From: Stevan Little <stevan.little@iinteractive.com>
Date: Tue, 3 Apr 2007 18:14:22 +0000 (+0000)
Subject: implemented cycle handling
X-Git-Tag: 0_02~22
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=7eb5dc635e43005020528128b012527cb5707559;p=gitmo%2FMooseX-Storage.git

implemented cycle handling
---

diff --git a/lib/MooseX/Storage/Engine.pm b/lib/MooseX/Storage/Engine.pm
index 7f3bbb4..558fb64 100644
--- a/lib/MooseX/Storage/Engine.pm
+++ b/lib/MooseX/Storage/Engine.pm
@@ -9,7 +9,13 @@ our $VERSION = '0.01';
 our $CLASS_MARKER = '__CLASS__';
 
 has 'storage' => (
-    is      => 'rw',
+    is      => 'ro',
+    isa     => 'HashRef',
+    default => sub {{}}
+);
+
+has 'seen' => (
+    is      => 'ro',
     isa     => 'HashRef',
     default => sub {{}}
 );
@@ -21,6 +27,11 @@ has 'class'  => (is => 'rw', isa => 'Str');
 
 sub collapse_object {
 	my $self = shift;
+
+	# NOTE:
+	# mark the root object as seen ...
+	$self->seen->{$self->object} = undef;
+	
     $self->map_attributes('collapse_attribute');
     $self->storage->{$CLASS_MARKER} = $self->object->meta->name;    
 	return $self->storage;
@@ -28,6 +39,11 @@ sub collapse_object {
 
 sub expand_object {
     my ($self, $data) = @_;
+    
+	# NOTE:
+	# mark the root object as seen ...
+	$self->seen->{$data} = undef;    
+    
     $self->map_attributes('expand_attribute', $data);
 	return $self->storage;    
 }
@@ -47,6 +63,10 @@ sub expand_attribute {
 sub collapse_attribute_value {
     my ($self, $attr)  = @_;
 	my $value = $attr->get_value($self->object);
+	
+    $self->check_for_cycle_in_collapse($value) 
+        if ref $value;
+	
     if (defined $value && $attr->has_type_constraint) {
         my $type_converter = $self->find_type_handler($attr->type_constraint);
         (defined $type_converter)
@@ -58,6 +78,10 @@ sub collapse_attribute_value {
 
 sub expand_attribute_value {
     my ($self, $attr, $value)  = @_;
+
+    $self->check_for_cycle_in_expansion($value) 
+        if ref $value;    
+    
     if (defined $value && $attr->has_type_constraint) {
         my $type_converter = $self->find_type_handler($attr->type_constraint);
         $value = $type_converter->{expand}->($value);
@@ -67,6 +91,20 @@ sub expand_attribute_value {
 
 # util methods ...
 
+sub check_for_cycle_in_collapse {
+    my ($self, $value) = @_;
+    (!exists $self->seen->{$value})
+        || confess "Basic Engine does not support cycles";
+    $self->seen->{$value} = undef;
+}
+
+sub check_for_cycle_in_expansion {
+    my ($self, $value) = @_;
+    (!exists $self->seen->{$value})
+        || confess "Basic Engine does not support cycles";
+    $self->seen->{$value} = undef;
+}
+
 sub map_attributes {
     my ($self, $method_name, @args) = @_;
     map { 
@@ -170,7 +208,7 @@ my %TYPES = (
     #'CodeRef' => {
     #    expand   => sub {}, # use eval ...
     #    collapse => sub {}, # use B::Deparse ...        
-    #}       
+    #} 
 );
 
 sub add_custom_type_handler {
diff --git a/t/004_w_cycles.t b/t/004_w_cycles.t
new file mode 100644
index 0000000..d08c9ae
--- /dev/null
+++ b/t/004_w_cycles.t
@@ -0,0 +1,47 @@
+#!/usr/bin/perl
+
+use strict;
+use warnings;
+
+use Test::More no_plan => 1;
+use Test::Exception;
+
+BEGIN {
+    use_ok('MooseX::Storage');
+}
+
+{
+
+    package Circular;
+    use Moose;
+    use MooseX::Storage;
+
+    with Storage;
+
+    has 'cycle' => (is => 'rw', isa => 'Circular');
+}
+
+{
+    my $circular = Circular->new;
+    isa_ok($circular, 'Circular');
+    
+    $circular->cycle($circular);
+    
+    throws_ok {
+        $circular->pack;
+    } qr/^Basic Engine does not support cycles/, 
+    '... cannot collapse a cycle with the basic engine';
+}
+
+{
+    my $packed_circular = { __CLASS__ => 'Circular' };
+    $packed_circular->{cycle} = $packed_circular;
+
+    throws_ok {
+        Circular->unpack($packed_circular);
+    } qr/^Basic Engine does not support cycles/, 
+    '... cannot expand a cycle with the basic engine';
+}
+
+
+