log-tree: factor out fmt_output_email_subject()

Use a strbuf to store the subject prefix string and move its
construction into its own function.  This gets rid of two arbitrary
length limits and allows the string to be added by callers directly.

Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/log-tree.h b/log-tree.h
index c8116e6..dd75dd7 100644
--- a/log-tree.h
+++ b/log-tree.h
@@ -30,5 +30,6 @@ void load_ref_decorations(int flags);
 #define FORMAT_PATCH_NAME_MAX 64
 void fmt_output_commit(struct strbuf *, struct commit *, struct rev_info *);
 void fmt_output_subject(struct strbuf *, const char *subject, struct rev_info *);
+void fmt_output_email_subject(struct strbuf *, struct rev_info *);
 
 #endif