i].help));
+       exit(EXIT_SUCCESS);
+}
 
-       fprintf(out, USAGE_MAN_TAIL("lscpu(1)"));
+static void __attribute__((__noreturn__)) list_columns(struct lscpu_cxt *cxt)
+{
+       struct libscols_table *col_tb = xcolumn_list_table_new("lscpu-columns", stdout, cxt->raw, cxt->json);
+       struct libscols_table *col_caches_tb = xcolumn_list_table_new("lscpu-caches-columns", stdout, cxt->raw, cxt->json);
+
+       fputs(_("Available output columns for -e or -p:\n"), stdout);
+       for (size_t i = 0; i < ARRAY_SIZE(coldescs_cpu); i++)
+               xcolumn_list_table_append_line(col_tb, coldescs_cpu[i].name,
+                                       coldescs_cpu[i].json_type, NULL,
+                                       _(coldescs_cpu[i].help));
+       scols_print_table(col_tb);
+       scols_unref_table(col_tb);
+
+       fputs(_("\nAvailable output columns for -C:\n"), stdout);
+       for (size_t i = 0; i < ARRAY_SIZE(coldescs_cache); i++)
+               xcolumn_list_table_append_line(col_caches_tb, coldescs_cache[i].name,
+                                               coldescs_cache[i].json_type, NULL,
+                                               _(coldescs_cache[i].help));
+       scols_print_table(col_caches_tb);
+       scols_unref_table(col_caches_tb);
 
        exit(EXIT_SUCCESS);
 }
@@ -1224,7 +1241,7 @@ static void __attribute__((__noreturn__)) usage(void)
 int main(int argc, char *argv[])
 {
        struct lscpu_cxt *cxt;
-       int c, all = 0;
+       int c, all = 0, collist = 0;
        int columns[ARRAY_SIZE(coldescs_cpu)];
        int cpu_modifier_specified = 0;
        char *outarg = NULL;
@@ -1250,6 +1267,7 @@ int main(int argc, char *argv[])
                { "version",    no_argument,       NULL, 'V' },
                { "output-all", no_argument,       NULL, OPT_OUTPUT_ALL },
                { "hierarchic", optional_argument, NULL, OPT_HIERARCHIC },
+               { "list-columns", no_argument,     NULL, 'H' },
                { NULL,         0, NULL, 0 }
        };
 
@@ -1267,7 +1285,7 @@ int main(int argc, char *argv[])
 
        cxt = lscpu_new_context();
 
-       while ((c = getopt_long(argc, argv, "aBbC::ce::hJp::rs:xyV", longopts, NULL)) != -1) {
+       while ((c = getopt_long(argc, argv, "aBbC::ce::HhJp::rs:xyV", longopts, NULL)) != -1) {
 
                err_exclusive_options(c, longopts, excl, excl_st);
 
@@ -1336,6 +1354,9 @@ int main(int argc, char *argv[])
                        } else
                                hierarchic = 1;
                        break;
+               case 'H':
+                       collist = 1;
+                       break;
                case 'h':
                        usage();
                case 'V':
@@ -1345,6 +1366,9 @@ int main(int argc, char *argv[])
                }
        }
 
+       if (collist)
+               list_columns(cxt);
+
        if (all && ncolumns == 0) {
                size_t maxsz = cxt->mode == LSCPU_OUTPUT_CACHES ?
                                ARRAY_SIZE(coldescs_cache) :