imap: mailboxes list across listeners

Since IMAP mailbox lists are tied to the PublicInbox::Config
object, we can share them the same way the config object is
shared when an -imapd or -netd instance has multiple listeners.

This ought to reduce memory use and startup time when binding
multiple sockets which share a common config file.

1 files changed, 27 insertions, 22 deletions

diff --git a/lib/PublicInbox/IMAPD.pm b/lib/PublicInbox/IMAPD.pm
index dd0d2c53..ba6ad05d 100644
--- a/lib/PublicInbox/IMAPD.pm
+++ b/lib/PublicInbox/IMAPD.pm
@@ -23,7 +23,7 @@ sub new {
         }, $class;
 }
 
-sub imapd_refresh_ibx { # pi_cfg->each_inbox cb
+sub _refresh_ibx { # pi_cfg->each_inbox cb
         my ($ibx, $imapd, $cache, $dummies) = @_;
         my $ngname = $ibx->{newsgroup} // return;
 
@@ -56,27 +56,32 @@ sub imapd_refresh_ibx { # pi_cfg->each_inbox cb
 sub refresh_groups {
         my ($self, $sig) = @_;
         my $pi_cfg = PublicInbox::Config->new;
-        my $mailboxes = $self->{mailboxes} = {};
-        my $cache = eval { $pi_cfg->ALL->misc->nntpd_cache_load } // {};
-        my $dummies = {};
-        $pi_cfg->each_inbox(\&imapd_refresh_ibx, $self, $cache, $dummies);
-        %$dummies = (%$dummies, %$mailboxes);
-        $mailboxes = $self->{mailboxes} = $dummies;
-        @{$self->{mailboxlist}} = map { $_->[2] }
-                sort { $a->[0] cmp $b->[0] || $a->[1] <=> $b->[1] }
-                map {
-                        my $u = $_; # capitalize "INBOX" for user-familiarity
-                        $u =~ s/\Ainbox(\.|\z)/INBOX$1/i;
-                        if ($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;
+        $self->{mailboxes} = $pi_cfg->{-imap_mailboxes} // do {
+                my $mailboxes = $self->{mailboxes} = {};
+                my $cache = eval { $pi_cfg->ALL->misc->nntpd_cache_load } // {};
+                my $dummies = {};
+                $pi_cfg->each_inbox(\&_refresh_ibx, $self, $cache, $dummies);
+                %$mailboxes = (%$dummies, %$mailboxes);
+                @{$pi_cfg->{-imap_mailboxlist}} = map { $_->[2] }
+                        sort { $a->[0] cmp $b->[0] || $a->[1] <=> $b->[1] }
+                        map {
+                                # capitalize "INBOX" for user-familiarity
+                                my $u = $_;
+                                $u =~ s/\Ainbox(\.|\z)/INBOX$1/i;
+                                if ($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, '* LIST '.
+                                          qq[(\\HasNoChildren) "." $u\r\n] ]
+                                }
+                        } keys %$mailboxes;
+                $pi_cfg->{-imap_mailboxes} = $mailboxes;
+        };
+        $self->{mailboxlist} = $pi_cfg->{-imap_mailboxlist} //
+                        die 'BUG: no mailboxlist';
         $self->{pi_cfg} = $pi_cfg;
         if (my $idler = $self->{idler}) {
                 $idler->refresh($pi_cfg);