No longer try to guess whether a mailbox was deleted or renamed.

This was too error-prone.  Instead, abort if a naming conflict occurs,
and provide explicit commands --delete and --rename to delete or rename
a mailbox.

3 files changed, 303 insertions, 324 deletions

diff --git a/imapsync b/imapsync
index 339979c..2a1bfcc 100755
--- a/imapsync
+++ b/imapsync
@@ -39,23 +39,28 @@ delete @ENV{qw/IFS CDPATH ENV BASH_ENV/};
 my %CONFIG;
 sub usage(;$) {
     my $rv = shift // 0;
-    print STDERR "$NAME [OPTIONS] [--] [MAILBOX [..]]\n";
     if ($rv) {
-        print STDERR "Try '$NAME --help' or consult the manpage for more information.\n";
+        print STDERR "Usage: $NAME [OPTIONS] [COMMAND] [MAILBOX [..]]\n"
+                    ."Try '$NAME --help' or consult the manpage for more information.\n";
     }
     else {
-        print STDERR "Synchronize the given MAILBOXes between two QRESYNC-capable IMAP4rev1 servers.\n"
-            ."Options:\n"
-            ."    --config=FILE    Specify an alternate configuration file\n"
-            ."    --repair         List the database anomalies and try to repair them\n"
-            ."    -q, --quiet      Try to be quiet\n"
-            ."    --debug          Turn on debug mode\n"
-            ."Consult the manpage for more information.\n";
+        print STDERR "Usage: $NAME [OPTIONS] [MAILBOX [..]]\n"
+                    ."  or: $NAME [OPTIONS] --repair [MAILBOX [..]]\n"
+                    ."  or: $NAME [OPTIONS] --delete MAILBOX [..]\n"
+                    ."  or: $NAME [OPTIONS] --rename SOURCE DEST\n"
+                    ."Consult the manpage for more information.\n";
     }
     exit $rv;
 }
-usage(1) unless GetOptions(\%CONFIG, qw/config=s quiet|q repair debug help|h/);
+usage(1) unless GetOptions(\%CONFIG, qw/config=s quiet|q target=s@ debug help|h repair delete rename/);
 usage(0) if $CONFIG{help};
+my $COMMAND = do {
+    my @command = grep {exists $CONFIG{$_}} qw/repair delete rename/;
+    usage(1) if $#command>0;
+    $command[0]
+};
+usage(1) if defined $COMMAND and (($COMMAND eq 'delete' and !@ARGV) or $COMMAND eq 'rename' and $#ARGV != 1);
+@ARGV = map {uc $_ eq 'INBOX' ? 'INBOX' : $_ } @ARGV; # INBOX is case-insensitive
 
 
 my $CONF = read_config( delete $CONFIG{config} // $NAME
@@ -207,7 +212,7 @@ logger(undef, ">>> $NAME $VERSION");
 my $IMAP;
 foreach my $name (qw/local remote/) {
     my %config = %{$CONF->{$name}};
-    $config{$_} = $CONFIG{$_} foreach keys %CONFIG;
+    $config{$_} = $CONFIG{$_} foreach grep {defined $CONFIG{$_}} qw/quiet debug/;
     $config{enable} = 'QRESYNC';
     $config{name} = $name;
     $config{'logger-fd'} = $LOGGER_FD if defined $LOGGER_FD;
@@ -229,316 +234,258 @@ foreach my $name (qw/local remote/) {
     # XXX We shouldn't need to ask for STATUS responses here, and use
     #     NOTIFY's STATUS indicator instead.  However Dovecot violates RFC
     #     5464: http://dovecot.org/pipermail/dovecot/2015-July/101474.html
-    @{$IMAP->{$name}}{qw/mailboxes delims/} = $client->list(q{"" "*"}, 'SUBSCRIBED', 'STATUS (UIDVALIDITY UIDNEXT HIGHESTMODSEQ)' );
+
+    my $list = '"" ';
+    my @params;
+    if (!defined $COMMAND or $COMMAND eq 'repair') {
+        $list .= '"*"' unless @ARGV;
+        @params = ('SUBSCRIBED', 'STATUS (UIDVALIDITY UIDNEXT HIGHESTMODSEQ)');
+    }
+    $list .= $#ARGV == 0 ? Net::IMAP::Sync::quote($ARGV[0])
+           : ('('.join(' ',map {Net::IMAP::Sync::quote($_)} @ARGV).')') if @ARGV;
+    @{$IMAP->{$name}}{qw/mailboxes delims/} = $client->list($list, @params);
 }
 
 
-#############################################################################
-# Synchronize mailbox and subscription lists
+##############################################################################
+#
 
