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; |
18748ad6 |
73 | my $handler = $class->can("throw_error"); # to avoid incrementing depth by 1 |
74 | goto $handler; |
be05faea |
75 | } |
76 | |
78cd1d3b |
77 | sub new { |
f3c4e20e |
78 | my ($class, $name, %options) = @_; |
c32c2c61 |
79 | $class->_process_options($name, \%options) unless $options{__hack_no_process_options}; # used from clone()... YECHKKK FIXME ICKY YUCK GROSS |
f3c4e20e |
80 | return $class->SUPER::new($name, %options); |
1d768fb1 |
81 | } |
82 | |
d5c30e52 |
83 | sub interpolate_class_and_new { |
84 | my ($class, $name, @args) = @_; |
85 | |
c32c2c61 |
86 | my ( $new_class, @traits ) = $class->interpolate_class(@args); |
87 | |
88 | $new_class->new($name, @args, ( scalar(@traits) ? ( traits => \@traits ) : () ) ); |
d5c30e52 |
89 | } |
90 | |
91 | sub interpolate_class { |
92 | my ($class, %options) = @_; |
93 | |
c32c2c61 |
94 | $class = ref($class) || $class; |
95 | |
96 | if ( my $metaclass_name = delete $options{metaclass} ) { |
97 | my $new_class = Moose::Util::resolve_metaclass_alias( Attribute => $metaclass_name ); |
98 | |
99 | if ( $class ne $new_class ) { |
100 | if ( $new_class->can("interpolate_class") ) { |
101 | return $new_class->interpolate_class(%options); |
102 | } else { |
103 | $class = $new_class; |
104 | } |
105 | } |
d5c30e52 |
106 | } |
107 | |
c32c2c61 |
108 | my @traits; |
109 | |
d5c30e52 |
110 | if (my $traits = $options{traits}) { |
c32c2c61 |
111 | if ( @traits = grep { not $class->does($_) } map { |
d5c30e52 |
112 | Moose::Util::resolve_metatrait_alias( Attribute => $_ ) |
113 | or |
114 | $_ |
c32c2c61 |
115 | } @$traits ) { |
116 | my $anon_class = Moose::Meta::Class->create_anon_class( |
117 | superclasses => [ $class ], |
118 | roles => [ @traits ], |
119 | cache => 1, |
120 | ); |
121 | |
122 | $class = $anon_class->name; |
123 | } |
d5c30e52 |
124 | } |
c32c2c61 |
125 | |
126 | return ( wantarray ? ( $class, @traits ) : $class ); |
d5c30e52 |
127 | } |
128 | |
e606ae5f |
129 | # ... |
130 | |
131 | my @legal_options_for_inheritance = qw( |
132 | default coerce required |
133 | documentation lazy handles |
134 | builder type_constraint |
135 | ); |
136 | |
137 | sub legal_options_for_inheritance { @legal_options_for_inheritance } |
138 | |
139 | # NOTE/TODO |
140 | # This method *must* be able to handle |
141 | # Class::MOP::Attribute instances as |
142 | # well. Yes, I know that is wrong, but |
143 | # apparently we didn't realize it was |
144 | # doing that and now we have some code |
145 | # which is dependent on it. The real |
146 | # solution of course is to push this |
147 | # feature back up into Class::MOP::Attribute |
148 | # but I not right now, I am too lazy. |
149 | # However if you are reading this and |
150 | # looking for something to do,.. please |
151 | # be my guest. |
152 | # - stevan |
ce0e8d63 |
153 | sub clone_and_inherit_options { |
154 | my ($self, %options) = @_; |
e606ae5f |
155 | |
c32c2c61 |
156 | my %copy = %options; |
e606ae5f |
157 | |
ce0e8d63 |
158 | my %actual_options; |
e606ae5f |
159 | |
160 | # NOTE: |
161 | # we may want to extends a Class::MOP::Attribute |
162 | # in which case we need to be able to use the |
163 | # core set of legal options that have always |
164 | # been here. But we allows Moose::Meta::Attribute |
165 | # instances to changes them. |
166 | # - SL |
167 | my @legal_options = $self->can('legal_options_for_inheritance') |
168 | ? $self->legal_options_for_inheritance |
169 | : @legal_options_for_inheritance; |
170 | |
171 | foreach my $legal_option (@legal_options) { |
ce0e8d63 |
172 | if (exists $options{$legal_option}) { |
173 | $actual_options{$legal_option} = $options{$legal_option}; |
