-# Copyright (C) 2014-2015 all contributors <meta@public-inbox.org>
-# License: GPLv2 or later (https://www.gnu.org/licenses/gpl-2.0.txt)
+# Copyright (C) 2014-2020 all contributors <meta@public-inbox.org>
+# License: GPLv2 or later <https://www.gnu.org/licenses/gpl-2.0.txt>
#
# Used to read files from a git repository without excessive forking.
# Used in our web interfaces as well as our -nntpd server.
package PublicInbox::Git;
use strict;
use warnings;
-use POSIX qw(dup2);
-require IO::Handle;
-use PublicInbox::Spawn qw(spawn popen_rd);
+use POSIX ();
+use IO::Handle; # ->autoflush
+use File::Glob qw(bsd_glob GLOB_NOSORT);
+use PublicInbox::Spawn qw(popen_rd);
+use PublicInbox::Tmpfile;
+use base qw(Exporter);
+our @EXPORT_OK = qw(git_unquote git_quote);
+
+use constant MAX_INFLIGHT =>
+ ($^O eq 'linux' ? 4096 : POSIX::_POSIX_PIPE_BUF())
+ /
+ 65; # SHA-256 hex size + "\n" in preparation for git using non-SHA1
+
+my %GIT_ESC = (
+ a => "\a",
+ b => "\b",
+ f => "\f",
+ n => "\n",
+ r => "\r",
+ t => "\t",
+ v => "\013",
+ '"' => '"',
+ '\\' => '\\',
+);
+my %ESC_GIT = map { $GIT_ESC{$_} => $_ } keys %GIT_ESC;
+
+
+# unquote pathnames used by git, see quote.c::unquote_c_style.c in git.git
+sub git_unquote ($) {
+ return $_[0] unless ($_[0] =~ /\A"(.*)"\z/);
+ $_[0] = $1;
+ $_[0] =~ s/\\([\\"abfnrtv])/$GIT_ESC{$1}/g;
+ $_[0] =~ s/\\([0-7]{1,3})/chr(oct($1))/ge;
+ $_[0];
+}
+
+sub git_quote ($) {
+ if ($_[0] =~ s/([\\"\a\b\f\n\r\t\013]|[^[:print:]])/
+ '\\'.($ESC_GIT{$1}||sprintf("%0o",ord($1)))/egs) {
+ return qq{"$_[0]"};
+ }
+ $_[0];
+}
sub new {
my ($class, $git_dir) = @_;
- bless { git_dir => $git_dir }, $class
+ my @st;
+ $st[7] = $st[10] = 0;
+ # may contain {-tmp} field for File::Temp::Dir
+ bless { git_dir => $git_dir, st => \@st, -git_path => {} }, $class
}
-sub _bidi_pipe {
- my ($self, $batch, $in, $out, $pid) = @_;
- return if $self->{$pid};
- my ($in_r, $in_w, $out_r, $out_w);
+sub git_path ($$) {
+ my ($self, $path) = @_;
+ $self->{-git_path}->{$path} ||= do {
+ local $/ = "\n";
+ chomp(my $str = $self->qx(qw(rev-parse --git-path), $path));
- pipe($in_r, $in_w) or fail($self, "pipe failed: $!");
- pipe($out_r, $out_w) or fail($self, "pipe failed: $!");
+ # git prior to 2.5.0 did not understand --git-path
+ if ($str eq "--git-path\n$path") {
+ $str = "$self->{git_dir}/$path";
+ }
+ $str;
+ };
+}
+
+sub alternates_changed {
+ my ($self) = @_;
+ my $alt = git_path($self, 'objects/info/alternates');
+ my @st = stat($alt) or return 0;
+ my $old_st = $self->{st};
+ # 10 - ctime, 7 - size
+ return 0 if ($st[10] == $old_st->[10] && $st[7] == $old_st->[7]);
+ $self->{st} = \@st;
+}
- my @cmd = ('git', "--git-dir=$self->{git_dir}", qw(cat-file), $batch);
- my $redir = { 0 => fileno($out_r), 1 => fileno($in_w) };
- my $p = spawn(\@cmd, undef, $redir);
