1 # Copyright (C) 2015, all contributors <meta@public-inbox.org>
2 # License: AGPLv3 or later (https://www.gnu.org/licenses/agpl-3.0.txt)
3 package PublicInbox::MID;
7 our @EXPORT_OK = qw/mid_clean mid_compressed mid2path/;
8 use Digest::SHA qw/sha1_hex/;
9 use constant MID_MAX => 40; # SHA-1 hex length
13 defined($mid) or die "no Message-ID";
14 # MDA->precheck did more checking for us
23 return $mid if (length($mid) <= MID_MAX);
29 my ($x2, $x38) = ($mid =~ /\A([a-f0-9]{2})([a-f0-9]{38})\z/);
31 unless (defined $x38) {
32 # compatibility with old links (or short Message-IDs :)
33 $mid = sha1_hex($mid);
34 ($x2, $x38) = ($mid =~ /\A([a-f0-9]{2})([a-f0-9]{38})\z/);