174 | delete $options{$legal_option}; |
175 | } |
e606ae5f |
176 | } |
26fbace8 |
177 | |
ce0e8d63 |
178 | if ($options{isa}) { |
179 | my $type_constraint; |
8de73ff1 |
180 | if (blessed($options{isa}) && $options{isa}->isa('Moose::Meta::TypeConstraint')) { |
181 | $type_constraint = $options{isa}; |
182 | } |
183 | else { |
d40ce9d5 |
184 | $type_constraint = Moose::Util::TypeConstraints::find_or_create_isa_type_constraint($options{isa}); |
8de73ff1 |
185 | (defined $type_constraint) |
be05faea |
186 | || $self->throw_error("Could not find the type constraint '" . $options{isa} . "'", data => $options{isa}); |
8de73ff1 |
187 | } |
5e98d2b6 |
188 | |
8de73ff1 |
189 | $actual_options{type_constraint} = $type_constraint; |
ce0e8d63 |
190 | delete $options{isa}; |
191 | } |
2ea379cb |
192 | |
193 | if ($options{does}) { |
194 | my $type_constraint; |
195 | if (blessed($options{does}) && $options{does}->isa('Moose::Meta::TypeConstraint')) { |
196 | $type_constraint = $options{does}; |
197 | } |
198 | else { |
d40ce9d5 |
199 | $type_constraint = Moose::Util::TypeConstraints::find_or_create_does_type_constraint($options{does}); |
2ea379cb |
200 | (defined $type_constraint) |
be05faea |
201 | || $self->throw_error("Could not find the type constraint '" . $options{does} . "'", data => $options{does}); |
2ea379cb |
202 | } |
203 | |
204 | $actual_options{type_constraint} = $type_constraint; |
205 | delete $options{does}; |
206 | } |
c32c2c61 |
207 | |
cbd141ca |
208 | # NOTE: |
209 | # this doesn't apply to Class::MOP::Attributes, |
210 | # so we can ignore it for them. |
211 | # - SL |
212 | if ($self->can('interpolate_class')) { |
213 | ( $actual_options{metaclass}, my @traits ) = $self->interpolate_class(%options); |
c32c2c61 |
214 | |
cbd141ca |
215 | my %seen; |
216 | my @all_traits = grep { $seen{$_}++ } @{ $self->applied_traits || [] }, @traits; |
217 | $actual_options{traits} = \@all_traits if @all_traits; |
c32c2c61 |
218 | |
cbd141ca |
219 | delete @options{qw(metaclass traits)}; |
220 | } |
c32c2c61 |
221 | |
26fbace8 |
222 | (scalar keys %options == 0) |
be05faea |
223 | || $self->throw_error("Illegal inherited options => (" . (join ', ' => keys %options) . ")", data => \%options); |
c32c2c61 |
224 | |
225 | |
ce0e8d63 |
226 | $self->clone(%actual_options); |
1d768fb1 |
227 | } |
228 | |
c32c2c61 |
229 | sub clone { |
230 | my ( $self, %params ) = @_; |
231 | |
232 | my $class = $params{metaclass} || ref $self; |
233 | |
234 | if ( 0 and $class eq ref $self ) { |
235 | return $self->SUPER::clone(%params); |
236 | } else { |
237 | my ( @init, @non_init ); |
238 | |
239 | foreach my $attr ( grep { $_->has_value($self) } $self->meta->compute_all_applicable_attributes ) { |
240 | push @{ $attr->has_init_arg ? \@init : \@non_init }, $attr; |
241 | } |
242 | |
243 | my %new_params = ( ( map { $_->init_arg => $_->get_value($self) } @init ), %params ); |
244 | |
245 | my $name = delete $new_params{name}; |
246 | |
247 | my $clone = $class->new($name, %new_params, __hack_no_process_options => 1 ); |
248 | |
249 | foreach my $attr ( @non_init ) { |
250 | $attr->set_value($clone, $attr->get_value($self)); |
251 | } |
252 | |
253 | |
254 | return $clone; |
255 | } |
256 | } |
257 | |
1d768fb1 |
258 | sub _process_options { |
259 | my ($class, $name, $options) = @_; |
8de73ff1 |
260 | |
f3c4e20e |
261 | if (exists $options->{is}) { |
21f1e231 |
262 | |
012fcbd1 |
263 | ### ------------------------- |
264 | ## is => ro, writer => _foo # turns into (reader => foo, writer => _foo) as before |
265 | ## is => rw, writer => _foo # turns into (reader => foo, writer => _foo) |
266 | ## is => rw, accessor => _foo # turns into (accessor => _foo) |
267 | ## is => ro, accessor => _foo # error, accesor is rw |
