Commit | Line | Data |
c0e30cf5 |
1 | |
2 | package Moose::Meta::Attribute; |
3 | |
4 | use strict; |
5 | use warnings; |
6 | |
21f1e231 |
7 | use Scalar::Util 'blessed', 'weaken'; |
a909a4df |
8 | use overload (); |
a15dff8d |
9 | |
e606ae5f |
10 | our $VERSION = '0.57'; |
d44714be |
11 | our $AUTHORITY = 'cpan:STEVAN'; |
78cd1d3b |
12 | |
8ee73eeb |
13 | use Moose::Meta::Method::Accessor; |
a05f85c1 |
14 | use Moose::Meta::Method::Delegation; |
d5c30e52 |
15 | use Moose::Util (); |
a3c7e2fe |
16 | use Moose::Util::TypeConstraints (); |
bc1e29b5 |
17 | |
c0e30cf5 |
18 | use base 'Class::MOP::Attribute'; |
19 | |
452bac1b |
20 | # options which are not directly used |
21 | # but we store them for metadata purposes |
98aae381 |
22 | __PACKAGE__->meta->add_attribute('isa' => (reader => '_isa_metadata')); |
23 | __PACKAGE__->meta->add_attribute('does' => (reader => '_does_metadata')); |
24 | __PACKAGE__->meta->add_attribute('is' => (reader => '_is_metadata')); |
452bac1b |
25 | |
26 | # these are actual options for the attrs |
1a563243 |
27 | __PACKAGE__->meta->add_attribute('required' => (reader => 'is_required' )); |
28 | __PACKAGE__->meta->add_attribute('lazy' => (reader => 'is_lazy' )); |
26fbace8 |
29 | __PACKAGE__->meta->add_attribute('lazy_build' => (reader => 'is_lazy_build' )); |
1a563243 |
30 | __PACKAGE__->meta->add_attribute('coerce' => (reader => 'should_coerce' )); |
31 | __PACKAGE__->meta->add_attribute('weak_ref' => (reader => 'is_weak_ref' )); |
32 | __PACKAGE__->meta->add_attribute('auto_deref' => (reader => 'should_auto_deref')); |
82168dbb |
33 | __PACKAGE__->meta->add_attribute('type_constraint' => ( |
34 | reader => 'type_constraint', |
35 | predicate => 'has_type_constraint', |
36 | )); |
8c9d74e7 |
37 | __PACKAGE__->meta->add_attribute('trigger' => ( |
38 | reader => 'trigger', |
39 | predicate => 'has_trigger', |
40 | )); |
452bac1b |
41 | __PACKAGE__->meta->add_attribute('handles' => ( |
42 | reader => 'handles', |
43 | predicate => 'has_handles', |
44 | )); |
ddbdc0cb |
45 | __PACKAGE__->meta->add_attribute('documentation' => ( |
46 | reader => 'documentation', |
47 | predicate => 'has_documentation', |
48 | )); |
82a5b1a7 |
49 | __PACKAGE__->meta->add_attribute('traits' => ( |
50 | reader => 'applied_traits', |
51 | predicate => 'has_applied_traits', |
52 | )); |
82168dbb |
53 | |
587e457d |
54 | # we need to have a ->does method in here to |
55 | # more easily support traits, and the introspection |
0db4f1d7 |
56 | # of those traits. We extend the does check to look |
57 | # for metatrait aliases. |
58 | sub does { |
59 | my ($self, $role_name) = @_; |
60 | my $name = eval { |
61 | Moose::Util::resolve_metatrait_alias(Attribute => $role_name) |
62 | }; |
63 | return 0 if !defined($name); # failed to load class |
64 | return Moose::Object::does($self, $name); |
65 | } |
587e457d |
66 | |
be05faea |
67 | sub throw_error { |
68 | my $self = shift; |
69 | my $class = ( ref $self && $self->associated_class ) || "Moose::Meta::Class"; |
70 | unshift @_, "message" if @_ % 2 == 1; |
71 | unshift @_, attr => $self if ref $self; |
72 | unshift @_, $class; |
73 | goto $class->can("throw_error"); # to avoid incrementing depth by 1 |
74 | } |
75 | |
78cd1d3b |
76 | sub new { |
f3c4e20e |
77 | my ($class, $name, %options) = @_; |
c32c2c61 |
78 | $class->_process_options($name, \%options) unless $options{__hack_no_process_options}; # used from clone()... YECHKKK FIXME ICKY YUCK GROSS |
f3c4e20e |
79 | return $class->SUPER::new($name, %options); |
1d768fb1 |
80 | } |
81 | |
d5c30e52 |
82 | sub interpolate_class_and_new { |
83 | my ($class, $name, @args) = @_; |
84 | |
c32c2c61 |
85 | my ( $new_class, @traits ) = $class->interpolate_class(@args); |
86 | |
87 | $new_class->new($name, @args, ( scalar(@traits) ? ( traits => \@traits ) : () ) ); |
d5c30e52 |
88 | } |
89 | |
90 | sub interpolate_class { |
91 | my ($class, %options) = @_; |
92 | |
c32c2c61 |
93 | $class = ref($class) || $class; |
94 | |
95 | if ( my $metaclass_name = delete $options{metaclass} ) { |
96 | my $new_class = Moose::Util::resolve_metaclass_alias( Attribute => $metaclass_name ); |
97 | |
98 | if ( $class ne $new_class ) { |
99 | if ( $new_class->can("interpolate_class") ) { |
100 | return $new_class->interpolate_class(%options); |
101 | } else { |
102 | $class = $new_class; |
103 | } |
104 | } |
d5c30e52 |
105 | } |
106 | |
c32c2c61 |
107 | my @traits; |
108 | |
d5c30e52 |
109 | if (my $traits = $options{traits}) { |
c32c2c61 |
110 | if ( @traits = grep { not $class->does($_) } map { |
d5c30e52 |
111 | Moose::Util::resolve_metatrait_alias( Attribute => $_ ) |
112 | or |
113 | $_ |
c32c2c61 |
114 | } @$traits ) { |
115 | my $anon_class = Moose::Meta::Class->create_anon_class( |
116 | superclasses => [ $class ], |
117 | roles => [ @traits ], |
