[PATCH v4] inbox: add `modified' sub

[Eric Wong <e@80x24.org>]

For inboxes with SQLite enabled (all v2, and probably most v1);
we can use the overview DB to get the timestamp of the latest
message.  It's faster than scanning git branches for commit times,
but not always the same.
---
 OK, this is definitely the version I'll go with...
 st_mtime of msgmap.sqlite3 isn't right for mirrors with
 intermittent polling or even if the DB gets rebuilt.

 lib/PublicInbox/Inbox.pm | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/lib/PublicInbox/Inbox.pm b/lib/PublicInbox/Inbox.pm
index cde4625..0d28dd0 100644
--- a/lib/PublicInbox/Inbox.pm
+++ b/lib/PublicInbox/Inbox.pm
@@ -333,4 +333,16 @@ sub recent {
 	search($self)->{over_ro}->recent($opts, $after, $before);
 }
 
+sub modified {
+	my ($self) = @_;
+	if (my $srch = search($self)) {
+		my $msgs = $srch->{over_ro}->recent({limit => 1});
+		if (my $smsg = $msgs->[0]) {
+			return $smsg->{ts};
+		}
+		return time;
+	}
+	git($self)->modified; # v1
+}
+
 1;
-- 
EW