searchidx: introduce "xref3" concept

This will be used to track cross-posted messages in the
external/detached index.

1 files changed, 13 insertions, 0 deletions

diff --git a/lib/PublicInbox/Smsg.pm b/lib/PublicInbox/Smsg.pm
index 14086538..c0fd85fd 100644
--- a/lib/PublicInbox/Smsg.pm
+++ b/lib/PublicInbox/Smsg.pm
@@ -137,4 +137,17 @@ sub subject_normalized ($) {
         $subj;
 }
 
+sub xref3 {
+        my ($self, $doc) = @_;
+        my $end = $doc->termlist_end;
+        my $it = $doc->termlist_begin;
+        $it->skip_to('P');
+        my @ret;
+        for (; $it != $end; $it++) {
+                my $val = $it->get_termname;
+                $val =~ s/\AP// and push @ret, $val;
+        }
+        \@ret;
+}
+
 1;