118 | cache => 1, |
119 | ); |
120 | |
121 | $class = $anon_class->name; |
122 | } |
d5c30e52 |
123 | } |
c32c2c61 |
124 | |
125 | return ( wantarray ? ( $class, @traits ) : $class ); |
d5c30e52 |
126 | } |
127 | |
e606ae5f |
128 | # ... |
129 | |
130 | my @legal_options_for_inheritance = qw( |
131 | default coerce required |
132 | documentation lazy handles |
133 | builder type_constraint |
134 | ); |
135 | |
136 | sub legal_options_for_inheritance { @legal_options_for_inheritance } |
137 | |
138 | # NOTE/TODO |
139 | # This method *must* be able to handle |
140 | # Class::MOP::Attribute instances as |
141 | # well. Yes, I know that is wrong, but |
142 | # apparently we didn't realize it was |
143 | # doing that and now we have some code |
144 | # which is dependent on it. The real |
145 | # solution of course is to push this |
146 | # feature back up into Class::MOP::Attribute |
147 | # but I not right now, I am too lazy. |
148 | # However if you are reading this and |
149 | # looking for something to do,.. please |
150 | # be my guest. |
151 | # - stevan |
ce0e8d63 |
152 | sub clone_and_inherit_options { |
153 | my ($self, %options) = @_; |
e606ae5f |
154 | |
c32c2c61 |
155 | my %copy = %options; |
e606ae5f |
156 | |
ce0e8d63 |
157 | my %actual_options; |
e606ae5f |
158 | |
159 | # NOTE: |
160 | # we may want to extends a Class::MOP::Attribute |
161 | # in which case we need to be able to use the |
162 | # core set of legal options that have always |
163 | # been here. But we allows Moose::Meta::Attribute |
164 | # instances to changes them. |
165 | # - SL |
166 | my @legal_options = $self->can('legal_options_for_inheritance') |
167 | ? $self->legal_options_for_inheritance |
168 | : @legal_options_for_inheritance; |
169 | |
170 | foreach my $legal_option (@legal_options) { |
ce0e8d63 |
171 | if (exists $options{$legal_option}) { |
172 | $actual_options{$legal_option} = $options{$legal_option}; |
173 | delete $options{$legal_option}; |
174 | } |
e606ae5f |
175 | } |
26fbace8 |
176 | |
ce0e8d63 |
177 | if ($options{isa}) { |
178 | my $type_constraint; |
8de73ff1 |
179 | if (blessed($options{isa}) && $options{isa}->isa('Moose::Meta::TypeConstraint')) { |
180 | $type_constraint = $options{isa}; |
181 | } |
182 | else { |
d40ce9d5 |
183 | $type_constraint = Moose::Util::TypeConstraints::find_or_create_isa_type_constraint($options{isa}); |
8de73ff1 |
184 | (defined $type_constraint) |
be05faea |
185 | || $self->throw_error("Could not find the type constraint '" . $options{isa} . "'", data => $options{isa}); |
8de73ff1 |
186 | } |
5e98d2b6 |
187 | |
8de73ff1 |
188 | $actual_options{type_constraint} = $type_constraint; |
ce0e8d63 |
189 | delete $options{isa}; |
190 | } |
2ea379cb |
191 | |
192 | if ($options{does}) { |
193 | my $type_constraint; |
194 | if (blessed($options{does}) && $options{does}->isa('Moose::Meta::TypeConstraint')) { |
195 | $type_constraint = $options{does}; |
196 | } |
197 | else { |
d40ce9d5 |
198 | $type_constraint = Moose::Util::TypeConstraints::find_or_create_does_type_constraint($options{does}); |
2ea379cb |
199 | (defined $type_constraint) |
be05faea |
200 | || $self->throw_error("Could not find the type constraint '" . $options{does} . "'", data => $options{does}); |
2ea379cb |
201 | } |
202 | |
203 | $actual_options{type_constraint} = $type_constraint; |
204 | delete $options{does}; |
205 | } |
c32c2c61 |
206 | |
cbd141ca |
207 | # NOTE: |
208 | # this doesn't apply to Class::MOP::Attributes, |
209 | # so we can ignore it for them. |
210 | # - SL |
211 | if ($self->can('interpolate_class')) { |
212 | ( $actual_options{metaclass}, my @traits ) = $self->interpolate_class(%options); |
c32c2c61 |
213 | |
cbd141ca |
214 | my %seen; |
215 | my @all_traits = grep { $seen{$_}++ } @{ $self->applied_traits || [] }, @traits; |
216 | $actual_options{traits} = \@all_traits if @all_traits; |
c32c2c61 |
217 | |
cbd141ca |
218 | delete @options{qw(metaclass traits)}; |
219 | } |
c32c2c61 |
220 | |
26fbace8 |
221 | (scalar keys %options == 0) |
be05faea |
222 | || $self->throw_error("Illegal inherited options => (" . (join ', ' => keys %options) . ")", data => \%options); |
c32c2c61 |
223 | |
224 | |
ce0e8d63 |
225 | $self->clone(%actual_options); |
1d768fb1 |
226 | } |
227 | |
c32c2c61 |
228 | sub clone { |
229 | my ( $self, %params ) = @_; |
230 | |
231 | my $class = $params{metaclass} || ref $self; |
232 | |
233 | if ( 0 and $class eq ref $self ) { |
234 | return $self->SUPER::clone(%params); |
235 | } else { |
236 | my ( @init, @non_init ); |
237 | |
238 | foreach my $attr ( grep { $_->has_value($self) } $self->meta->compute_all_applicable_attributes ) { |
239 | push @{ $attr->has_init_arg ? \@init : \@non_init }, $attr; |
240 | } |
241 | |
