File Coverage

blib/lib/B/Hooks/EndOfScope/XS.pm

Criterion	Covered	Total	%
statement	19	19	100.0
branch	2	2	100.0
condition			n/a
subroutine	6	6	100.0
pod	1	1	100.0
total	28	28	100.0

package B::Hooks::EndOfScope::XS;
# ABSTRACT: Execute code after a scope finished compilation - XS implementation

use strict;
use warnings;

our $VERSION = '0.25';

# Limit the V::M-based (XS) version to perl 5.8.4+
#
# Given the unorthodox stuff we do to work around the hinthash double-free
# might as well play it safe and only implement it in the PP version
# and leave it at that
# https://rt.perl.org/Public/Bug/Display.html?id=27040#txn-82797
#
use 5.008004;

use Variable::Magic 0.48 ();
use Sub::Exporter::Progressive 0.001006 -setup => {
  exports => ['on_scope_end'],
  groups  => { default => ['on_scope_end'] },
};

my $wiz = Variable::Magic::wizard
  data => sub { [$_[1]] },
  free => sub { $_->() for @{ $_[1] }; () },
  # When someone localise %^H, our magic doesn't want to be copied
  # down. We want it to be around only for the scope we've initially
  # attached ourselves to. Merely having MGf_LOCAL and a noop svt_local
  # callback achieves this. If anything wants to attach more magic of our
  # kind to a localised %^H, things will continue to just work as we'll be
  # attached with a new and empty callback list.
  local => \undef
;

sub on_scope_end (&) {
  $^H |= 0x020000;

  if (my $stack = Variable::Magic::getdata %^H, $wiz) {
    push @{ $stack }, $_[0];
  }
  else {
    Variable::Magic::cast %^H, $wiz, $_[0];
  }
}

1;

__END__