-sub make_tree(%);
-sub print_tree($%);
-sub mv_tree($$$%);
-sub sync_tree($$%);
-
-# Take a hash of delimiters, and recursively build a tree out of it.
-# For instance ( a => "/", b => "/", "a/c" => ".", "a/c.d" => "/", "a/d" => ".")
-# is transformed into the hash reference
-#   { b => {},
-#   { a => { "/c" => { ".d" => {} } }
-#          , "/d" => {}
-#          }
-#   }
-sub make_tree(%) {
-    my %delims = @_;
-    my @list = sort {length($a) <=> length($b)} keys %delims;
-
-    my %tree;
-    foreach my $x (@list) {
-        next unless exists $delims{$x}; # already a children of something
-        my %children;
-        foreach (keys %delims) {
-            next unless defined $delims{$x} and s/\A\Q$x$delims{$x}\E/$delims{$x}/;
-            $children{$_} = delete $delims{"$x$_"};
-        }
-        delete $delims{$x};
-        $tree{$x} = make_tree(%children);
+# Add a new mailbox to the database.
+my $STH_INSERT_MAILBOX= $DBH->prepare(q{INSERT INTO mailboxes (mailbox,subscribed) VALUES (?,?)});
+
+# Get the index associated with a mailbox.
+my $STH_GET_INDEX = $DBH->prepare(q{SELECT idx,subscribed FROM mailboxes WHERE mailbox = ?});
+
+# Ensure local and remote delimiter match
+sub check_delim($) {
+    my $mbx = shift;
+    my ($lDelims, $rDelims) = map {$IMAP->{$_}->{delims}} qw/local remote/;
+    if (exists $lDelims->{$mbx} and exists $rDelims->{$mbx} and
+        ((defined $lDelims->{$mbx} xor defined $rDelims->{$mbx}) or
+         (defined $lDelims->{$mbx} and defined $rDelims->{$mbx} and $lDelims->{$mbx} ne $rDelims->{$mbx}))) {
+        my ($ld, $rd) = ($lDelims->{$mbx}, $rDelims->{$mbx});
+        $ld =~ s/([\x22\x5C])/\\$1/g if defined $ld;
+        $rd =~ s/([\x22\x5C])/\\$1/g if defined $rd;
+        die "Error: Hierarchy delimiter for $mbx don't match: "
+           ."local \"". ($ld // '')."\", remote \"".($rd // '')."\"\n"
     }
-    return \%tree;
+    return exists $lDelims->{$mbx} ? $lDelims->{$mbx} : exists $rDelims->{$mbx} ? $rDelims->{$mbx} : undef;
 }
-#sub print_tree($%) {
-#    my $indent = shift;
-#    my %tree = @_;
-#    while (my ($root, $children) = each %tree) {
-#        print " "x$indent, '|- ', $root, "\n";
-#        print_tree($indent+2, %$children);
-#    }
-#}
-
-# Retrun true if $mailbox exists for $name that is, if doesn't have the
-# '\NonExistent' flag set.
-sub exists_mbx($$) {
-    my $name = shift;
-    my $mailbox = shift;
+
+# Return true if $mailbox exists on $name
+sub mbx_exists($$) {
+    my ($name, $mailbox) = @_;
     my $flags = $IMAP->{$name}->{mailboxes}->{$mailbox};
     return (defined $flags and !grep {lc $_ eq lc '\NonExistent'} @$flags) ? 1 : 0;
 }
-# Retrun true if $mailbox is subscribed for $name.
-sub subscribed_mbx($$) {
-    my $name = shift;
-    my $mailbox = shift;
+
+# Return true if $mailbox is subscribed to on $name
+sub mbx_subscribed($$) {
+    my ($name, $mailbox) = @_;
     my $flags = $IMAP->{$name}->{mailboxes}->{$mailbox};
     return (defined $flags and grep {lc $_ eq lc '\Subscribed'} @$flags) ? 1 : 0;
 }
 
-# Rename a root recursively in a tree
-sub mv_tree($$$%) {
-    my ($mailboxes, $mbx, $mbx2, %children) = @_;
-    $mailboxes->{$mbx2} = delete $mailboxes->{$mbx};
-    while (my ($root, $children) = each %children) {
-        mv_tree($mailboxes, $mbx.$root, $mbx2.$root, %children);
-    }
-}
 
-# Syncronize mailbox list
-# XXX DELETE and RENAME not tested
-sub sync_tree($$%) {
-    my ($sth, $mbx, %children) = @_;
-    my %exists = map { $_ => exists_mbx($_,$mbx) } qw/local remote/;
-
-    my $rv = 0;
-    if ($exists{local} xor $exists{remote}) {
-        my ($exists,$missing) = $exists{local} ? ('local','remote') : ('remote','local');
-        my ($sth_by_mbx, $sth_by_uidvalidity) = @$sth{($missing.'_by_mbx', $exists.'_by_uidvalidity')};
-
-        # check if there is an entry matching $mbx for $missing in the database
-        $sth_by_mbx->execute($mbx);
-        my $row_by_mbx = $sth_by_mbx->fetch();
-        die if defined $sth_by_mbx->fetch(); # sanity check
-
-        if (defined $row_by_mbx) {
-            # $mbx was seen on $missing during the previous round: it
-            # has either been DELETEd or RENAMEd to another name on
-            # $missing.
-
-            my %uidvalidities = $IMAP->{$missing}->{client}->uidvalidity();
-            my ($idx,$uidvalidity) = @$row_by_mbx;
-            my @mbx2 = grep { $uidvalidities{$_} == $uidvalidity and !exists_mbx($exists,$_) }
-                            keys %uidvalidities;
-
-            if ($#mbx2 > 0) {
-                # XXX this is allowed by RFC3501, but we can't guess...
-                msg($missing, "Multiple mailboxes have same UIDVALIDITY $uidvalidity: ",
-                              join(',',@mbx2), "\n",
-                             "Dunno which one $mbx should be renamed to.");
-                exit 1;
-            }
-            elsif (@mbx2) {
-                # $mbx's known (from the DB) UIDVALIDITY is that of
-                # $missing's $mbx2, which is not in the database and
-                # doesn't exist on $exists
-                msg($exists, "Rename mailbox $mbx to $mbx2[0]");
-                $sth->{rename}->execute($mbx2[0],$idx) or
-                    msg('database', "WARNING: Can't rename $mbx to $mbx2[0]");
-                $IMAP->{$exists}->{client}->rename($mbx, $mbx2[0]);
-                $DBH->commit();
-                mv_tree($IMAP->{$exists}->{mailboxes}, $mbx, $mbx2[0], %children);
-                $mbx = $mbx2[0];
-            }
-            else {
-                # $mbx's known (from the DB) UIDVALIDITY on $missing
-                # was not found in any of $missing's mailboxes.
-                msg($exists, "Delete mailbox $mbx");
-                push @{$IMAP->{$exists}->{mailboxes}->{$mbx}}, '\NonExistent';
-                $IMAP->{$exists}->{client}->delete($mbx);
-            }
-        }
-        else {
-            # $mbx was never seen on $missing: it has either been
-            # CREATEd or RENAMEd from another name on $exists.
-
-            my ($idx,$mbx2);
-            if (defined (my $uidvalidity = $IMAP->{$exists}->{client}->uidvalidity($mbx))) {
-                $sth_by_uidvalidity->execute($uidvalidity);
-                my $by_uidvalidity = $sth_by_uidvalidity->fetchall_arrayref();
-                if (defined $by_uidvalidity and $#$by_uidvalidity > 0) {
-                    # XXX this is allowed by RFC3501, but we can't guess...
-                    my @mbx2 = map {$_->[1]} @$by_uidvalidity;
-                    msg($exists, "Multiple mailboxes have same UIDVALIDITY $uidvalidity: ",
-                                  join(',',@mbx2), "\n",
-                                 "Dunno which one $mbx should be renamed to.");
-                    exit 1;
-                }
-                ($idx,$mbx2) = @{$by_uidvalidity->[0]} if defined $by_uidvalidity and @$by_uidvalidity;
-            }
+##############################################################################
+# Process --delete command
+#
+if (defined $COMMAND and $COMMAND eq 'delete') {
+    my $sth_delete_mailboxes = $DBH->prepare(q{DELETE FROM mailboxes WHERE idx = ?});
+    my $sth_delete_local     = $DBH->prepare(q{DELETE FROM local     WHERE idx = ?});
+    my $sth_delete_remote    = $DBH->prepare(q{DELETE FROM remote    WHERE idx = ?});
+    my $sth_delete_mapping   = $DBH->prepare(q{DELETE FROM mapping   WHERE idx = ?});
 
