X-Git-Url: http://www.git.stargrave.org/?a=blobdiff_plain;f=lib%2FPublicInbox%2FHTTPD%2FAsync.pm;h=bd1fd8faf2c1ea49569a702a16c75407ffd4220e;hb=af0b0fb7a454470a32c452119d0392e0dedb3fe1;hp=a1f7551819700e1a48d91f7aa36818a4e5a3ee80;hpb=891c6f0d5c47e93166cfd8b29785ebb1f0545119;p=public-inbox.git

diff --git a/lib/PublicInbox/HTTPD/Async.pm b/lib/PublicInbox/HTTPD/Async.pm
index a1f75518..bd1fd8fa 100644
--- a/lib/PublicInbox/HTTPD/Async.pm
+++ b/lib/PublicInbox/HTTPD/Async.pm
@@ -1,83 +1,110 @@
-# Copyright (C) 2016-2018 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
 # 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 cleanup);
-require PublicInbox::EvCleanup;
+use parent qw(PublicInbox::DS);
+use Errno qw(EAGAIN);
+use PublicInbox::Syscall qw(EPOLLIN EPOLLET);
 
+# 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, $cleanup) = @_;
-	my $self = fields::new($class);
+	my ($class, $io, $cb, $arg, $end_obj) = @_;
+
+	# 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
+	}, $class;
 	IO::Handle::blocking($io, 0);
-	$self->SUPER::new($io);
-	$self->{cb} = $cb;
-	$self->{cleanup} = $cleanup;
-	$self->watch_read(1);
-	$self;
+	$self->SUPER::new($io, EPOLLIN | EPOLLET);
 }
 
-# fires after pending writes are complete:
-sub restart_read_cb ($) {
+sub event_step {
 	my ($self) = @_;
-	sub { $self->watch_read(1) }
-}
-
-sub main_cb ($$$) {
-	my ($http, $fh, $bref) = @_;
-	sub {
-		my ($self) = @_;
-		my $r = sysread($self->{sock}, $$bref, 8192);
+	if (my $cb = delete $self->{cb}) {
+		# this may call async_pass when headers are done
+		$cb->(delete $self->{arg});
+	} elsif (my $sock = $self->{sock}) {
+		my $http = $self->{http};
+		# $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) {
-			$fh->write($$bref);
-			unless ($http->{closed}) { # Danga::Socket sets this
-				if ($http->{write_buf_size}) {
-					$self->watch_read(0);
-					$http->write(restart_read_cb($self));
-				}
-				# stay in watch_read, but let other clients
-				# get some work done, too.
+			$self->{fh}->write($buf); # may call $http->close
+			if ($http->{sock}) { # !closed
+				$self->requeue;
+				# let other clients get some work done, too
 				return;
 			}
-			# fall through to close below...
-		} elsif (!defined $r) {
-			return if $!{EAGAIN} || $!{EINTR};
+
+			# else: fall through to close below...
+		} elsif (!defined $r && $! == EAGAIN) {
+			return; # EPOLLET means we'll be notified
 		}
 
-		# Done! Error handling will happen in $fh->close
-		# called by the {cleanup} handler
-		$http->{forward} = undef;
-		$self->close;
-	}
+		# Done! Error handling will happen in $self->{fh}->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
 }
 
+# once this is called, all data we read is passed to the
+# to the PublicInbox::HTTP instance ($http) via $fh->write
 sub async_pass {
 	my ($self, $http, $fh, $bref) = @_;
 	# In case the client HTTP connection ($http) dies, it
 	# will automatically close this ($self) object.
 	$http->{forward} = $self;
+
+	# write anything we overread when we were reading headers
 	$fh->write($$bref); # PublicInbox:HTTP::{chunked,identity}_wcb
-	$self->{cb} = main_cb($http, $fh, $bref);
-}
 
-sub event_read { $_[0]->{cb}->(@_) }
-sub event_hup { $_[0]->{cb}->(@_) }
-sub event_err { $_[0]->{cb}->(@_) }
+	# we're done with this, free this memory up ASAP since the
+	# calls after this may use much memory:
+	$$bref = undef;
+
+	$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)
 sub close {
-	my $self = shift;
-	my $cleanup = $self->{cleanup};
-	$self->{cleanup} = $self->{cb} = undef;
-	$self->SUPER::close(@_);
+	my $self = $_[0];
+	$self->SUPER::close; # DS::close
 
 	# we defer this to the next timer loop since close is deferred
-	PublicInbox::EvCleanup::next_tick($cleanup) if $cleanup;
+	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;