# Copyright (C) 2014-2018 all contributors # License: GPLv2 or later # # 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) = @_; my @st; $st[7] = $st[10] = 0; bless { git_dir => $git_dir, st => \@st }, $class } sub alternates_changed { my ($self) = @_; my $alt = "$self->{git_dir}/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]); $self->{st} = \@st; } sub _bidi_pipe { my ($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, $ref) = @_; my ($retried, $in, $head); again: batch_prepare($self); $self->{out}->print($obj, "\n") or fail($self, "write error: $!"); $in = $self->{in}; local $/ = "\n"; $head = $in->getline; if ($head =~ / missing$/) { if (!$retried && alternates_changed($self)) { $retried = 1; cleanup($self); goto again; } return; } $head =~ /^[0-9a-f]{40} \S+ (\d+)$/ 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($self, qw(in_c out_c pid_c)); } # assuming a well-maintained repo, this should be a somewhat # accurate estimation of its size # TODO: show this in the WWW UI as a hint to potential cloners sub packed_bytes { my ($self) = @_; my $n = 0; foreach my $p (glob("$self->{git_dir}/objects/pack/*.pack")) { $n += -s $p; } $n } 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 method. It requires L 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 This is the only public API method we support. Everything else in this module is subject to change. =head1 SEE ALSO L, L =head1 CONTACT All feedback welcome via plain-text mail to L The mail archives are hosted at L =head1 COPYRIGHT Copyright (C) 2016 all contributors L License: AGPL-3.0+ L =cut