perl_ref_swap

#!/usr/bin/env perl
use Scalar::Util qw(weaken refaddr);

my $c = Test->load("child");
my $test;
{
  my $p = Test->load("parent");
  $test = $p;
  weaken($test);
  
  $c->set_parent($p);
  warn("Child addr: ".sprintf("%x", refaddr(\$c)).", test ref addr: ".sprintf("%x", refaddr(\$test))."\n");
  $p->set_child($c);
  
}
warn("Destroy of parent should have been called before this point.");



####################### packages below ##########################
package ProxyStub;
use Scalar::Util qw(weaken);

sub new {
  my $class = shift;
  my $obj_instance = shift;
  my $self = { 
    __instance => $obj_instance,
    __instance_id => $obj_instance->get_id(),
    __instance_class => ref $obj_instance 
  };
  weaken($self->{__instance});
  return bless $self, $class;
}

sub _get_instance {
  my ($self) = shift;
  
  unless ($self->{__instance}) {
    warn("Instance is garbage collected, loading... [".
          $self->{__instance_class}."->load(" . $self->{__instance_id} . ")]\n");
    $self->{__instance} = $self->{__instance_class}->load($self->{__instance_id});
  }
  return $self->{__instance};  
}

sub AUTOLOAD {
  my $self = shift;
  my $method = $AUTOLOAD;
  $method =~ s/.*:://;
  warn("Proxying: $method\n");  
  $self->_get_instance()->$method(@_);
}

package Test;
use Scalar::Util qw(weaken);
use Devel::Peek;

sub load {
  my ($class, $id) = @_;
  warn("Loading $class as $id");
  return bless {__id => $id}, $class;
}

sub set_parent {
  my ($self, $p) = @_;
  $self->{__parent} = $p;
  weaken($self->{__parent});
  # warn("Weak ref addr: " . refaddr($self));
}

sub get_parent {
  my ($self) = @_;
  return $self->{__parent};
}

sub set_child {
  my ($self, $c) = @_;
  $self->{__child} = $c;
}

sub get_id {
  return shift->{__id};
}

sub DESTROY {
  my $self = shift;
  warn("Destroying: " . ref($self) . ", " . $self->get_id());
  ## Here, I'd love to swap any weak references to this object with a proxy???
  Dump($self);
}