2 package MooseX::Storage::Engine;
4 use Scalar::Util qw(refaddr);
7 our $AUTHORITY = 'cpan:STEVAN';
9 # the class marker when
10 # serializing an object.
11 our $CLASS_MARKER = '__CLASS__';
21 isa => 'HashRef[Int]', # int is the refaddr
25 has 'object' => (is => 'rw', isa => 'Object');
26 has 'class' => (is => 'rw', isa => 'Str');
28 ## this is the API used by other modules ...
31 my ( $self, %options ) = @_;
34 # mark the root object as seen ...
35 $self->seen->{refaddr $self->object} = undef;
37 $self->map_attributes('collapse_attribute', \%options);
38 $self->storage->{$CLASS_MARKER} = $self->object->meta->identifier;
39 return $self->storage;
43 my ($self, $data, %options) = @_;
45 $options{check_version} = 1 unless exists $options{check_version};
46 $options{check_authority} = 1 unless exists $options{check_authority};
49 # mark the root object as seen ...
50 $self->seen->{refaddr $data} = undef;
52 $self->map_attributes('expand_attribute', $data, \%options);
53 return $self->storage;
56 ## this is the internal API ...
58 sub collapse_attribute {
59 my ($self, $attr, $options) = @_;
60 my $value = $self->collapse_attribute_value($attr, $options);
61 return if !defined($value);
62 $self->storage->{$attr->name} = $value;
65 sub expand_attribute {
66 my ($self, $attr, $data, $options) = @_;
67 my $value = $self->expand_attribute_value($attr, $data->{$attr->name}, $options);
68 $self->storage->{$attr->name} = defined $value ? $value : return;
71 sub collapse_attribute_value {
72 my ($self, $attr, $options) = @_;
73 # Faster, but breaks attributes without readers, do we care?
74 #my $value = $attr->get_read_method_ref->($self->object);
75 my $value = $attr->get_value($self->object);
78 # this might not be enough, we might
79 # need to make it possible for the
80 # cycle checker to return the value
81 $self->check_for_cycle_in_collapse($attr, $value)
84 if (defined $value && $attr->has_type_constraint) {
85 my $type_converter = $self->find_type_handler($attr->type_constraint);
86 (defined $type_converter)
87 || confess "Cannot convert " . $attr->type_constraint->name;
88 $value = $type_converter->{collapse}->($value, $options);
93 sub expand_attribute_value {
94 my ($self, $attr, $value, $options) = @_;
97 # (see comment in method above ^^)
98 if( ref $value and not(
99 $options->{disable_cycle_check} or
100 $self->class->does('MooseX::Storage::Traits::DisableCycleDetection')
102 $self->check_for_cycle_in_collapse($attr, $value)
105 if (defined $value && $attr->has_type_constraint) {
106 my $type_converter = $self->find_type_handler($attr->type_constraint);
107 $value = $type_converter->{expand}->($value, $options);
113 # possibly these two methods will
114 # be used by a cycle supporting
115 # engine. However, I am not sure
116 # if I can make a cycle one work
119 sub check_for_cycle_in_collapse {
120 my ($self, $attr, $value) = @_;
121 (!exists $self->seen->{refaddr $value})
122 || confess "Basic Engine does not support cycles in class("
123 . ($attr->associated_class->name) . ").attr("
124 . ($attr->name) . ") with $value";
125 $self->seen->{refaddr $value} = undef;
128 sub check_for_cycle_in_expansion {
129 my ($self, $attr, $value) = @_;
130 (!exists $self->seen->{refaddr $value})
131 || confess "Basic Engine does not support cycles in class("
132 . ($attr->associated_class->name) . ").attr("
133 . ($attr->name) . ") with $value";
134 $self->seen->{refaddr $value} = undef;
140 my ($self, $method_name, @args) = @_;
142 # The $self->object check is here to differentiate a ->pack from a
143 # ->unpack; ->object is only defined for a ->pack
145 # no checks needed if this is class based (ie, restore)
146 unless( $self->object ) {
147 return map { $self->$method_name($_, @args) }
148 $self->class->meta->get_all_attributes;
151 # if it's object based, it's a store -- in that case,
154 my $o = $self->object;
155 for my $attr ( $o->meta->get_all_attributes ) {
157 # Skip our special skip attribute :)
159 'MooseX::Storage::Meta::Attribute::Trait::DoNotSerialize');
161 # If we're invoked with the 'OnlyWhenBuilt' trait, we should
162 # only serialize the attribute if it's already built. So, go ahead
163 # and check if the attribute has a predicate. If so, check if it's
164 # set and then go ahead and look it up.
