# Copyright (C) 2020-2021 all contributors
# License: AGPL-3.0+
package PublicInbox::LeiDedupe;
use strict;
use v5.10.1;
use PublicInbox::ContentHash qw(content_hash git_sha);
use Digest::SHA ();
# n.b. mutt sets most of these headers not sure about Bytes
our @OID_IGNORE = qw(Status X-Status Content-Length Lines Bytes);
# best-effort regeneration of OID when augmenting existing results
sub _regen_oid ($) {
my ($eml) = @_;
my @stash; # stash away headers we shouldn't have in git
for my $k (@OID_IGNORE) {
my @v = $eml->header_raw($k) or next;
push @stash, [ $k, \@v ];
$eml->header_set($k); # restore below
}
my $dig = git_sha(1, $eml);
for my $kv (@stash) { # restore stashed headers
my ($k, @v) = @$kv;
$eml->header_set($k, @v);
}
$dig->digest;
}
sub _oidbin ($) { defined($_[0]) ? pack('H*', $_[0]) : undef }
sub smsg_hash ($) {
my ($smsg) = @_;
my $dig = Digest::SHA->new(256);
my $x = join("\0", @$smsg{qw(from to cc ds subject references mid)});
utf8::encode($x);
$dig->add($x);
$dig->digest;
}
# the paranoid option
sub dedupe_oid ($) {
my ($skv) = @_;
(sub { # may be called in a child process
my ($eml, $oidhex) = @_;
$skv->set_maybe(_oidbin($oidhex) // _regen_oid($eml), '');
}, sub {
my ($smsg) = @_;
$skv->set_maybe(_oidbin($smsg->{blob}), '');
});
}
# dangerous if there's duplicate messages with different Message-IDs
sub dedupe_mid ($) {
my ($skv) = @_;
(sub { # may be called in a child process
my ($eml, $oidhex) = @_;
# lei supports non-public drafts w/o Message-ID
my $mid = $eml->header_raw('Message-ID') // _oidbin($oidhex) //
content_hash($eml);
$skv->set_maybe($mid, '');
}, sub {
my ($smsg) = @_;
my $mid = $smsg->{mid};
$mid = undef if $mid eq '';
$mid //= smsg_hash($smsg) // _oidbin($smsg->{blob});
$skv->set_maybe($mid, '');
});
}
# our default deduplication strategy (used by v2, also)
sub dedupe_content ($) {
my ($skv) = @_;
(sub { # may be called in a child process
my ($eml) = @_; # $oidhex = $_[1], ignored
$skv->set_maybe(content_hash($eml), '');
}, sub {
my ($smsg) = @_;
$skv->set_maybe(smsg_hash($smsg), '');
});
}
# no deduplication at all
sub true { 1 }
sub dedupe_none ($) { (\&true, \&true) }
sub new {
my ($cls, $lei) = @_;
my $dd = $lei->{opt}->{dedupe} // 'content';
my $dst = $lei->{ovv}->{dst};
# allow "none" to bypass Eml->new if writing to directory:
return if ($dd eq 'none' && substr($dst // '', -1) eq '/');
my $m = "dedupe_$dd";
$cls->can($m) or die "unsupported dedupe strategy: $dd\n";
my $skv;
if ($dd ne 'none') {
require PublicInbox::SharedKV;
$skv = PublicInbox::SharedKV->new;
}
# [ $skv, $eml_cb, $smsg_cb, "dedupe_$dd" ]
bless [ $skv, undef, undef, $m ], $cls;
}
# returns true on seen messages according to the deduplication strategy,
# returns false if unseen
sub is_dup {
my ($self, $eml, $smsg) = @_;
!$self->[1]->($eml, $smsg ? $smsg->{blob} : undef);
}
sub is_smsg_dup {
my ($self, $smsg) = @_;
!$self->[2]->($smsg);
}
sub prepare_dedupe {
my ($self) = @_;
my $skv = $self->[0];
$self->[1] or @$self[1,2] = $self->can($self->[3])->($skv);
$skv ? $skv->dbh : undef;
}
sub pause_dedupe {
my ($self) = @_;
my $skv = $self->[0] or return;
$skv->dbh_release;
delete($skv->{dbh}) if $skv;
}
sub has_entries {
my $skv = $_[0]->[0] or return undef;
$skv->has_entries;
}
1;