-            if (defined $mbx2) {
-                # $mbx's UIDVALIDITY on $exists can be found in the
-                # database as associated with $mbx2, which exists on
-                # $missing but not on $exists
-                msg($missing, "Rename mailbox $mbx2 to $mbx");
-                $sth->{rename}->execute($mbx,$idx) or
-                    msg('database', "WARNING: Can't rename $mbx2 to $mbx2");
-                $IMAP->{$missing}->{client}->rename($mbx2, $mbx);
-                $DBH->commit();
-                mv_tree($IMAP->{$missing}->{mailboxes}, $mbx2, $mbx, %children);
-            }
-            else {
-                # $mbx's UIDVALIDITY on $exists has never been found in
-                # the database.
-                msg($missing, "Create mailbox $mbx");
-                $IMAP->{$missing}->{mailboxes}->{$mbx} =
-                    grep {lc $_ ne lc '\NonExistent'} @{$IMAP->{$missing}->{mailboxes}->{$mbx} // []};
-                $IMAP->{$missing}->{client}->create($mbx);
-            }
+    foreach my $mailbox (@ARGV) {
+        $STH_GET_INDEX->execute($mailbox);
+        my ($idx) = $STH_GET_INDEX->fetchrow_array();
+        die if defined $STH_GET_INDEX->fetch(); # sanity check
+
+        # delete $mailbox on servers where $mailbox exists.  note that
+        # there is a race condition where the mailbox could have
+        # appeared meanwhile
+        foreach my $name (qw/local remote/) {
+            next if defined $CONFIG{target} and !grep {$_ eq $name} @{$CONFIG{target}};
+            $IMAP->{$name}->{client}->delete($mailbox) if mbx_exists($name, $mailbox);
         }
-        $rv = 1;
-    }
 
-    while (my ($root, $children) = each %children) {
-        my $r = sync_tree($sth, $mbx.$root, %$children);
-        $rv ||= $r;
+        if (defined $idx and (!defined $CONFIG{target} or grep {$_ eq 'database'} @{$CONFIG{target}})) {
+            my $r1 = $sth_delete_mapping->execute($idx);
+            msg('database', "WARNING: `DELETE FROM mapping WHERE idx = $idx` failed") unless $r1;
+            my $r2 = $sth_delete_local->execute($idx);
+            msg('database', "WARNING: `DELETE FROM local WHERE idx = $idx` failed") unless $r2;
+            my $r3 = $sth_delete_remote->execute($idx);
+            msg('database', "WARNING: `DELETE FROM remote WHERE idx = $idx` failed") unless $r3;
+            my $r4 = $sth_delete_mailboxes->execute($idx);
+            msg('database', "WARNING: `DELETE FROM mailboxes WHERE idx = $idx` failed") unless $r4;
+
+            $DBH->commit();
+            msg('database', "Removed mailbox $mailbox") if $r4;
+        }
     }
-    return $rv;
+    exit 0;
 }
 
-{
-    my %delims;
+
+##############################################################################
+# Process --rename command
+#
+elsif (defined $COMMAND and $COMMAND eq 'rename') {
+    my ($from, $to) = @ARGV;
+
+    # get index of the original name
+    $STH_GET_INDEX->execute($from);
+    my ($idx) = $STH_GET_INDEX->fetchrow_array();
+    die if defined $STH_GET_INDEX->fetch(); # sanity check
+
+    # ensure the local and remote hierarchy delimiter match
+    my $delim = check_delim($from);
+
+    # ensure the target name doesn't already exist on the servers. there
+    # is a race condition where the mailbox would be created before we
+    # issue the RENAME command, then the server would reply with a
+    # tagged NO response
     foreach my $name (qw/local remote/) {
-        while (my ($mbx, $sep) = each %{$IMAP->{$name}->{delims}}) {
-            if (!exists $delims{$mbx}) {
-                $delims{$mbx} = $sep;
-            } else {
-                die "Hierarchy delimeters for mailbox $mbx don't match!\n"
-                    unless (!defined $sep and !defined $delims{$mbx}) or
-                           (defined $sep and defined $delims{$mbx} and $sep eq $delims{$mbx});
-            }
+        next if defined $CONFIG{target} and !grep {$_ eq $name} @{$CONFIG{target}};
+        if (mbx_exists($name, $to)) {
+            msg($name, "ERROR: Mailbox $to exists.  Run `$NAME --delete $to` to delete.");
+            exit 1;
         }
     }
 
