2 package MooseX::Storage::Engine;
7 # the class marker when
8 # serializing an object.
9 our $CLASS_MARKER = '__CLASS__';
23 has 'object' => (is => 'rw', isa => 'Object');
24 has 'class' => (is => 'rw', isa => 'Str');
26 ## this is the API used by other modules ...
32 # mark the root object as seen ...
33 $self->seen->{$self->object} = undef;
35 $self->map_attributes('collapse_attribute');
36 $self->storage->{$CLASS_MARKER} = $self->object->meta->name;
37 return $self->storage;
41 my ($self, $data) = @_;
44 # mark the root object as seen ...
45 $self->seen->{$data} = undef;
47 $self->map_attributes('expand_attribute', $data);
48 return $self->storage;
51 ## this is the internal API ...
53 sub collapse_attribute {
54 my ($self, $attr) = @_;
55 $self->storage->{$attr->name} = $self->collapse_attribute_value($attr) || return;
58 sub expand_attribute {
59 my ($self, $attr, $data) = @_;
60 $self->storage->{$attr->name} = $self->expand_attribute_value($attr, $data->{$attr->name}) || return;
63 sub collapse_attribute_value {
64 my ($self, $attr) = @_;
65 my $value = $attr->get_value($self->object);
68 # this might not be enough, we might
69 # need to make it possible for the
70 # cycle checker to return the value
71 $self->check_for_cycle_in_collapse($value)
74 if (defined $value && $attr->has_type_constraint) {
75 my $type_converter = $self->find_type_handler($attr->type_constraint);
76 (defined $type_converter)
77 || confess "Cannot convert " . $attr->type_constraint->name;
78 $value = $type_converter->{collapse}->($value);
83 sub expand_attribute_value {
84 my ($self, $attr, $value) = @_;
87 # (see comment in method above ^^)
88 $self->check_for_cycle_in_expansion($value)
91 if (defined $value && $attr->has_type_constraint) {
92 my $type_converter = $self->find_type_handler($attr->type_constraint);
93 $value = $type_converter->{expand}->($value);
99 # possibly these two methods will
100 # be used by a cycle supporting
101 # engine. However, I am not sure
102 # if I can make a cycle one work
105 sub check_for_cycle_in_collapse {
106 my ($self, $value) = @_;
107 (!exists $self->seen->{$value})
108 || confess "Basic Engine does not support cycles";
109 $self->seen->{$value} = undef;
112 sub check_for_cycle_in_expansion {
113 my ($self, $value) = @_;
114 (!exists $self->seen->{$value})
115 || confess "Basic Engine does not support cycles";
116 $self->seen->{$value} = undef;
122 my ($self, $method_name, @args) = @_;
124 $self->$method_name($_, @args)
126 # Skip our special skip attribute :)
127 !$_->isa('MooseX::Storage::Meta::Attribute::DoNotSerialize')
128 } ($self->object || $self->class)->meta->compute_all_applicable_attributes;
131 ## ------------------------------------------------------------------
132 ## This is all the type handler stuff, it is in a state of flux
133 ## right now, so this may change, or it may just continue to be
134 ## improved upon. Comments and suggestions are welcomed.
135 ## ------------------------------------------------------------------
138 # these are needed by the
139 # ArrayRef and HashRef handlers
140 # below, so I need easy access
141 my %OBJECT_HANDLERS = (
144 (exists $data->{$CLASS_MARKER})
145 || confess "Serialized item has no class marker";
146 $data->{$CLASS_MARKER}->unpack($data);
150 ($obj->can('does') && $obj->does('MooseX::Storage::Basic'))
151 || confess "Bad object ($obj) does not do MooseX::Storage::Basic role";
158 # These are boring ones, so they use the identity function ...
159 'Int' => { expand => sub { shift }, collapse => sub { shift } },
160 'Num' => { expand => sub { shift }, collapse => sub { shift } },
161 'Str' => { expand => sub { shift }, collapse => sub { shift } },
162 # These are the trickier ones, (see notes)
164 # Because we are nice guys, we will check
165 # your ArrayRef and/or HashRef one level
166 # down and inflate any objects we find.
