[PATCH 3/3] imapd: sort LIST response

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

While RFC 3501 doesn't require LIST responses be sorted,
it makes reading protocol dumps easier and we memoize it
once per-refresh, so it shouldn't be too expensive even
with thousands of folders.
---
 lib/PublicInbox/IMAP.pm  |  4 ++--
 lib/PublicInbox/IMAPD.pm | 15 ++++++++++++---
 2 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/lib/PublicInbox/IMAP.pm b/lib/PublicInbox/IMAP.pm
index 37e07dae..27013ea5 100644
--- a/lib/PublicInbox/IMAP.pm
+++ b/lib/PublicInbox/IMAP.pm
@@ -384,7 +384,7 @@ sub ensure_slices_exist ($$$) {
 		push @created, $sub_mailbox;
 	}
 	return unless @created;
-	my $l = $imapd->{inboxlist} or return;
+	my $l = $imapd->{mailboxlist} or return;
 	push @$l, map { qq[* LIST (\\HasNoChildren) "." $_\r\n] } @created;
 }
 
@@ -850,7 +850,7 @@ sub cmd_status ($$$;@) {
 my %patmap = ('*' => '.*', '%' => '[^\.]*');
 sub cmd_list ($$$$) {
 	my ($self, $tag, $refname, $wildcard) = @_;
-	my $l = $self->{imapd}->{inboxlist};
+	my $l = $self->{imapd}->{mailboxlist};
 	if ($refname eq '' && $wildcard eq '') {
 		# request for hierarchy delimiter
 		$l = [ qq[* LIST (\\Noselect) "." ""\r\n] ];
diff --git a/lib/PublicInbox/IMAPD.pm b/lib/PublicInbox/IMAPD.pm
index 7425409d..6aa3d12f 100644
--- a/lib/PublicInbox/IMAPD.pm
+++ b/lib/PublicInbox/IMAPD.pm
@@ -70,12 +70,21 @@ sub imapd_refresh_finalize {
 	}
 	%$mailboxes = (%$mailboxes, %{$imapd->{mailboxes}});
 	$imapd->{mailboxes} = $mailboxes;
-	$imapd->{inboxlist} = [
+	$imapd->{mailboxlist} = [
+		map { $_->[2] }
+		sort { $a->[0] cmp $b->[0] || $a->[1] <=> $b->[1] }
 		map {
-			my $no = $mailboxes->{$_} == $dummy ? '' : 'No';
 			my $u = $_; # capitalize "INBOX" for user-familiarity
 			$u =~ s/\Ainbox(\.|\z)/INBOX$1/i;
-			qq[* LIST (\\Has${no}Children) "." $u\r\n]
+			if ($mailboxes->{$_} == $dummy) {
+				[ $u, -1,
+				  qq[* LIST (\\HasChildren) "." $u\r\n]]
+			} else {
+				$u =~ /\A(.+)\.([0-9]+)\z/ or
+					die "BUG: `$u' has no slice digit(s)";
+				[ $1, $2 + 0,
+				  qq[* LIST (\\HasNoChildren) "." $u\r\n] ]
+			}
 		} keys %$mailboxes
 	];
 	$imapd->{pi_cfg} = $pi_cfg;