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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>
#
# This makes select(2) look like epoll to simplify the code in DS.pm.
# Unlike IO::Select, it does NOT hold references to IO handles.
# This is NOT meant to be an all encompassing emulation of epoll
# via select, but only to support cases we care about.
package PublicInbox::Select;
use v5.12;
use PublicInbox::Syscall qw(EPOLLONESHOT EPOLLIN EPOLLOUT);
use Errno;
sub new { bless {}, __PACKAGE__ } # fd => events
sub ep_wait {
my ($self, $msec, $events) = @_;
my ($rvec, $wvec) = ('', ''); # we don't use EPOLLERR
while (my ($fd, $ev) = each %$self) {
vec($rvec, $fd, 1) = 1 if $ev & EPOLLIN;
vec($wvec, $fd, 1) = 1 if $ev & EPOLLOUT;
}
@$events = ();
my $to = $msec < 0 ? undef : ($msec/1000);
my $n = select $rvec, $wvec, undef, $to or return; # timeout expired
return if $n < 0 && $! == Errno::EINTR; # caller recalculates timeout
die "select: $!" if $n < 0;
while (my ($fd, $ev) = each %$self) {
if (vec($rvec, $fd, 1) || vec($wvec, $fd, 1)) {
delete($self->{$fd}) if $ev & EPOLLONESHOT;
push @$events, $fd;
}
}
$n == scalar(@$events) or
warn "BUG? select() returned $n, but got ".scalar(@$events);
}
sub ep_del { delete($_[0]->{fileno($_[1])}); 0 }
sub ep_add { $_[0]->{fileno($_[1])} = $_[2]; 0 }
no warnings 'once';
*ep_mod = \&ep_add;
1;
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