lei: switch to use SEQPACKET socketpair instead of pipe

[public-inbox.git] / lib / PublicInbox / PktOp.pm

diff --git a/lib/PublicInbox/PktOp.pm b/lib/PublicInbox/PktOp.pm
new file mode 100644 (file)
index 0000000..d5b95a7
--- /dev/null
+++ b/lib/PublicInbox/PktOp.pm
@@ -0,0 +1,79 @@
+# Copyright (C) 2021 all contributors <meta@public-inbox.org>
+# License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
+
+# op dispatch socket, reads a message, runs a sub
+# There may be multiple producers, but (for now) only one consumer
+# Used for lei_xsearch and maybe other things
+# "literal" => [ sub, @operands ]
+# /regexp/ => [ sub, @operands ]
+package PublicInbox::PktOp;
+use strict;
+use v5.10.1;
+use parent qw(PublicInbox::DS);
+use Errno qw(EAGAIN EINTR);
+use PublicInbox::Syscall qw(EPOLLIN EPOLLET);
+use Socket qw(AF_UNIX MSG_EOR SOCK_SEQPACKET);
+
+sub new {
+       my ($cls, $r, $ops, $in_loop) = @_;
+       my $self = bless { sock => $r, ops => $ops, re => [] }, $cls;
+       if (ref($ops) eq 'ARRAY') {
+               my %ops;
+               for my $op (@$ops) {
+                       if (ref($op->[0])) {
+                               push @{$self->{re}}, $op;
+                       } else {
+                               $ops{$op->[0]} = $op->[1];
+                       }
+               }
+               $self->{ops} = \%ops;
+       }
+       if ($in_loop) { # iff using DS->EventLoop
+               $r->blocking(0);
+               $self->SUPER::new($r, EPOLLIN|EPOLLET);
+       }
+       $self;
+}
+
+# returns a blessed object as the consumer, and a GLOB/IO for the producer
+sub pair {
+       my ($cls, $ops, $in_loop) = @_;
+       my ($c, $p);
+       socketpair($c, $p, AF_UNIX, SOCK_SEQPACKET, 0) or die "socketpair: $!";
+       (new($cls, $c, $ops, $in_loop), $p);
+}
+
+sub close {
+       my ($self) = @_;
+       my $c = $self->{sock} or return;
+       $c->blocking ? delete($self->{sock}) : $self->SUPER::close;
+}
+
+sub event_step {
+       my ($self) = @_;
+       my $c = $self->{sock};
+       my $msg;
+       do {
+               my $n = recv($c, $msg, 128, 0);
+               unless (defined $n) {
+                       return if $! == EAGAIN;
+                       next if $! == EINTR;
+                       $self->close;
+                       die "recv: $!";
+               }
+               my $op = $self->{ops}->{$msg};
+               unless ($op) {
+                       for my $re_op (@{$self->{re}}) {
+                               $msg =~ $re_op->[0] or next;
+                               $op = $re_op->[1];
+                               last;
+                       }
+               }
+               die "BUG: unknown message: `$msg'" unless $op;
+               my ($sub, @args) = @$op;
+               $sub->(@args);
+               return $self->close if $msg eq ''; # close on EOF
+       } while (1);
+}
+
+1;