268 | ### ------------------------- |
21f1e231 |
269 | |
8de73ff1 |
270 | if ($options->{is} eq 'ro') { |
be05faea |
271 | $class->throw_error("Cannot define an accessor name on a read-only attribute, accessors are read/write", data => $options) |
21f1e231 |
272 | if exists $options->{accessor}; |
8de73ff1 |
273 | $options->{reader} ||= $name; |
8de73ff1 |
274 | } |
275 | elsif ($options->{is} eq 'rw') { |
21f1e231 |
276 | if ($options->{writer}) { |
277 | $options->{reader} ||= $name; |
278 | } |
279 | else { |
280 | $options->{accessor} ||= $name; |
281 | } |
8de73ff1 |
282 | } |
283 | else { |
e606ae5f |
284 | $class->throw_error("I do not understand this option (is => " . $options->{is} . ") on attribute ($name)", data => $options->{is}); |
8de73ff1 |
285 | } |
f3c4e20e |
286 | } |
8de73ff1 |
287 | |
f3c4e20e |
288 | if (exists $options->{isa}) { |
f3c4e20e |
289 | if (exists $options->{does}) { |
290 | if (eval { $options->{isa}->can('does') }) { |
291 | ($options->{isa}->does($options->{does})) |
e606ae5f |
292 | || $class->throw_error("Cannot have an isa option and a does option if the isa does not do the does on attribute ($name)", data => $options); |
f3c4e20e |
293 | } |
294 | else { |
e606ae5f |
295 | $class->throw_error("Cannot have an isa option which cannot ->does() on attribute ($name)", data => $options); |
26fbace8 |
296 | } |
26fbace8 |
297 | } |
8de73ff1 |
298 | |
f3c4e20e |
299 | # allow for anon-subtypes here ... |
300 | if (blessed($options->{isa}) && $options->{isa}->isa('Moose::Meta::TypeConstraint')) { |
8de73ff1 |
301 | $options->{type_constraint} = $options->{isa}; |
302 | } |
303 | else { |
620db045 |
304 | $options->{type_constraint} = Moose::Util::TypeConstraints::find_or_create_isa_type_constraint($options->{isa}); |
8de73ff1 |
305 | } |
f3c4e20e |
306 | } |
307 | elsif (exists $options->{does}) { |
308 | # allow for anon-subtypes here ... |
309 | if (blessed($options->{does}) && $options->{does}->isa('Moose::Meta::TypeConstraint')) { |
238b424d |
310 | $options->{type_constraint} = $options->{does}; |
8de73ff1 |
311 | } |
312 | else { |
620db045 |
313 | $options->{type_constraint} = Moose::Util::TypeConstraints::find_or_create_does_type_constraint($options->{does}); |
8de73ff1 |
314 | } |
f3c4e20e |
315 | } |
8de73ff1 |
316 | |
f3c4e20e |
317 | if (exists $options->{coerce} && $options->{coerce}) { |
318 | (exists $options->{type_constraint}) |
e606ae5f |
319 | || $class->throw_error("You cannot have coercion without specifying a type constraint on attribute ($name)", data => $options); |
320 | $class->throw_error("You cannot have a weak reference to a coerced value on attribute ($name)", data => $options) |
8de73ff1 |
321 | if $options->{weak_ref}; |
f3c4e20e |
322 | } |
8de73ff1 |
323 | |
0b7df53c |
324 | if (exists $options->{trigger}) { |
21f1e231 |
325 | ('CODE' eq ref $options->{trigger}) |
e606ae5f |
326 | || $class->throw_error("Trigger must be a CODE ref on attribute ($name)", data => $options->{trigger}); |
0b7df53c |
327 | } |
328 | |
f3c4e20e |
329 | if (exists $options->{auto_deref} && $options->{auto_deref}) { |
330 | (exists $options->{type_constraint}) |
e606ae5f |
331 | || $class->throw_error("You cannot auto-dereference without specifying a type constraint on attribute ($name)", data => $options); |
f3c4e20e |
332 | ($options->{type_constraint}->is_a_type_of('ArrayRef') || |
8de73ff1 |
333 | $options->{type_constraint}->is_a_type_of('HashRef')) |
e606ae5f |
334 | || $class->throw_error("You cannot auto-dereference anything other than a ArrayRef or HashRef on attribute ($name)", data => $options); |
f3c4e20e |
335 | } |
8de73ff1 |
336 | |
f3c4e20e |
337 | if (exists $options->{lazy_build} && $options->{lazy_build} == 1) { |