165 if( $o->does('MooseX::Storage::Traits::OnlyWhenBuilt') and
166 my $pred = $attr->predicate
168 next unless $self->object->$pred;
170 push @rv, $self->$method_name($attr, @args);
176 ## ------------------------------------------------------------------
177 ## This is all the type handler stuff, it is in a state of flux
178 ## right now, so this may change, or it may just continue to be
179 ## improved upon. Comments and suggestions are welcomed.
180 ## ------------------------------------------------------------------
183 # these are needed by the
184 # ArrayRef and HashRef handlers
185 # below, so I need easy access
186 my %OBJECT_HANDLERS = (
188 my ($data, $options) = @_;
189 (exists $data->{$CLASS_MARKER})
190 || confess "Serialized item has no class marker";
191 # check the class more thoroughly here ...
192 my ($class, $version, $authority) = (split '-' => $data->{$CLASS_MARKER});
193 my $meta = eval { $class->meta };
194 confess "Class ($class) is not loaded, cannot unpack" if $@;
196 if ($options->{check_version}) {
197 my $meta_version = $meta->version;
198 if (defined $meta_version && $version) {
199 if ($options->{check_version} eq 'allow_less_than') {
200 ($meta_version <= $version)
201 || confess "Class ($class) versions is not less than currently available."
202 . " got=($version) available=($meta_version)";
204 elsif ($options->{check_version} eq 'allow_greater_than') {
205 ($meta->version >= $version)
206 || confess "Class ($class) versions is not greater than currently available."
207 . " got=($version) available=($meta_version)";
210 ($meta->version == $version)
211 || confess "Class ($class) versions don't match."
212 . " got=($version) available=($meta_version)";
217 if ($options->{check_authority}) {
218 my $meta_authority = $meta->authority;
219 ($meta->authority eq $authority)
220 || confess "Class ($class) authorities don't match."
221 . " got=($authority) available=($meta_authority)"
222 if defined $meta_authority && defined $authority;
226 $class->unpack($data, %$options);
229 my ( $obj, $options ) = @_;
230 # ($obj->can('does') && $obj->does('MooseX::Storage::Basic'))
231 # || confess "Bad object ($obj) does not do MooseX::Storage::Basic role";
233 || confess "Object ($obj) does not have a &pack method, cannot collapse";
234 $obj->pack(%$options);
241 # we need to make sure that we properly numify the numbers
242 # before and after them being futzed with, because some of
243 # the JSON engines are stupid/annoying/frustrating
244 'Int' => { expand => sub { $_[0] + 0 }, collapse => sub { $_[0] + 0 } },
245 'Num' => { expand => sub { $_[0] + 0 }, collapse => sub { $_[0] + 0 } },
246 # These are boring ones, so they use the identity function ...
247 'Str' => { expand => sub { shift }, collapse => sub { shift } },
248 'Bool' => { expand => sub { shift }, collapse => sub { shift } },
249 # These are the trickier ones, (see notes)
251 # Because we are nice guys, we will check
252 # your ArrayRef and/or HashRef one level
253 # down and inflate any objects we find.
254 # But this is where it ends, it is too
255 # expensive to try and do this any more
256 # recursively, when it is probably not
257 # nessecary in most of the use cases.
258 # However, if you need more then this, subtype
259 # and add a custom handler.
262 my ( $array, @args ) = @_;
263 foreach my $i (0 .. $#{$array}) {
264 next unless ref($array->[$i]) eq 'HASH'
265 && exists $array->[$i]->{$CLASS_MARKER};
266 $array->[$i] = $OBJECT_HANDLERS{expand}->($array->[$i], @args);
271 my ( $array, @args ) = @_;
273 # we need to make a copy cause
274 # otherwise it will affect the
275 # other real version.