-    my $tree = make_tree(%delims);
-    my %sth;
-    $sth{$_.'_by_mbx'} = $DBH->prepare("SELECT idx,UIDVALIDITY FROM mailboxes NATURAL JOIN $_ WHERE mailbox = ?")
-        foreach qw/local remote/;
-    $sth{$_.'_by_uidvalidity'} = $DBH->prepare("SELECT idx,mailbox FROM mailboxes NATURAL JOIN $_ WHERE UIDVALIDITY = ?")
-        foreach qw/local remote/;
-    $sth{rename} = $DBH->prepare(q{UPDATE mailboxes SET mailbox = ? WHERE idx = ?});
-
-    my $updated = 0;
-    while (my ($mbx,$children) = each %$tree) {
-        #print $mbx, "\n";
-        #print_tree(0, %$children);
-        my $u = sync_tree(\%sth, $mbx, %$children);
-        $updated ||= $u;
+    # ensure the target name doesn't already exist in the database
+    $STH_GET_INDEX->execute($to);
+    if (defined $STH_GET_INDEX->fetch() and
+        (!defined $CONFIG{target} or grep {$_ eq 'database'} @{$CONFIG{target}})) {
+        msg('database', "ERROR: Mailbox $to exists.  Run `$NAME --delete $to` to delete.");
+        exit 1;
     }
 
-    if ($updated) {
-        # refresh the mailbox list
-        foreach my $name (qw/local remote/) {
-            @{$IMAP->{$name}}{qw/mailboxes delims/} = $IMAP->{$name}->{client}->list(q{"" "*"}, 'SUBSCRIBED');
-        }
-        my %mailboxes;
-        $mailboxes{$_} = 1 foreach (keys %{$IMAP->{local}->{mailboxes}}, keys %{$IMAP->{remote}->{mailboxes}});
-        foreach my $mbx (keys %mailboxes) {
-            die "Couldn't sync mailbox list.\n" if exists_mbx('local',$mbx) xor exists_mbx('remote',$mbx);
+
+    # rename $from to $to on servers where $from exists.  again there is
+    # a race condition, but if $to has been created meanwhile the server
+    # will reply with a tagged NO response
+    foreach my $name (qw/local remote/) {
+        next if defined $CONFIG{target} and !grep {$_ eq $name} @{$CONFIG{target}};
+        $IMAP->{$name}->{client}->rename($from, $to) if mbx_exists($name, $from);
+    }
+
+    # rename from to $to in the database
+    if (defined $idx and (!defined $CONFIG{target} or grep {$_ eq 'database'} @{$CONFIG{target}})) {
+        my $sth_rename_mailbox = $DBH->prepare(q{UPDATE mailboxes SET mailbox = ? WHERE idx = ?});
+        my $r = $sth_rename_mailbox->execute($to, $idx);
+        msg('database', "WARNING: `UPDATE mailboxes SET mailbox = ".$DBH->quote($to)." WHERE idx = $idx` failed") unless $r;
+
+        # for non-flat mailboxes, rename the children as well
+        if (defined $delim) {
+            my $prefix = $from.$delim;
+            my $sth_rename_children = $DBH->prepare(q{
+                UPDATE mailboxes SET mailbox = ? || SUBSTR(mailbox,?)
+                WHERE SUBSTR(mailbox,1,?) = ?
+            });
+            $sth_rename_children->execute($to, length($prefix), length($prefix), $prefix);
         }
+
+        $DBH->commit();
+        msg('database', "Renamed mailbox $from to $to") if $r;
     }
+    exit 0;
 }
 
-# Synchronize subscription list
-my @SUBSCRIPTIONS;
+
+##############################################################################
+# Synchronize mailbox and subscription lists
+
+my @MAILBOXES;
 {
-    my $sth_search = $DBH->prepare(q{SELECT idx,subscribed FROM mailboxes WHERE mailbox = ?});
+    my %mailboxes;
+    $mailboxes{$_} = 1 foreach keys %{$IMAP->{local}->{mailboxes}};
+    $mailboxes{$_} = 1 foreach keys %{$IMAP->{remote}->{mailboxes}};
     my $sth_subscribe = $DBH->prepare(q{UPDATE mailboxes SET subscribed = ? WHERE idx = ?});
 
