searchidx: store indexlevel=medium as metadata

And use it from Admin.

It's easy to tell what indexlevel=basic is from unconfigured
inboxes, but distinguishing between 'medium' and 'full' would
require stat()-ing position.* files which is fragile and
Xapian-implementation-dependent.

So use the metadata facility of Xapian and store it in the main
partition so Admin tools can deal better with unconfigured
inboxes copied using generic tools like cp(1) or rsync(1).

1 files changed, 25 insertions, 0 deletions

diff --git a/lib/PublicInbox/Admin.pm b/lib/PublicInbox/Admin.pm
index 07d8b572..4a862c6d 100644
--- a/lib/PublicInbox/Admin.pm
+++ b/lib/PublicInbox/Admin.pm
@@ -41,6 +41,31 @@ sub resolve_repo_dir {
         }
 }
 
+# for unconfigured inboxes
+sub detect_indexlevel ($) {
+        my ($ibx) = @_;
+
+        # brand new or never before indexed inboxes default to full
+        return 'full' unless $ibx->over;
+        delete $ibx->{over}; # don't leave open FD lying around
+
+        my $l = 'basic';
+        my $srch = $ibx->search or return $l;
+        delete $ibx->{search}; # don't leave open FD lying around
+        if (my $xdb = $srch->xdb) {
+                $l = 'full';
+                my $m = $xdb->get_metadata('indexlevel');
+                if ($m eq 'medium') {
+                        $l = $m;
+                } elsif ($m ne '') {
+                        warn <<"";
+$ibx->{mainrepo} has unexpected indexlevel in Xapian: $m
+
+                }
+        }
+        $l;
+}
+
 sub resolve_inboxes {
         my ($argv, $warn_on_unconfigured) = @_;
         require PublicInbox::Config;