1 # Copyright (C) 2016-2021 all contributors <meta@public-inbox.org>
2 # License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
4 # XXX This is a totally unstable API for public-inbox internal use only
5 # This is exposed via the 'pi-httpd.async' key in the PSGI env hash.
6 # The name of this key is not even stable!
7 # Currently intended for use with read-only pipes with expensive
8 # processes such as git-http-backend(1), cgit(1)
11 # http: PublicInbox::HTTP ref
12 # fh: PublicInbox::HTTP::{Identity,Chunked} ref (can ->write + ->close)
13 # cb: initial read callback
15 # end_obj: CODE or object which responds to ->event_step when ->close is called
16 package PublicInbox::HTTPD::Async;
18 use parent qw(PublicInbox::DS);
20 use PublicInbox::Syscall qw(EPOLLIN);
22 # This is called via: $env->{'pi-httpd.async'}->()
23 # $io is a read-only pipe ($rpipe) for now, but may be a
24 # bidirectional socket in the future.
26 my ($class, $io, $cb, $arg, $end_obj) = @_;
28 # no $io? call $cb at the top of the next event loop to
30 unless (defined($io)) {
31 PublicInbox::DS::requeue($cb ? $cb : $arg);
32 die '$end_obj unsupported w/o $io' if $end_obj;
36 cb => $cb, # initial read callback
37 arg => $arg, # arg for $cb
38 end_obj => $end_obj, # like END{}, can ->event_step
41 $pp->{fh}->blocking(0) // die "$io->blocking(0): $!";
42 $self->SUPER::new($io, EPOLLIN);
47 if (my $cb = delete $self->{cb}) {
48 # this may call async_pass when headers are done
49 $cb->(my $refcnt_guard = delete $self->{arg});
50 } elsif (my $sock = $self->{sock}) {
51 my $http = $self->{http};
52 # $self->{sock} is a read pipe for git-http-backend or cgit
53 # and 65536 is the default Linux pipe size
54 my $r = sysread($sock, my $buf, 65536);
56 $self->{fh}->write($buf); # may call $http->close
57 # let other clients get some work done, too
58 return if $http->{sock}; # !closed
60 # else: fall through to close below...
61 } elsif (!defined $r && $! == EAGAIN) {
62 return; # EPOLLIN means we'll be notified
65 # Done! Error handling will happen in $self->{fh}->close
66 # called by end_obj->event_step handler
67 delete $http->{forward};
68 $self->close; # queues end_obj->event_step to be called
69 } # else { # we may've been requeued but closed by $http
72 # once this is called, all data we read is passed to the
73 # to the PublicInbox::HTTP instance ($http) via $fh->write
75 my ($self, $http, $fh, $bref) = @_;
76 # In case the client HTTP connection ($http) dies, it
77 # will automatically close this ($self) object.
78 $http->{forward} = $self;
80 # write anything we overread when we were reading headers
81 $fh->write($$bref); # PublicInbox:HTTP::{chunked,identity}_wcb
83 # we're done with this, free this memory up ASAP since the
84 # calls after this may use much memory:
87 $self->{http} = $http;
91 # may be called as $forward->close in PublicInbox::HTTP or EOF (event_step)
94 $self->SUPER::close; # DS::close
96 # we defer this to the next timer loop since close is deferred
97 if (my $end_obj = delete $self->{end_obj}) {
98 # this calls $end_obj->event_step
99 # (likely PublicInbox::Qspawn::event_step,
100 # NOT PublicInbox::HTTPD::Async::event_step)
101 PublicInbox::DS::requeue($end_obj);