-    my %mailboxes;
-    $mailboxes{$_} = 1 foreach (keys %{$IMAP->{local}->{mailboxes}}, keys %{$IMAP->{remote}->{mailboxes}});
-
-    foreach my $mbx (keys %mailboxes) {
-        $sth_search->execute($mbx);
-        my $row = $sth_search->fetch();
-        die if defined $sth_search->fetch(); # sanity check
-
-        my ($lSubscribed,$rSubscribed) = map {subscribed_mbx($_,$mbx)} qw/local remote/;
-        if ($lSubscribed == $rSubscribed) {
-            if (defined $row) {
-                my ($idx,$status) = @$row;
-                if (defined $status and $status != $lSubscribed) {
-                    $sth_subscribe->execute($lSubscribed, $idx) or
-                        msg('database', "WARNING: Can't (un)subscribe $mbx");
-                    $DBH->commit();
-                }
-            }
-        }
-        else {
-            my ($subscribed,$unsubscribed) = $lSubscribed ? qw/local remote/ : qw/remote local/;
-            if (defined $row) {
-                my ($idx,$status) = @$row;
-                if ($status) {
-                    # $mbx was SUBSCRIBEd before, UNSUBSCRIBE it now
-                    msg($subscribed, "Unsubscribe to mailbox $mbx");
-                    $sth_subscribe->execute(0,$idx) or
-                        msg('database', "WARNING: Can't unsubscribe $mbx");
-                    $IMAP->{$subscribed}->{client}->unsubscribe($mbx);
+    @MAILBOXES = keys %mailboxes;
+
+    foreach my $mailbox (@MAILBOXES) {
+        check_delim($mailbox); # ensure that the delimiter match
+        my ($lExists, $rExists) = map {mbx_exists($_,$mailbox)} qw/local remote/;
+
+        $STH_GET_INDEX->execute($mailbox);
+        my ($idx,$subscribed) = $STH_GET_INDEX->fetchrow_array();
+        die if defined $STH_GET_INDEX->fetch(); # sanity check
+
+        if ($lExists and $rExists) {
+            # $mailbox exists on both sides
+            my ($lSubscribed,$rSubscribed) = map {mbx_subscribed($_, $mailbox)} qw/local remote/;
+            if (defined $idx) {
+                if ($lSubscribed xor $rSubscribed) {
+                    # mailbox is subscribed on only one server
+                    if ($subscribed) { # unsubscribe
+                        my $name = $lSubscribed ? 'local' : 'remote';
+                        $IMAP->{$name}->{client}->unsubscribe($mailbox);
+                    }
+                    else { # subscribe
+                        my $name = $lSubscribed ? 'remote' : 'local';
+                        $IMAP->{$name}->{client}->subscribe($mailbox);
+                    }
+                    # toggle subscribtion in the database
+                    $subscribed = $subscribed ? 0 : 1;
+                    $sth_subscribe->execute($subscribed, $idx) or
+                        msg('database', "WARNING: `UPDATE mailboxes SET subscribed = $subscribed WHERE idx = $idx` failed");
                     $DBH->commit();
-                    $lSubscribed = $rSubscribed = 0;
                 }
-                else {
-                    # $mbx was UNSUBSCRIBEd before, SUBSCRIBE it now
-                    msg($unsubscribed, "Subscribe to mailbox $mbx");
-                    $sth_subscribe->execute(1,$idx) or
-                        msg('database', "WARNING: Can't subscribe $mbx");
-                    $IMAP->{$unsubscribed}->{client}->subscribe($mbx);
+                # $mailbox is either subscribed on both servers, or subscribed on both
+                elsif ($lSubscribed xor $subscribed) {
+                    # update the database if needed
+                    $sth_subscribe->execute($lSubscribed, $idx) or
+                        msg('database', "WARNING: `UPDATE mailboxes SET subscribed = $lSubscribed WHERE idx = $idx` failed");
                     $DBH->commit();
-                    $lSubscribed = $rSubscribed = 1;
                 }
             }
             else {
-                # $mbx is unknown; assume the user wants to SUBSCRIBE
-                msg($unsubscribed, "Subscribe to mailbox $mbx");
-                $IMAP->{$unsubscribed}->{client}->subscribe($mbx);
-                $lSubscribed = $rSubscribed = 1;
+                # add new mailbox; subscribe on both servers if $mailbox is subscribed on one of them
+                my $subscribed = ($lSubscribed or $rSubscribed) ? 1 : 0;
+                $STH_INSERT_MAILBOX->execute($mailbox, $subscribed);
+                $IMAP->{local}->{client}->subscribe($mailbox)  if $subscribed and !$lSubscribed;
+                $IMAP->{remote}->{client}->subscribe($mailbox) if $subscribed and !$rSubscribed;
+                $DBH->commit();
             }
         }
-        push @SUBSCRIPTIONS, $mbx if $lSubscribed;
-    }
-}
-
-# Clean database: remove mailboxes that no longer exist
-{
-    my $sth = $DBH->prepare(q{SELECT idx,mailbox,subscribed FROM mailboxes});
-    my $sth_delete_mailboxes = $DBH->prepare(q{DELETE FROM mailboxes WHERE idx = ?});
-    my $sth_delete_local     = $DBH->prepare(q{DELETE FROM local     WHERE idx = ?});
-    my $sth_delete_remote    = $DBH->prepare(q{DELETE FROM remote    WHERE idx = ?});
-    my $sth_delete_mapping   = $DBH->prepare(q{DELETE FROM mapping   WHERE idx = ?});
-
-    my @idx;
-    $sth->execute();
-    while (defined (my $row = $sth->fetch)) {
-        my ($idx,$mbx,$subscribed) = @$row;
-        if (!exists_mbx('local',$mbx) and !exists_mbx('remote',$mbx)) {
-            $_->execute($idx) foreach ($sth_delete_mapping,$sth_delete_local,$sth_delete_remote);
-            $sth_delete_mailboxes->execute($idx) if
-                !exists $IMAP->{local}->{mailboxes}->{$mbx} and
-                !exists $IMAP->{remote}->{mailboxes}->{$mbx};
+        elsif ($lExists and !$rExists) {
+            # $mailbox is on 'local' only
+            if (defined $idx) {
+                msg('database', "ERROR: Mailbox $mailbox exists.  Run `$NAME --delete $mailbox` to delete.");
+                exit 1;
+            }
+            my $subscribed = mbx_subscribed('local', $mailbox);
+            $STH_INSERT_MAILBOX->execute($mailbox, $subscribed);
+            $IMAP->{remote}->{client}->create($mailbox);
+            $IMAP->{remote}->{client}->subscribe($mailbox) if $subscribed;
+            $DBH->commit();
+        }
+        elsif (!$lExists and $rExists) {
+            # $mailbox is on 'remote' only
+            if (defined $idx) {
+                msg('database', "ERROR: Mailbox $mailbox exists.  Run `$NAME --delete $mailbox` to delete.");
+                exit 1;
+            }
+            my $subscribed = mbx_subscribed('remote', $mailbox);
+            $STH_INSERT_MAILBOX->execute($mailbox, $subscribed);
+            $IMAP->{local}->{client}->create($mailbox);
+            $IMAP->{local}->{client}->subscribe($mailbox) if $subscribed;
             $DBH->commit();
         }
     }
 }
-
+my ($lIMAP, $rIMAP) = map {$IMAP->{$_}->{client}} qw/local remote/;
+undef $IMAP;
 
