[PATCH 3/3] git-http-backend: fix aborts for generic PSGI clone

[Eric Wong <e@80x24.org>]

We need to avoid circular references in the generic PSGI layer,
do it by abusing DESTROY.
---
 lib/PublicInbox/GetlineBody.pm    | 31 +++++++++++++++++++++++++++++++
 lib/PublicInbox/GitHTTPBackend.pm | 13 ++++---------
 2 files changed, 35 insertions(+), 9 deletions(-)
 create mode 100644 lib/PublicInbox/GetlineBody.pm

diff --git a/lib/PublicInbox/GetlineBody.pm b/lib/PublicInbox/GetlineBody.pm
new file mode 100644
index 0000000..4f8765b
--- /dev/null
+++ b/lib/PublicInbox/GetlineBody.pm
@@ -0,0 +1,31 @@
+# Copyright (C) 2016 all contributors <meta@public-inbox.org>
+# License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
+
+# Wrap a pipe or file for PSGI streaming response bodies and calls the
+# end callback when the object goes out-of-scope.
+# This depends on rpipe being _blocking_ on getline.
+package PublicInbox::GetlineBody;
+use strict;
+use warnings;
+
+sub new {
+	my ($class, $rpipe, $end, $buf) = @_;
+	bless { rpipe => $rpipe, end => $end, buf => $buf }, $class;
+}
+
+sub DESTROY { $_[0]->close }
+
+sub getline {
+	my ($self) = @_;
+	my $buf = delete $self->{buf};
+	defined $buf ? $buf : $self->{rpipe}->getline;
+}
+
+sub close {
+	my ($self) = @_;
+	delete $self->{rpipe};
+	my $end = delete $self->{end} or return;
+	$end->();
+}
+
+1;
diff --git a/lib/PublicInbox/GitHTTPBackend.pm b/lib/PublicInbox/GitHTTPBackend.pm
index 9464cb4..fd7afbc 100644
--- a/lib/PublicInbox/GitHTTPBackend.pm
+++ b/lib/PublicInbox/GitHTTPBackend.pm
@@ -186,7 +186,7 @@ sub serve_smart {
 	my $x = PublicInbox::Qspawn->new([qw(git http-backend)], \%env, \%rdr);
 	my ($fh, $rpipe);
 	my $end = sub {
-		$rpipe = undef;
+		close $rpipe if $rpipe && !$fh; # generic PSGI
 		if (my $err = $x->finish) {
 			err($env, "git http-backend ($git_dir): $err");
 			drop_client($env);
@@ -201,7 +201,7 @@ sub serve_smart {
 		my $r = sysread($rpipe, $buf, 1024, length($buf));
 		return if !defined($r) && ($!{EINTR} || $!{EAGAIN});
 		return r(500, 'http-backend error') unless $r;
-		$r = parse_cgi_headers(\$buf) or return;
+		$r = parse_cgi_headers(\$buf) or return; # incomplete headers
 		$r->[0] == 403 ? serve_dumb($cgi, $git, $path) : $r;
 	};
 	my $res;
@@ -220,13 +220,8 @@ sub serve_smart {
 		}
 
 		# for synchronous PSGI servers
-		$r->[2] = Plack::Util::inline_object(
-			close => $end,
-			getline => sub {
-				my $ret = $buf;
-				$buf = undef;
-				defined $ret ? $ret : $rpipe->getline;
-			});
+		require PublicInbox::GetlineBody;
+		$r->[2] = PublicInbox::GetlineBody->new($rpipe, $end, $buf);
 		$res->($r);
 	};
 	sub {