[PATCH 3/5] git: ->modified uses cat_async

[Eric Wong <e@yhbt.net>]

While v1 inboxes are typically only a single branch, coderepos
will have many branches and being able to pipeline requests
to "git cat-file --batch" can help us mask seek times.
---
 lib/PublicInbox/Git.pm | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/lib/PublicInbox/Git.pm b/lib/PublicInbox/Git.pm
index 2aaf1866..9d0f660b 100644
--- a/lib/PublicInbox/Git.pm
+++ b/lib/PublicInbox/Git.pm
@@ -339,6 +339,15 @@ sub commit_title ($$) {
 	($$buf =~ /\r?\n\r?\n([^\r\n]+)\r?\n?/)[0]
 }
 
+sub extract_cmt_time {
+	my ($bref, undef, undef, undef, $modified) = @_;
+
+	if ($$bref =~ /^committer .*?> ([0-9]+) [\+\-]?[0-9]+/sm) {
+		my $cmt_time = $1 + 0;
+		$$modified = $cmt_time if $cmt_time > $$modified;
+	}
+}
+
 # returns the modified time of a git repo, same as the "modified" field
 # of a grokmirror manifest
 sub modified ($) {
@@ -346,14 +355,13 @@ sub modified ($) {
 	my $modified = 0;
 	my $fh = popen($self, qw(rev-parse --branches));
 	defined $fh or return $modified;
+	cat_async_begin($self);
 	local $/ = "\n";
 	foreach my $oid (<$fh>) {
 		chomp $oid;
-		my $buf = cat_file($self, $oid) or next;
-		$$buf =~ /^committer .*?> ([0-9]+) [\+\-]?[0-9]+/sm or next;
-		my $cmt_time = $1 + 0;
-		$modified = $cmt_time if $cmt_time > $modified;
+		cat_async($self, $oid, \&extract_cmt_time, \$modified);
 	}
+	cat_async_wait($self);
 	$modified || time;
 }