 
 #############################################################################
 # Synchronize messages
-# Consider only the mailboxes in @ARGV, if the list is non-empty.
-
-my ($lIMAP, $rIMAP) = map {$IMAP->{$_}->{client}} qw/local remote/;
-undef $IMAP;
-
 
 # Get all cached states from the database.
 my $STH_GET_CACHE = $DBH->prepare(q{
-    SELECT mailbox,
+    SELECT mailbox, m.idx as idx,
            l.UIDVALIDITY as lUIDVALIDITY, l.UIDNEXT as lUIDNEXT, l.HIGHESTMODSEQ as lHIGHESTMODSEQ,
            r.UIDVALIDITY as rUIDVALIDITY, r.UIDNEXT as rUIDNEXT, r.HIGHESTMODSEQ as rHIGHESTMODSEQ
     FROM mailboxes m JOIN local l ON m.idx = l.idx JOIN remote r ON m.idx = r.idx
@@ -551,9 +498,6 @@ my $STH_GET_CACHE_BY_IDX = $DBH->prepare(q{
     WHERE m.idx = ?
 });
 
-# Get the index associated with a mailbox.
-my $STH_GET_INDEX = $DBH->prepare(q{SELECT idx FROM mailboxes WHERE mailbox = ?});
-
 # Find local/remote UID from the map.
 my $STH_GET_LOCAL_UID  = $DBH->prepare(q{SELECT lUID FROM mapping WHERE idx = ? and rUID = ?});
 my $STH_GET_REMOTE_UID = $DBH->prepare(q{SELECT rUID FROM mapping WHERE idx = ? and lUID = ?});
@@ -571,7 +515,6 @@ my $STH_UPDATE_LOCAL  = $DBH->prepare(q{UPDATE local  SET UIDNEXT = ?, HIGHESTMO
 my $STH_UPDATE_REMOTE = $DBH->prepare(q{UPDATE remote SET UIDNEXT = ?, HIGHESTMODSEQ = ? WHERE idx = ?});
 
 # Add a new mailbox.
-my $STH_INSERT_MAILBOX= $DBH->prepare(q{INSERT INTO mailboxes (mailbox,subscribed) VALUES (?,?)});
 my $STH_INSERT_LOCAL  = $DBH->prepare(q{INSERT INTO local  (idx,UIDVALIDITY,UIDNEXT,HIGHESTMODSEQ) VALUES (?,?,0,0)});
 my $STH_INSERT_REMOTE = $DBH->prepare(q{INSERT INTO remote (idx,UIDVALIDITY,UIDNEXT,HIGHESTMODSEQ) VALUES (?,?,0,0)});
 
@@ -650,9 +593,20 @@ sub delete_mapping($$) {
 
 # Check and repair synchronization of a mailbox between the two servers
 # (in a very crude way, by downloading all existing UID with their flags)
-my @REPAIR;
-sub repair($$) {
-    my ($idx, $mailbox) = @_;
+sub repair($) {
+    my $mailbox = shift;
+
+    $STH_GET_INDEX->execute($mailbox);
+    my ($idx) = $STH_GET_INDEX->fetchrow_array();
+    die if defined $STH_GET_INDEX->fetch(); # sanity check
+
+    return unless defined $idx; # not in the database
+    $lIMAP->select($mailbox);
+    $rIMAP->select($mailbox);
+
+    $STH_GET_CACHE_BY_IDX->execute($idx);
+    my $cache = $STH_GET_CACHE_BY_IDX->fetchrow_hashref() // return; # no cache
+    die if defined $STH_GET_CACHE_BY_IDX->fetch(); # sanity check
 
     # get all existing UID with their flags
     my ($lVanished, $lModified) = $lIMAP->pull_updates(1);
@@ -665,10 +619,6 @@ sub repair($$) {
     my (@rToRemove, %rToUpdate, @rMissing);
     my @delete_mapping;
 
-    $STH_GET_CACHE_BY_IDX->execute($idx);
-    my $cache = $STH_GET_CACHE_BY_IDX->fetchrow_hashref() // die "Missing cache for index $idx";
-    die if defined $STH_GET_CACHE_BY_IDX->fetch(); # sanity check
-
     # process each pair ($lUID,$rUID) found in the mapping table, and
     # compare with the result from the IMAP servers to detect anomalies
 
@@ -1024,11 +974,14 @@ sub wait_notifications(;$) {
 }
 
 
+#############################################################################
 # Resume interrupted mailbox syncs.
+#
 my ($MAILBOX, $IDX);
 $STH_LIST_INTERRUPTED->execute();
 while (defined (my $row = $STH_LIST_INTERRUPTED->fetchrow_arrayref())) {
     ($IDX, $MAILBOX) = @$row;
+    next unless grep { $_ eq $MAILBOX } @MAILBOXES;
     msg(undef, "Resuming interrupted sync for $MAILBOX");
 
     my %lUIDs;
@@ -1075,8 +1028,10 @@ while (defined (my $row = $STH_LIST_INTERRUPTED->fetchrow_arrayref())) {
 }
 
 
-
+#############################################################################
 # Initialize $lIMAP and $rIMAP states to detect mailbox dirtyness.
+#
+my %KNOWN_INDEXES;
 $STH_GET_CACHE->execute();
 while (defined (my $row = $STH_GET_CACHE->fetchrow_hashref())) {
     $lIMAP->set_cache($row->{mailbox},
@@ -1089,22 +1044,13 @@ while (defined (my $row = $STH_GET_CACHE->fetchrow_hashref())) {
         UIDNEXT       => $row->{rUIDNEXT},
         HIGHESTMODSEQ => $row->{rHIGHESTMODSEQ}
     );
-    push @REPAIR, $row->{mailbox} if $CONFIG{repair} and
-        (!@ARGV or grep { $_ eq $row->{mailbox} } @ARGV);
+    $KNOWN_INDEXES{$row->{idx}} = 1;
 }
 
