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.

1 files changed, 12 insertions, 19 deletions

diff --git a/lib/PublicInbox/Xapcmd.pm b/lib/PublicInbox/Xapcmd.pm
index 22e56f42..95d472b0 100644
--- 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;