- defined $p or fail($self, "spawn failed: $!");
+sub last_check_err {
+ my ($self) = @_;
+ my $fh = $self->{err_c} or return;
+ sysseek($fh, 0, 0) or fail($self, "sysseek failed: $!");
+ defined(sysread($fh, my $buf, -s $fh)) or
+ fail($self, "sysread failed: $!");
+ $buf;
+}
+
+sub _bidi_pipe {
+ my ($self, $batch, $in, $out, $pid, $err) = @_;
+ if ($self->{$pid}) {
+ if (defined $err) { # "err_c"
+ my $fh = $self->{$err};
+ sysseek($fh, 0, 0) or fail($self, "sysseek failed: $!");
+ truncate($fh, 0) or fail($self, "truncate failed: $!");
+ }
+ return;
+ }
+ my ($out_r, $out_w);
+ pipe($out_r, $out_w) or fail($self, "pipe failed: $!");
+ my @cmd = (qw(git), "--git-dir=$self->{git_dir}",
+ qw(-c core.abbrev=40 cat-file), $batch);
+ my $redir = { 0 => $out_r };
+ if ($err) {
+ my $id = "git.$self->{git_dir}$batch.err";
+ my $fh = tmpfile($id) or fail($self, "tmpfile($id): $!");
+ $self->{$err} = $fh;
+ $redir->{2} = $fh;
+ }
+ my ($in_r, $p) = popen_rd(\@cmd, undef, $redir);
$self->{$pid} = $p;
$out_w->autoflush(1);
+ if ($^O eq 'linux') { # 1031: F_SETPIPE_SZ
+ fcntl($out_w, 1031, 4096);
+ fcntl($in_r, 1031, 4096) if $batch eq '--batch-check';
+ }
$self->{$out} = $out_w;
$self->{$in} = $in_r;
}
+sub read_cat_in_full ($$$) {
+ my ($self, $in, $left) = @_;
+ my $offset = 0;
+ my $buf = '';
+ while ($left > 0) {
+ my $r = read($in, $buf, $left, $offset);
+ defined($r) or fail($self, "read failed: $!");
+ $r == 0 and fail($self, 'exited unexpectedly');
+ $left -= $r;
+ $offset += $r;
+ }
+ my $r = read($in, my $lf, 1);
+ defined($r) or fail($self, "read failed: $!");
+ fail($self, 'newline missing after blob') if ($r != 1 || $lf ne "\n");
+ \$buf;
+}
+
+sub _cat_async_step ($$$) {
+ my ($self, $inflight, $in) = @_;
+ my $pair = shift @$inflight or die 'BUG: inflight empty';
+ my ($cb, $arg) = @$pair;
+ local $/ = "\n";
+ my $head = $in->getline;
+ $head =~ / missing$/ and return
+ eval { $cb->(undef, undef, undef, undef, $arg) };
+
+ $head =~ /^([0-9a-f]{40}) (\S+) ([0-9]+)$/ or
+ fail($self, "Unexpected result from async git cat-file: $head");
+ my ($oid_hex, $type, $size) = ($1, $2, $3 + 0);
+ my $bref = read_cat_in_full($self, $in, $size);
+ eval { $cb->($bref, $oid_hex, $type, $size, $arg) };
+}
+
+sub cat_async_wait ($) {
+ my ($self) = @_;
+ my $inflight = delete $self->{inflight} or return;
+ my $in = $self->{in};
+ while (scalar(@$inflight)) {
+ _cat_async_step($self, $inflight, $in);
+ }
+}
+
sub cat_file {
my ($self, $obj, $ref) = @_;
-
+ my ($retried, $in, $head);
+ cat_async_wait($self);
+again:
batch_prepare($self);
$self->{out}->print($obj, "\n") or fail($self, "write error: $!");
- my $in = $self->{in};
+ $in = $self->{in};
local $/ = "\n";
- my $head = $in->getline;
- $head =~ / missing$/ and return undef;
- $head =~ /^[0-9a-f]{40} \S+ (\d+)$/ or
