httpd/async: switch to level-triggered epoll

[public-inbox.git] / lib / PublicInbox / HTTPD / Async.pm

diff --git a/lib/PublicInbox/HTTPD/Async.pm b/lib/PublicInbox/HTTPD/Async.pm
index f4de2719d249b50c8f807b6a039955e9f46385fa..1651da88ac034cfcc022f8739b7ab25246b09975 100644 (file)
--- a/lib/PublicInbox/HTTPD/Async.pm
+++ b/lib/PublicInbox/HTTPD/Async.pm
@@ -1,4 +1,4 @@
-# Copyright (C) 2016-2019 all contributors <meta@public-inbox.org>
+# Copyright (C) 2016-2021 all contributors <meta@public-inbox.org>
 # License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
 #
 # XXX This is a totally unstable API for public-inbox internal use only
@@ -6,13 +6,18 @@
 # The name of this key is not even stable!
 # Currently intended for use with read-only pipes with expensive
 # processes such as git-http-backend(1), cgit(1)
+#
+# fields:
+# http: PublicInbox::HTTP ref
+# fh: PublicInbox::HTTP::{Identity,Chunked} ref (can ->write + ->close)
+# cb: initial read callback
+# arg: arg for {cb}
+# end_obj: CODE or object which responds to ->event_step when ->close is called
 package PublicInbox::HTTPD::Async;
 use strict;
-use warnings;
-use base qw(PublicInbox::DS);
-use fields qw(http fh cb arg end_obj);
+use parent qw(PublicInbox::DS);
 use Errno qw(EAGAIN);
-use PublicInbox::Syscall qw(EPOLLIN EPOLLET);
+use PublicInbox::Syscall qw(EPOLLIN);
 
 # This is called via: $env->{'pi-httpd.async'}->()
 # $io is a read-only pipe ($rpipe) for now, but may be a
@@ -27,21 +32,21 @@ sub new {
                die '$end_obj unsupported w/o $io' if $end_obj;
                return;
        }
-
-       my $self = fields::new($class);
-       IO::Handle::blocking($io, 0);
-       $self->SUPER::new($io, EPOLLIN | EPOLLET);
-       $self->{cb} = $cb; # initial read callback
-       $self->{arg} = $arg; # arg for $cb
-       $self->{end_obj} = $end_obj; # like END{}, can ->event_step
-       $self;
+       my $self = bless {
+               cb => $cb, # initial read callback
+               arg => $arg, # arg for $cb
+               end_obj => $end_obj, # like END{}, can ->event_step
+       }, $class;
+       my $pp = tied *$io;
+       $pp->{fh}->blocking(0) // die "$io->blocking(0): $!";
+       $self->SUPER::new($io, EPOLLIN);
 }
 
 sub event_step {
        my ($self) = @_;
        if (my $cb = delete $self->{cb}) {
                # this may call async_pass when headers are done
-               $cb->(delete $self->{arg});
+               $cb->(my $refcnt_guard = delete $self->{arg});
        } elsif (my $sock = $self->{sock}) {
                my $http = $self->{http};
                # $self->{sock} is a read pipe for git-http-backend or cgit
@@ -49,15 +54,12 @@ sub event_step {
                my $r = sysread($sock, my $buf, 65536);
                if ($r) {
                        $self->{fh}->write($buf); # may call $http->close
-                       if ($http->{sock}) { # !closed
-                               $self->requeue;
-                               # let other clients get some work done, too
-                               return;
-                       }
+                       # let other clients get some work done, too
+                       return if $http->{sock}; # !closed
 
                        # else: fall through to close below...
                } elsif (!defined $r && $! == EAGAIN) {
-                       return; # EPOLLET means we'll be notified
+                       return; # EPOLLIN means we'll be notified
                }
 
                # Done! Error handling will happen in $self->{fh}->close
@@ -84,9 +86,6 @@ sub async_pass {
 
        $self->{http} = $http;
        $self->{fh} = $fh;
-
-       # either hit EAGAIN or ->requeue to keep EPOLLET happy
-       event_step($self);
 }
 
 # may be called as $forward->close in PublicInbox::HTTP or EOF (event_step)