+ $LIVE->{spawn($cmd, undef, $opt)} = [ \&reap_cmd, $self, $cmd, $fini ]
+}
+
+sub fetch_args ($$) {
+ my ($lei, $opt) = @_;
+ my @cmd; # (git --git-dir=...) to be added by caller
+ $opt->{$_} = $lei->{$_} for (0..2);
+ # we support "-c $key=$val" for arbitrary git config options
+ # e.g.: git -c http.proxy=socks5h://127.0.0.1:9050
+ push(@cmd, '-c', $_) for @{$lei->{opt}->{c} // []};
+ push @cmd, 'fetch';
+ push @cmd, '-q' if $lei->{opt}->{quiet} ||
+ ($lei->{opt}->{jobs} // 1) > 1;
+ push @cmd, '-v' if $lei->{opt}->{verbose};
+ @cmd;
+}
+
+sub fgrp_update_old ($) { # for git <1.8.5
+ my ($fgrp) = @_;
+ my $cmd = [ 'git', "--git-dir=$fgrp->{cur_dst}",
+ fetch_args($fgrp->{lei}, my $opt = {}) ];
+ $fgrp->{lei}->qerr("# @$cmd");
+ $LIVE->{spawn($cmd, undef, $opt)} = [ \&reap_cmd, $fgrp, $cmd ];
+ my $jobs = $fgrp->{lei}->{opt}->{jobs} // 1;
+ reap_live() while keys(%$LIVE) >= $jobs;
+}
+
+sub upr { # feed `git update-ref --stdin -z' verbosely
+ my ($fgrp, $w, $op, $ref, $oid) = @_;
+ $fgrp->{lei}->qerr("# $op $ref $oid");
+ print $w "$op $ref\0$oid\0" or die "print(w): $!";
+}
+
+sub fgrp_update {
+ my ($fgrp) = @_;
+ my $srcfh = delete $fgrp->{srcfh} or return;
+ my $dstfh = delete $fgrp->{dstfh} or return;
+ seek($srcfh, SEEK_SET, 0) or die "seek(src): $!";
+ seek($dstfh, SEEK_SET, 0) or die "seek(dst): $!";
+ my %src = map { chomp; split(/\0/) } (<$srcfh>);
+ close $srcfh;
+ my %dst = map { chomp; split(/\0/) } (<$dstfh>);
+ close $dstfh;
+ pipe(my ($r, $w)) or die "pipe: $!";
+ my $cmd = [ 'git', "--git-dir=$fgrp->{cur_dst}",
+ qw(update-ref --stdin -z) ];
+ $fgrp->{lei}->qerr("# @$cmd");
+ my $opt = { 0 => $r, 1 => $fgrp->{lei}->{1}, 2 => $fgrp->{lei}->{2} };
+ my $pid = spawn($cmd, undef, $opt);
+ close $r or die "close(r): $!";
+ for my $ref (keys %dst) {
+ my $new = delete $src{$ref};
+ my $old = $dst{$ref};
+ if (defined $new) {
+ upr($fgrp, $w, 'update', $ref, $new) if $new ne $old;
+ } else {
+ upr($fgrp, $w, 'delete', $ref, $old);
+ }
+ }
+ while (my ($ref, $oid) = each %src) {
+ upr($fgrp, $w, 'create', $ref, $oid);
+ }
+ if (close($w)) { # git >= 1.8.5
+ $LIVE->{$pid} = [ \&reap_cmd, $fgrp, $cmd ];
+ my $jobs = $fgrp->{lei}->{opt}->{jobs} // 1;
+ reap_live() while keys(%$LIVE) >= $jobs;
+ } else { # git <1.8.5 w/o update-ref --stdin
+ warn "E: close(update-ref --stdin): $!\n";
+ $update_ref_stdin = 0;
+ waitpid($pid, 0) // die "waitpid(update-ref --stdin): $!";
+ fgrp_update_old($fgrp);
+ }
+}
+
+sub fgrp_fetched {
+ my ($fgrp) = @_;
+ return if $fgrp->{dry_run} || !$LIVE;
+ my $rn = $fgrp->{-remote};
+ my %opt = map { $_ => $fgrp->{lei}->{$_} } (0..2);
+ my $cmd = [ 'git', "--git-dir=$fgrp->{-osdir}",
+ qw(pack-refs --all --prune) ];
+ $fgrp->{lei}->qerr("# @$cmd");
+ $LIVE->{spawn($cmd, undef, \%opt)} = [ \&reap_cmd, $fgrp, $cmd ];
+ my $jobs = $fgrp->{lei}->{opt}->{jobs} // 1;
+ reap_live() while keys(%$LIVE) >= $jobs;
+
+ $update_ref_stdin or return fgrp_update_old($fgrp);
+
+ my $update_ref = PublicInbox::OnDestroy->new($$, \&fgrp_update, $fgrp);