242 | my %new_params = ( ( map { $_->init_arg => $_->get_value($self) } @init ), %params ); |
243 | |
244 | my $name = delete $new_params{name}; |
245 | |
246 | my $clone = $class->new($name, %new_params, __hack_no_process_options => 1 ); |
247 | |
248 | foreach my $attr ( @non_init ) { |
249 | $attr->set_value($clone, $attr->get_value($self)); |
250 | } |
251 | |
252 | |
253 | return $clone; |
254 | } |
255 | } |
256 | |
1d768fb1 |
257 | sub _process_options { |
258 | my ($class, $name, $options) = @_; |
8de73ff1 |
259 | |
f3c4e20e |
260 | if (exists $options->{is}) { |
21f1e231 |
261 | |
012fcbd1 |
262 | ### ------------------------- |
263 | ## is => ro, writer => _foo # turns into (reader => foo, writer => _foo) as before |
264 | ## is => rw, writer => _foo # turns into (reader => foo, writer => _foo) |
265 | ## is => rw, accessor => _foo # turns into (accessor => _foo) |
266 | ## is => ro, accessor => _foo # error, accesor is rw |
267 | ### ------------------------- |
21f1e231 |
268 | |
8de73ff1 |
269 | if ($options->{is} eq 'ro') { |
be05faea |
270 | $class->throw_error("Cannot define an accessor name on a read-only attribute, accessors are read/write", data => $options) |
21f1e231 |
271 | if exists $options->{accessor}; |
8de73ff1 |
272 | $options->{reader} ||= $name; |
8de73ff1 |
273 | } |
274 | elsif ($options->{is} eq 'rw') { |
21f1e231 |
275 | if ($options->{writer}) { |
276 | $options->{reader} ||= $name; |
277 | } |
278 | else { |
279 | $options->{accessor} ||= $name; |
280 | } |
8de73ff1 |
281 | } |
282 | else { |
e606ae5f |
283 | $class->throw_error("I do not understand this option (is => " . $options->{is} . ") on attribute ($name)", data => $options->{is}); |
8de73ff1 |
284 | } |
f3c4e20e |
285 | } |
8de73ff1 |
286 | |
f3c4e20e |
287 | if (exists $options->{isa}) { |
f3c4e20e |
288 | if (exists $options->{does}) { |
289 | if (eval { $options->{isa}->can('does') }) { |
290 | ($options->{isa}->does($options->{does})) |
e606ae5f |
291 | || $class->throw_error("Cannot have an isa option and a does option if the isa does not do the does on attribute ($name)", data => $options); |
f3c4e20e |
292 | } |
293 | else { |
e606ae5f |
294 | $class->throw_error("Cannot have an isa option which cannot ->does() on attribute ($name)", data => $options); |
26fbace8 |
295 | } |
26fbace8 |
296 | } |
8de73ff1 |
297 | |
f3c4e20e |
298 | # allow for anon-subtypes here ... |
299 | if (blessed($options->{isa}) && $options->{isa}->isa('Moose::Meta::TypeConstraint')) { |
8de73ff1 |
300 | $options->{type_constraint} = $options->{isa}; |
301 | } |
302 | else { |
620db045 |
303 | $options->{type_constraint} = Moose::Util::TypeConstraints::find_or_create_isa_type_constraint($options->{isa}); |
8de73ff1 |
304 | } |
f3c4e20e |
305 | } |
306 | elsif (exists $options->{does}) { |
307 | # allow for anon-subtypes here ... |
308 | if (blessed($options->{does}) && $options->{does}->isa('Moose::Meta::TypeConstraint')) { |
238b424d |
309 | $options->{type_constraint} = $options->{does}; |
8de73ff1 |
310 | } |
311 | else { |
620db045 |
312 | $options->{type_constraint} = Moose::Util::TypeConstraints::find_or_create_does_type_constraint($options->{does}); |
8de73ff1 |
313 | } |
f3c4e20e |
314 | } |
8de73ff1 |
315 | |
f3c4e20e |
316 | if (exists $options->{coerce} && $options->{coerce}) { |
317 | (exists $options->{type_constraint}) |
e606ae5f |
318 | || $class->throw_error("You cannot have coercion without specifying a type constraint on attribute ($name)", data => $options); |
319 | $class->throw_error("You cannot have a weak reference to a coerced value on attribute ($name)", data => $options) |
8de73ff1 |
320 | if $options->{weak_ref}; |
f3c4e20e |
321 | } |
8de73ff1 |
322 | |
0b7df53c |
323 | if (exists $options->{trigger}) { |
21f1e231 |
324 | ('CODE' eq ref $options->{trigger}) |
e606ae5f |
325 | || $class->throw_error("Trigger must be a CODE ref on attribute ($name)", data => $options->{trigger}); |
0b7df53c |
326 | } |
327 | |
f3c4e20e |
328 | if (exists $options->{auto_deref} && $options->{auto_deref}) { |
329 | (exists $options->{type_constraint}) |
e606ae5f |
330 | || $class->throw_error("You cannot auto-dereference without specifying a type constraint on attribute ($name)", data => $options); |
f3c4e20e |
331 | ($options->{type_constraint}->is_a_type_of('ArrayRef') || |
8de73ff1 |
332 | $options->{type_constraint}->is_a_type_of('HashRef')) |
e606ae5f |
333 | || $class->throw_error("You cannot auto-dereference anything other than a ArrayRef or HashRef on attribute ($name)", data => $options); |
f3c4e20e |
334 | } |
8de73ff1 |
335 | |
f3c4e20e |
336 | if (exists $options->{lazy_build} && $options->{lazy_build} == 1) { |
e606ae5f |
337 | $class->throw_error("You can not use lazy_build and default for the same attribute ($name)", data => $options) |
8de73ff1 |
