git: factor out cat_file_begin and cat_file_finish

Unfortunately, it seems being able to handle callbacks is
insufficient; and these methods will allow us to avoid making
an extra $git->check call.

1 files changed, 28 insertions, 16 deletions

diff --git a/lib/PublicInbox/Git.pm b/lib/PublicInbox/Git.pm
index 4bc879ff..aec2db0b 100644
--- a/lib/PublicInbox/Git.pm
+++ b/lib/PublicInbox/Git.pm
@@ -34,9 +34,8 @@ sub _bidi_pipe {
         $self->{$in} = $in_r;
 }
 
-sub cat_file {
-        my ($self, $obj, $ref) = @_;
-
+sub cat_file_begin {
+        my ($self, $obj) = @_;
         $self->_bidi_pipe(qw(--batch in out pid));
         $self->{out}->print($obj, "\n") or fail($self, "write error: $!");
 
@@ -46,7 +45,31 @@ sub cat_file {
         $head =~ /^([0-9a-f]{40}) (\S+) (\d+)$/ or
                 fail($self, "Unexpected result from git cat-file: $head");
 
-        my ($hex, $type, $size) = ($1, $2, $3);
+        ($in, $1, $2, $3);
+}
+
+sub cat_file_finish {
+        my ($self, $left) = @_;
+        my $max = 8192;
+        my $in = $self->{in};
+        my $buf;
+        while ($left > 0) {
+                my $r = read($in, $buf, $left > $max ? $max : $left);
+                defined($r) or fail($self, "read failed: $!");
+                $r == 0 and fail($self, 'exited unexpectedly');
+                $left -= $r;
+        }
+
+        my $r = read($in, $buf, 1);
+        defined($r) or fail($self, "read failed: $!");
+        fail($self, 'newline missing after blob') if ($r != 1 || $buf ne "\n");
+}
+
+sub cat_file {
+        my ($self, $obj, $ref) = @_;
+
+        my ($in, $hex, $type, $size) = $self->cat_file_begin($obj);
+        return unless $in;
         my $ref_type = $ref ? ref($ref) : '';
 
         my $rv;
@@ -57,14 +80,6 @@ sub cat_file {
         if ($ref_type eq 'CODE') {
                 $rv = eval { $ref->($in, \$left, $type, $hex) };
                 $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 = '';
@@ -77,10 +92,7 @@ sub cat_file {
                 }
                 $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");
+        $self->cat_file_finish($left);
         die $cb_err if $cb_err;
 
         $rv;