From 659cdc6edac406aba897f1986f063d3b7f45313b Mon Sep 17 00:00:00 2001
From: Eric Wong <e@80x24.org>
Date: Sun, 25 Dec 2016 08:53:19 +0000
Subject: repobrowse: port patch generation over to qspawn

And start generalizing the qspawn usage code for PSGI
with psgi_return.
---
 lib/PublicInbox/Qspawn.pm             | 58 +++++++++++++++++++++++++++++++++
 lib/PublicInbox/RepobrowseGitPatch.pm | 60 +++++++----------------------------
 2 files changed, 69 insertions(+), 49 deletions(-)

diff --git a/lib/PublicInbox/Qspawn.pm b/lib/PublicInbox/Qspawn.pm
index 697c55a1..099c1f34 100644
--- a/lib/PublicInbox/Qspawn.pm
+++ b/lib/PublicInbox/Qspawn.pm
@@ -9,6 +9,7 @@ package PublicInbox::Qspawn;
 use strict;
 use warnings;
 use PublicInbox::Spawn qw(popen_rd);
+my $def_limiter;
 
 sub new ($$$;) {
 	my ($class, $cmd, $env, $opt) = @_;
@@ -54,6 +55,63 @@ sub start {
 	}
 }
 
+sub psgi_return {
+	my ($self, $env, $limiter, $parse_hdr) = @_;
+	my ($fh, $rpipe);
+	my $end = sub {
+		if (my $err = $self->finish) {
+			$err = join(' ', @{$self->{args}->{cmd}}).": $err\n";
+			$env->{'psgi.errors'}->print($err);
+		}
+		$fh->close if $fh; # async-only
+	};
+
+	# Danga::Socket users, we queue up the read_enable callback to
+	# fire after pending writes are complete:
+	my $buf = '';
+	my $rd_hdr = sub {
+		my $r = sysread($rpipe, $buf, 1024, length($buf));
+		return if !defined($r) && ($!{EINTR} || $!{EAGAIN});
+		$parse_hdr->($r, $buf);
+	};
+	my $res;
+	my $async = $env->{'pi-httpd.async'};
+	my $cb = sub {
+		my $r = $rd_hdr->() or return;
+		$rd_hdr = undef;
+		if (scalar(@$r) == 3) { # error
+			if ($async) {
+				$async->close; # calls rpipe->close
+			} else {
+				$rpipe->close;
+				$end->();
+			}
+			$res->($r);
+		} elsif ($async) {
+			$fh = $res->($r); # scalar @$r == 2
+			$async->async_pass($env->{'psgix.io'}, $fh, \$buf);
+		} else { # for synchronous PSGI servers
+			require PublicInbox::GetlineBody;
+			$r->[2] = PublicInbox::GetlineBody->new($rpipe, $end,
+								$buf);
+			$res->($r);
+		}
+	};
+	$limiter ||= $def_limiter ||= PublicInbox::Qspawn::Limiter->new(32);
+	sub {
+		($res) = @_;
+		$self->start($limiter, sub { # may run later, much later...
+			($rpipe) = @_;
+			if ($async) {
+			# PublicInbox::HTTPD::Async->new($rpipe, $cb, $end)
+				$async = $async->($rpipe, $cb, $end);
+			} else { # generic PSGI
+				$cb->() while $rd_hdr;
+			}
+		});
+	};
+}
+
 package PublicInbox::Qspawn::Limiter;
 use strict;
 use warnings;
diff --git a/lib/PublicInbox/RepobrowseGitPatch.pm b/lib/PublicInbox/RepobrowseGitPatch.pm
index eeffc5cb..e8820f72 100644
--- a/lib/PublicInbox/RepobrowseGitPatch.pm
+++ b/lib/PublicInbox/RepobrowseGitPatch.pm
@@ -7,6 +7,7 @@ package PublicInbox::RepobrowseGitPatch;
 use strict;
 use warnings;
 use base qw(PublicInbox::RepobrowseBase);
+use PublicInbox::Qspawn;
 
 # try to be educational and show the command-line used in the signature
 my @CMD = qw(format-patch -M --stdout);
@@ -23,58 +24,19 @@ sub call_git_patch {
 	# limit scope, don't take extra args to avoid wasting server
 	# resources buffering:
 	my $range = "$id~1..$id^0";
-	my @cmd = (@CMD, $sig." $range", $range, '--');
+	my @cmd = ('git', "--git-dir=$git->{git_dir}", @CMD,
+			$sig." $range", $range, '--');
 	if (defined(my $expath = $req->{expath})) {
-		push @cmd, $expath;
+		push @cmd, $expath if $expath ne '';
 	}
-	my $rpipe = $git->popen(@cmd);
-	my $err = $env->{'psgi.errors'};
-	my ($n, $res, $vin, $fh);
-	my $end = sub {
-		if ($fh) {
-			$fh->close;
-			$fh = undef;
-		} elsif ($res) {
-			$res->($self->r(500));
-		}
-		if ($rpipe) {
-			$rpipe->close; # _may_ be Danga::Socket::close
-			$rpipe = undef;
-		}
-	};
-	my $fail = sub {
-		if ($!{EAGAIN} || $!{EINTR}) {
-			select($vin, undef, undef, undef) if defined $vin;
-			# $vin is undef on async, so this is a noop on EAGAIN
-			return;
-		}
-		my $e = $!;
-		$end->();
-		$err->print("git format-patch ($git->{git_dir}): $e\n");
-	};
-	my $cb = sub {
-		$n = $rpipe->sysread(my $buf, 65536);
-		return $fail->() unless defined $n;
-		return $end->() if $n == 0;
-		if ($res) {
-			my $h = ['Content-Type', 'text/plain; charset=UTF-8'];
-			$fh = $res->([200, $h]);
-			$res = undef;
-		}
-		$fh->write($buf);
-	};
 
-	if (my $async = $env->{'pi-httpd.async'}) {
-		$rpipe = $async->($rpipe, $cb);
-		sub { ($res) = @_ } # let Danga::Socket handle the rest.
-	} else { # synchronous loop for other PSGI servers
-		$vin = '';
-		vec($vin, fileno($rpipe), 1) = 1;
-		sub {
-			($res) = @_;
-			while ($rpipe) { $cb->() }
-		}
-	}
+	# FIXME: generalize this with other qspawn users
+	my $qsp = PublicInbox::Qspawn->new(\@cmd);
+	$qsp->psgi_return($env, undef, sub {
+		my ($r) = @_;
+		my $h = ['Content-Type', 'text/plain; charset=UTF-8'];
+		$r ? [ 200, $h ] : [ 500, $h, [ "format-patch error\n" ] ];
+	});
 }
 
 1;
-- 
cgit v1.2.3-24-ge0c7