pop3: remove untouched rows on QUIT/disconnect

Some POP3 clients may connect and never retrieve messages nor
trigger deletes.  In that case, save some storage by removing
unused rows from the `deletes' and `users' tables.

diff --git a/lib/PublicInbox/POP3.pm b/lib/PublicInbox/POP3.pm
index 53fb2e05900b0b94f1a112189817fc12571ae0b6..c993e558db09c2fbd8de5a15f342099fe6fc4ccd 100644 (file)
--- a/lib/PublicInbox/POP3.pm
+++ b/lib/PublicInbox/POP3.pm
@@ -301,6 +301,27 @@ sub close {
        $self->SUPER::close;
 }
 
+# must be called inside a state_dbh transaction with flock held
+sub __cleanup_state {
+       my ($self, $txn_id) = @_;
+       my $user_id = $self->{user_id} // die 'BUG: no {user_id}';
+       $self->{pop3d}->{-state_dbh}->prepare_cached(<<'')->execute($txn_id);
+DELETE FROM deletes WHERE txn_id = ? AND uid_dele = -1
+
+       my $sth = $self->{pop3d}->{-state_dbh}->prepare_cached(<<'');
+SELECT COUNT(*) FROM deletes WHERE user_id = ?
+
+       $sth->execute($user_id);
+       my $nr = $sth->fetchrow_array;
+       if ($nr == 0) {
+               $sth = $self->{pop3d}->{-state_dbh}->prepare_cached(<<'');
+DELETE FROM users WHERE user_id = ?
+
+               $sth->execute($user_id);
+       }
+       $nr;
+}
+
 sub cmd_quit {
        my ($self) = @_;
        if (defined(my $txn_id = $self->{txn_id})) {
@@ -308,23 +329,25 @@ sub cmd_quit {
                if (my $exp = delete $self->{expire}) {
                        mark_dele($self, $_) for unpack('S*', $exp);
                }
+               my $keep = 1;
                my $dbh = $self->{pop3d}->{-state_dbh};
                my $lk = $self->{pop3d}->lock_for_scope;
-               my $sth;
                $dbh->begin_work;
 
-               if (defined $self->{txn_max_uid}) {
-                       $sth = $dbh->prepare_cached(<<'');
+               if (defined(my $max = $self->{txn_max_uid})) {
+                       $dbh->prepare_cached(<<'')->execute($max, $txn_id, $max)
 UPDATE deletes SET uid_dele = ? WHERE txn_id = ? AND uid_dele < ?
 
-                       $sth->execute($self->{txn_max_uid}, $txn_id,
-                                       $self->{txn_max_uid});
+               } else {
+                       $keep = $self->__cleanup_state($txn_id);
                }
-               $sth = $dbh->prepare_cached(<<'');
+               $dbh->prepare_cached(<<'')->execute(time, $user_id) if $keep;
 UPDATE users SET last_seen = ? WHERE user_id = ?
 
-               $sth->execute(time, $user_id);
                $dbh->commit;
+               # we MUST do txn_id F_UNLCK here inside ->lock_for_scope:
+               $self->{did_quit} = 1;
+               $self->{pop3d}->unlock_mailbox($self);
        }
        $self->write(\"+OK public-inbox POP3 server signing off\r\n");
        $self->close;

diff --git a/lib/PublicInbox/POP3D.pm b/lib/PublicInbox/POP3D.pm
index 764f9ffe8f8073ef2208f74a92ecd271016925e1..7432a9640c89a20a0e818a9c7262d7ca7bda80f9 100644 (file)
--- a/lib/PublicInbox/POP3D.pm
+++ b/lib/PublicInbox/POP3D.pm
@@ -245,6 +245,12 @@ SELECT txn_id,uid_dele FROM deletes WHERE user_id = ? AND mailbox_id = ?
 sub unlock_mailbox {
        my ($self, $pop3) = @_;
        my $txn_id = delete($pop3->{txn_id}) // return;
+       if (!$pop3->{did_quit}) { # deal with QUIT-less disconnects
+               my $lk = $self->lock_for_scope;
+               $self->{-state_dbh}->begin_work;
+               $pop3->__cleanup_state($txn_id);
+               $self->{-state_dbh}->commit;
+       }
        delete $self->{txn_locks}->{$txn_id}; # same worker
 
