# Copyright (C) 2016 all contributors
# License: AGPL-3.0+
#
# Emergency Maildir delivery for MDA
package PublicInbox::Emergency;
use strict;
use warnings;
use Fcntl qw(:DEFAULT SEEK_SET);
use Sys::Hostname qw(hostname);
use IO::Handle;
sub new {
my ($class, $dir) = @_;
-d $dir or mkdir($dir) or die "failed to mkdir($dir): $!\n";
foreach (qw(new tmp cur)) {
my $d = "$dir/$_";
next if -d $d;
-d $d or mkdir($d) or die "failed to mkdir($d): $!\n";
}
bless { dir => $dir, files => {}, t => 0, cnt => 0 }, $class;
}
sub _fn_in {
my ($self, $dir) = @_;
my @host = split(/\./, hostname);
my $now = time;
if ($self->{t} != $now) {
$self->{t} = $now;
$self->{cnt} = 0;
} else {
$self->{cnt}++;
}
my $f;
do {
$f = "$self->{dir}/$dir/$self->{t}.$$"."_$self->{cnt}.$host[0]";
$self->{cnt}++;
} while (-e $f);
$f;
}
sub prepare {
my ($self, $strref) = @_;
die "already in transaction: $self->{tmp}" if $self->{tmp};
my ($tmp, $fh);
do {
$tmp = _fn_in($self, 'tmp');
$! = undef;
} while (!sysopen($fh, $tmp, O_CREAT|O_EXCL|O_RDWR) && $!{EEXIST});
print $fh $$strref or die "write failed: $!";
$fh->flush or die "flush failed: $!";
$fh->autoflush(1);
$self->{fh} = $fh;
$self->{tmp} = $tmp;
}
sub abort {
my ($self) = @_;
delete $self->{fh};
my $tmp = delete $self->{tmp} or return;
unlink($tmp) or warn "Failed to unlink $tmp: $!";
undef;
}
sub fh {
my ($self) = @_;
my $fh = $self->{fh} or die "{fh} not open!\n";
seek($fh, 0, SEEK_SET) or die "seek(fh) failed: $!";
sysseek($fh, 0, SEEK_SET) or die "sysseek(fh) failed: $!";
$fh;
}
sub commit {
my ($self) = @_;
delete $self->{fh};
my $tmp = delete $self->{tmp} or return;
my $new;
do {
$new = _fn_in($self, 'new');
} while (!link($tmp, $new) && $!{EEXIST});
my @sn = stat($new) or die "stat $new failed: $!";
my @st = stat($tmp) or die "stat $tmp failed: $!";
if ($st[0] == $sn[0] && $st[1] == $sn[1]) {
unlink($tmp) or warn "Failed to unlink $tmp: $!";
} else {
warn "stat($new) and stat($tmp) differ";
}
}
sub DESTROY { commit($_[0]) }
1;