1 # Copyright (C) 2020-2021 all contributors <meta@public-inbox.org>
2 # License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
4 # backend for a git-cat-file-workalike based on libgit2,
5 # other libgit2 stuff may go here, too.
6 package PublicInbox::Gcf2;
9 use PublicInbox::Spawn qw(which popen_rd); # may set PERL_INLINE_DIRECTORY
10 use Fcntl qw(LOCK_EX SEEK_SET);
11 use IO::Handle; # autoflush
14 # PublicInbox::Spawn will set PERL_INLINE_DIRECTORY
15 # to ~/.cache/public-inbox/inline-c if it exists
16 my $inline_dir = $ENV{PERL_INLINE_DIRECTORY} //
17 die 'PERL_INLINE_DIRECTORY not defined';
18 my $f = "$inline_dir/.public-inbox.lock";
19 open my $fh, '+>', $f or die "open($f): $!";
20 my $pc = which($ENV{PKG_CONFIG} // 'pkg-config') //
21 die "pkg-config missing for libgit2";
22 my ($dir) = (__FILE__ =~ m!\A(.+?)/[^/]+\z!);
24 open $rdr->{2}, '>', '/dev/null' or die "open /dev/null: $!";
25 for my $x (qw(libgit2)) {
26 my $l = popen_rd([$pc, '--libs', $x], undef, $rdr);
27 $l = do { local $/; <$l> };
29 my $c = popen_rd([$pc, '--cflags', $x], undef, $rdr);
30 $c = do { local $/; <$c> };
33 # note: we name C source files .h to prevent
34 # ExtUtils::MakeMaker from automatically trying to
36 my $f = "$dir/gcf2_$x.h";
37 if (open(my $fh, '<', $f)) {
40 defined($c_src = <$fh>) or die "read $f: $!";
48 die "E: libgit2 not installed\n" unless $c_src;
50 open my $oldout, '>&', \*STDOUT or die "dup(1): $!";
51 open my $olderr, '>&', \*STDERR or die "dup(2): $!";
52 open STDOUT, '>&', $fh or die "1>$f: $!";
53 open STDERR, '>&', $fh or die "2>$f: $!";
57 # CentOS 7.x ships Inline 0.53, 0.64+ has built-in locking
58 flock($fh, LOCK_EX) or die "LOCK_EX($f): $!\n";
59 # we use Capitalized and ALLCAPS for compatibility with old Inline::C
61 use Inline C => Config => %CFG, BOOT => q[git_libgit2_init();];
62 use Inline C => $c_src, BUILD_NOISY => 1;
65 open(STDERR, '>&', $olderr) or warn "restore stderr: $!";
66 open(STDOUT, '>&', $oldout) or warn "restore stdout: $!";
68 seek($fh, 0, SEEK_SET);
70 die "Inline::C Gcf2 build failed:\n", $err, "\n", @msg;
75 my ($gcf2, $objdir) = @_;
77 # libgit2 (tested 0.27.7+dfsg.1-0.2 and 0.28.3+dfsg.1-1~bpo10+1
78 # in Debian) doesn't handle relative epochs properly when nested
79 # multiple levels. Add all the absolute paths to workaround it,
80 # since $EXTINDEX_DIR/ALL.git/objects/info/alternates uses absolute
81 # paths to reference $V2INBOX_DIR/all.git/objects and
82 # $V2INBOX_DIR/all.git/objects/info/alternates uses relative paths
83 # to refer to $V2INBOX_DIR/git/$EPOCH.git/objects
85 # See https://bugs.debian.org/975607
86 if (open(my $fh, '<', "$objdir/info/alternates")) {
87 chomp(my @abs_alt = grep(m!^/!, <$fh>));
88 $gcf2->add_alternate($_) for @abs_alt;
90 $gcf2->add_alternate($objdir);
94 # Usage: $^X -MPublicInbox::Gcf2 -e PublicInbox::Gcf2::loop
95 # (see lib/PublicInbox/Gcf2Client.pm)
100 STDOUT->autoflush(1);
104 my ($oid, $git_dir) = split(/ /, $_, 2);
105 $seen{$git_dir} //= add_alt($gcf2, "$git_dir/objects");
106 if (!$gcf2->cat_oid(1, $oid)) {
107 # retry once if missing. We only get unabbreviated OIDs
108 # from SQLite or Xapian DBs, here, so malicious clients
109 # can't trigger excessive retries:
110 warn "I: $$ $oid missing, retrying in $git_dir\n";
113 %seen = ($git_dir => add_alt($gcf2,"$git_dir/objects"));
115 if ($gcf2->cat_oid(1, $oid)) {
116 warn "I: $$ $oid found after retry\n";
118 warn "W: $$ $oid missing after retry\n";
119 print "$oid missing\n"; # mimic git-cat-file