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 $self->check_for_cycle_in_expansion($attr, $value)
101 if (defined $value && $attr->has_type_constraint) {
102 my $type_converter = $self->find_type_handler($attr->type_constraint);
103 $value = $type_converter->{expand}->($value, $options);
109 # possibly these two methods will
110 # be used by a cycle supporting
111 # engine. However, I am not sure
112 # if I can make a cycle one work
115 sub check_for_cycle_in_collapse {
116 my ($self, $attr, $value) = @_;
117 (!exists $self->seen->{refaddr $value})
118 || confess "Basic Engine does not support cycles in class("
119 . ($attr->associated_class->name) . ").attr("
120 . ($attr->name) . ") with $value";
121 $self->seen->{refaddr $value} = undef;
124 sub check_for_cycle_in_expansion {
125 my ($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 $value} = undef;
136 my ($self, $method_name, @args) = @_;
138 $self->$method_name($_, @args)
140 # Skip our special skip attribute :)
141 !$_->does('MooseX::Storage::Meta::Attribute::Trait::DoNotSerialize')
143 # If we're invoked with the 'OnlyWhenBuilt' trait, we should
144 # only serialize the attribute if it's already built. So, go ahead
145 # and check if the attribute has a predicate. If so, check if it's set
146 # and then go ahead and look it up.
147 # The $self->object check is here to differentiate a ->pack from a
148 # ->unpack; ->object is only defined for a ->pack
150 if( $self->object and my $pred = $_->predicate and
151 $self->object->does('MooseX::Storage::Traits::OnlyWhenBuilt')
153 $self->object->$pred ? 1 : 0;
158 } ($self->object || $self->class)->meta->get_all_attributes;
161 ## ------------------------------------------------------------------
162 ## This is all the type handler stuff, it is in a state of flux
163 ## right now, so this may change, or it may just continue to be
164 ## improved upon. Comments and suggestions are welcomed.
165 ## ------------------------------------------------------------------
168 # these are needed by the
169 # ArrayRef and HashRef handlers
170 # below, so I need easy access
171 my %OBJECT_HANDLERS = (
173 my ($data, $options) = @_;
174 (exists $data->{$CLASS_MARKER})
175 || confess "Serialized item has no class marker";
176 # check the class more thoroughly here ...
177 my ($class, $version, $authority) = (split '-' => $data->{$CLASS_MARKER});
178 my $meta = eval { $class->meta };
179 confess "Class ($class) is not loaded, cannot unpack" if $@;
181 if ($options->{check_version}) {
182 my $meta_version = $meta->version;
183 if (defined $meta_version && $version) {
184 if ($options->{check_version} eq 'allow_less_than') {
185 ($meta_version <= $version)
186 || confess "Class ($class) versions is not less than currently available."
187 . " got=($version) available=($meta_version)";
189 elsif ($options->{check_version} eq 'allow_greater_than') {
190 ($meta->version >= $version)
191 || confess "Class ($class) versions is not greater than currently available."
192 . " got=($version) available=($meta_version)";
195 ($meta->version == $version)
196 || confess "Class ($class) versions don't match."
197 . " got=($version) available=($meta_version)";
202 if ($options->{check_authority}) {
203 my $meta_authority = $meta->authority;
204 ($meta->authority eq $authority)
205 || confess "Class ($class) authorities don't match."
206 . " got=($authority) available=($meta_authority)"
207 if defined $meta_authority && defined $authority;
211 $class->unpack($data, %$options);
214 my ( $obj, $options ) = @_;
215 # ($obj->can('does') && $obj->does('MooseX::Storage::Basic'))
216 # || confess "Bad object ($obj) does not do MooseX::Storage::Basic role";
218 || confess "Object ($obj) does not have a &pack method, cannot collapse";
219 $obj->pack(%$options);
226 # we need to make sure that we properly numify the numbers
227 # before and after them being futzed with, because some of
228 # the JSON engines are stupid/annoying/frustrating
229 'Int' => { expand => sub { $_[0] + 0 }, collapse => sub { $_[0] + 0 } },
230 'Num' => { expand => sub { $_[0] + 0 }, collapse => sub { $_[0] + 0 } },
231 # These are boring ones, so they use the identity function ...
232 'Str' => { expand => sub { shift }, collapse => sub { shift } },
233 'Bool' => { expand => sub { shift }, collapse => sub { shift } },
234 # These are the trickier ones, (see notes)
236 # Because we are nice guys, we will check
237 # your ArrayRef and/or HashRef one level
238 # down and inflate any objects we find.
239 # But this is where it ends, it is too
240 # expensive to try and do this any more
241 # recursively, when it is probably not
242 # nessecary in most of the use cases.
