xapcmd: localize %SIG changes using "local"

Perl's "local" allows changes to %SIG (and %ENV) to be limited
to its enclosing block.  This allows us to get rid of a global
variable and ad-hoc method for restoring signal handlers.

diff --git a/lib/PublicInbox/Xapcmd.pm b/lib/PublicInbox/Xapcmd.pm
index 22e56f42263bf2e85b4a857cfd7b8c4a8381228c..95d472b05d4d23122da60fd06f0d876301c71ceb 100644 (file)
--- a/lib/PublicInbox/Xapcmd.pm
+++ b/lib/PublicInbox/Xapcmd.pm
@@ -26,6 +26,7 @@ sub commit_changes ($$$) {
        my @old_shard;
 
        while (my ($old, $new) = each %$tmp) {
+               next if $old eq ''; # no invalid paths
                my @st = stat($old);
                if (!@st && !defined($opt->{reshard})) {
                        die "failed to stat($old): $!";
@@ -59,7 +60,7 @@ sub commit_changes ($$$) {
                }
        }
        remove_tree(@old_shard);
-       $tmp->done;
+       $tmp = undef;
        if (!$opt->{-coarse_lock}) {
                $opt->{-skip_lock} = 1;
 
@@ -176,6 +177,9 @@ sub run {
                die "--reshard must be a positive number\n";
        }
 
+       local %SIG = %SIG;
+       $tmp->setup_signals;
+
        # we want temporary directories to be as deep as possible,
        # so v2 shards can keep "xap$SCHEMA_VERSION" on a separate FS.
        if ($v == 1) {
@@ -373,11 +377,13 @@ sub cpdb ($$) {
        }
 
        my ($xtmp, $tmp);
+       local %SIG = %SIG;
        if ($opt->{compact}) {
                my $newdir = dirname($new);
                same_fs_or_die($newdir, $new);
                $tmp = tempdir("$new.compact-XXXXXX", DIR => $newdir);
                $xtmp = PublicInbox::Xtmpdirs->new;
+               $xtmp->setup_signals;
                $xtmp->{$new} = $tmp;
        } else {
                $tmp = $new;
@@ -445,7 +451,7 @@ sub cpdb ($$) {
        # since $dst isn't readable by HTTP or NNTP clients, yet:
        compact([ $tmp, $new ], $opt);
        remove_tree($tmp) or die "failed to remove $tmp: $!\n";
-       $xtmp->done;
+       $xtmp = undef;
 }
 
 # slightly easier-to-manage manage than END{} blocks
@@ -453,38 +459,25 @@ package PublicInbox::Xtmpdirs;
 use strict;
 use warnings;
 use File::Path qw(remove_tree);
-my %owner;
 
-sub new {
+sub setup_signals () {
        # http://www.tldp.org/LDP/abs/html/exitcodes.html
        $SIG{INT} = sub { exit(130) };
        $SIG{HUP} = $SIG{PIPE} = $SIG{TERM} = sub { exit(1) };
-       my $self = bless {}, $_[0]; # old shard => new (WIP) shard
-       $owner{"$self"} = $$;
-       $self;
 }
 
-sub done {
-       my ($self) = @_;
-       delete $owner{"$self"};
-
-       my %known_pids;
-       $known_pids{$_}++ foreach values %owner;
-       if (!$known_pids{$$}) {
-               $SIG{INT} = $SIG{HUP} = $SIG{PIPE} = $SIG{TERM} = 'DEFAULT';
-       }
-       %$self = ();
+sub new {
+       bless { '' => $$ }, $_[0]; # old shard => new (WIP) shard
 }
 
 sub DESTROY {
        my ($self) = @_;
-       my $owner_pid = delete $owner{"$self"} or return;
+       my $owner_pid = delete($self->{''}) or return;
        return if $owner_pid != $$;
        foreach my $new (values %$self) {
                defined $new or next; # may be undef if resharding
                remove_tree($new) unless -d "$new/old";
        }
-       done($self);
 }
 
 1;