solver: initial Perl implementation

[public-inbox.git] / lib / PublicInbox / Git.pm

diff --git a/lib/PublicInbox/Git.pm b/lib/PublicInbox/Git.pm
index d8211827f1aa85e82934b2e83616a77015e8c3b5..9676086f648d4482d548640d7bc17c01144caff3 100644 (file)
--- a/lib/PublicInbox/Git.pm
+++ b/lib/PublicInbox/Git.pm
@@ -1,5 +1,5 @@
-# Copyright (C) 2014-2015 all contributors <meta@public-inbox.org>
-# License: GPLv2 or later (https://www.gnu.org/licenses/gpl-2.0.txt)
+# 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.
@@ -12,10 +12,46 @@ use warnings;
 use POSIX qw(dup2);
 require IO::Handle;
 use PublicInbox::Spawn qw(spawn popen_rd);
+use base qw(Exporter);
+our @EXPORT_OK = qw(git_unquote);
+
+my %GIT_ESC = (
+       a => "\a",
+       b => "\b",
+       f => "\f",
+       n => "\n",
+       r => "\r",
+       t => "\t",
+       v => "\013",
+       '"' => '"',
+       '\\' => '\\',
+);
+
+# unquote pathnames used by git, see quote.c::unquote_c_style.c in git.git
+sub git_unquote ($) {
+       return $_[0] unless ($_[0] =~ /\A"(.*)"\z/);
+       $_[0] = $1;
+       $_[0] =~ s/\\([\\"abfnrtv])/$GIT_ESC{$1}/g;
+       $_[0] =~ s/\\([0-7]{1,3})/chr(oct($1))/ge;
+       $_[0];
+}
 
 sub new {
        my ($class, $git_dir) = @_;
-       bless { git_dir => $git_dir }, $class
+       my @st;
+       $st[7] = $st[10] = 0;
+       # may contain {-wt} field (working-tree (File::Temp::Dir))
+       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 {
@@ -25,10 +61,16 @@ sub _bidi_pipe {
 
        pipe($in_r, $in_w) or fail($self, "pipe failed: $!");
        pipe($out_r, $out_w) or fail($self, "pipe failed: $!");
+       if ($^O eq 'linux') { # 1031: F_SETPIPE_SZ
+               fcntl($out_w, 1031, 4096);
+               fcntl($in_w, 1031, 4096) if $batch eq '--batch-check';
+       }
 
        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);
+       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;
@@ -36,13 +78,23 @@ sub _bidi_pipe {
 
 sub cat_file {
        my ($self, $obj, $ref) = @_;
+       my ($retried, $in, $head);
 
-       $self->_bidi_pipe(qw(--batch in out pid));
+again:
+       batch_prepare($self);
        $self->{out}->print($obj, "\n") or fail($self, "write error: $!");
 
-       my $in = $self->{in};
-       my $head = $in->getline;
-       $head =~ / missing$/ and return undef;
+       $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");
 
@@ -86,10 +138,13 @@ sub cat_file {
        $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 $type eq 'missing';
@@ -120,6 +175,8 @@ sub popen {
 sub qx {
        my ($self, @cmd) = @_;
        my $fh = $self->popen(@cmd);
+       defined $fh or return;
+       local $/ = "\n";
        return <$fh> if wantarray;
        local $/;
        <$fh>
@@ -131,8 +188,35 @@ sub cleanup {
        _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(@_) }
 
+# show the blob URL for cgit/gitweb/whatever
+sub src_blob_url {
+       my ($self, $oid) = @_;
+       # blob_fmt = "https://example.com/foo.git/blob/%s"
+       if (my $bfu = $self->{blob_fmt_url}) {
+               return sprintf($bfu, $oid);
+       }
+
+       # don't show full FS path, basename should be OK:
+       if ($self->{git_dir} =~ m!/([^/]+)\z!) {
+               return "/path/to/$1";
+       }
+       '???';
+}
+
 1;
 __END__
 =pod