thread: common sorting code

We'll be sharing the same threading, so it makes sense to sort
replies using the same code and message headers without repeating
ourselves.

This also standardizes on sorting on X-PI-TS (Unix epoch in seconds)
instead over using X-PI-Date differently in two different places

1 files changed, 14 insertions, 0 deletions

diff --git a/lib/PublicInbox/Thread.pm b/lib/PublicInbox/Thread.pm
index 7dabf243..58efb8dc 100644
--- a/lib/PublicInbox/Thread.pm
+++ b/lib/PublicInbox/Thread.pm
@@ -12,6 +12,20 @@ if ($Mail::Thread::VERSION <= 2.55) {
         eval q(sub _container_class { 'PublicInbox::Thread::Container' });
 }
 
+sub sort_ts {
+        sort {
+                (eval { $a->topmost->message->header('X-PI-TS') } || 0) <=>
+                (eval { $b->topmost->message->header('X-PI-TS') } || 0)
+        } @_;
+}
+
+sub rsort_ts {
+        sort {
+                (eval { $b->topmost->message->header('X-PI-TS') } || 0) <=>
+                (eval { $a->topmost->message->header('X-PI-TS') } || 0)
+        } @_;
+}
+
 package PublicInbox::Thread::Container;
 use strict;
 use warnings;