338 | if exists $options->{default}; |
a6c84c69 |
339 | $options->{lazy} = 1; |
340 | $options->{required} = 1; |
341 | $options->{builder} ||= "_build_${name}"; |
342 | if ($name =~ /^_/) { |
f3c4e20e |
343 | $options->{clearer} ||= "_clear${name}"; |
344 | $options->{predicate} ||= "_has${name}"; |
a6c84c69 |
345 | } |
346 | else { |
f3c4e20e |
347 | $options->{clearer} ||= "clear_${name}"; |
348 | $options->{predicate} ||= "has_${name}"; |
26fbace8 |
349 | } |
f3c4e20e |
350 | } |
8de73ff1 |
351 | |
f3c4e20e |
352 | if (exists $options->{lazy} && $options->{lazy}) { |
9edba990 |
353 | (exists $options->{default} || defined $options->{builder} ) |
be05faea |
354 | || $class->throw_error("You cannot have lazy attribute ($name) without specifying a default value for it", data => $options); |
f3c4e20e |
355 | } |
26fbace8 |
356 | |
9edba990 |
357 | if ( $options->{required} && !( ( !exists $options->{init_arg} || defined $options->{init_arg} ) || exists $options->{default} || defined $options->{builder} ) ) { |
be05faea |
358 | $class->throw_error("You cannot have a required attribute ($name) without a default, builder, or an init_arg", data => $options); |
9edba990 |
359 | } |
360 | |
78cd1d3b |
361 | } |
c0e30cf5 |
362 | |
d500266f |
363 | sub initialize_instance_slot { |
ddd0ec20 |
364 | my ($self, $meta_instance, $instance, $params) = @_; |
d500266f |
365 | my $init_arg = $self->init_arg(); |
366 | # try to fetch the init arg from the %params ... |
ddd0ec20 |
367 | |
26fbace8 |
368 | my $val; |
1ed0b94f |
369 | my $value_is_set; |
625d571f |
370 | if ( defined($init_arg) and exists $params->{$init_arg}) { |
d500266f |
371 | $val = $params->{$init_arg}; |
2c78d811 |
372 | $value_is_set = 1; |
d500266f |
373 | } |
374 | else { |
375 | # skip it if it's lazy |
376 | return if $self->is_lazy; |
377 | # and die if it's required and doesn't have a default value |
be05faea |
378 | $self->throw_error("Attribute (" . $self->name . ") is required", object => $instance, data => $params) |
26fbace8 |
379 | if $self->is_required && !$self->has_default && !$self->has_builder; |
ddd0ec20 |
380 | |
1ed0b94f |
381 | # if nothing was in the %params, we can use the |
382 | # attribute's default value (if it has one) |
383 | if ($self->has_default) { |
384 | $val = $self->default($instance); |
385 | $value_is_set = 1; |
a6c84c69 |
386 | } |
387 | elsif ($self->has_builder) { |
e606ae5f |
388 | $val = $self->_call_builder($instance); |
389 | $value_is_set = 1; |
a0748c37 |
390 | } |
26fbace8 |
391 | } |
392 | |
1ed0b94f |
393 | return unless $value_is_set; |
394 | |
395 | if ($self->has_type_constraint) { |
396 | my $type_constraint = $self->type_constraint; |
397 | if ($self->should_coerce && $type_constraint->has_coercion) { |
398 | $val = $type_constraint->coerce($val); |
d500266f |
399 | } |
ab76842e |
400 | $type_constraint->check($val) |
be05faea |
401 | || $self->throw_error("Attribute (" |
688fcdda |
402 | . $self->name |
403 | . ") does not pass the type constraint because: " |
be05faea |
404 | . $type_constraint->get_message($val), data => $val, object => $instance); |
1ed0b94f |
405 | } |
ddd0ec20 |
406 | |
759e4e8f |
407 | $self->set_initial_value($instance, $val); |
26fbace8 |
408 | $meta_instance->weaken_slot_value($instance, $self->name) |
a6c84c69 |
409 | if ref $val && $self->is_weak_ref; |
d500266f |
410 | } |
411 | |
e606ae5f |
412 | sub _call_builder { |
413 | my ( $self, $instance ) = @_; |
414 | |
415 | my $builder = $self->builder(); |
416 | |
417 | return $instance->$builder() |
418 | if $instance->can( $self->builder ); |
419 | |
420 | $self->throw_error( blessed($instance) |
421 | . " does not support builder method '" |
422 | . $self->builder |
423 | . "' for attribute '" |
424 | . $self->name |
425 | . "'", |
426 | object => $instance, |
427 | ); |
428 | } |
429 | |
d617b644 |
430 | ## Slot management |
9e93dd19 |
431 | |
8abe9636 |
432 | # FIXME: |
433 | # this duplicates too much code from |
434 | # Class::MOP::Attribute, we need to |
435 | # refactor these bits eventually. |
436 | # - SL |
437 | sub _set_initial_slot_value { |
438 | my ($self, $meta_instance, $instance, $value) = @_; |
439 | |
440 | my $slot_name = $self->name; |
441 | |
442 | return $meta_instance->set_slot_value($instance, $slot_name, $value) |
443 | unless $self->has_initializer; |
444 | |
445 | my ($type_constraint, $can_coerce); |
446 | if ($self->has_type_constraint) { |
447 | $type_constraint = $self->type_constraint; |
448 | $can_coerce = ($self->should_coerce && $type_constraint->has_coercion); |
449 | } |
450 | |
451 | my $callback = sub { |
452 | my $val = shift; |
453 | if ($type_constraint) { |
454 | $val = $type_constraint->coerce($val) |
455 | if $can_coerce; |
456 | $type_constraint->check($val) |
be05faea |
