Re: [PATCH 08/18] link_alt_odb_entry: refactor string handling

> The string handling in link_alt_odb_entry() is mostly an
> artifact of the original version, which took the path as a
> ptr/len combo, and did not have a NUL-terminated string
> until we created one in the alternate_object_database
> struct.  But since 5bdf0a8 (sha1_file: normalize alt_odb
> path before comparing and storing, 2011-09-07), the first
> thing we do is put the path into a strbuf, which gives us
> some easy opportunities for cleanup.
>
> In particular:
>
>   - we call strlen(pathbuf.buf), which is silly; we can look
>     at pathbuf.len.
>
>   - even though we have a strbuf, we don't maintain its
>     "len" field when chomping extra slashes from the
>     end, and instead keep a separate "pfxlen" variable. We
>     can fix this and then drop "pfxlen" entirely.
>
>   - we don't check whether the path is usable until after we
>     allocate the new struct, making extra cleanup work for
>     ourselves. Since we have a NUL-terminated string, we can
>     bump the "is it usable" checks higher in the function.
>     While we're at it, we can move that logic to its own
>     helper, which makes the flow of link_alt_odb_entry()
>     easier to follow.

>  	/* recursively add alternates */
> -	read_info_alternates(ent->base, depth + 1);
> -
> -	ent->base[pfxlen] = '/';
> +	read_info_alternates(pathbuf.buf, depth + 1);