- fail($self, "Unexpected result from git cat-file: $head");
-
- my $size = $1;
- my $ref_type = $ref ? ref($ref) : '';
-
- my $rv;
- my $left = $size;
- $$ref = $size if ($ref_type eq 'SCALAR');
- my $cb_err;
-
- if ($ref_type eq 'CODE') {
- $rv = eval { $ref->($in, \$left) };
- $cb_err = $@;
- # drain the rest
- my $max = 8192;
- while ($left > 0) {
- my $r = read($in, my $x, $left > $max ? $max : $left);
- defined($r) or fail($self, "read failed: $!");
- $r == 0 and fail($self, 'exited unexpectedly');
- $left -= $r;
- }
- } else {
- my $offset = 0;
- my $buf = '';
- while ($left > 0) {
- my $r = read($in, $buf, $left, $offset);
- defined($r) or fail($self, "read failed: $!");
- $r == 0 and fail($self, 'exited unexpectedly');
- $left -= $r;
- $offset += $r;
+ $head = $in->getline;
+ if ($head =~ / missing$/) {
+ if (!$retried && alternates_changed($self)) {
+ $retried = 1;
+ cleanup($self);
+ goto again;
}
- $rv = \$buf;
+ return;
}
+ $head =~ /^[0-9a-f]{40} \S+ ([0-9]+)$/ or
+ fail($self, "Unexpected result from git cat-file: $head");
- my $r = read($in, my $buf, 1);
- defined($r) or fail($self, "read failed: $!");
- fail($self, 'newline missing after blob') if ($r != 1 || $buf ne "\n");
- die $cb_err if $cb_err;
-
- $rv;
+ my $size = $1;
+ $$ref = $size if $ref;
+ read_cat_in_full($self, $in, $size);
}
sub batch_prepare ($) { _bidi_pipe($_[0], qw(--batch in out pid)) }
sub check {
my ($self, $obj) = @_;
- $self->_bidi_pipe(qw(--batch-check in_c out_c pid_c));
+ _bidi_pipe($self, qw(--batch-check in_c out_c pid_c err_c));
$self->{out_c}->print($obj, "\n") or fail($self, "write error: $!");
local $/ = "\n";
chomp(my $line = $self->{in_c}->getline);
my ($hex, $type, $size) = split(' ', $line);
- return if $type eq 'missing';
+
+ # Future versions of git.git may show 'ambiguous', but for now,
+ # we must handle 'dangling' below (and maybe some other oddball
+ # stuff):
+ # https://public-inbox.org/git/20190118033845.s2vlrb3wd3m2jfzu@dcvr/T/
+ return if $type eq 'missing' || $type eq 'ambiguous';
+
+ if ($hex eq 'dangling' || $hex eq 'notdir' || $hex eq 'loop') {
+ $size = $type + length("\n");
+ my $r = read($self->{in_c}, my $buf, $size);
+ defined($r) or fail($self, "read failed: $!");
+ return;
+ }
+
($hex, $type, $size);
}
sub _destroy {
- my ($self, $in, $out, $pid) = @_;
+ my ($self, $in, $out, $pid, $err) = @_;
my $p = delete $self->{$pid} or return;
- foreach my $f ($in, $out) {
- delete $self->{$f};
- }
- waitpid $p, 0;
+ delete @$self{($in, $out)};
+ delete $self->{$err} if $err; # `err_c'
+
+ # PublicInbox::DS may not be loaded
+ eval { PublicInbox::DS::dwaitpid($p, undef, undef) };
+ waitpid($p, 0) if $@; # wait synchronously if not in event loop
+}
+
+sub cat_async_abort ($) {
+ my ($self) = @_;
+ my $inflight = delete $self->{inflight} or die 'BUG: not in async';