e606ae5f |
338 | $class->throw_error("You can not use lazy_build and default for the same attribute ($name)", data => $options) |
8de73ff1 |
339 | if exists $options->{default}; |
a6c84c69 |
340 | $options->{lazy} = 1; |
341 | $options->{required} = 1; |
342 | $options->{builder} ||= "_build_${name}"; |
343 | if ($name =~ /^_/) { |
f3c4e20e |
344 | $options->{clearer} ||= "_clear${name}"; |
345 | $options->{predicate} ||= "_has${name}"; |
a6c84c69 |
346 | } |
347 | else { |
f3c4e20e |
348 | $options->{clearer} ||= "clear_${name}"; |
349 | $options->{predicate} ||= "has_${name}"; |
26fbace8 |
350 | } |
f3c4e20e |
351 | } |
8de73ff1 |
352 | |
f3c4e20e |
353 | if (exists $options->{lazy} && $options->{lazy}) { |
9edba990 |
354 | (exists $options->{default} || defined $options->{builder} ) |
be05faea |
355 | || $class->throw_error("You cannot have lazy attribute ($name) without specifying a default value for it", data => $options); |
f3c4e20e |
356 | } |
26fbace8 |
357 | |
9edba990 |
358 | if ( $options->{required} && !( ( !exists $options->{init_arg} || defined $options->{init_arg} ) || exists $options->{default} || defined $options->{builder} ) ) { |
be05faea |
359 | $class->throw_error("You cannot have a required attribute ($name) without a default, builder, or an init_arg", data => $options); |
9edba990 |
360 | } |
361 | |
78cd1d3b |
362 | } |
c0e30cf5 |
363 | |
d500266f |
364 | sub initialize_instance_slot { |
ddd0ec20 |
365 | my ($self, $meta_instance, $instance, $params) = @_; |
d500266f |
366 | my $init_arg = $self->init_arg(); |
367 | # try to fetch the init arg from the %params ... |
ddd0ec20 |
368 | |
26fbace8 |
369 | my $val; |
1ed0b94f |
370 | my $value_is_set; |
625d571f |
371 | if ( defined($init_arg) and exists $params->{$init_arg}) { |
d500266f |
372 | $val = $params->{$init_arg}; |
2c78d811 |
373 | $value_is_set = 1; |
d500266f |
374 | } |
375 | else { |
376 | # skip it if it's lazy |
377 | return if $self->is_lazy; |
378 | # and die if it's required and doesn't have a default value |
be05faea |
379 | $self->throw_error("Attribute (" . $self->name . ") is required", object => $instance, data => $params) |
26fbace8 |
380 | if $self->is_required && !$self->has_default && !$self->has_builder; |
ddd0ec20 |
381 | |
1ed0b94f |
382 | # if nothing was in the %params, we can use the |
383 | # attribute's default value (if it has one) |
384 | if ($self->has_default) { |
385 | $val = $self->default($instance); |
386 | $value_is_set = 1; |
a6c84c69 |
387 | } |
388 | elsif ($self->has_builder) { |
e606ae5f |
389 | $val = $self->_call_builder($instance); |
390 | $value_is_set = 1; |
a0748c37 |
391 | } |
26fbace8 |
392 | } |
393 | |
1ed0b94f |
394 | return unless $value_is_set; |
395 | |
396 | if ($self->has_type_constraint) { |
397 | my $type_constraint = $self->type_constraint; |
398 | if ($self->should_coerce && $type_constraint->has_coercion) { |
399 | $val = $type_constraint->coerce($val); |
d500266f |
400 | } |
ab76842e |
401 | $type_constraint->check($val) |
be05faea |
402 | || $self->throw_error("Attribute (" |
688fcdda |
403 | . $self->name |
404 | . ") does not pass the type constraint because: " |
be05faea |
405 | . $type_constraint->get_message($val), data => $val, object => $instance); |
1ed0b94f |
406 | } |
ddd0ec20 |
407 | |
759e4e8f |
408 | $self->set_initial_value($instance, $val); |
26fbace8 |
409 | $meta_instance->weaken_slot_value($instance, $self->name) |
a6c84c69 |
410 | if ref $val && $self->is_weak_ref; |
d500266f |
411 | } |
412 | |
e606ae5f |
413 | sub _call_builder { |
414 | my ( $self, $instance ) = @_; |
415 | |
416 | my $builder = $self->builder(); |
417 | |
418 | return $instance->$builder() |