-while (@REPAIR) {
-    $MAILBOX = shift @REPAIR;
-
-    $STH_GET_INDEX->execute($MAILBOX);
-    ($IDX) = $STH_GET_INDEX->fetchrow_array();
-    die if defined $STH_GET_INDEX->fetch(); # sanity check
-
-    $lIMAP->select($MAILBOX);
-    $rIMAP->select($MAILBOX);
-    repair($IDX, $MAILBOX);
+if (defined $COMMAND and $COMMAND eq 'repair') {
+    repair($_) foreach @MAILBOXES;
+    exit 0;
 }
-exit 0 if $CONFIG{repair};
 
 
 while(1) {
@@ -1116,28 +1062,23 @@ while(1) {
             sync_messages($IDX, $MAILBOX);
         }
         else {
-            $MAILBOX = $lIMAP->next_dirty_mailbox(@ARGV) // $rIMAP->next_dirty_mailbox(@ARGV) // last;
+            $MAILBOX = $lIMAP->next_dirty_mailbox(@MAILBOXES) // $rIMAP->next_dirty_mailbox(@MAILBOXES) // last;
             $MAILBOX = 'INBOX' if uc $MAILBOX eq 'INBOX'; # INBOX is case insensitive
 
             $STH_GET_INDEX->execute($MAILBOX);
             ($IDX) = $STH_GET_INDEX->fetchrow_array();
             die if defined $STH_GET_INDEX->fetch(); # sanity check
+            die unless defined $IDX; # sanity check;
 
             $lIMAP->select($MAILBOX);
             $rIMAP->select($MAILBOX);
 
-            # new mailbox
-            if (!defined $IDX) {
-                my $subscribed = (grep { $_ eq $MAILBOX} @SUBSCRIPTIONS) ? 1 : 0;
-                $STH_INSERT_MAILBOX->execute($MAILBOX, $subscribed);
-                $STH_GET_INDEX->execute($MAILBOX);
-                ($IDX) = $STH_GET_INDEX->fetchrow_array();
-                die if !defined $IDX or defined $STH_GET_INDEX->fetchrow_arrayref(); # sanity check
-
+            if (!$KNOWN_INDEXES{$IDX}) {
                 $STH_INSERT_LOCAL->execute( $IDX, $lIMAP->uidvalidity($MAILBOX));
                 $STH_INSERT_REMOTE->execute($IDX, $rIMAP->uidvalidity($MAILBOX));
 
-                # don't commit before the first mapping (lUID,rUID)
+                # no need to commit before the first mapping (lUID,rUID)
+                $KNOWN_INDEXES{$IDX} = 1;
             }
             elsif (sync_known_messages($IDX, $MAILBOX)) {
                 # sync updates to known messages before fetching new messages
@@ -1152,7 +1093,7 @@ while(1) {
         }
     }
     # clean state!
-    exit 0 unless $CONFIG{watch};
+    exit 0 unless defined $COMMAND and $COMMAND eq 'watch';
     wait_notifications(900);
 }
 
diff --git a/imapsync.1 b/imapsync.1
index 0f286ce..e274943 100644
--- a/imapsync.1
+++ b/imapsync.1
@@ -4,7 +4,7 @@
 imapsync \- IMAP-to-IMAP synchronization program for QRESYNC-capable servers
 
 .SH SYNOPSIS
-.B imapsync\fR [\fIOPTION\fR ...] [\fIMAILBOX\fR ...]
+.B imapsync\fR [\fIOPTION\fR ...] [\fICOMMAND\fR] [\fIMAILBOX\fR ...]
 
 
 .SH DESCRIPTION
@@ -69,6 +69,7 @@ Go back to step 2 if the server sent some updates in the meantime.
 .IP \n+[step].
 Go back to step 1 to proceed with the next unsynchronized mailbox.
 
+.SH COMMANDS
 .PP
 By default \fBimapsync\fR synchronizes each mailbox listed by the
 \(lqLIST "" "*"\(rq IMAP command;
@@ -86,16 +87,15 @@ their flags have changed in the meantime.
 Finally, after propagating the offline changes for these messages,
 \fBimapsync\fR resumes the synchronization for the rest of the mailbox.
 
-.SH OPTIONS
-.TP
-.B \-\-config=\fR\fIFILE\fR
-Specify an alternate configuration file.  Relative paths start from
-\fI$XDG_CONFIG_HOME\fR, or \fI~/.config\fR if the XDG_CONFIG_HOME
-environment variable is unset.
+.PP
+Specifying one of the commands below makes \fBimapsync\fR perform an
+action other than the default QRESYNC-based synchronization.
 
 .TP
-.B \-\-repair
+.B \-\-repair \fR[\fIMAILBOX\fR ...]
 List the database anomalies and try to repair them.
+(Consider only the given \fIMAILBOX\fRes if non-optional arguments are
+provided.)
 This is done by performing a so\-called \(lqfull synchronization\(rq,
 namely 1/ download all UIDs along with their flags from both the local
 and remote servers, 2/ ensure that each entry in the database corresponds
@@ -107,6 +107,37 @@ Flag conflicts are solved by updating each message to the union of both
 lists.
 
