-# Copyright (C) 2020 all contributors <meta@public-inbox.org>
+# Copyright (C) 2020-2021 all contributors <meta@public-inbox.org>
# License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
#
-# internal class used by PublicInbox::Git + Danga::Socket
+# internal class used by PublicInbox::Git + PublicInbox::DS
# This parses the output pipe of "git cat-file --batch"
-#
-# Note: this does NOT set the non-blocking flag, we expect `git cat-file'
-# to be a local process, and git won't start writing a blob until it's
-# fully read. So minimize context switching and read as much as possible
-# and avoid holding a buffer in our heap any longer than it has to live.
package PublicInbox::GitAsyncCat;
use strict;
use parent qw(PublicInbox::DS Exporter);
-use fields qw(git);
+use POSIX qw(WNOHANG);
use PublicInbox::Syscall qw(EPOLLIN EPOLLET);
-our @EXPORT = qw(git_async_cat);
+our @EXPORT = qw(ibx_async_cat ibx_async_prefetch);
+use PublicInbox::Git ();
+
+our $GCF2C; # singleton PublicInbox::Gcf2Client
-sub _add {
- my ($class, $git) = @_;
- my $self = fields::new($class);
- $git->batch_prepare;
- $self->SUPER::new($git->{in}, EPOLLIN|EPOLLET);
- $self->{git} = $git;
- \undef; # this is a true ref()
+sub close {
+ my ($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; # ->close-ed
+ 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);
- $self->requeue if @$inflight || exists $git->{cat_rbuf};
+
+ # child death?
+ if (($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";
+ $self->close;
}
}
-sub close {
- my ($self) = @_;
- if (my $git = delete $self->{git}) {
- delete $git->{async_cat};
+sub ibx_async_cat ($$$$) {
+ my ($ibx, $oid, $cb, $arg) = @_;
+ my $git = $ibx->git;
+ # {topdir} means ExtSearch (likely [extindex "all"]) with potentially
+ # 100K alternates. git(1) has a proposed patch for 100K alternates:
+ # <https://lore.kernel.org/git/20210624005806.12079-1-e@80x24.org/>
+ if (!defined($ibx->{topdir}) && ($GCF2C //= eval {
+ require PublicInbox::Gcf2Client;
+ PublicInbox::Gcf2Client::new();
+ } // 0)) { # 0: do not retry if libgit2 or Inline::C are missing
+ $GCF2C->gcf2_async(\"$oid $git->{git_dir}\n", $cb, $arg);
+ \undef;
+ } else { # read-only end of git-cat-file pipe
+ $git->cat_async($oid, $cb, $arg);
+ $git->{async_cat} //= do {
+ my $self = bless { git => $git }, __PACKAGE__;
+ $git->{in}->blocking(0);
+ $self->SUPER::new($git->{in}, EPOLLIN|EPOLLET);
+ \undef; # this is a true ref()
+ };
}
- $self->SUPER::close; # PublicInbox::DS::close
}
-sub git_async_cat ($$$$) {
- my ($git, $oid, $cb, $arg) = @_;
- $git->cat_async($oid, $cb, $arg);
- $git->{async_cat} //= _add(__PACKAGE__, $git);
+# 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;