by_cipher has a bit of a problem because it uses unmodified b64-encoded
hashes as directory names, which can include / characters, so rather
than the intended xy/sha256-checksum/filename.tar.gz layout, there are
a bunch of xy/sha25/6-chec/ksum/filename.tar.gz.
I'm looking at one machine which has 130k hashes so should have approx
134k dirs counting the various xy/, but because of this, actually has
220k dirs. So for the sake of namecache it might be advantageous to
replace / with _ or another char.
More radical but if changing filenames anyway, we probably don't need
an extra level of dirs and filename.tar.gz either; for sha256 it might
as well just be xy/hash and avoid a huge number of dirs holding either
a single file, or a handful of links to a single file. (If sha256
collisions are a concern there are a whole bunch of problems with the
open-source ecosystem).
...however, by_cipher is only used by ports infrastructure when fetching
files from ftp.openbsd.org etc, or when dpb fetches files. Specifically
when _building_, ports only looks in ${FULLDISTDIR}/file, not
${DISTDIR}/by_ciphers.
As all bulk builds (including for -stable and -current) share a distfiles
dir, any change in contents for a filename means we have to explicitly
rename the file (either with DISTFILES {url} syntax or DIST_SUBDIR)
anyway.
So I'm not convinced by_cipher is doing anything useful...do we need to
keep it at all?
