lei forget-mail-sync: new command to drop sync information

Sometimes a user stops caring to sync an IMAP or Maildir
folder, or wants to force a resync.  Let them run this
command to have lei forget all the sync information about
the mail folder.

This won't delete any stored messages in git, but will
leave "lei index" users with dangling references.

3 files changed, 43 insertions, 1 deletions

diff --git a/lib/PublicInbox/LEI.pm b/lib/PublicInbox/LEI.pm
index 628908b5..c8d2f315 100644
--- a/lib/PublicInbox/LEI.pm
+++ b/lib/PublicInbox/LEI.pm
@@ -243,7 +243,8 @@ our %CMD = ( # sorted in order of importance/use:
         qw(stdin| offset=i recursive|r exclude=s include|I=s
         lock=s@ in-format|F=s kw! verbose|v+ incremental! mail-sync!),
         qw(no-torsocks torsocks=s), PublicInbox::LeiQuery::curl_opt(), @c_opt ],
-
+'forget-mail-sync' => [ 'LOCATION...',
+        'forget sync information for a mail folder', @c_opt ],
 'export-kw' => [ 'LOCATION...|--all',
         'one-time export of keywords of sync sources',
         qw(all:s mode=s), @c_opt ],
diff --git a/lib/PublicInbox/LeiForgetMailSync.pm b/lib/PublicInbox/LeiForgetMailSync.pm
new file mode 100644
index 00000000..46dde1a7
--- /dev/null
+++ b/lib/PublicInbox/LeiForgetMailSync.pm
@@ -0,0 +1,30 @@
+# Copyright (C) 2021 all contributors <meta@public-inbox.org>
+# License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
+
+# "lei forget-mail-sync" drop synchronization information
+# TODO: figure out what to do about "lei index" users having
+# dangling references.  Perhaps just documenting "lei index"
+# use being incompatible with "forget-mail-sync" use is
+# sufficient.
+
+package PublicInbox::LeiForgetMailSync;
+use strict;
+use v5.10.1;
+use PublicInbox::LeiExportKw;
+
+sub lei_forget_mail_sync {
+        my ($lei, @folders) = @_;
+        my $sto = $lei->_lei_store or return;
+        my $lms = $sto->search->lms or return;
+        my $err = $lms->arg2folder($lei, \@folders);
+        $lei->qerr(@{$err->{qerr}}) if $err->{qerr};
+        return $lei->fail($err->{fail}) if $err->{fail};
+        delete $lms->{dbh};
+        $lms->lms_begin;
+        $lms->forget_folder($_) for @folders;
+        $lms->lms_commit;
+}
+
+*_complete_forget_mail_sync = \&PublicInbox::LeiExportKw::_complete_export_kw;
+
+1;
diff --git a/lib/PublicInbox/LeiMailSync.pm b/lib/PublicInbox/LeiMailSync.pm
index 094cf1fd..d9c30580 100644
--- a/lib/PublicInbox/LeiMailSync.pm
+++ b/lib/PublicInbox/LeiMailSync.pm
@@ -345,4 +345,15 @@ EOF
         $err;
 }
 
+sub forget_folder {
+        my ($self, $folder) = @_;
+        my ($fid, $sth);
+        $fid = delete($self->{fmap}->{$folder}) //
+                _fid_for($self, $folder) // return;
+        my $dbh = $self->{dbh};
+        $dbh->do('DELETE FROM blob2name WHERE fid = ?', undef, $fid);
+        $dbh->do('DELETE FROM blob2num WHERE fid = ?', undef, $fid);
+        $dbh->do('DELETE FROM folders WHERE fid = ?', undef, $fid);
+}
+
 1;