1 files changed, 41 insertions, 0 deletions
diff --git a/lib/PublicInbox/OpPipe.pm b/lib/PublicInbox/OpPipe.pm
new file mode 100644
index 00000000..295a8aa5
--- /dev/null
+++ b/lib/PublicInbox/OpPipe.pm
@@ -0,0 +1,41 @@
+# Copyright (C) 2021 all contributors <meta@public-inbox.org>
+# License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
+
+# bytecode dispatch pipe, reads a byte, runs a sub
+# byte => [ sub, @operands ]
+package PublicInbox::OpPipe;
+use strict;
+use v5.10.1;
+use parent qw(PublicInbox::DS);
+use PublicInbox::Syscall qw(EPOLLIN);
+
+sub new {
+        my ($cls, $rd, $op_map, $in_loop) = @_;
+        my $self = bless { sock => $rd, op_map => $op_map }, $cls;
+        # 1031: F_SETPIPE_SZ, 4096: page size
+        fcntl($rd, 1031, 4096) if $^O eq 'linux';
+        if ($in_loop) { # iff using DS->EventLoop
+                $rd->blocking(0);
+                $self->SUPER::new($rd, EPOLLIN);
+        }
+        $self;
+}
+
+sub event_step {
+        my ($self) = @_;
+        my $rd = $self->{sock};
+        my $byte;
+        until (defined(sysread($rd, $byte, 1))) {
+                return if $!{EAGAIN};
+                next if $!{EINTR};
+                die "read \$rd: $!";
+        }
+        my $op = $self->{op_map}->{$byte} or die "BUG: unknown byte `$byte'";
+        if ($byte eq '') { # close on EOF
+                $rd->blocking ? delete($self->{sock}) : $self->close;
+        }
+        my ($sub, @args) = @$op;
+        $sub->(@args);
+}
+
+1;