457 | || $self->throw_error("Attribute (" |
8abe9636 |
458 | . $slot_name |
459 | . ") does not pass the type constraint because: " |
be05faea |
460 | . $type_constraint->get_message($val), data => $val, object => $instance); |
8abe9636 |
461 | } |
462 | $meta_instance->set_slot_value($instance, $slot_name, $val); |
463 | }; |
464 | |
465 | my $initializer = $self->initializer; |
466 | |
467 | # most things will just want to set a value, so make it first arg |
468 | $instance->$initializer($value, $callback, $self); |
469 | } |
470 | |
946289d1 |
471 | sub set_value { |
b6af66f8 |
472 | my ($self, $instance, @args) = @_; |
473 | my $value = $args[0]; |
26fbace8 |
474 | |
946289d1 |
475 | my $attr_name = $self->name; |
26fbace8 |
476 | |
b6af66f8 |
477 | if ($self->is_required and not @args) { |
be05faea |
478 | $self->throw_error("Attribute ($attr_name) is required", object => $instance); |
946289d1 |
479 | } |
26fbace8 |
480 | |
946289d1 |
481 | if ($self->has_type_constraint) { |
26fbace8 |
482 | |
946289d1 |
483 | my $type_constraint = $self->type_constraint; |
26fbace8 |
484 | |
946289d1 |
485 | if ($self->should_coerce) { |
26fbace8 |
486 | $value = $type_constraint->coerce($value); |
688fcdda |
487 | } |
42bc21a4 |
488 | $type_constraint->_compiled_type_constraint->($value) |
be05faea |
489 | || $self->throw_error("Attribute (" |
688fcdda |
490 | . $self->name |
491 | . ") does not pass the type constraint because " |
be05faea |
492 | . $type_constraint->get_message($value), object => $instance, data => $value); |
946289d1 |
493 | } |
26fbace8 |
494 | |
946289d1 |
495 | my $meta_instance = Class::MOP::Class->initialize(blessed($instance)) |
496 | ->get_meta_instance; |
26fbace8 |
497 | |
498 | $meta_instance->set_slot_value($instance, $attr_name, $value); |
499 | |
946289d1 |
500 | if (ref $value && $self->is_weak_ref) { |
26fbace8 |
501 | $meta_instance->weaken_slot_value($instance, $attr_name); |
946289d1 |
502 | } |
26fbace8 |
503 | |
946289d1 |
504 | if ($self->has_trigger) { |
505 | $self->trigger->($instance, $value, $self); |
506 | } |
507 | } |
508 | |
509 | sub get_value { |
510 | my ($self, $instance) = @_; |
26fbace8 |
511 | |
946289d1 |
512 | if ($self->is_lazy) { |
8de73ff1 |
513 | unless ($self->has_value($instance)) { |
e606ae5f |
514 | my $value; |
8de73ff1 |
515 | if ($self->has_default) { |
e606ae5f |
516 | $value = $self->default($instance); |
3f11800d |
517 | } elsif ( $self->has_builder ) { |
e606ae5f |
518 | $value = $self->_call_builder($instance); |
519 | } |
520 | if ($self->has_type_constraint) { |
521 | my $type_constraint = $self->type_constraint; |
522 | $value = $type_constraint->coerce($value) |
523 | if ($self->should_coerce); |
524 | $type_constraint->check($value) |
525 | || c$self->throw_error("Attribute (" . $self->name |
526 | . ") does not pass the type constraint because: " |
527 | . $type_constraint->get_message($value), type_constraint => $type_constraint, data => $value); |
26fbace8 |
528 | } |
e606ae5f |
529 | $self->set_initial_value($instance, $value); |
8de73ff1 |
530 | } |
946289d1 |
531 | } |
26fbace8 |
532 | |
946289d1 |
533 | if ($self->should_auto_deref) { |
26fbace8 |
534 | |
946289d1 |
535 | my $type_constraint = $self->type_constraint; |
536 | |
537 | if ($type_constraint->is_a_type_of('ArrayRef')) { |
538 | my $rv = $self->SUPER::get_value($instance); |
539 | return unless defined $rv; |
540 | return wantarray ? @{ $rv } : $rv; |
26fbace8 |
541 | } |
946289d1 |
542 | elsif ($type_constraint->is_a_type_of('HashRef')) { |
543 | my $rv = $self->SUPER::get_value($instance); |
544 | return unless defined $rv; |
545 | return wantarray ? %{ $rv } : $rv; |
26fbace8 |
546 | } |
946289d1 |
547 | else { |
46cb090f |
548 | $self->throw_error("Can not auto de-reference the type constraint '" . $type_constraint->name . "'", object => $instance, type_constraint => $type_constraint); |
946289d1 |
549 | } |
26fbace8 |
550 | |
946289d1 |
551 | } |
552 | else { |
26fbace8 |
553 | |
946289d1 |
554 | return $self->SUPER::get_value($instance); |
26fbace8 |
555 | } |
946289d1 |
556 | } |
a15dff8d |
557 | |
26fbace8 |
558 | ## installing accessors |
c0e30cf5 |
559 | |
d617b644 |
560 | sub accessor_metaclass { 'Moose::Meta::Method::Accessor' } |
d7f17ebb |
561 | |
452bac1b |
562 | sub install_accessors { |
563 | my $self = shift; |
26fbace8 |
564 | $self->SUPER::install_accessors(@_); |
e606ae5f |
565 | $self->install_delegation if $self->has_handles; |
566 | return; |
567 | } |
26fbace8 |
568 | |
e606ae5f |
569 | sub install_delegation { |
570 | my $self = shift; |
26fbace8 |
571 | |
e606ae5f |
572 | # NOTE: |
573 | # Here we canonicalize the 'handles' option |
574 | # this will sort out any details and always |
575 | # return an hash of methods which we want |
