Re: [PATCH 3/3] introduce "format" date-mode

> This does get called a lot (e.g., once per commit). One extra allocation
> would probably not kill us there, but I think we could fairly trivially
> put this on the unlikely path:
>
>   size_t hint = 128;
>   size_t len;
>
>   /* optimize out obvious 0-length case */
>   if (!*fmt)
> 	return;
>
>   strbuf_grow(sb, hint);
>   len = strftime(sb->buf + sb->len, sb->alloc - sb->len, fmt, tm);
>
>   /* maybe not enough room, or maybe 0-length output */
>   if (!len) {
> 	struct strbuf f = STRBUF_INIT;
> 	strbuf_addf(&f, "%s ", fmt);
> 	while (!len) {
> 		hint *= 2;
> 		strbuf_grow(sb, hint);
> 		len = strftime(sb->buf + sb->len, sb->alloc - sb->len, f.buf, tm);
> 	}
>   }
>
> I'd guess most cases will fit in 128 bytes and never even hit this code
> path. You could also get fancier and start the buffer smaller, but only
> do the fmt hack when we cross a threshold.