2 package MooseX::Storage::Engine;
6 our $AUTHORITY = 'cpan:STEVAN';
8 # the class marker when
9 # serializing an object.
10 our $CLASS_MARKER = '__CLASS__';
24 has 'object' => (is => 'rw', isa => 'Object');
25 has 'class' => (is => 'rw', isa => 'Str');
27 ## this is the API used by other modules ...
30 my ( $self, %options ) = @_;
33 # mark the root object as seen ...
34 $self->seen->{$self->object} = undef;
36 $self->map_attributes('collapse_attribute', \%options);
37 $self->storage->{$CLASS_MARKER} = $self->object->meta->identifier;
38 return $self->storage;
42 my ($self, $data, %options) = @_;
44 $options{check_version} = 1 unless exists $options{check_version};
45 $options{check_authority} = 1 unless exists $options{check_authority};
48 # mark the root object as seen ...
49 $self->seen->{$data} = undef;
51 $self->map_attributes('expand_attribute', $data, \%options);
52 return $self->storage;
55 ## this is the internal API ...
57 sub collapse_attribute {
58 my ($self, $attr, $options) = @_;
59 my $value = $self->collapse_attribute_value($attr, $options);
60 return if !defined($value);
61 $self->storage->{$attr->name} = $value;
64 sub expand_attribute {
65 my ($self, $attr, $data, $options) = @_;
66 my $value = $self->expand_attribute_value($attr, $data->{$attr->name}, $options);
67 $self->storage->{$attr->name} = defined $value ? $value : return;
70 sub collapse_attribute_value {
71 my ($self, $attr, $options) = @_;
72 my $value = $attr->get_value($self->object);
75 # this might not be enough, we might
76 # need to make it possible for the
77 # cycle checker to return the value
78 $self->check_for_cycle_in_collapse($attr, $value)
81 if (defined $value && $attr->has_type_constraint) {
82 my $type_converter = $self->find_type_handler($attr->type_constraint);
83 (defined $type_converter)
84 || confess "Cannot convert " . $attr->type_constraint->name;
85 $value = $type_converter->{collapse}->($value, $options);
90 sub expand_attribute_value {
91 my ($self, $attr, $value, $options) = @_;
94 # (see comment in method above ^^)
95 $self->check_for_cycle_in_expansion($attr, $value)
98 if (defined $value && $attr->has_type_constraint) {
99 my $type_converter = $self->find_type_handler($attr->type_constraint);
100 $value = $type_converter->{expand}->($value, $options);
106 # possibly these two methods will
107 # be used by a cycle supporting
108 # engine. However, I am not sure
109 # if I can make a cycle one work
112 sub check_for_cycle_in_collapse {
113 my ($self, $attr, $value) = @_;
114 (!exists $self->seen->{$value})
115 || confess "Basic Engine does not support cycles in class("
116 . ($attr->associated_class->name) . ").attr("
117 . ($attr->name) . ") with $value";
118 $self->seen->{$value} = undef;
121 sub check_for_cycle_in_expansion {
122 my ($self, $attr, $value) = @_;
123 (!exists $self->seen->{$value})
124 || confess "Basic Engine does not support cycles in class("
125 . ($attr->associated_class->name) . ").attr("
126 . ($attr->name) . ") with $value";
127 $self->seen->{$value} = undef;
133 my ($self, $method_name, @args) = @_;
135 $self->$method_name($_, @args)
137 # Skip our special skip attribute :)
138 !$_->does('MooseX::Storage::Meta::Attribute::Trait::DoNotSerialize')
139 } ($self->object || $self->class)->meta->compute_all_applicable_attributes;
142 ## ------------------------------------------------------------------
143 ## This is all the type handler stuff, it is in a state of flux
144 ## right now, so this may change, or it may just continue to be
145 ## improved upon. Comments and suggestions are welcomed.
146 ## ------------------------------------------------------------------
149 # these are needed by the
150 # ArrayRef and HashRef handlers
151 # below, so I need easy access
152 my %OBJECT_HANDLERS = (
154 my ($data, $options) = @_;
155 (exists $data->{$CLASS_MARKER})
156 || confess "Serialized item has no class marker";
157 # check the class more thoroughly here ...
158 my ($class, $version, $authority) = (split '-' => $data->{$CLASS_MARKER});
159 my $meta = eval { $class->meta };
160 confess "Class ($class) is not loaded, cannot unpack" if $@;
162 if ($options->{check_version}) {
163 my $meta_version = $meta->version;
164 if (defined $meta_version && $version) {
165 if ($options->{check_version} eq 'allow_less_than') {
166 ($meta_version <= $version)
167 || confess "Class ($class) versions is not less than currently available."
168 . " got=($version) available=($meta_version)";
170 elsif ($options->{check_version} eq 'allow_greater_than') {
171 ($meta->version >= $version)
172 || confess "Class ($class) versions is not greater than currently available."
173 . " got=($version) available=($meta_version)";
176 ($meta->version == $version)
177 || confess "Class ($class) versions don't match."
178 . " got=($version) available=($meta_version)";
183 if ($options->{check_authority}) {
184 my $meta_authority = $meta->authority;
185 ($meta->authority eq $authority)
186 || confess "Class ($class) authorities don't match."