+
+ my $src = [ 'git', "--git-dir=$fgrp->{-osdir}", 'for-each-ref',
+ "--format=refs/%(refname:lstrip=3)%00%(objectname)",
+ "refs/remotes/$rn/" ];
+ open($fgrp->{srcfh}, '+>', undef) or die "open(src): $!";
+ $fgrp->{lei}->qerr("# @$src >SRC");
+ my $pid = spawn($src, undef, { %opt, 1 => $fgrp->{srcfh} });
+ $LIVE->{$pid} = [ \&reap_cmd, $fgrp, $src, $update_ref ];
+ reap_live() while keys(%$LIVE) >= $jobs;
+
+ my $dst = [ 'git', "--git-dir=$fgrp->{cur_dst}", 'for-each-ref',
+ '--format=%(refname)%00%(objectname)' ];
+ open($fgrp->{dstfh}, '+>', undef) or die "open(dst): $!";
+ $fgrp->{lei}->qerr("# @$dst >DST");
+ $pid = spawn($dst, undef, { %opt, 1 => $fgrp->{dstfh} });
+ $LIVE->{$pid} = [ \&reap_cmd, $fgrp, $dst, $update_ref ];
+ reap_live() while keys(%$LIVE) >= $jobs;
+}
+
+sub fgrp_fetch {
+ my ($fgrp, $pfx, $fini) = @_;
+ my $cmd = [ @$pfx, 'git', "--git-dir=$fgrp->{-osdir}",
+ fetch_args($fgrp->{lei}, my $opt = {}),
+ $fgrp->{-remote} ];
+ $fgrp->{-fini} = $fini;
+ my $jobs = $fgrp->{lei}->{opt}->{jobs} // 1;
+ reap_live() while keys(%$LIVE) >= $jobs;
+ $fgrp->{lei}->qerr("# @$cmd");
+ return if $fgrp->{dry_run};
+ my $fgrp_fini = PublicInbox::OnDestroy->new($$, \&fgrp_fetched, $fgrp);
+ my $pid = spawn($cmd, undef, $opt);
+ $LIVE->{$pid} = [ \&reap_cmd, $fgrp, $cmd, $fgrp_fini ];
+}
+
+# keep this idempotent for future use by public-inbox-fetch
+sub forkgroup_prep {
+ my ($self, $uri) = @_;
+ $self->{-ent} // return;
+ my $os = $self->{-objstore} // return;
+ my $fg = $self->{-ent}->{forkgroup} // return;
+ my $dir = "$os/$fg.git";
+ my @cmd = ('git', "--git-dir=$dir", 'config');
+ my $opt = +{ map { $_ => $self->{lei}->{$_} } (0..2) };
+ if (!-d $dir) {
+ PublicInbox::Import::init_bare($dir);
+ for ('repack.useDeltaIslands=true',
+ 'pack.island=refs/remotes/([^/]+)/') {
+ run_die([@cmd, split(/=/, $_, 2)], undef, $opt);
+ }
+ }
+ my $key = $self->{-key} // die 'BUG: no -key';
+ my ($bn) = ($key =~ m{/([a-z0-9_,;=!\+\{\}\|][^/]*)(?:\.git)?\z}i);
+ my $rn = "$bn-".substr(sha256_hex($key), 0, 16);
+ for ("url=$uri", "fetch=+refs/*:refs/remotes/$rn/*") {
+ my @kv = split(/=/, $_, 2);
+ $kv[0] = "remote.$rn.$kv[0]";
+ run_die([@cmd, @kv], undef, $opt);
+ }
+ if (!-d $self->{cur_dst}) {
+ my $alt = File::Spec->rel2abs("$dir/objects");
+ PublicInbox::Import::init_bare($self->{cur_dst});
+ my $o = "$self->{cur_dst}/objects";
+ my $f = "$o/info/alternates";
+ my $l = File::Spec->abs2rel($alt, File::Spec->rel2abs($o));
+ open my $fh, '+>>', $f or die "open($f): $!";
+ seek($fh, SEEK_SET, 0) or die "seek($f): $!";
+ chomp(my @cur = <$fh>);
+ if (!grep(/\A\Q$l\E\z/, @cur)) {
+ say $fh $l or die "say($f): $!";
+ }
+ close $fh or die "close($f): $!";
+ @cmd = ('git', "--git-dir=$self->{cur_dst}",
+ qw(remote add --mirror=fetch origin), "$uri");
+ my $pid = spawn(\@cmd, undef, $opt);
+ waitpid($pid, 0) // die "waitpid(@cmd): $!";
+ die "E: @cmd: \$?=$?" if ($? && ($? >> 8) != 3);
+ }
+ bless { %$self, -osdir => $dir, -remote => $rn }, __PACKAGE__;