# Copyright (C) 2014-2015 all contributors # 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) }; $self->{$pid} = spawn(\@cmd, undef, $redir); $out_w->autoflush(1); $self->{$out} = $out_w; $self->{$in} = $in_r; } sub cat_file { my ($self, $obj, $ref) = @_; $self->_bidi_pipe(qw(--batch in out pid)); $self->{out}->print($obj, "\n") or fail($self, "write error: $!"); my $in = $self->{in}; 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; $rv; } sub check { my ($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: $!"); 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 = $self->popen(@cmd); return <$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;