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): $!";
21 # CentOS 7.x ships Inline 0.53, 0.64+ has built-in locking
22 flock($fh, LOCK_EX) or die "LOCK_EX($f): $!\n";
24 my $pc = which($ENV{PKG_CONFIG} // 'pkg-config') //
25 die "pkg-config missing for libgit2";
26 my ($dir) = (__FILE__ =~ m!\A(.+?)/[^/]+\z!);
27 my $ef = "$inline_dir/.public-inbox.pkg-config.err";
28 open my $err, '+>', $ef or die "open($ef): $!";
29 for my $x (qw(libgit2)) {
30 my $rdr = { 2 => $err };
31 my ($l, $pid) = popen_rd([$pc, '--libs', $x], undef, $rdr);
32 $l = do { local $/; <$l> };
35 (my $c, $pid) = popen_rd([$pc, '--cflags', $x], undef, $rdr);
36 $c = do { local $/; <$c> };
40 # note: we name C source files .h to prevent
41 # ExtUtils::MakeMaker from automatically trying to
43 my $f = "$dir/gcf2_$x.h";
44 open(my $src, '<', $f) or die "E: open($f): $!";
47 defined($c_src = <$src>) or die "read $f: $!";
53 seek($err, 0, SEEK_SET);
54 $err = do { local $/; <$err> };
55 die "E: libgit2 not installed: $err\n";
57 open my $oldout, '>&', \*STDOUT or die "dup(1): $!";
58 open my $olderr, '>&', \*STDERR or die "dup(2): $!";
59 open STDOUT, '>&', $fh or die "1>$f: $!";
60 open STDERR, '>&', $fh or die "2>$f: $!";
64 # we use Capitalized and ALLCAPS for compatibility with old Inline::C
66 use Inline C => Config => %CFG, BOOT => q[git_libgit2_init();];
67 use Inline C => $c_src, BUILD_NOISY => 1;
70 open(STDERR, '>&', $olderr) or warn "restore stderr: $!";
71 open(STDOUT, '>&', $oldout) or warn "restore stdout: $!";
73 seek($fh, 0, SEEK_SET);
75 die "Inline::C Gcf2 build failed:\n", $err, "\n", @msg;
80 my ($gcf2, $objdir) = @_;
82 # libgit2 (tested 0.27.7+dfsg.1-0.2 and 0.28.3+dfsg.1-1~bpo10+1
83 # in Debian) doesn't handle relative epochs properly when nested
84 # multiple levels. Add all the absolute paths to workaround it,
85 # since $EXTINDEX_DIR/ALL.git/objects/info/alternates uses absolute
86 # paths to reference $V2INBOX_DIR/all.git/objects and
87 # $V2INBOX_DIR/all.git/objects/info/alternates uses relative paths
88 # to refer to $V2INBOX_DIR/git/$EPOCH.git/objects
90 # See https://bugs.debian.org/975607
91 if (open(my $fh, '<', "$objdir/info/alternates")) {
92 chomp(my @abs_alt = grep(m!^/!, <$fh>));
93 $gcf2->add_alternate($_) for @abs_alt;
95 $gcf2->add_alternate($objdir);
99 # Usage: $^X -MPublicInbox::Gcf2 -e PublicInbox::Gcf2::loop
100 # (see lib/PublicInbox/Gcf2Client.pm)
104 STDERR->autoflush(1);
105 STDOUT->autoflush(1);
109 my ($oid, $git_dir) = split(/ /, $_, 2);
110 $seen{$git_dir} //= add_alt($gcf2, "$git_dir/objects");
111 if (!$gcf2->cat_oid(1, $oid)) {
112 # retry once if missing. We only get unabbreviated OIDs
113 # from SQLite or Xapian DBs, here, so malicious clients
114 # can't trigger excessive retries:
115 warn "I: $$ $oid missing, retrying in $git_dir\n";
118 %seen = ($git_dir => add_alt($gcf2,"$git_dir/objects"));
120 if ($gcf2->cat_oid(1, $oid)) {
121 warn "I: $$ $oid found after retry\n";
123 warn "W: $$ $oid missing after retry\n";
124 print "$oid missing\n"; # mimic git-cat-file