419 | if $instance->can( $self->builder ); |
420 | |
421 | $self->throw_error( blessed($instance) |
422 | . " does not support builder method '" |
423 | . $self->builder |
424 | . "' for attribute '" |
425 | . $self->name |
426 | . "'", |
427 | object => $instance, |
428 | ); |
429 | } |
430 | |
d617b644 |
431 | ## Slot management |
9e93dd19 |
432 | |
8abe9636 |
433 | # FIXME: |
434 | # this duplicates too much code from |
435 | # Class::MOP::Attribute, we need to |
436 | # refactor these bits eventually. |
437 | # - SL |
438 | sub _set_initial_slot_value { |
439 | my ($self, $meta_instance, $instance, $value) = @_; |
440 | |
441 | my $slot_name = $self->name; |
442 | |
443 | return $meta_instance->set_slot_value($instance, $slot_name, $value) |
444 | unless $self->has_initializer; |
445 | |
446 | my ($type_constraint, $can_coerce); |
447 | if ($self->has_type_constraint) { |
448 | $type_constraint = $self->type_constraint; |
449 | $can_coerce = ($self->should_coerce && $type_constraint->has_coercion); |
450 | } |
451 | |
452 | my $callback = sub { |
453 | my $val = shift; |
454 | if ($type_constraint) { |
455 | $val = $type_constraint->coerce($val) |
456 | if $can_coerce; |
457 | $type_constraint->check($val) |
be05faea |
458 | || $self->throw_error("Attribute (" |
8abe9636 |
459 | . $slot_name |
460 | . ") does not pass the type constraint because: " |
be05faea |
461 | . $type_constraint->get_message($val), data => $val, object => $instance); |
8abe9636 |
462 | } |
463 | $meta_instance->set_slot_value($instance, $slot_name, $val); |
464 | }; |
465 | |
466 | my $initializer = $self->initializer; |
467 | |
468 | # most things will just want to set a value, so make it first arg |
469 | $instance->$initializer($value, $callback, $self); |
470 | } |
471 | |
946289d1 |
472 | sub set_value { |
b6af66f8 |
473 | my ($self, $instance, @args) = @_; |
474 | my $value = $args[0]; |
26fbace8 |
475 | |
946289d1 |
476 | my $attr_name = $self->name; |
26fbace8 |
477 | |
b6af66f8 |
478 | if ($self->is_required and not @args) { |
be05faea |
479 | $self->throw_error("Attribute ($attr_name) is required", object => $instance); |
946289d1 |
480 | } |
26fbace8 |
481 | |
946289d1 |
482 | if ($self->has_type_constraint) { |
26fbace8 |
483 | |
946289d1 |
484 | my $type_constraint = $self->type_constraint; |
26fbace8 |
485 | |
946289d1 |
486 | if ($self->should_coerce) { |
26fbace8 |
487 | $value = $type_constraint->coerce($value); |
688fcdda |
488 | } |
42bc21a4 |
489 | $type_constraint->_compiled_type_constraint->($value) |
be05faea |
490 | || $self->throw_error("Attribute (" |
688fcdda |
491 | . $self->name |
492 | . ") does not pass the type constraint because " |
be05faea |
493 | . $type_constraint->get_message($value), object => $instance, data => $value); |
946289d1 |
494 | } |
26fbace8 |
495 | |
946289d1 |
496 | my $meta_instance = Class::MOP::Class->initialize(blessed($instance)) |
497 | ->get_meta_instance; |
26fbace8 |
498 | |
499 | $meta_instance->set_slot_value($instance, $attr_name, $value); |
500 | |
946289d1 |
501 | if (ref $value && $self->is_weak_ref) { |
26fbace8 |
502 | $meta_instance->weaken_slot_value($instance, $attr_name); |
946289d1 |
503 | } |
26fbace8 |
504 | |
946289d1 |
505 | if ($self->has_trigger) { |
506 | $self->trigger->($instance, $value, $self); |
507 | } |
508 | } |
509 | |
510 | sub get_value { |
511 | my ($self, $instance) = @_; |
26fbace8 |
512 | |
946289d1 |
513 | if ($self->is_lazy) { |
8de73ff1 |
514 | unless ($self->has_value($instance)) { |
e606ae5f |
515 | my $value; |
8de73ff1 |
516 | if ($self->has_default) { |
e606ae5f |
517 | $value = $self->default($instance); |
3f11800d |
518 | } elsif ( $self->has_builder ) { |
e606ae5f |