187 . " got=($authority) available=($meta_authority)"
188 if defined $meta_authority && defined $authority;
192 $class->unpack($data, %$options);
195 my ( $obj, $options ) = @_;
196 # ($obj->can('does') && $obj->does('MooseX::Storage::Basic'))
197 # || confess "Bad object ($obj) does not do MooseX::Storage::Basic role";
199 || confess "Object ($obj) does not have a &pack method, cannot collapse";
200 $obj->pack(%$options);
207 # we need to make sure that we properly numify the numbers
208 # before and after them being futzed with, because some of
209 # the JSON engines are stupid/annoying/frustrating
210 'Int' => { expand => sub { $_[0] + 0 }, collapse => sub { $_[0] + 0 } },
211 'Num' => { expand => sub { $_[0] + 0 }, collapse => sub { $_[0] + 0 } },
212 # These are boring ones, so they use the identity function ...
213 'Str' => { expand => sub { shift }, collapse => sub { shift } },
214 'Bool' => { expand => sub { shift }, collapse => sub { shift } },
215 # These are the trickier ones, (see notes)
217 # Because we are nice guys, we will check
218 # your ArrayRef and/or HashRef one level
219 # down and inflate any objects we find.
220 # But this is where it ends, it is too
221 # expensive to try and do this any more
222 # recursively, when it is probably not
223 # nessecary in most of the use cases.
224 # However, if you need more then this, subtype
225 # and add a custom handler.
228 my ( $array, @args ) = @_;
229 foreach my $i (0 .. $#{$array}) {
230 next unless ref($array->[$i]) eq 'HASH'
231 && exists $array->[$i]->{$CLASS_MARKER};
232 $array->[$i] = $OBJECT_HANDLERS{expand}->($array->[$i], @args);
237 my ( $array, @args ) = @_;
239 # we need to make a copy cause
240 # otherwise it will affect the
241 # other real version.
244 ? $OBJECT_HANDLERS{collapse}->($_, @args)
251 my ( $hash, @args ) = @_;
252 foreach my $k (keys %$hash) {
253 next unless ref($hash->{$k}) eq 'HASH'
254 && exists $hash->{$k}->{$CLASS_MARKER};
255 $hash->{$k} = $OBJECT_HANDLERS{expand}->($hash->{$k}, @args);
260 my ( $hash, @args ) = @_;
262 # we need to make a copy cause
263 # otherwise it will affect the
264 # other real version.
267 ? ($_ => $OBJECT_HANDLERS{collapse}->($hash->{$_}, @args))
268 : ($_ => $hash->{$_})
272 'Object' => \%OBJECT_HANDLERS,
274 # The sanity of enabling this feature by
275 # default is very questionable.
278 # expand => sub {}, # use eval ...
279 # collapse => sub {}, # use B::Deparse ...
283 sub add_custom_type_handler {
284 my ($class, $type_name, %handlers) = @_;
285 (exists $handlers{expand} && exists $handlers{collapse})
286 || confess "Custom type handlers need an expand *and* a collapse method";
287 $TYPES{$type_name} = \%handlers;
290 sub remove_custom_type_handler {
291 my ($class, $type_name) = @_;
292 delete $TYPES{$type_name} if exists $TYPES{$type_name};
295 sub find_type_handler {
296 my ($self, $type_constraint) = @_;
298 # this should handle most type usages
299 # since they they are usually just
300 # the standard set of built-ins
301 return $TYPES{$type_constraint->name}
302 if exists $TYPES{$type_constraint->name};
304 # the next possibility is they are
305 # a subtype of the built-in types,
306 # in which case this will DWIM in
307 # most cases. It is probably not
308 # 100% ideal though, but until I
309 # come up with a decent test case
310 # it will do for now.
311 foreach my $type (keys %TYPES) {
313 if $type_constraint->is_subtype_of($type);
317 # the reason the above will work has to
318 # do with the fact that custom subtypes
319 # are mostly used for validation of
320 # the guts of a type, and not for some
321 # weird structural thing which would
322 # need to be accomidated by the serializer.
323 # Of course, mst or phaylon will probably
324 # do something to throw this assumption
325 # totally out the door ;)
329 # if this method hasnt returned by now
330 # then we have no been able to find a
331 # type constraint handler to match
332 confess "Cannot handle type constraint (" . $type_constraint->name . ")";
335 sub find_type_handler_for {
336 my ($self, $type_handler_name) = @_;
337 $TYPES{$type_handler_name}
348 MooseX::Storage::Engine - The meta-engine to handle collapsing and expanding objects
352 No user serviceable parts inside. If you really want to know, read the source :)
374 =item B<expand_object>
376 =item B<collapse_object>
384 =item B<collapse_attribute>
386 =item B<collapse_attribute_value>
388 =item B<expand_attribute>
390 =item B<expand_attribute_value>
392 =item B<check_for_cycle_in_collapse>
394 =item B<check_for_cycle_in_expansion>
396 =item B<map_attributes>
400 =head2 Type Constraint Handlers
404 =item B<find_type_handler ($type)>
406 =item B<find_type_handler_for ($name)>
408 =item B<add_custom_type_handler ($name, %handlers)>
410 =item B<remove_custom_type_handler ($name)>
424 All complex software has bugs lurking in it, and this module is no
425 exception. If you find a bug please either email me, or add the bug
430 Chris Prather E<lt>chris.prather@iinteractive.comE<gt>
432 Stevan Little E<lt>stevan.little@iinteractive.comE<gt>
434 =head1 COPYRIGHT AND LICENSE
436 Copyright 2007-2008 by Infinity Interactive, Inc.
438 L<http://www.iinteractive.com>
440 This library is free software; you can redistribute it and/or modify
441 it under the same terms as Perl itself.