576 | # to delagate to, see that method for details |
577 | my %handles = $self->_canonicalize_handles; |
578 | |
e606ae5f |
579 | |
580 | # install the delegation ... |
581 | my $associated_class = $self->associated_class; |
582 | foreach my $handle (keys %handles) { |
583 | my $method_to_call = $handles{$handle}; |
584 | my $class_name = $associated_class->name; |
585 | my $name = "${class_name}::${handle}"; |
26fbace8 |
586 | |
452bac1b |
587 | (!$associated_class->has_method($handle)) |
cee532a1 |
588 | || $self->throw_error("You cannot overwrite a locally defined method ($handle) with a delegation", method_name => $handle); |
26fbace8 |
589 | |
e606ae5f |
590 | # NOTE: |
591 | # handles is not allowed to delegate |
592 | # any of these methods, as they will |
593 | # override the ones in your class, which |
594 | # is almost certainly not what you want. |
4fe78472 |
595 | |
e606ae5f |
596 | # FIXME warn when $handle was explicitly specified, but not if the source is a regex or something |
597 | #cluck("Not delegating method '$handle' because it is a core method") and |
598 | next if $class_name->isa("Moose::Object") and $handle =~ /^BUILD|DEMOLISH$/ || Moose::Object->can($handle); |
26fbace8 |
599 | |
46f7e6a5 |
600 | my $method = $self->_make_delegation_method($handle, $method_to_call); |
a05f85c1 |
601 | |
602 | $self->associated_class->add_method($method->name, $method); |
e606ae5f |
603 | } |
452bac1b |
604 | } |
605 | |
98aae381 |
606 | # private methods to help delegation ... |
607 | |
452bac1b |
608 | sub _canonicalize_handles { |
609 | my $self = shift; |
610 | my $handles = $self->handles; |
c84f324f |
611 | if (my $handle_type = ref($handles)) { |
612 | if ($handle_type eq 'HASH') { |
613 | return %{$handles}; |
614 | } |
615 | elsif ($handle_type eq 'ARRAY') { |
616 | return map { $_ => $_ } @{$handles}; |
617 | } |
618 | elsif ($handle_type eq 'Regexp') { |
619 | ($self->has_type_constraint) |
be05faea |
620 | || $self->throw_error("Cannot delegate methods based on a RegExpr without a type constraint (isa)", data => $handles); |
26fbace8 |
621 | return map { ($_ => $_) } |
c84f324f |
622 | grep { /$handles/ } $self->_get_delegate_method_list; |
623 | } |
624 | elsif ($handle_type eq 'CODE') { |
625 | return $handles->($self, $self->_find_delegate_metaclass); |
626 | } |
627 | else { |
be05faea |
628 | $self->throw_error("Unable to canonicalize the 'handles' option with $handles", data => $handles); |
c84f324f |
629 | } |
452bac1b |
630 | } |
631 | else { |
c84f324f |
632 | my $role_meta = eval { $handles->meta }; |
633 | if ($@) { |
be05faea |
634 | $self->throw_error("Unable to canonicalize the 'handles' option with $handles because : $@", data => $handles, error => $@); |
c84f324f |
635 | } |
636 | |
637 | (blessed $role_meta && $role_meta->isa('Moose::Meta::Role')) |
be05faea |
638 | || $self->throw_error("Unable to canonicalize the 'handles' option with $handles because ->meta is not a Moose::Meta::Role", data => $handles); |
26fbace8 |
639 | |
c84f324f |
640 | return map { $_ => $_ } ( |
26fbace8 |
641 | $role_meta->get_method_list, |
c84f324f |
642 | $role_meta->get_required_method_list |
643 | ); |
452bac1b |
644 | } |
645 | } |
646 | |
647 | sub _find_delegate_metaclass { |
648 | my $self = shift; |
98aae381 |
649 | if (my $class = $self->_isa_metadata) { |
26fbace8 |
650 | # if the class does have |
452bac1b |
651 | # a meta method, use it |
652 | return $class->meta if $class->can('meta'); |
26fbace8 |
653 | # otherwise we might be |
452bac1b |
654 | # dealing with a non-Moose |
26fbace8 |
655 | # class, and need to make |
452bac1b |
656 | # our own metaclass |
657 | return Moose::Meta::Class->initialize($class); |
658 | } |
98aae381 |
659 | elsif (my $role = $self->_does_metadata) { |
26fbace8 |
660 | # our role will always have |
452bac1b |
661 | # a meta method |
98aae381 |
662 | return $role->meta; |
452bac1b |
663 | } |
664 | else { |
be05faea |
665 | $self->throw_error("Cannot find delegate metaclass for attribute " . $self->name); |
452bac1b |
666 | } |
667 | } |
668 | |
669 | sub _get_delegate_method_list { |
670 | my $self = shift; |
671 | my $meta = $self->_find_delegate_metaclass; |
672 | if ($meta->isa('Class::MOP::Class')) { |
e606ae5f |
673 | return map { $_->name } # NOTE: !never! delegate &meta |
674 | grep { $_->package_name ne 'Moose::Object' && $_->name ne 'meta' } |
675 | $meta->get_all_methods; |
452bac1b |
676 | } |
677 | elsif ($meta->isa('Moose::Meta::Role')) { |
26fbace8 |
678 | return $meta->get_method_list; |
452bac1b |
679 | } |
680 | else { |
be05faea |
681 | $self->throw_error("Unable to recognize the delegate metaclass '$meta'", data => $meta); |
452bac1b |
682 | } |
683 | } |
684 | |
a05f85c1 |
685 | sub _make_delegation_method { |
46f7e6a5 |
