[tip:perf/core] perf tools: Improve ambiguous option help message

[tip-bot for Namhyung Kim <tipbot@zytor.com>]

Commit-ID:  a5f4a6932ec2e1a53642e97a1be64bc7b169942f
Gitweb:     http://git.kernel.org/tip/a5f4a6932ec2e1a53642e97a1be64bc7b169942f
Author:     Namhyung Kim <namhyung@kernel.org>
AuthorDate: Sun, 25 Oct 2015 00:49:24 +0900
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Mon, 26 Oct 2015 13:59:06 -0300

perf tools: Improve ambiguous option help message

Currently if an option name is ambiguous it only prints first two
matched option names but no help.  It'd be better it could show all
possible names and help messages too.

Before:
  $ perf report --show
    Error: Ambiguous option: show (could be --show-total-period or
                                            --show-ref-call-graph)
   Usage: perf report [<options>]

After:
  $ perf report --show
    Error: Ambiguous option: show (could be --show-total-period or
                                            --show-ref-call-graph)
   Usage: perf report [<options>]

      -n, --show-nr-samples
                              Show a column with the number of samples
          --showcpuutilization
                              Show sample percentage for different cpu modes
      -I, --show-info         Display extended information about perf.data file
          --show-total-period
                              Show a column with the sum of periods
          --show-ref-call-graph
                              Show callgraph from reference event

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1445701767-12731-1-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/parse-options.c | 17 ++++++++---------
 1 file changed, 8 insertions(+), 9 deletions(-)

diff --git a/tools/perf/util/parse-options.c b/tools/perf/util/parse-options.c
index 22c2806..b8d9822 100644
--- a/tools/perf/util/parse-options.c
+++ b/tools/perf/util/parse-options.c
@@ -770,24 +770,23 @@ int parse_options_usage(const char * const *usagestr,
 opt:
 	for (  ; opts->type != OPTION_END; opts++) {
 		if (short_opt) {
-			if (opts->short_name == *optstr)
+			if (opts->short_name == *optstr) {
+				print_option_help(opts, 0);
 				break;
+			}
 			continue;
 		}
 
 		if (opts->long_name == NULL)
 			continue;
 
-		if (!prefixcmp(optstr, opts->long_name))
-			break;
-		if (!prefixcmp(optstr, "no-") &&
-		    !prefixcmp(optstr + 3, opts->long_name))
-			break;
+		if (!prefixcmp(opts->long_name, optstr))
+			print_option_help(opts, 0);
+		if (!prefixcmp("no-", optstr) &&
+		    !prefixcmp(opts->long_name, optstr + 3))
+			print_option_help(opts, 0);
 	}
 
-	if (opts->type != OPTION_END)
-		print_option_help(opts, 0);
-
 	return PARSE_OPT_HELP;
 }