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 # Check cycles unless explicitly disabled
82 if( ref $value and not(
83 $options->{disable_cycle_check} or
84 $self->object->does('MooseX::Storage::Traits::DisableCycleDetection')
86 $self->check_for_cycle_in_collapse($attr, $value)
89 if (defined $value && $attr->has_type_constraint) {
90 my $type_converter = $self->find_type_handler($attr->type_constraint);
91 (defined $type_converter)
92 || confess "Cannot convert " . $attr->type_constraint->name;
93 $value = $type_converter->{collapse}->($value, $options);
98 sub expand_attribute_value {
99 my ($self, $attr, $value, $options) = @_;
102 # (see comment in method above ^^)
103 if( ref $value and not(
104 $options->{disable_cycle_check} or
105 $self->class->does('MooseX::Storage::Traits::DisableCycleDetection')
107 $self->check_for_cycle_in_collapse($attr, $value)
110 if (defined $value && $attr->has_type_constraint) {
111 my $type_converter = $self->find_type_handler($attr->type_constraint);
112 $value = $type_converter->{expand}->($value, $options);
118 # possibly these two methods will
119 # be used by a cycle supporting
120 # engine. However, I am not sure
121 # if I can make a cycle one work
124 sub check_for_cycle_in_collapse {
125 my ($self, $attr, $value) = @_;
126 (!exists $self->seen->{refaddr $value})
127 || confess "Basic Engine does not support cycles in class("
128 . ($attr->associated_class->name) . ").attr("
129 . ($attr->name) . ") with $value";
130 $self->seen->{refaddr $value} = undef;
133 sub check_for_cycle_in_expansion {
134 my ($self, $attr, $value) = @_;
135 (!exists $self->seen->{refaddr $value})
136 || confess "Basic Engine does not support cycles in class("
137 . ($attr->associated_class->name) . ").attr("
138 . ($attr->name) . ") with $value";
139 $self->seen->{refaddr $value} = undef;
145 my ($self, $method_name, @args) = @_;
147 # The $self->object check is here to differentiate a ->pack from a
148 # ->unpack; ->object is only defined for a ->pack
150 # no checks needed if this is class based (ie, restore)
151 unless( $self->object ) {
152 return map { $self->$method_name($_, @args) }
153 $self->class->meta->get_all_attributes;
156 # if it's object based, it's a store -- in that case,
159 my $o = $self->object;
160 for my $attr ( $o->meta->get_all_attributes ) {
162 # Skip our special skip attribute :)
164 'MooseX::Storage::Meta::Attribute::Trait::DoNotSerialize');
166 # If we're invoked with the 'OnlyWhenBuilt' trait, we should
167 # only serialize the attribute if it's already built. So, go ahead
168 # and check if the attribute has a predicate. If so, check if it's
169 # set and then go ahead and look it up.
170 if( $o->does('MooseX::Storage::Traits::OnlyWhenBuilt') and
171 my $pred = $attr->predicate
173 next unless $self->object->$pred;
175 push @rv, $self->$method_name($attr, @args);
181 ## ------------------------------------------------------------------
182 ## This is all the type handler stuff, it is in a state of flux
183 ## right now, so this may change, or it may just continue to be
184 ## improved upon. Comments and suggestions are welcomed.
185 ## ------------------------------------------------------------------
188 # these are needed by the
189 # ArrayRef and HashRef handlers
190 # below, so I need easy access
191 my %OBJECT_HANDLERS = (
193 my ($data, $options) = @_;
194 (exists $data->{$CLASS_MARKER})
195 || confess "Serialized item has no class marker";
196 # check the class more thoroughly here ...
197 my ($class, $version, $authority) = (split '-' => $data->{$CLASS_MARKER});
198 my $meta = eval { $class->meta };
199 confess "Class ($class) is not loaded, cannot unpack" if $@;
201 if ($options->{check_version}) {
202 my $meta_version = $meta->version;
203 if (defined $meta_version && $version) {
204 if ($options->{check_version} eq 'allow_less_than') {
205 ($meta_version <= $version)
206 || confess "Class ($class) versions is not less than currently available."
207 . " got=($version) available=($meta_version)";
209 elsif ($options->{check_version} eq 'allow_greater_than') {
210 ($meta->version >= $version)
211 || confess "Class ($class) versions is not greater than currently available."
212 . " got=($version) available=($meta_version)";
215 ($meta->version == $version)
216 || confess "Class ($class) versions don't match."
217 . " got=($version) available=($meta_version)";
222 if ($options->{check_authority}) {
223 my $meta_authority = $meta->authority;
224 ($meta->authority eq $authority)
225 || confess "Class ($class) authorities don't match."
226 . " got=($authority) available=($meta_authority)"
227 if defined $meta_authority && defined $authority;
231 $class->unpack($data, %$options);
234 my ( $obj, $options ) = @_;
235 # ($obj->can('does') && $obj->does('MooseX::Storage::Basic'))
236 # || confess "Bad object ($obj) does not do MooseX::Storage::Basic role";
238 || confess "Object ($obj) does not have a &pack method, cannot collapse";
239 $obj->pack(%$options);
246 # we need to make sure that we properly numify the numbers
247 # before and after them being futzed with, because some of
248 # the JSON engines are stupid/annoying/frustrating
249 'Int' => { expand => sub { $_[0] + 0 }, collapse => sub { $_[0] + 0 } },
250 'Num' => { expand => sub { $_[0] + 0 }, collapse => sub { $_[0] + 0 } },
251 # These are boring ones, so they use the identity function ...
