notes: make expand_notes_ref globally accessible

This function is useful for other commands besides "git
notes" which want to let users refer to notes by their
shorthand name.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/notes.c

@@ -100,16 +100,6 @@ struct msg_arg {
 	struct strbuf buf;
 };
 
-static void expand_notes_ref(struct strbuf *sb)
-{
-	if (!prefixcmp(sb->buf, "refs/notes/"))
-		return; /* we're happy */
-	else if (!prefixcmp(sb->buf, "notes/"))
-		strbuf_insert(sb, 0, "refs/", 5);
-	else
-		strbuf_insert(sb, 0, "refs/notes/", 11);
-}
-
 static int list_each_note(const unsigned char *object_sha1,
 		const unsigned char *note_sha1, char *note_path,
 		void *cb_data)

notes.c

@@ -1285,3 +1285,13 @@ int copy_note(struct notes_tree *t,
 
 	return 0;
 }
+
+void expand_notes_ref(struct strbuf *sb)
+{
+	if (!prefixcmp(sb->buf, "refs/notes/"))
+		return; /* we're happy */
+	else if (!prefixcmp(sb->buf, "notes/"))
+		strbuf_insert(sb, 0, "refs/", 5);
+	else
+		strbuf_insert(sb, 0, "refs/notes/", 11);
+}

notes.h

@@ -307,4 +307,7 @@ void string_list_add_refs_by_glob(struct string_list *list, const char *glob);
 void string_list_add_refs_from_colon_sep(struct string_list *list,
 					 const char *globs);
 
+/* Expand inplace a note ref like "foo" or "notes/foo" into "refs/notes/foo" */
+void expand_notes_ref(struct strbuf *sb);
+
 #endif