243 # However, if you need more then this, subtype
244 # and add a custom handler.
247 my ( $array, @args ) = @_;
248 foreach my $i (0 .. $#{$array}) {
249 next unless ref($array->[$i]) eq 'HASH'
250 && exists $array->[$i]->{$CLASS_MARKER};
251 $array->[$i] = $OBJECT_HANDLERS{expand}->($array->[$i], @args);
256 my ( $array, @args ) = @_;
258 # we need to make a copy cause
259 # otherwise it will affect the
260 # other real version.
263 ? $OBJECT_HANDLERS{collapse}->($_, @args)
270 my ( $hash, @args ) = @_;
271 foreach my $k (keys %$hash) {
272 next unless ref($hash->{$k}) eq 'HASH'
273 && exists $hash->{$k}->{$CLASS_MARKER};
274 $hash->{$k} = $OBJECT_HANDLERS{expand}->($hash->{$k}, @args);
279 my ( $hash, @args ) = @_;
281 # we need to make a copy cause
282 # otherwise it will affect the
283 # other real version.
286 ? ($_ => $OBJECT_HANDLERS{collapse}->($hash->{$_}, @args))
287 : ($_ => $hash->{$_})
291 'Object' => \%OBJECT_HANDLERS,
293 # The sanity of enabling this feature by
294 # default is very questionable.
297 # expand => sub {}, # use eval ...
298 # collapse => sub {}, # use B::Deparse ...
302 sub add_custom_type_handler {
303 my ($class, $type_name, %handlers) = @_;
304 (exists $handlers{expand} && exists $handlers{collapse})
305 || confess "Custom type handlers need an expand *and* a collapse method";
306 $TYPES{$type_name} = \%handlers;
309 sub remove_custom_type_handler {
310 my ($class, $type_name) = @_;
311 delete $TYPES{$type_name} if exists $TYPES{$type_name};
314 sub find_type_handler {
315 my ($self, $type_constraint) = @_;
317 # check if the type is a Maybe and
318 # if its parent is not parameterized.
319 # If both is true recurse this method
320 # using ->type_parameter.
321 return $self->find_type_handler($type_constraint->type_parameter)
322 if $type_constraint->parent eq 'Maybe'
323 and not $type_constraint->parent->can('type_parameter');
325 # this should handle most type usages
326 # since they they are usually just
327 # the standard set of built-ins
328 return $TYPES{$type_constraint->name}
329 if exists $TYPES{$type_constraint->name};
331 # the next possibility is they are
332 # a subtype of the built-in types,
333 # in which case this will DWIM in
334 # most cases. It is probably not
335 # 100% ideal though, but until I
336 # come up with a decent test case
337 # it will do for now.
338 foreach my $type (keys %TYPES) {
340 if $type_constraint->is_subtype_of($type);
344 # the reason the above will work has to
345 # do with the fact that custom subtypes
346 # are mostly used for validation of
347 # the guts of a type, and not for some
348 # weird structural thing which would
349 # need to be accomidated by the serializer.
350 # Of course, mst or phaylon will probably
351 # do something to throw this assumption
352 # totally out the door ;)
356 # if this method hasnt returned by now
357 # then we have no been able to find a
358 # type constraint handler to match
359 confess "Cannot handle type constraint (" . $type_constraint->name . ")";
362 sub find_type_handler_for {
363 my ($self, $type_handler_name) = @_;
364 $TYPES{$type_handler_name}
375 MooseX::Storage::Engine - The meta-engine to handle collapsing and expanding objects
379 No user serviceable parts inside. If you really want to know, read the source :)
401 =item B<expand_object>
403 =item B<collapse_object>
411 =item B<collapse_attribute>
413 =item B<collapse_attribute_value>
415 =item B<expand_attribute>
417 =item B<expand_attribute_value>
419 =item B<check_for_cycle_in_collapse>
421 =item B<check_for_cycle_in_expansion>
423 =item B<map_attributes>
427 =head2 Type Constraint Handlers
431 =item B<find_type_handler ($type)>
433 =item B<find_type_handler_for ($name)>
435 =item B<add_custom_type_handler ($name, %handlers)>
437 =item B<remove_custom_type_handler ($name)>
451 All complex software has bugs lurking in it, and this module is no
452 exception. If you find a bug please either email me, or add the bug
457 Chris Prather E<lt>chris.prather@iinteractive.comE<gt>
459 Stevan Little E<lt>stevan.little@iinteractive.comE<gt>
461 =head1 COPYRIGHT AND LICENSE
463 Copyright 2007-2008 by Infinity Interactive, Inc.
465 L<http://www.iinteractive.com>
467 This library is free software; you can redistribute it and/or modify
468 it under the same terms as Perl itself.