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| | # Copyright (C) 2014-2018 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.
# This is based on code in Git.pm which is GPLv2+, but modified to avoid
# dependence on environment variables for compatibility with mod_perl.
# There are also API changes to simplify our usage and data set.
package PublicInbox::Git;
use strict;
use warnings;
use POSIX qw(dup2);
require IO::Handle;
use PublicInbox::Spawn qw(spawn popen_rd);
sub new {
my ($class, $git_dir) = @_;
bless { git_dir => $git_dir }, $class
}
sub _bidi_pipe {
my ($self, $batch, $in, $out, $pid) = @_;
return if $self->{$pid};
my ($in_r, $in_w, $out_r, $out_w);
pipe($in_r, $in_w) or fail($self, "pipe failed: $!");
pipe($out_r, $out_w) or fail($self, "pipe failed: $!");
my @cmd = ('git', "--git-dir=$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: $!");
$self->{$pid} = $p;
$out_w->autoflush(1);
$self->{$out} = $out_w;
$self->{$in} = $in_r;
}
sub cat_file {
my ($self, $obj, $ref) = @_;
batch_prepare($self);
$self->{out}->print($obj, "\n") or fail($self, "write error: $!");
my $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;
}
$rv = \$buf;
}
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;
$rv;
}
sub batch_prepare ($) { _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));
$self->{out_c}->print($obj, "\n") or fail($self, "write error: $!");
local $/ = "\n";
chomp(my $line = $self->{in_c}->getline);
my ($hex, $type, $size) = split(' ', $line);
return if $type eq 'missing';
($hex, $type, $size);
}
sub _destroy {
my ($self, $in, $out, $pid) = @_;
my $p = delete $self->{$pid} or return;
foreach my $f ($in, $out) {
delete $self->{$f};
}
waitpid $p, 0;
}
sub fail {
my ($self, $msg) = @_;
cleanup($self);
die $msg;
}
sub popen {
my ($self, @cmd) = @_;
@cmd = ('git', "--git-dir=$self->{git_dir}", @cmd);
popen_rd(\@cmd);
}
sub qx {
my ($self, @cmd) = @_;
my $fh = $self->popen(@cmd);
defined $fh or return;
local $/ = "\n";
return <$fh> if wantarray;
local $/;
<$fh>
}
sub cleanup {
my ($self) = @_;
_destroy($self, qw(in out pid));
_destroy($self, qw(in_c out_c pid_c));
}
sub DESTROY { cleanup(@_) }
1;
__END__
=pod
=head1 NAME
PublicInbox::Git - git wrapper
=head1 VERSION
version 1.0
=head1 SYNOPSIS
use PublicInbox::Git;
chomp(my $git_dir = `git rev-parse --git-dir`);
$git_dir or die "GIT_DIR= must be specified\n";
my $git = PublicInbox::Git->new($git_dir);
=head1 DESCRIPTION
Unstable API outside of the L</new> method.
It requires L<git(1)> to be installed.
=head1 METHODS
=cut
=head2 new
my $git = PublicInbox::Git->new($git_dir);
Initialize a new PublicInbox::Git object for use with L<PublicInbox::Import>
This is the only public API method we support. Everything else
in this module is subject to change.
=head1 SEE ALSO
L<Git>, L<PublicInbox::Import>
=head1 CONTACT
All feedback welcome via plain-text mail to L<mailto:meta@public-inbox.org>
The mail archives are hosted at L<https://public-inbox.org/meta/>
=head1 COPYRIGHT
Copyright (C) 2016 all contributors L<mailto:meta@public-inbox.org>
License: AGPL-3.0+ L<http://www.gnu.org/licenses/agpl-3.0.txt>
=cut
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