 .TP
+.B \-\-delete \fIMAILBOX\fR [...]
+Delete the given \fIMAILBOX\fRes on each target (by default each server
+plus the database, unless \fB\-\-target\fR specifies otherwise) where
+it exists.
+Note that per [RFC3501] deletion is not recursive: \fIMAILBOX\fR's
+children are not deleted.
+
+.TP
+.B \-\-rename \fISOURCE\fR \fIDEST\fR
+Rename the mailbox \fISOURCE\fR to \fIDEST\fR on each target (by default
+each server plus the database, unless \fB\-\-target\fR specifies
+otherwise) where it exists.
+\fBimapsync\fR aborts if \fIDEST\fR already exists on either target.
+Note that per [RFC3501] the renaming is recursive: \fISOURCE\fR's
+children are moved to become \fIDEST\fR's children instead.
+
+
+.SH OPTIONS
+.TP
+.B \-\-config=\fR\fIFILE\fR
+Specify an alternate configuration file.  Relative paths start from
+\fI$XDG_CONFIG_HOME\fR, or \fI~/.config\fR if the XDG_CONFIG_HOME
+environment variable is unset.
+
+.TP
+.B \fB\-\-target=\fR{local,remote,database}
+Limit the scope of a \fB\-\-delete\fR or \fB\-\-rename\fR command
+to the given target.  Can be repeated to act on multiple targets.  By
+default all three targets are considered.
+
+.TP
 .B \-q\fR, \fB\-\-quiet\fR
 Try to be quiet.
 
@@ -231,21 +262,11 @@ Authorities, used for server certificate verification.
 
 .SH KNOWN BUGS AND LIMITATIONS
 
-.IP \[bu] 2
-Mailbox deletion and renaming are not very well tested yet.
 .IP \[bu]
 Using \fBimapsync\fR on two identical servers with a non-existent or
 empty database will duplicate each message due to absence of
 local/remote UID association.
 .IP \[bu]
-Detecting whether a mailbox has been renamed or deleted while
-\fBimapsync\fR wasn't running is done by looking for a mailbox with same
-UIDVALIDITY.  [RFC3501] describes the purpose of UIDVALIDITY as to let
-clients know when to invalidate their UID cache.  In particular, there
-is no requirement that two mailboxes can't share same UIDVALIDITY.
-However such a possibility would defeat \fBimapsync\fR's heuristic to
-detect whether a mailbox has been renamed or deleted offline.
-.IP \[bu]
 \fBimapsync\fR is single threaded and doesn't use IMAP command
 pipelining.  Performance improvement could be achieved by sending
 independent commands to each server in parallel, and for a given server,
diff --git a/lib/Net/IMAP/Sync.pm b/lib/Net/IMAP/Sync.pm
index 3216483..c1bccbf 100644
--- a/lib/Net/IMAP/Sync.pm
+++ b/lib/Net/IMAP/Sync.pm
@@ -520,11 +520,13 @@ sub create($$) {
     my ($self, $mailbox) = @_;
     $self->fail("Server is read-only.") if $self->{'read-only'};
     $self->_send("CREATE ".quote($mailbox));
+    $self->log("Created mailbox ".$mailbox) unless $self->{quiet};
 }
 sub delete($$) {
     my ($self, $mailbox) = @_;
     $self->fail("Server is read-only.") if $self->{'read-only'};
-    #$self->_send("DELETE ".quote($mailbox));
+    $self->_send("DELETE ".quote($mailbox));
+    $self->log("Deleted mailbox ".$mailbox) unless $self->{quiet};
     delete $self->{_CACHE}->{$mailbox};
     delete $self->{_PCACHE}->{$mailbox};
 }
@@ -533,12 +535,24 @@ sub delete($$) {
 # $self->rename($oldname, $newname)
 #   RENAME the mailbox $oldname to $newname.  Requires the 'read-only'
 #   flag to be unset.
+#   /!\ Requires a LIST command to be issued to determine the hierarchy
+#       delimiter for the original name.
 sub rename($$$) {
     my ($self, $from, $to) = @_;
+    my $delim = $self->{_CACHE}->{$from}->{DELIMITER} if defined $self->{_CACHE}->{$from};
     $self->fail("Server is read-only.") if $self->{'read-only'};
     $self->_send("RENAME ".quote($from).' '.quote($to));
+    $self->log("Renamed mailbox ".$from.' to '.$to) unless $self->{quiet};
     $self->{_CACHE}->{$to}  = delete $self->{_CACHE}->{$from}  if exists $self->{_CACHE}->{$from};
     $self->{_PCACHE}->{$to} = delete $self->{_PCACHE}->{$from} if exists $self->{_PCACHE}->{$from};
+    if (defined $delim) {
+        # on non-flat mailboxes, move children as well (cf 3501)
+        foreach my $c1 (grep /\A\Q$from$delim\E/, keys %{$self->{_CACHE}}) {
+            my $c2 = $c1 =~ s/\A\Q$from$delim\E/$to$delim/r;
+            $self->{_CACHE}->{$c2}  = delete $self->{_CACHE}->{$c1}  if exists $self->{_CACHE}->{$c1};
+            $self->{_PCACHE}->{$c2} = delete $self->{_PCACHE}->{$c1} if exists $self->{_PCACHE}->{$c1};
+        }
+    }
 }
 
 
@@ -550,11 +564,13 @@ sub subscribe($$) {
     my ($self, $mailbox) = @_;
     $self->fail("Server is read-only.") if $self->{'read-only'};
     $self->_send("SUBSCRIBE ".quote($mailbox));
+    $self->log("Subscribed to mailbox ".$mailbox) unless $self->{quiet};
 }
 sub unsubscribe($$) {
     my ($self, $mailbox) = @_;
     $self->fail("Server is read-only.") if $self->{'read-only'};
     $self->_send("UNSUBSCRIBE ".quote($mailbox));
+    $self->log("Unsubscribed to mailbox ".$mailbox) unless $self->{quiet};
 }
 
 
@@ -1456,6 +1472,7 @@ sub _resp($$;$$$) {
             $mailbox = 'INBOX' if uc $mailbox eq 'INBOX'; # INBOX is case-insensitive
             undef $delim if uc $delim eq 'NIL';
             $delim =~ s/\A"(.*)"\Z/$1/ if defined $delim;
+            $self->_update_cache_for($mailbox, DELIMITER => $delim);
             $callback->($mailbox, $delim, @flags) if defined $callback and $cmd eq 'LIST';
         }
         elsif (s/\ASTATUS //) {