1 files changed, 73 insertions, 0 deletions
diff --git a/lib/PublicInbox/GitCatFile.pm b/lib/PublicInbox/GitCatFile.pm
new file mode 100644
index 00000000..bdad2b56
--- /dev/null
+++ b/lib/PublicInbox/GitCatFile.pm
@@ -0,0 +1,73 @@
+# Copyright (C) 2014, Eric Wong <normalperson@yhbt.net> and all contributors
+# License: GPLv2 or later (https://www.gnu.org/licenses/gpl-2.0.txt)
+# 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::GitCatFile;
+use strict;
+use warnings;
+use IPC::Open2 qw(open2);
+
+sub new {
+        my ($class, $git_dir) = @_;
+        bless { git_dir => $git_dir }, $class;
+}
+
+sub _cat_file_begin {
+        my ($self) = @_;
+        return if $self->{pid};
+        my ($in, $out);
+        my $pid = open2($in, $out, 'git', '--git-dir', $self->{git_dir},
+                        'cat-file', '--batch');
+
+        $self->{pid} = $pid;
+        $self->{in} = $in;
+        $self->{out} = $out;
+}
+
+sub cat_file {
+        my ($self, $object) = @_;
+
+        $self->_cat_file_begin;
+        print { $self->{out} } $object, "\n" or die "write error: $!\n";
+
+        my $in = $self->{in};
+        my $head = <$in>;
+        $head =~ / missing$/ and return undef;
+        $head =~ /^[0-9a-f]{40} \S+ (\d+)$/ or
+                die "Unexpected result from git cat-file: $head\n";
+
+        my $size = $1;
+        my $bytes_left = $size;
+        my $buf;
+        my $rv = '';
+
+        while ($bytes_left) {
+                my $read = read($in, $buf, $bytes_left);
+                defined($read) or die "read pipe failed: $!\n";
+                $rv .= $buf;
+                $bytes_left -= $read;
+        }
+
+        my $read = read($in, $buf, 1);
+        defined($read) or die "read pipe failed: $!\n";
+        if ($read != 1 || $buf ne "\n") {
+                die "newline missing after blob\n";
+        }
+        \$rv;
+}
+
+sub DESTROY {
+        my ($self) = @_;
+        my $pid = $self->{pid} or return;
+        $self->{pid} = undef;
+        foreach my $f (qw(in out)) {
+                my $fh = $self->{$f};
+                defined $fh or next;
+                close $fh;
+                $self->{$f} = undef;
+        }
+        waitpid $pid, 0;
+}
+
+1;