519 | $value = $self->_call_builder($instance); |
520 | } |
521 | if ($self->has_type_constraint) { |
522 | my $type_constraint = $self->type_constraint; |
523 | $value = $type_constraint->coerce($value) |
524 | if ($self->should_coerce); |
525 | $type_constraint->check($value) |
4b7538e7 |
526 | || $self->throw_error("Attribute (" . $self->name |
e606ae5f |
527 | . ") does not pass the type constraint because: " |
528 | . $type_constraint->get_message($value), type_constraint => $type_constraint, data => $value); |
26fbace8 |
529 | } |
e606ae5f |
530 | $self->set_initial_value($instance, $value); |
8de73ff1 |
531 | } |
946289d1 |
532 | } |
26fbace8 |
533 | |
946289d1 |
534 | if ($self->should_auto_deref) { |
26fbace8 |
535 | |
946289d1 |
536 | my $type_constraint = $self->type_constraint; |
537 | |
538 | if ($type_constraint->is_a_type_of('ArrayRef')) { |
539 | my $rv = $self->SUPER::get_value($instance); |
540 | return unless defined $rv; |
541 | return wantarray ? @{ $rv } : $rv; |
26fbace8 |
542 | } |
946289d1 |
543 | elsif ($type_constraint->is_a_type_of('HashRef')) { |
544 | my $rv = $self->SUPER::get_value($instance); |
545 | return unless defined $rv; |
546 | return wantarray ? %{ $rv } : $rv; |
26fbace8 |
547 | } |
946289d1 |
548 | else { |
46cb090f |
549 | $self->throw_error("Can not auto de-reference the type constraint '" . $type_constraint->name . "'", object => $instance, type_constraint => $type_constraint); |
946289d1 |
550 | } |
26fbace8 |
551 | |
946289d1 |
552 | } |
553 | else { |
26fbace8 |
554 | |
946289d1 |
555 | return $self->SUPER::get_value($instance); |
26fbace8 |
556 | } |
946289d1 |
557 | } |
a15dff8d |
558 | |
26fbace8 |
559 | ## installing accessors |
c0e30cf5 |
560 | |
d617b644 |
561 | sub accessor_metaclass { 'Moose::Meta::Method::Accessor' } |
d7f17ebb |
562 | |
452bac1b |
563 | sub install_accessors { |
564 | my $self = shift; |
26fbace8 |
565 | $self->SUPER::install_accessors(@_); |
e606ae5f |
566 | $self->install_delegation if $self->has_handles; |
567 | return; |
568 | } |
26fbace8 |
569 | |
e606ae5f |
570 | sub install_delegation { |
571 | my $self = shift; |
26fbace8 |
572 | |
e606ae5f |
573 | # NOTE: |
574 | # Here we canonicalize the 'handles' option |
575 | # this will sort out any details and always |
576 | # return an hash of methods which we want |
577 | # to delagate to, see that method for details |
578 | my %handles = $self->_canonicalize_handles; |
579 | |
e606ae5f |
580 | |
581 | # install the delegation ... |
582 | my $associated_class = $self->associated_class; |
583 | foreach my $handle (keys %handles) { |
584 | my $method_to_call = $handles{$handle}; |
585 | my $class_name = $associated_class->name; |
586 | my $name = "${class_name}::${handle}"; |
26fbace8 |
587 | |
452bac1b |
588 | (!$associated_class->has_method($handle)) |
cee532a1 |
589 | || $self->throw_error("You cannot overwrite a locally defined method ($handle) with a delegation", method_name => $handle); |
26fbace8 |
590 | |
e606ae5f |
591 | # NOTE: |
592 | # handles is not allowed to delegate |
593 | # any of these methods, as they will |
594 | # override the ones in your class, which |
595 | # is almost certainly not what you want. |
4fe78472 |
596 | |
e606ae5f |
597 | # FIXME warn when $handle was explicitly specified, but not if the source is a regex or something |
598 | #cluck("Not delegating method '$handle' because it is a core method") and |
599 | next if $class_name->isa("Moose::Object") and $handle =~ /^BUILD|DEMOLISH$/ || Moose::Object->can($handle); |
26fbace8 |
600 | |
46f7e6a5 |
601 | my $method = $self->_make_delegation_method($handle, $method_to_call); |
a05f85c1 |
602 | |
603 | $self->associated_class->add_method($method->name, $method); |
