From: Matt S Trout <matthewt@hercule.scsys.co.uk>
Date: Mon, 15 Jun 2009 20:12:05 +0000 (+0100)
Subject: making a weak ref strong
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=dd944db57e1969dc93f5916c7f343d47ed9cba56;p=p5sagit%2FMutually-Assured-Destruction.git

making a weak ref strong
---

diff --git a/notes/saved-by-strength.pl b/notes/saved-by-strength.pl
new file mode 100644
index 0000000..cdad638
--- /dev/null
+++ b/notes/saved-by-strength.pl
@@ -0,0 +1,39 @@
+#!/usr/bin/env perl
+
+use strict;
+use warnings;
+use Devel::GlobalDestruction ();
+use Scalar::Util ();
+
+BEGIN {
+  package Foo;
+
+  sub DESTROY {
+    return if Devel::GlobalDestruction::in_global_destruction();
+    warn "DESTROY\n";
+
+    my $self = shift;
+
+    if (ref $self->{other_side}) {
+      if (
+        Scalar::Util::refaddr($self->{other_side}{reference})
+        eq Scalar::Util::refaddr($self)
+      ) {
+        warn "Enlivening";
+        $self->{other_side}{reference} = $self;
+        delete $self->{other_side};
+      }
+    }
+  }
+}
+
+my $near = {};
+my $far = $near->{reference} = bless({ other_side => $near }, 'Foo');
+warn $near->{reference};
+warn $far;
+Scalar::Util::weaken($near->{reference});
+warn "Setup done\n";
+undef($far);
+warn $near->{reference};
+Scalar::Util::weaken($near->{reference});
+warn $near->{reference};