1 # Copyright (C) 2016-2019 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)
9 package PublicInbox::HTTPD::Async;
12 use base qw(PublicInbox::DS);
13 use fields qw(cb end);
15 use PublicInbox::Syscall qw(EPOLLIN EPOLLET);
17 # This is called via: $env->{'pi-httpd.async'}->()
18 # $io is a read-only pipe ($rpipe) for now, but may be a
19 # bidirectional socket in the future.
21 my ($class, $io, $cb, $end) = @_;
23 # no $io? call $cb at the top of the next event loop to
25 unless (defined($io)) {
26 PublicInbox::DS::requeue($cb);
27 die '$end unsupported w/o $io' if $end;
31 my $self = fields::new($class);
32 IO::Handle::blocking($io, 0);
33 $self->SUPER::new($io, EPOLLIN | EPOLLET);
34 $self->{cb} = $cb; # initial read callback, later replaced by main_cb
35 $self->{end} = $end; # like END {}, but only for this object
43 # $self->{sock} is a read pipe for git-http-backend or cgit
44 # and 65536 is the default Linux pipe size
45 my $r = sysread($self->{sock}, my $buf, 65536);
47 $fh->write($buf); # may call $http->close
48 if ($http->{sock}) { # !closed
50 # let other clients get some work done, too
54 # else: fall through to close below...
55 } elsif (!defined $r && $! == EAGAIN) {
56 return; # EPOLLET means we'll be notified
59 # Done! Error handling will happen in $fh->close
60 # called by the {end} handler
61 delete $http->{forward};
62 $self->close; # queues ->{end} to be called
66 # once this is called, all data we read is passed to the
67 # to the PublicInbox::HTTP instance ($http) via $fh->write
69 my ($self, $http, $fh, $bref) = @_;
70 # In case the client HTTP connection ($http) dies, it
71 # will automatically close this ($self) object.
72 $http->{forward} = $self;
74 # write anything we overread when we were reading headers
75 $fh->write($$bref); # PublicInbox:HTTP::{chunked,identity}_wcb
77 # we're done with this, free this memory up ASAP since the
78 # calls after this may use much memory:
81 # replace the header read callback with the main one
82 my $cb = $self->{cb} = main_cb($http, $fh);
83 $cb->($self); # either hit EAGAIN or ->requeue to keep EPOLLET happy
87 # {cb} may be undef after ->requeue due to $http->close happening
88 my $cb = $_[0]->{cb} or return;
92 # may be called as $forward->close in PublicInbox::HTTP or EOF (main_cb)
96 $self->SUPER::close; # DS::close
98 # we defer this to the next timer loop since close is deferred
99 if (my $end = delete $self->{end}) {
100 PublicInbox::DS::requeue($end);