e606ae5f |
604 | } |
452bac1b |
605 | } |
606 | |
98aae381 |
607 | # private methods to help delegation ... |
608 | |
452bac1b |
609 | sub _canonicalize_handles { |
610 | my $self = shift; |
611 | my $handles = $self->handles; |
c84f324f |
612 | if (my $handle_type = ref($handles)) { |
613 | if ($handle_type eq 'HASH') { |
614 | return %{$handles}; |
615 | } |
616 | elsif ($handle_type eq 'ARRAY') { |
617 | return map { $_ => $_ } @{$handles}; |
618 | } |
619 | elsif ($handle_type eq 'Regexp') { |
620 | ($self->has_type_constraint) |
be05faea |
621 | || $self->throw_error("Cannot delegate methods based on a RegExpr without a type constraint (isa)", data => $handles); |
26fbace8 |
622 | return map { ($_ => $_) } |
c84f324f |
623 | grep { /$handles/ } $self->_get_delegate_method_list; |
624 | } |
625 | elsif ($handle_type eq 'CODE') { |
626 | return $handles->($self, $self->_find_delegate_metaclass); |
627 | } |
628 | else { |
be05faea |
629 | $self->throw_error("Unable to canonicalize the 'handles' option with $handles", data => $handles); |
c84f324f |
630 | } |
452bac1b |
631 | } |
632 | else { |
c84f324f |
633 | my $role_meta = eval { $handles->meta }; |
634 | if ($@) { |
be05faea |
635 | $self->throw_error("Unable to canonicalize the 'handles' option with $handles because : $@", data => $handles, error => $@); |
c84f324f |
636 | } |
637 | |
638 | (blessed $role_meta && $role_meta->isa('Moose::Meta::Role')) |
be05faea |
639 | || $self->throw_error("Unable to canonicalize the 'handles' option with $handles because ->meta is not a Moose::Meta::Role", data => $handles); |
26fbace8 |
640 | |
c84f324f |
641 | return map { $_ => $_ } ( |
26fbace8 |
642 | $role_meta->get_method_list, |
c84f324f |
643 | $role_meta->get_required_method_list |
644 | ); |
452bac1b |
645 | } |
646 | } |
647 | |
648 | sub _find_delegate_metaclass { |
649 | my $self = shift; |
98aae381 |
650 | if (my $class = $self->_isa_metadata) { |
26fbace8 |
651 | # if the class does have |
452bac1b |
652 | # a meta method, use it |
653 | return $class->meta if $class->can('meta'); |
26fbace8 |
654 | # otherwise we might be |
452bac1b |
655 | # dealing with a non-Moose |
26fbace8 |
656 | # class, and need to make |
452bac1b |
657 | # our own metaclass |
658 | return Moose::Meta::Class->initialize($class); |
659 | } |
98aae381 |
660 | elsif (my $role = $self->_does_metadata) { |
26fbace8 |
661 | # our role will always have |
452bac1b |
662 | # a meta method |
98aae381 |
663 | return $role->meta; |
452bac1b |
664 | } |
665 | else { |
be05faea |
666 | $self->throw_error("Cannot find delegate metaclass for attribute " . $self->name); |
452bac1b |
667 | } |
668 | } |
669 | |
670 | sub _get_delegate_method_list { |
671 | my $self = shift; |
672 | my $meta = $self->_find_delegate_metaclass; |
673 | if ($meta->isa('Class::MOP::Class')) { |
e606ae5f |
674 | return map { $_->name } # NOTE: !never! delegate &meta |
675 | grep { $_->package_name ne 'Moose::Object' && $_->name ne 'meta' } |
676 | $meta->get_all_methods; |
452bac1b |
677 | } |
678 | elsif ($meta->isa('Moose::Meta::Role')) { |
26fbace8 |
679 | return $meta->get_method_list; |
452bac1b |
680 | } |
681 | else { |
be05faea |
682 | $self->throw_error("Unable to recognize the delegate metaclass '$meta'", data => $meta); |
452bac1b |
683 | } |
684 | } |
685 | |
a05f85c1 |
686 | sub _make_delegation_method { |
46f7e6a5 |
687 | my ( $self, $handle_name, $method_to_call ) = @_; |
a05f85c1 |
688 | |
689 | my $method_body; |
690 | |
46f7e6a5 |
691 | $method_body = $method_to_call |
692 | if 'CODE' eq ref($method_to_call); |
a05f85c1 |
693 | |
694 | return Moose::Meta::Method::Delegation->new( |
46f7e6a5 |
695 | name => $handle_name, |
696 | package_name => $self->associated_class->name, |
