X-Git-Url: http://www.git.stargrave.org/?a=blobdiff_plain;f=lib%2FPublicInbox%2FHTTPD%2FAsync.pm;h=e03daafac8d1a7994042fa52e94e4eac60f7ac4c;hb=1556c660030b7ebb4006f522026e638285e94f46;hp=8f3a6a0907c72d00aadcb69b09a651197032dd31;hpb=6b5e35ca6dc6a505d26f129627b5eb7ff8476539;p=public-inbox.git

diff --git a/lib/PublicInbox/HTTPD/Async.pm b/lib/PublicInbox/HTTPD/Async.pm
index 8f3a6a09..e03daafa 100644
--- a/lib/PublicInbox/HTTPD/Async.pm
+++ b/lib/PublicInbox/HTTPD/Async.pm
@@ -1,56 +1,107 @@
-# Copyright (C) 2016 all contributors <meta@public-inbox.org>
+# Copyright (C) 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
 # This is exposed via the 'pi-httpd.async' key in the PSGI env hash.
 # The name of this key is not even stable!
-# Currently is is intended for use with read-only pipes.
+# 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(Danga::Socket);
-use fields qw(cb);
+use parent qw(PublicInbox::DS);
+use Errno qw(EAGAIN);
+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
+# bidirectional socket in the future.
 sub new {
-	my ($class, $io, $cb) = @_;
-	my $self = fields::new($class);
-	IO::Handle::blocking($io, 0);
-	$self->SUPER::new($io);
-	$self->{cb} = $cb;
-	$self->watch_read(1);
-	$self;
-}
+	my ($class, $io, $cb, $arg, $end_obj) = @_;
 
-sub async_pass { $_[0]->{cb} = $_[1] }
-sub event_read { $_[0]->{cb}->() }
-sub event_hup { $_[0]->{cb}->() }
-sub event_err { $_[0]->{cb}->() }
-sub sysread { shift->{sock}->sysread(@_) }
+	# no $io? call $cb at the top of the next event loop to
+	# avoid recursion:
+	unless (defined($io)) {
+		PublicInbox::DS::requeue($cb ? $cb : $arg);
+		die '$end_obj unsupported w/o $io' if $end_obj;
+		return;
+	}
+	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; # ProcessPipe
+	$pp->{fh}->blocking(0) // die "$io->blocking(0): $!";
+	$self->SUPER::new($io, EPOLLIN);
+}
 
-sub getline {
+sub event_step {
 	my ($self) = @_;
-	die 'getline called without $/ ref' unless ref $/;
-	while (1) {
-		my $ret = $self->read(8192); # Danga::Socket::read
-		return $$ret if defined $ret;
-
-		return unless $!{EAGAIN} || $!{EINTR};
-
-		# in case of spurious wakeup, hopefully we never hit this
-		my $vin = '';
-		vec($vin, $self->{fd}, 1) = 1;
-		my $n;
-		do { $n = select($vin, undef, undef, undef) } until $n;
-	}
+	if (my $cb = delete $self->{cb}) {
+		# this may call async_pass when headers are done
+		$cb->(my $refcnt_guard = delete $self->{arg});
+	} elsif (my $sock = $self->{sock}) {
+		# $http may be undef if discarding body output from cgit on 404
+		my $http = $self->{http} or return $self->close;
+		# $self->{sock} is a read pipe for git-http-backend or cgit
+		# and 65536 is the default Linux pipe size
+		my $r = sysread($sock, my $buf, 65536);
+		if ($r) {
+			$self->{ofh}->write($buf); # may call $http->close
+			# let other clients get some work done, too
+			return if $http->{sock}; # !closed
+
+			# else: fall through to close below...
+		} elsif (!defined $r && $! == EAGAIN) {
+			return; # EPOLLIN means we'll be notified
+		}
+
+		# Done! Error handling will happen in $self->{ofh}->close
+		# called by end_obj->event_step handler
+		delete $http->{forward};
+		$self->close; # queues end_obj->event_step to be called
+	} # else { # we may've been requeued but closed by $http
 }
 
-sub close {
-	my $self = shift;
-	$self->{cb} = undef;
-	$self->SUPER::close(@_);
+# once this is called, all data we read is passed to the
+# to the PublicInbox::HTTP instance ($http) via $ofh->write
+# $ofh is typically PublicInbox::HTTP::{Chunked,Identity}, but
+# may be PublicInbox::GzipFilter or $PublicInbox::Qspawn::qx_fh
+sub async_pass {
+	my ($self, $http, $ofh, $bref) = @_;
+	# In case the client HTTP connection ($http) dies, it
+	# will automatically close this ($self) object.
+	$http->{forward} = $self;
+
+	# write anything we overread when we were reading headers.
+	# This is typically PublicInbox:HTTP::{chunked,identity}_wcb,
+	# but may be PublicInbox::GzipFilter::write.  PSGI requires
+	# *_wcb methods respond to ->write (and ->close), not ->print
+	$ofh->write($$bref);
+
+	$self->{http} = $http;
+	$self->{ofh} = $ofh;
 }
 
-# do not let ourselves be closed during graceful termination
-sub busy () { $_[0]->{cb} }
+# may be called as $forward->close in PublicInbox::HTTP or EOF (event_step)
+sub close {
+	my $self = $_[0];
+	$self->SUPER::close; # DS::close
+
+	# we defer this to the next timer loop since close is deferred
+	if (my $end_obj = delete $self->{end_obj}) {
+		# this calls $end_obj->event_step
+		# (likely PublicInbox::Qspawn::event_step,
+		#  NOT PublicInbox::HTTPD::Async::event_step)
+		PublicInbox::DS::requeue($end_obj);
+	}
+}
 
 1;