686 | my ( $self, $handle_name, $method_to_call ) = @_; |
a05f85c1 |
687 | |
688 | my $method_body; |
689 | |
46f7e6a5 |
690 | $method_body = $method_to_call |
691 | if 'CODE' eq ref($method_to_call); |
a05f85c1 |
692 | |
693 | return Moose::Meta::Method::Delegation->new( |
46f7e6a5 |
694 | name => $handle_name, |
695 | package_name => $self->associated_class->name, |
696 | attribute => $self, |
697 | delegate_to_method => $method_to_call, |
a05f85c1 |
698 | ); |
699 | } |
700 | |
21f1e231 |
701 | package Moose::Meta::Attribute::Custom::Moose; |
702 | sub register_implementation { 'Moose::Meta::Attribute' } |
703 | |
c0e30cf5 |
704 | 1; |
705 | |
706 | __END__ |
707 | |
708 | =pod |
709 | |
710 | =head1 NAME |
711 | |
6ba6d68c |
712 | Moose::Meta::Attribute - The Moose attribute metaclass |
c0e30cf5 |
713 | |
714 | =head1 DESCRIPTION |
715 | |
26fbace8 |
716 | This is a subclass of L<Class::MOP::Attribute> with Moose specific |
717 | extensions. |
6ba6d68c |
718 | |
26fbace8 |
719 | For the most part, the only time you will ever encounter an |
720 | instance of this class is if you are doing some serious deep |
721 | introspection. To really understand this class, you need to refer |
6ba6d68c |
722 | to the L<Class::MOP::Attribute> documentation. |
e522431d |
723 | |
c0e30cf5 |
724 | =head1 METHODS |
725 | |
6ba6d68c |
726 | =head2 Overridden methods |
727 | |
26fbace8 |
728 | These methods override methods in L<Class::MOP::Attribute> and add |
729 | Moose specific features. You can safely assume though that they |
6ba6d68c |
730 | will behave just as L<Class::MOP::Attribute> does. |
731 | |
c0e30cf5 |
732 | =over 4 |
733 | |
734 | =item B<new> |
735 | |
c32c2c61 |
736 | =item B<clone> |
737 | |
6e2840b7 |
738 | =item B<does> |
739 | |
d500266f |
740 | =item B<initialize_instance_slot> |
741 | |
452bac1b |
742 | =item B<install_accessors> |
743 | |
e606ae5f |
744 | =item B<install_delegation> |
745 | |
39b3bc94 |
746 | =item B<accessor_metaclass> |
747 | |
946289d1 |
748 | =item B<get_value> |
749 | |
750 | =item B<set_value> |
751 | |
bcbaa845 |
752 | eval { $point->meta->get_attribute('x')->set_value($point, 'fourty-two') }; |
753 | if($@) { |
754 | print "Oops: $@\n"; |
755 | } |
756 | |
757 | I<Attribute (x) does not pass the type constraint (Int) with 'fourty-two'> |
758 | |
759 | Before setting the value, a check is made on the type constraint of |
760 | the attribute, if it has one, to see if the value passes it. If the |
46cb090f |
761 | value fails to pass, the set operation dies with a L<throw_error>. |
bcbaa845 |
762 | |
763 | Any coercion to convert values is done before checking the type constraint. |
764 | |
765 | To check a value against a type constraint before setting it, fetch the |
ec00fa75 |
766 | attribute instance using L<Class::MOP::Class/find_attribute_by_name>, |
bcbaa845 |
767 | fetch the type_constraint from the attribute using L<Moose::Meta::Attribute/type_constraint> |
e606ae5f |
768 | and call L<Moose::Meta::TypeConstraint/check>. See L<Moose::Cookbook::Basics::Recipe4> |
bcbaa845 |
769 | for an example. |
770 | |
a15dff8d |
771 | =back |
772 | |
6ba6d68c |
773 | =head2 Additional Moose features |
774 | |
26fbace8 |
775 | Moose attributes support type-constraint checking, weak reference |
776 | creation and type coercion. |
6ba6d68c |
777 | |
a15dff8d |
778 | =over 4 |
779 | |
be05faea |
780 | =item B<throw_error> |
781 | |
782 | Delegates to C<associated_class> or C<Moose::Meta::Class> if there is none. |
783 | |
d5c30e52 |
784 | =item B<interpolate_class_and_new> |
785 | |
786 | =item B<interpolate_class> |
787 | |
788 | When called as a class method causes interpretation of the C<metaclass> and |
789 | C<traits> options. |
790 | |
9e93dd19 |
791 | =item B<clone_and_inherit_options> |
792 | |
26fbace8 |
793 | This is to support the C<has '+foo'> feature, it clones an attribute |
794 | from a superclass and allows a very specific set of changes to be made |
9e93dd19 |
795 | to the attribute. |
796 | |
e606ae5f |
797 | =item B<legal_options_for_inheritance> |
798 | |
799 | Whitelist with options you can change. You can overload it in your custom |
800 | metaclass to allow your options be inheritable. |
801 | |
a15dff8d |
802 | =item B<has_type_constraint> |
803 | |
6ba6d68c |
804 | Returns true if this meta-attribute has a type constraint. |
805 | |
a15dff8d |
806 | =item B<type_constraint> |
807 | |
26fbace8 |
808 | A read-only accessor for this meta-attribute's type constraint. For |
809 | more information on what you can do with this, see the documentation |
6ba6d68c |
810 | for L<Moose::Meta::TypeConstraint>. |
a15dff8d |
811 | |
452bac1b |
812 | =item B<has_handles> |
813 | |
814 | Returns true if this meta-attribute performs delegation. |
815 | |
816 | =item B<handles> |
817 | |