167 # But this is where it ends, it is too
168 # expensive to try and do this any more
169 # recursively, when it is probably not
170 # nessecary in most of the use cases.
171 # However, if you need more then this, subtype
172 # and add a custom handler.
176 foreach my $i (0 .. $#{$array}) {
177 next unless ref($array->[$i]) eq 'HASH'
178 && exists $array->[$i]->{$CLASS_MARKER};
179 $array->[$i] = $OBJECT_HANDLERS{expand}->($array->[$i])
186 # we need to make a copy cause
187 # otherwise it will affect the
188 # other real version.
191 ? $OBJECT_HANDLERS{collapse}->($_)
199 foreach my $k (keys %$hash) {
200 next unless ref($hash->{$k}) eq 'HASH'
201 && exists $hash->{$k}->{$CLASS_MARKER};
202 $hash->{$k} = $OBJECT_HANDLERS{expand}->($hash->{$k})
209 # we need to make a copy cause
210 # otherwise it will affect the
211 # other real version.
214 ? ($_ => $OBJECT_HANDLERS{collapse}->($hash->{$_}))
215 : ($_ => $hash->{$_})
219 'Object' => \%OBJECT_HANDLERS,
221 # The sanity of enabling this feature by
222 # default is very questionable.
225 # expand => sub {}, # use eval ...
226 # collapse => sub {}, # use B::Deparse ...
230 sub add_custom_type_handler {
231 my ($class, $type_name, %handlers) = @_;
232 (exists $handlers{expand} && exists $handlers{collapse})
233 || confess "Custom type handlers need an expand *and* a collapse method";
234 $TYPES{$type_name} = \%handlers;
237 sub remove_custom_type_handler {
238 my ($class, $type_name) = @_;
239 delete $TYPES{$type_name} if exists $TYPES{$type_name};
242 sub find_type_handler {
243 my ($self, $type_constraint) = @_;
245 # this should handle most type usages
246 # since they they are usually just
247 # the standard set of built-ins
248 return $TYPES{$type_constraint->name}
249 if exists $TYPES{$type_constraint->name};
251 # the next possibility is they are
252 # a subtype of the built-in types,
253 # in which case this will DWIM in
254 # most cases. It is probably not
255 # 100% ideal though, but until I
256 # come up with a decent test case
257 # it will do for now.
258 foreach my $type (keys %TYPES) {
260 if $type_constraint->is_subtype_of($type);
264 # the reason the above will work has to
265 # do with the fact that custom subtypes
266 # are mostly used for validation of
267 # the guts of a type, and not for some
268 # weird structural thing which would
269 # need to be accomidated by the serializer.
270 # Of course, mst or phaylon will probably
271 # do something to throw this assumption
272 # totally out the door ;)
276 # if this method hasnt returned by now
277 # then we have no been able to find a
278 # type constraint handler to match
279 confess "Cannot handle type constraint (" . $type_constraint->name . ")";
290 MooseX::Storage::Engine - The meta-engine to handle collapsing and expanding objects
294 No user serviceable parts inside. If you really want to know, read the source :)
316 =item B<expand_object>
318 =item B<collapse_object>
326 =item B<collapse_attribute>
328 =item B<collapse_attribute_value>
330 =item B<expand_attribute>
332 =item B<expand_attribute_value>
334 =item B<check_for_cycle_in_collapse>
336 =item B<check_for_cycle_in_expansion>
338 =item B<map_attributes>
342 =head2 Type Constraint Handlers
346 =item B<find_type_handler>
348 =item B<add_custom_type_handler>
350 =item B<remove_custom_type_handler>
364 All complex software has bugs lurking in it, and this module is no
365 exception. If you find a bug please either email me, or add the bug
370 Chris Prather E<lt>chris.prather@iinteractive.comE<gt>
372 Stevan Little E<lt>stevan.little@iinteractive.comE<gt>
374 =head1 COPYRIGHT AND LICENSE
376 Copyright 2007 by Infinity Interactive, Inc.
378 L<http://www.iinteractive.com>
380 This library is free software; you can redistribute it and/or modify
381 it under the same terms as Perl itself.