tag: libify parse_opt_points_at()

Rename 'parse_opt_points_at()' to 'parse_opt_object_name()' and
move it from 'tag.c' to 'parse-options'. This now acts as a common
parse_opt function which accepts an objectname and stores it into
a sha1_array.

Based-on-patch-by: Jeff King <peff@peff.net>
Mentored-by: Christian Couder <christian.couder@gmail.com>
Mentored-by: Matthieu Moy <matthieu.moy@grenoble-inp.fr>
Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/tag.c

@@ -546,23 +546,6 @@ static int strbuf_check_tag_ref(struct strbuf *sb, const char *name)
 	return check_refname_format(sb->buf, 0);
 }
 
-static int parse_opt_points_at(const struct option *opt __attribute__((unused)),
-			const char *arg, int unset)
-{
-	unsigned char sha1[20];
-
-	if (unset) {
-		sha1_array_clear(&points_at);
-		return 0;
-	}
-	if (!arg)
-		return error(_("switch 'points-at' requires an object"));
-	if (get_sha1(arg, sha1))
-		return error(_("malformed object name '%s'"), arg);
-	sha1_array_append(&points_at, sha1);
-	return 0;
-}
-
 static int parse_opt_sort(const struct option *opt, const char *arg, int unset)
 {
 	int *sort = opt->value;
@@ -625,8 +608,8 @@ int cmd_tag(int argc, const char **argv, const char *prefix)
 			parse_opt_with_commit, (intptr_t)"HEAD",
 		},
 		{
-			OPTION_CALLBACK, 0, "points-at", NULL, N_("object"),
-			N_("print only tags of the object"), 0, parse_opt_points_at
+			OPTION_CALLBACK, 0, "points-at", &points_at, N_("object"),
+			N_("print only tags of the object"), 0, parse_opt_object_name
 		},
 		OPT_END()
 	};

parse-options-cb.c

@@ -4,6 +4,7 @@
 #include "commit.h"
 #include "color.h"
 #include "string-list.h"
+#include "sha1-array.h"
 
 /*----- some often used options -----*/
 
@@ -92,6 +93,22 @@ int parse_opt_with_commit(const struct option *opt, const char *arg, int unset)
 	return 0;
 }
 
+int parse_opt_object_name(const struct option *opt, const char *arg, int unset)
+{
+	unsigned char sha1[20];
+
+	if (unset) {
+		sha1_array_clear(opt->value);
+		return 0;
+	}
+	if (!arg)
+		return -1;
+	if (get_sha1(arg, sha1))
+		return error(_("malformed object name '%s'"), arg);
+	sha1_array_append(opt->value, sha1);
+	return 0;
+}
+
 int parse_opt_tertiary(const struct option *opt, const char *arg, int unset)
 {
 	int *target = opt->value;

parse-options.h

@@ -220,6 +220,7 @@ extern int parse_opt_approxidate_cb(const struct option *, const char *, int);
 extern int parse_opt_expiry_date_cb(const struct option *, const char *, int);
 extern int parse_opt_color_flag_cb(const struct option *, const char *, int);
 extern int parse_opt_verbosity_cb(const struct option *, const char *, int);
+extern int parse_opt_object_name(const struct option *, const char *, int);
 extern int parse_opt_with_commit(const struct option *, const char *, int);
 extern int parse_opt_tertiary(const struct option *, const char *, int);
 extern int parse_opt_string_list(const struct option *, const char *, int);