# Copyright (C) 2020-2021 all contributors
# License: AGPL-3.0+
#
# internal class used by PublicInbox::Git + PublicInbox::DS
# This parses the output pipe of "git cat-file --batch"
package PublicInbox::GitAsyncCat;
use strict;
use parent qw(PublicInbox::DS Exporter);
use POSIX qw(WNOHANG);
use PublicInbox::Syscall qw(EPOLLIN EPOLLET);
our @EXPORT = qw(ibx_async_cat ibx_async_prefetch);
use PublicInbox::Git ();
our $GCF2C; # singleton PublicInbox::Gcf2Client
sub close {
my ($self) = @_;
if (my $git = delete $self->{git}) {
$git->async_abort;
}
$self->SUPER::close; # PublicInbox::DS::close
}
sub event_step {
my ($self) = @_;
my $git = $self->{git} or return;
return $self->close if ($git->{in} // 0) != ($self->{sock} // 1);
my $inflight = $git->{inflight};
if ($inflight && @$inflight) {
$git->cat_async_step($inflight);
# child death?
if (($git->{in} // 0) != ($self->{sock} // 1)) {
$self->close;
} elsif (@$inflight || exists $git->{rbuf}) {
# ok, more to do, requeue for fairness
$self->requeue;
}
} elsif ((my $pid = waitpid($git->{pid}, WNOHANG)) > 0) {
# May happen if the child process is killed by a BOFH
# (or segfaults)
delete $git->{pid};
warn "E: git $pid exited with \$?=$?\n";
$self->close;
}
}
sub ibx_async_cat ($$$$) {
my ($ibx, $oid, $cb, $arg) = @_;
my $git = $ibx->git;
# {topdir} means ExtSearch (likely [extindex "all"]) with potentially
# 100K alternates. git(1) has a proposed patch for 100K alternates:
#
if (!defined($ibx->{topdir}) && ($GCF2C //= eval {
require PublicInbox::Gcf2Client;
PublicInbox::Gcf2Client::new();
} // 0)) { # 0: do not retry if libgit2 or Inline::C are missing
$GCF2C->gcf2_async(\"$oid $git->{git_dir}\n", $cb, $arg);
\undef;
} else { # read-only end of git-cat-file pipe
$git->cat_async($oid, $cb, $arg);
$git->{async_cat} //= do {
my $self = bless { git => $git }, __PACKAGE__;
$git->{in}->blocking(0);
$self->SUPER::new($git->{in}, EPOLLIN|EPOLLET);
\undef; # this is a true ref()
};
}
}
# this is safe to call inside $cb, but not guaranteed to enqueue
# returns true if successful, undef if not.
sub ibx_async_prefetch {
my ($ibx, $oid, $cb, $arg) = @_;
my $git = $ibx->git;
if (!defined($ibx->{topdir}) && $GCF2C) {
if (!$GCF2C->{wbuf}) {
$oid .= " $git->{git_dir}\n";
return $GCF2C->gcf2_async(\$oid, $cb, $arg); # true
}
} elsif ($git->{async_cat} && (my $inflight = $git->{inflight})) {
# we could use MAX_INFLIGHT here w/o the halving,
# but lets not allow one client to monopolize a git process
if (@$inflight < int(PublicInbox::Git::MAX_INFLIGHT/2)) {
print { $git->{out} } $oid, "\n" or
$git->fail("write error: $!");
return push(@$inflight, $oid, $cb, $arg);
}
}
undef;
}
1;