From: Matt S Trout <mst@shadowcat.co.uk>
Date: Sat, 20 Jun 2009 20:49:21 +0000 (-0400)
Subject: tentative endeavour at recusive comprehension during serialization perigrinations
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?p=gitmo%2FMooseX-Antlers.git;a=commitdiff_plain;h=3aa089043a81238f12264b987ec1d6e20287821a

tentative endeavour at recusive comprehension during serialization perigrinations
---

diff --git a/tracer.pl b/tracer.pl
index 4cee5c5..a58c25a 100644
--- a/tracer.pl
+++ b/tracer.pl
@@ -49,6 +49,8 @@ extends 'Data::Visitor';
 
 with 'Visitor::NameTracking';
 
+# dump the lazy when we get a sensible version of D::V on the dev system
+
 has '_traced_refs' => (is => 'ro', lazy => 1, default => sub { {} });
 has '_traced_names' => (is => 'ro', lazy => 1, default => sub { {} });
 
@@ -94,8 +96,49 @@ package Ref::Replacer;
 # actually be faster for reconstructing structures but it's fairly academic
 # as yet
 
-#use Moose;
-#use Variable::Magic qw(getdata);
+use Moose;
+# ensure we have next::method available - just because Moose loads it
+# as a side effect doesn't mean it's clever to rely on that
+use MRO::Compat ();
+use Scalar::Util qw(refaddr isweak);
+use namespace::clean -except => 'meta';
+
+extends 'Data::Visitor';
+
+with 'Visitor::NameTracking';
+
+has 'external_mappings' => (is => 'ro', lazy => 1, default => sub { {} });
+has 'weaken_these' => (is => 'ro', lazy => 1, default => sub { {} });
+has 'map_these' => (is => 'ro', lazy => 1, default => sub { {} });
+
+# fairly sure an around modifier will get severely fucked up here
+# in that the copying of @_ will lose the weakness we need to check
+
+sub visit_ref {
+  my $self = shift;
+
+  # have to test $_[0] directly since copying a weak ref gives a strong ref
+
+  if (isweak $_[0]) {
+    $self->weaken_these->{$self->_current_trace_name} = 1;
+  }
+
+  # if we've got a mapping for a reference (i.e. it's supplied from
+  # somewhere else) then we need to record where we are and then
+  # return undef for the fmap process so we serialize an undefined
+  # value and the fixup puts the external reference back in later
+
+  if (my $m = $self->external_mappings->{refaddr $_[0]}) {
+    $self->map_these->{$self->_current_trace_name} = $m;
+    return undef;
+  }
+
+  return $self->next::method(@_);
+}
+
+# force recursion into objects (Data::Visitor doesn't by default)
+
+sub visit_object { shift->visit_ref(@_) }
 
 }