1 # Copyright (C) 2020-2021 all contributors <meta@public-inbox.org>
2 # License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
4 # internal class used by PublicInbox::Git + PublicInbox::DS
5 # This parses the output pipe of "git cat-file --batch"
6 package PublicInbox::GitAsyncCat;
8 use parent qw(PublicInbox::DS Exporter);
10 use PublicInbox::Syscall qw(EPOLLIN EPOLLET);
11 our @EXPORT = qw(git_async_cat git_async_prefetch);
12 use PublicInbox::Git ();
14 our $GCF2C; # singleton PublicInbox::Gcf2Client
18 if (my $git = delete $self->{git}) {
19 $git->cat_async_abort;
21 $self->SUPER::close; # PublicInbox::DS::close
26 my $git = $self->{git} or return;
27 return $self->close if ($git->{in} // 0) != ($self->{sock} // 1);
28 my $inflight = $git->{inflight};
29 if ($inflight && @$inflight) {
30 $git->cat_async_step($inflight);
33 if (($git->{in} // 0) != ($self->{sock} // 1)) {
35 } elsif (@$inflight || exists $git->{cat_rbuf}) {
36 # ok, more to do, requeue for fairness
39 } elsif ((my $pid = waitpid($git->{pid}, WNOHANG)) > 0) {
40 # May happen if the child process is killed by a BOFH
43 warn "E: git $pid exited with \$?=$?\n";
48 sub git_async_cat ($$$$) {
49 my ($git, $oid, $cb, $arg) = @_;
51 require PublicInbox::Gcf2Client;
52 PublicInbox::Gcf2Client::new();
53 } // 0) { # 0: do not retry if libgit2 or Inline::C are missing
54 $GCF2C->gcf2_async(\"$oid $git->{git_dir}\n", $cb, $arg);
56 } else { # read-only end of git-cat-file pipe
57 $git->cat_async($oid, $cb, $arg);
58 $git->{async_cat} //= do {
59 my $self = bless { git => $git }, __PACKAGE__;
60 $git->{in}->blocking(0);
61 $self->SUPER::new($git->{in}, EPOLLIN|EPOLLET);
62 \undef; # this is a true ref()
67 # this is safe to call inside $cb, but not guaranteed to enqueue
68 # returns true if successful, undef if not.
69 sub git_async_prefetch {
70 my ($git, $oid, $cb, $arg) = @_;
72 if (!$GCF2C->{wbuf}) {
73 $oid .= " $git->{git_dir}\n";
74 return $GCF2C->gcf2_async(\$oid, $cb, $arg); # true
76 } elsif ($git->{async_cat} && (my $inflight = $git->{inflight})) {
77 # we could use MAX_INFLIGHT here w/o the halving,
78 # but lets not allow one client to monopolize a git process
79 if (@$inflight < int(PublicInbox::Git::MAX_INFLIGHT/2)) {
80 print { $git->{out} } $oid, "\n" or
81 $git->fail("write error: $!");
82 return push(@$inflight, $oid, $cb, $arg);