818 | This returns the value which was passed into the handles option. |
819 | |
6ba6d68c |
820 | =item B<is_weak_ref> |
a15dff8d |
821 | |
02a0fb52 |
822 | Returns true if this meta-attribute produces a weak reference. |
4b598ea3 |
823 | |
ca01a97b |
824 | =item B<is_required> |
825 | |
02a0fb52 |
826 | Returns true if this meta-attribute is required to have a value. |
ca01a97b |
827 | |
828 | =item B<is_lazy> |
829 | |
02a0fb52 |
830 | Returns true if this meta-attribute should be initialized lazily. |
ca01a97b |
831 | |
26fbace8 |
832 | NOTE: lazy attributes, B<must> have a C<default> or C<builder> field set. |
833 | |
834 | =item B<is_lazy_build> |
835 | |
836 | Returns true if this meta-attribute should be initialized lazily through |
837 | the builder generated by lazy_build. Using C<lazy_build =E<gt> 1> will |
838 | make your attribute required and lazy. In addition it will set the builder, clearer |
839 | and predicate options for you using the following convention. |
840 | |
841 | #If your attribute name starts with an underscore: |
842 | has '_foo' => (lazy_build => 1); |
843 | #is the same as |
e606ae5f |
844 | has '_foo' => (lazy => 1, required => 1, predicate => '_has_foo', clearer => '_clear_foo', builder => '_build__foo'); |
26fbace8 |
845 | # or |
58f85113 |
846 | has '_foo' => (lazy => 1, required => 1, predicate => '_has_foo', clearer => '_clear_foo', default => sub{shift->_build__foo}); |
26fbace8 |
847 | |
848 | #If your attribute name does not start with an underscore: |
58f85113 |
849 | has 'foo' => (lazy_build => 1); |
850 | #is the same as |
e606ae5f |
851 | has 'foo' => (lazy => 1, required => 1, predicate => 'has_foo', clearer => 'clear_foo', builder => '_build_foo'); |
26fbace8 |
852 | # or |
58f85113 |
853 | has 'foo' => (lazy => 1, required => 1, predicate => 'has_foo', clearer => 'clear_foo', default => sub{shift->_build_foo}); |
854 | |
855 | The reason for the different naming of the C<builder> is that the C<builder> |
856 | method is a private method while the C<clearer> and C<predicate> methods |
857 | are public methods. |
26fbace8 |
858 | |
859 | NOTE: This means your class should provide a method whose name matches the value |
58f85113 |
860 | of the builder part, in this case _build__foo or _build_foo. |
ca01a97b |
861 | |
34a66aa3 |
862 | =item B<should_coerce> |
4b598ea3 |
863 | |
02a0fb52 |
864 | Returns true if this meta-attribute should perform type coercion. |
6ba6d68c |
865 | |
536f0b17 |
866 | =item B<should_auto_deref> |
867 | |
26fbace8 |
868 | Returns true if this meta-attribute should perform automatic |
869 | auto-dereferencing. |
536f0b17 |
870 | |
26fbace8 |
871 | NOTE: This can only be done for attributes whose type constraint is |
536f0b17 |
872 | either I<ArrayRef> or I<HashRef>. |
873 | |
8c9d74e7 |
874 | =item B<has_trigger> |
875 | |
02a0fb52 |
876 | Returns true if this meta-attribute has a trigger set. |
877 | |
8c9d74e7 |
878 | =item B<trigger> |
879 | |
26fbace8 |
880 | This is a CODE reference which will be executed every time the |
881 | value of an attribute is assigned. The CODE ref will get two values, |
882 | the invocant and the new value. This can be used to handle I<basic> |
02a0fb52 |
883 | bi-directional relations. |
884 | |
ddbdc0cb |
885 | =item B<documentation> |
886 | |
26fbace8 |
887 | This is a string which contains the documentation for this attribute. |
ddbdc0cb |
888 | It serves no direct purpose right now, but it might in the future |
889 | in some kind of automated documentation system perhaps. |
890 | |
891 | =item B<has_documentation> |
892 | |
893 | Returns true if this meta-attribute has any documentation. |
894 | |
88f23977 |
895 | =item B<applied_traits> |
896 | |
897 | This will return the ARRAY ref of all the traits applied to this |
898 | attribute, or if no traits have been applied, it returns C<undef>. |
899 | |
900 | =item B<has_applied_traits> |
901 | |
902 | Returns true if this meta-attribute has any traits applied. |
903 | |
c0e30cf5 |
904 | =back |
905 | |
906 | =head1 BUGS |
907 | |
26fbace8 |
908 | All complex software has bugs lurking in it, and this module is no |
c0e30cf5 |
909 | exception. If you find a bug please either email me, or add the bug |
910 | to cpan-RT. |
911 | |
c0e30cf5 |
912 | =head1 AUTHOR |
913 | |
914 | Stevan Little E<lt>stevan@iinteractive.comE<gt> |
915 | |
98aae381 |
916 | Yuval Kogman E<lt>nothingmuch@woobling.comE<gt> |
917 | |
c0e30cf5 |
918 | =head1 COPYRIGHT AND LICENSE |
919 | |
778db3ac |
920 | Copyright 2006-2008 by Infinity Interactive, Inc. |
c0e30cf5 |
921 | |
922 | L<http://www.iinteractive.com> |
923 | |
924 | This library is free software; you can redistribute it and/or modify |
26fbace8 |
925 | it under the same terms as Perl itself. |
c0e30cf5 |
926 | |
8a7a9c53 |
927 | =cut |