252 'Str' => { expand => sub { shift }, collapse => sub { shift } },
253 'Bool' => { expand => sub { shift }, collapse => sub { shift } },
254 # These are the trickier ones, (see notes)
256 # Because we are nice guys, we will check
257 # your ArrayRef and/or HashRef one level
258 # down and inflate any objects we find.
259 # But this is where it ends, it is too
260 # expensive to try and do this any more
261 # recursively, when it is probably not
262 # nessecary in most of the use cases.
263 # However, if you need more then this, subtype
264 # and add a custom handler.
267 my ( $array, @args ) = @_;
268 foreach my $i (0 .. $#{$array}) {
269 next unless ref($array->[$i]) eq 'HASH'
270 && exists $array->[$i]->{$CLASS_MARKER};
271 $array->[$i] = $OBJECT_HANDLERS{expand}->($array->[$i], @args);
276 my ( $array, @args ) = @_;
278 # we need to make a copy cause
279 # otherwise it will affect the
280 # other real version.
283 ? $OBJECT_HANDLERS{collapse}->($_, @args)
290 my ( $hash, @args ) = @_;
291 foreach my $k (keys %$hash) {
292 next unless ref($hash->{$k}) eq 'HASH'
293 && exists $hash->{$k}->{$CLASS_MARKER};
294 $hash->{$k} = $OBJECT_HANDLERS{expand}->($hash->{$k}, @args);
299 my ( $hash, @args ) = @_;
301 # we need to make a copy cause
302 # otherwise it will affect the
303 # other real version.
306 ? ($_ => $OBJECT_HANDLERS{collapse}->($hash->{$_}, @args))
307 : ($_ => $hash->{$_})
311 'Object' => \%OBJECT_HANDLERS,
313 # The sanity of enabling this feature by
314 # default is very questionable.
317 # expand => sub {}, # use eval ...
318 # collapse => sub {}, # use B::Deparse ...
322 sub add_custom_type_handler {
323 my ($class, $type_name, %handlers) = @_;
324 (exists $handlers{expand} && exists $handlers{collapse})
325 || confess "Custom type handlers need an expand *and* a collapse method";
326 $TYPES{$type_name} = \%handlers;
329 sub remove_custom_type_handler {
330 my ($class, $type_name) = @_;
331 delete $TYPES{$type_name} if exists $TYPES{$type_name};
334 sub find_type_handler {
335 my ($self, $type_constraint) = @_;
337 # check if the type is a Maybe and
338 # if its parent is not parameterized.
339 # If both is true recurse this method
340 # using ->type_parameter.
341 return $self->find_type_handler($type_constraint->type_parameter)
342 if $type_constraint->parent eq 'Maybe'
343 and not $type_constraint->parent->can('type_parameter');
345 # this should handle most type usages
346 # since they they are usually just
347 # the standard set of built-ins
348 return $TYPES{$type_constraint->name}
349 if exists $TYPES{$type_constraint->name};
351 # the next possibility is they are
352 # a subtype of the built-in types,
353 # in which case this will DWIM in
354 # most cases. It is probably not
355 # 100% ideal though, but until I
356 # come up with a decent test case
357 # it will do for now.
358 foreach my $type (keys %TYPES) {
360 if $type_constraint->is_subtype_of($type);
364 # the reason the above will work has to
365 # do with the fact that custom subtypes
366 # are mostly used for validation of
367 # the guts of a type, and not for some
368 # weird structural thing which would
369 # need to be accomidated by the serializer.
370 # Of course, mst or phaylon will probably
371 # do something to throw this assumption
372 # totally out the door ;)
376 # if this method hasnt returned by now
377 # then we have no been able to find a
378 # type constraint handler to match
379 confess "Cannot handle type constraint (" . $type_constraint->name . ")";
382 sub find_type_handler_for {
383 my ($self, $type_handler_name) = @_;
384 $TYPES{$type_handler_name}
395 MooseX::Storage::Engine - The meta-engine to handle collapsing and expanding objects
399 No user serviceable parts inside. If you really want to know, read the source :)
421 =item B<expand_object>
423 =item B<collapse_object>
431 =item B<collapse_attribute>
433 =item B<collapse_attribute_value>
435 =item B<expand_attribute>
437 =item B<expand_attribute_value>
439 =item B<check_for_cycle_in_collapse>
441 =item B<check_for_cycle_in_expansion>
443 =item B<map_attributes>
447 =head2 Type Constraint Handlers
451 =item B<find_type_handler ($type)>
453 =item B<find_type_handler_for ($name)>
455 =item B<add_custom_type_handler ($name, %handlers)>
457 =item B<remove_custom_type_handler ($name)>
471 All complex software has bugs lurking in it, and this module is no
472 exception. If you find a bug please either email me, or add the bug
477 Chris Prather E<lt>chris.prather@iinteractive.comE<gt>
479 Stevan Little E<lt>stevan.little@iinteractive.comE<gt>
481 =head1 COPYRIGHT AND LICENSE
483 Copyright 2007-2008 by Infinity Interactive, Inc.
485 L<http://www.iinteractive.com>
487 This library is free software; you can redistribute it and/or modify
488 it under the same terms as Perl itself.