check_help_option(): a helper for early check of "-h" optionjc/wip-check-help-option

As "show help when we get '-h' as the only option." often appears,
let's give an easy helper to call for these call sites.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 11 insertions, 0 deletions

diff --git a/usage.c b/usage.c
index 2f87ca69a8..007d732094 100644
--- a/usage.c
+++ b/usage.c
@@ -5,6 +5,7 @@
  */
 #include "git-compat-util.h"
 #include "cache.h"
+#include "parse-options.h"
 
 void vreportf(const char *prefix, const char *err, va_list params)
 {
@@ -225,3 +226,13 @@ NORETURN void BUG(const char *fmt, ...)
 	va_end(ap);
 }
 #endif
+
+void check_help_option(int argc, const char **argv, const void *help, struct option *opt)
+{
+	if (argc == 2 && !strcmp(argv[1], "-h")) {
+		if (opt)
+			usage_with_options((const char * const *)help, opt);
+		else
+			usage((const char *)help);
+	}
+}