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| | # Copyright (C) all contributors <meta@public-inbox.org>
# License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
# a tied handle for auto reaping of children tied to a pipe, see perltie(1)
package PublicInbox::ProcessPipe;
use v5.12;
use Carp qw(carp);
use PublicInbox::DS qw(awaitpid);
sub waitcb { # awaitpid callback
my ($pid, $err_ref, $cb, @args) = @_;
$$err_ref = $?; # sets >{pp_chld_err} for _close
$cb->($pid, @args) if $cb;
}
sub TIEHANDLE {
my ($cls, $pid, $fh, @cb_arg) = @_;
my $self = bless { pid => $pid, fh => $fh, ppid => $$ }, $cls;
# we share $err (and not $self) with awaitpid to avoid a ref cycle
$self->{pp_chld_err} = \(my $err);
awaitpid($pid, \&waitcb, \$err, @cb_arg);
$self;
}
sub BINMODE { binmode(shift->{fh}) } # for IO::Uncompress::Gunzip
sub READ { read($_[0]->{fh}, $_[1], $_[2], $_[3] || 0) }
sub READLINE { readline($_[0]->{fh}) }
sub WRITE {
use bytes qw(length);
syswrite($_[0]->{fh}, $_[1], $_[2] // length($_[1]), $_[3] // 0);
}
sub PRINT {
my $self = shift;
print { $self->{fh} } @_;
}
sub FILENO { fileno($_[0]->{fh}) }
sub _close ($;$) {
my ($self, $wait) = @_;
my ($fh, $pid) = delete(@$self{qw(fh pid)});
my $ret = defined($fh) ? close($fh) : '';
return $ret unless defined($pid) && $self->{ppid} == $$;
if ($wait) { # caller cares about the exit status:
# synchronous wait via defined(wantarray) on awaitpid:
defined(${$self->{pp_chld_err}}) or $wait = awaitpid($pid);
($? = ${$self->{pp_chld_err}}) and $ret = '';
} else {
awaitpid($pid); # depends on $in_loop or not
}
$ret;
}
# if caller uses close(), assume they want to check $? immediately so
# we'll waitpid() synchronously. n.b. wantarray doesn't seem to
# propagate `undef' down to tied methods, otherwise I'd rely on that.
sub CLOSE { _close($_[0], 1) }
# if relying on DESTROY, assume the caller doesn't care about $? and
# we can let the event loop call waitpid() whenever it gets SIGCHLD
sub DESTROY {
_close($_[0]);
undef;
}
1;
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