+ cleanup($self);
}
sub fail {
my ($self, $msg) = @_;
- cleanup($self);
+ $self->{inflight} ? cat_async_abort($self) : cleanup($self);
die $msg;
}
sub qx {
my ($self, @cmd) = @_;
my $fh = $self->popen(@cmd);
- defined $fh or return;
local $/ = "\n";
return <$fh> if wantarray;
local $/;
<$fh>
}
+# returns true if there are pending "git cat-file" processes
sub cleanup {
my ($self) = @_;
_destroy($self, qw(in out pid));
- _destroy($self, qw(in_c out_c pid_c));
+ _destroy($self, qw(in_c out_c pid_c err_c));
+ !!($self->{pid} || $self->{pid_c});
+}
+
+# assuming a well-maintained repo, this should be a somewhat
+# accurate estimation of its size
+# TODO: show this in the WWW UI as a hint to potential cloners
+sub packed_bytes {
+ my ($self) = @_;
+ my $n = 0;
+ my $pack_dir = git_path($self, 'objects/pack');
+ foreach my $p (bsd_glob("$pack_dir/*.pack", GLOB_NOSORT)) {
+ $n += -s $p;
+ }
+ $n
}
sub DESTROY { cleanup(@_) }
+sub local_nick ($) {
+ my ($self) = @_;
+ my $ret = '???';
+ # don't show full FS path, basename should be OK:
+ if ($self->{git_dir} =~ m!/([^/]+)(?:/\.git)?\z!) {
+ $ret = "/path/to/$1";
+ }
+ wantarray ? ($ret) : $ret;
+}
+
+sub host_prefix_url ($$) {
+ my ($env, $url) = @_;
+ return $url if index($url, '//') >= 0;
+ my $scheme = $env->{'psgi.url_scheme'};
+ my $host_port = $env->{HTTP_HOST} //
+ "$env->{SERVER_NAME}:$env->{SERVER_PORT}";
+ "$scheme://$host_port". ($env->{SCRIPT_NAME} || '/') . $url;
+}
+
+sub pub_urls {
+ my ($self, $env) = @_;
+ if (my $urls = $self->{cgit_url}) {
+ return map { host_prefix_url($env, $_) } @$urls;
+ }
+ local_nick($self);
+}
+
+sub cat_async_begin {
+ my ($self) = @_;
+ cleanup($self) if alternates_changed($self);
+ batch_prepare($self);
+ die 'BUG: already in async' if $self->{inflight};
+ $self->{inflight} = [];
+}
+
+sub cat_async ($$$;$) {
+ my ($self, $oid, $cb, $arg) = @_;
+ my $inflight = $self->{inflight} or die 'BUG: not in async';
+ if (scalar(@$inflight) >= MAX_INFLIGHT) {
+ _cat_async_step($self, $inflight, $self->{in});
+ }
+
+ $self->{out}->print($oid, "\n") or fail($self, "write error: $!");
+ push(@$inflight, [ $cb, $arg ]);
+}
+
+sub extract_cmt_time {
+ my ($bref, undef, undef, undef, $modified) = @_;
+
+ if ($$bref =~ /^committer .*?> ([0-9]+) [\+\-]?[0-9]+/sm) {
+ my $cmt_time = $1 + 0;
+ $$modified = $cmt_time if $cmt_time > $$modified;
+ }
+}
+
+# returns the modified time of a git repo, same as the "modified" field
+# of a grokmirror manifest
+sub modified ($) {
+ my ($self) = @_;
+ my $modified = 0;
+ my $fh = popen($self, qw(rev-parse --branches));
+ cat_async_begin($self);
+ local $/ = "\n";
+ while (my $oid = <$fh>) {
+ chomp $oid;
+ cat_async($self, $oid, \&extract_cmt_time, \$modified);
+ }
+ cat_async_wait($self);
+ $modified || time;
+}
+
1;
__END__
=pod