        # other workers

diff --git a/t/pop3d.t b/t/pop3d.t
index e5d537671292657b17dd5e75e4151c82ea18993b..7248c03f47c5f28726fa4b8fe88b4226359486ad 100644 (file)
--- a/t/pop3d.t
+++ b/t/pop3d.t
@@ -60,6 +60,14 @@ my $oldc = Net::POP3->new(@old_args);
 my $locked_mb = ('e'x32)."\@$group";
 ok($oldc->apop("$locked_mb.0", 'anonymous'), 'APOP to old');
 
+my $dbh = DBI->connect("dbi:SQLite:dbname=$tmpdir/p3state/db.sqlite3",'','', {
+       AutoCommit => 1,
+       RaiseError => 1,
+       PrintError => 0,
+       sqlite_use_immediate_transaction => 1,
+       sqlite_see_if_its_a_number => 1,
+});
+
 { # locking within the same process
        my $x = Net::POP3->new(@old_args);
        ok(!$x->apop("$locked_mb.0", 'anonymous'), 'APOP lock failure');
@@ -146,11 +154,26 @@ for my $args (
                ok(!$np3->apop($mailbox, 'anonymous'), "APOP $mailbox reject");
                ok($np3->quit, "QUIT after APOP fail $mailbox");
        }
+
+       # we do connect+QUIT bumps to try ensuring non-QUIT disconnects
+       # get processed below:
        for my $mailbox ($group, "$group.0") {
                my $u = ('f'x32)."\@$mailbox";
+               undef $np3;
+               ok(Net::POP3->new(@np3_args)->quit, 'connect+QUIT bump');
                $np3 = Net::POP3->new(@np3_args);
+               my $n0 = $dbh->selectrow_array('SELECT COUNT(*) FROM deletes');
+               my $u0 = $dbh->selectrow_array('SELECT COUNT(*) FROM users');
                ok($np3->user($u), "UUID\@$mailbox accept");
                ok($np3->pass('anonymous'), 'pass works');
+               my $n1 = $dbh->selectrow_array('SELECT COUNT(*) FROM deletes');
+               is($n1 - $n0, 1, 'deletes bumped while connected');
+               ok($np3->quit, 'client QUIT');
+
+               $n1 = $dbh->selectrow_array('SELECT COUNT(*) FROM deletes');
+               is($n1, $n0, 'deletes row gone on no-op after QUIT');
+               my $u1 = $dbh->selectrow_array('SELECT COUNT(*) FROM users');
+               is($u1, $u0, 'users row gone on no-op after QUIT');
 
                $np3 = Net::POP3->new(@np3_args);
                ok($np3->user($u), "UUID\@$mailbox accept");
@@ -163,9 +186,32 @@ for my $args (
                ok($_ > 0, 'bytes in LIST result') for values %$list;
                like($_, qr/\A[a-z0-9]{40,}\z/,
                        'blob IDs in UIDL result') for values %$uidl;
+               ok($np3->quit, 'QUIT after LIST+UIDL');
+               $n1 = $dbh->selectrow_array('SELECT COUNT(*) FROM deletes');
+               is($n1, $n0, 'deletes row gone on no-op after LIST+UIDL');
+               $n0 = $n1;
+
+               $np3 = Net::POP3->new(@np3_args);
+               ok($np3->user($u), "UUID\@$mailbox accept");
+               ok($np3->pass('anonymous'), 'pass works');
+               undef $np3; # QUIT-less disconnect
+               ok(Net::POP3->new(@np3_args)->quit, 'connect+QUIT bump');
+
+               $u1 = $dbh->selectrow_array('SELECT COUNT(*) FROM users');
+               is($u1, $u0, 'users row gone on QUIT-less disconnect');
+               $n1 = $dbh->selectrow_array('SELECT COUNT(*) FROM deletes');
+               is($n1, $n0, 'deletes row gone on QUIT-less disconnect');
+               $n0 = $n1;
 
                $np3 = Net::POP3->new(@np3_args);
                ok(!$np3->apop($u, 'anonumuss'), 'APOP wrong pass reject');
+               $n1 = $dbh->selectrow_array('SELECT COUNT(*) FROM deletes');
+               is($n1, $n0, 'deletes row not bumped w/ wrong pass');
+               undef $np3; # QUIT-less disconnect
+               ok(Net::POP3->new(@np3_args)->quit, 'connect+QUIT bump');
+
+               $n1 = $dbh->selectrow_array('SELECT COUNT(*) FROM deletes');
+               is($n1, $n0, 'deletes row not bumped w/ wrong pass');
 
                $np3 = Net::POP3->new(@np3_args);
                ok($np3->apop($u, 'anonymous'), "APOP UUID\@$mailbox");