278 ? $OBJECT_HANDLERS{collapse}->($_, @args)
285 my ( $hash, @args ) = @_;
286 foreach my $k (keys %$hash) {
287 next unless ref($hash->{$k}) eq 'HASH'
288 && exists $hash->{$k}->{$CLASS_MARKER};
289 $hash->{$k} = $OBJECT_HANDLERS{expand}->($hash->{$k}, @args);
294 my ( $hash, @args ) = @_;
296 # we need to make a copy cause
297 # otherwise it will affect the
298 # other real version.
301 ? ($_ => $OBJECT_HANDLERS{collapse}->($hash->{$_}, @args))
302 : ($_ => $hash->{$_})
306 'Object' => \%OBJECT_HANDLERS,
308 # The sanity of enabling this feature by
309 # default is very questionable.
312 # expand => sub {}, # use eval ...
313 # collapse => sub {}, # use B::Deparse ...
317 sub add_custom_type_handler {
318 my ($class, $type_name, %handlers) = @_;
319 (exists $handlers{expand} && exists $handlers{collapse})
320 || confess "Custom type handlers need an expand *and* a collapse method";
321 $TYPES{$type_name} = \%handlers;
324 sub remove_custom_type_handler {
325 my ($class, $type_name) = @_;
326 delete $TYPES{$type_name} if exists $TYPES{$type_name};
329 sub find_type_handler {
330 my ($self, $type_constraint) = @_;
332 # check if the type is a Maybe and
333 # if its parent is not parameterized.
334 # If both is true recurse this method
335 # using ->type_parameter.
336 return $self->find_type_handler($type_constraint->type_parameter)
337 if $type_constraint->parent eq 'Maybe'
338 and not $type_constraint->parent->can('type_parameter');
340 # this should handle most type usages
341 # since they they are usually just
342 # the standard set of built-ins
343 return $TYPES{$type_constraint->name}
344 if exists $TYPES{$type_constraint->name};
346 # the next possibility is they are
347 # a subtype of the built-in types,
348 # in which case this will DWIM in
349 # most cases. It is probably not
350 # 100% ideal though, but until I
351 # come up with a decent test case
352 # it will do for now.
353 foreach my $type (keys %TYPES) {
355 if $type_constraint->is_subtype_of($type);
359 # the reason the above will work has to
360 # do with the fact that custom subtypes
361 # are mostly used for validation of
362 # the guts of a type, and not for some
363 # weird structural thing which would
364 # need to be accomidated by the serializer.
365 # Of course, mst or phaylon will probably
366 # do something to throw this assumption
367 # totally out the door ;)
371 # if this method hasnt returned by now
372 # then we have no been able to find a
373 # type constraint handler to match
374 confess "Cannot handle type constraint (" . $type_constraint->name . ")";
377 sub find_type_handler_for {
378 my ($self, $type_handler_name) = @_;
379 $TYPES{$type_handler_name}
390 MooseX::Storage::Engine - The meta-engine to handle collapsing and expanding objects
394 No user serviceable parts inside. If you really want to know, read the source :)
416 =item B<expand_object>
418 =item B<collapse_object>
426 =item B<collapse_attribute>
428 =item B<collapse_attribute_value>
430 =item B<expand_attribute>
432 =item B<expand_attribute_value>
434 =item B<check_for_cycle_in_collapse>
436 =item B<check_for_cycle_in_expansion>
438 =item B<map_attributes>
442 =head2 Type Constraint Handlers
446 =item B<find_type_handler ($type)>
448 =item B<find_type_handler_for ($name)>
450 =item B<add_custom_type_handler ($name, %handlers)>
452 =item B<remove_custom_type_handler ($name)>
466 All complex software has bugs lurking in it, and this module is no
467 exception. If you find a bug please either email me, or add the bug
472 Chris Prather E<lt>chris.prather@iinteractive.comE<gt>
474 Stevan Little E<lt>stevan.little@iinteractive.comE<gt>
476 =head1 COPYRIGHT AND LICENSE
478 Copyright 2007-2008 by Infinity Interactive, Inc.
480 L<http://www.iinteractive.com>
482 This library is free software; you can redistribute it and/or modify
483 it under the same terms as Perl itself.