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| | # Copyright (C) 2018 all contributors <meta@public-inbox.org>
# License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
package PublicInbox::ContentId;
use strict;
use warnings;
use base qw/Exporter/;
our @EXPORT_OK = qw/content_id content_digest/;
use PublicInbox::MID qw(mids references);
use PublicInbox::MsgIter;
# not sure if less-widely supported hash families are worth bothering with
use Digest::SHA;
sub digest_addr ($$$) {
my ($dig, $h, $v) = @_;
$v =~ tr/"//d;
$v =~ s/@([a-z0-9\_\.\-\(\)]*([A-Z])\S*)/'@'.lc($1)/ge;
utf8::encode($v);
$dig->add("$h\0$v\0");
}
sub content_digest ($) {
my ($mime) = @_;
my $dig = Digest::SHA->new(256);
my $hdr = $mime->header_obj;
# References: and In-Reply-To: get used interchangeably
# in some "duplicates" in LKML. We treat them the same
# in SearchIdx, so treat them the same for this:
my %seen;
foreach my $mid (@{mids($hdr)}) {
# do NOT consider the Message-ID as part of the content_id
# if we got here, we've already got Message-ID reuse
$seen{$mid} = 1;
}
foreach my $mid (@{references($hdr)}) {
next if $seen{$mid};
$dig->add("ref\0$mid\0");
}
# Only use Sender: if From is not present
foreach my $h (qw(From Sender)) {
my @v = $hdr->header($h);
if (@v) {
digest_addr($dig, $h, $_) foreach @v;
}
}
foreach my $h (qw(Subject Date)) {
my @v = $hdr->header($h);
foreach my $v (@v) {
utf8::encode($v);
$dig->add("$h\0$v\0");
}
}
# Some mail processors will add " to unquoted names that were
# not in the original message. For the purposes of deduplication,
# do not take it into account:
foreach my $h (qw(To Cc)) {
my @v = $hdr->header($h);
digest_addr($dig, $h, $_) foreach @v;
}
msg_iter($mime, sub {
my ($part, $depth, @idx) = @{$_[0]};
$dig->add("\0$depth:".join('.', @idx)."\0");
my $fn = $part->filename;
if (defined $fn) {
utf8::encode($fn);
$dig->add("fn\0$fn\0");
}
my @d = $part->header('Content-Description');
foreach my $d (@d) {
utf8::encode($d);
$dig->add("d\0$d\0");
}
$dig->add("b\0");
my $ct = $part->content_type || 'text/plain';
my ($s, undef) = msg_part_text($part, $ct);
if (defined $s) {
$s =~ s/\r\n/\n/gs;
$s =~ s/\s*\z//s;
utf8::encode($s);
} else {
$s = $part->body;
}
$dig->add($s);
});
$dig;
}
sub content_id ($) {
content_digest($_[0])->digest;
}
1;
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