697 | attribute => $self, |
698 | delegate_to_method => $method_to_call, |
a05f85c1 |
699 | ); |
700 | } |
701 | |
21f1e231 |
702 | package Moose::Meta::Attribute::Custom::Moose; |
703 | sub register_implementation { 'Moose::Meta::Attribute' } |
704 | |
c0e30cf5 |
705 | 1; |
706 | |
707 | __END__ |
708 | |
709 | =pod |
710 | |
711 | =head1 NAME |
712 | |
6ba6d68c |
713 | Moose::Meta::Attribute - The Moose attribute metaclass |
c0e30cf5 |
714 | |
715 | =head1 DESCRIPTION |
716 | |
26fbace8 |
717 | This is a subclass of L<Class::MOP::Attribute> with Moose specific |
718 | extensions. |
6ba6d68c |
719 | |
26fbace8 |
720 | For the most part, the only time you will ever encounter an |
721 | instance of this class is if you are doing some serious deep |
722 | introspection. To really understand this class, you need to refer |
6ba6d68c |
723 | to the L<Class::MOP::Attribute> documentation. |
e522431d |
724 | |
c0e30cf5 |
725 | =head1 METHODS |
726 | |
6ba6d68c |
727 | =head2 Overridden methods |
728 | |
26fbace8 |
729 | These methods override methods in L<Class::MOP::Attribute> and add |
730 | Moose specific features. You can safely assume though that they |
6ba6d68c |
731 | will behave just as L<Class::MOP::Attribute> does. |
732 | |
c0e30cf5 |
733 | =over 4 |
734 | |
735 | =item B<new> |
736 | |
c32c2c61 |
737 | =item B<clone> |
738 | |
6e2840b7 |
739 | =item B<does> |
740 | |
d500266f |
741 | =item B<initialize_instance_slot> |
742 | |
452bac1b |
743 | =item B<install_accessors> |
744 | |
e606ae5f |
745 | =item B<install_delegation> |
746 | |
39b3bc94 |
747 | =item B<accessor_metaclass> |
748 | |
946289d1 |
749 | =item B<get_value> |
750 | |
751 | =item B<set_value> |
752 | |
bcbaa845 |
753 | eval { $point->meta->get_attribute('x')->set_value($point, 'fourty-two') }; |
754 | if($@) { |
755 | print "Oops: $@\n"; |
756 | } |
757 | |
758 | I<Attribute (x) does not pass the type constraint (Int) with 'fourty-two'> |
759 | |
760 | Before setting the value, a check is made on the type constraint of |
761 | the attribute, if it has one, to see if the value passes it. If the |
46cb090f |
762 | value fails to pass, the set operation dies with a L<throw_error>. |
bcbaa845 |
763 | |
764 | Any coercion to convert values is done before checking the type constraint. |
765 | |
766 | To check a value against a type constraint before setting it, fetch the |
ec00fa75 |
767 | attribute instance using L<Class::MOP::Class/find_attribute_by_name>, |
bcbaa845 |
768 | fetch the type_constraint from the attribute using L<Moose::Meta::Attribute/type_constraint> |
e606ae5f |
769 | and call L<Moose::Meta::TypeConstraint/check>. See L<Moose::Cookbook::Basics::Recipe4> |
bcbaa845 |
770 | for an example. |
771 | |
a15dff8d |
772 | =back |
773 | |
6ba6d68c |
774 | =head2 Additional Moose features |
775 | |
26fbace8 |
776 | Moose attributes support type-constraint checking, weak reference |
777 | creation and type coercion. |
6ba6d68c |
778 | |
a15dff8d |
779 | =over 4 |
780 | |
be05faea |
781 | =item B<throw_error> |
782 | |
783 | Delegates to C<associated_class> or C<Moose::Meta::Class> if there is none. |
784 | |
d5c30e52 |
785 | =item B<interpolate_class_and_new> |
786 | |
787 | =item B<interpolate_class> |
788 | |
789 | When called as a class method causes interpretation of the C<metaclass> and |
790 | C<traits> options. |
791 | |
9e93dd19 |
792 | =item B<clone_and_inherit_options> |
793 | |
26fbace8 |
794 | This is to support the C<has '+foo'> feature, it clones an attribute |
795 | from a superclass and allows a very specific set of changes to be made |
9e93dd19 |
796 | to the attribute. |
797 | |
e606ae5f |
798 | =item B<legal_options_for_inheritance> |
799 | |
800 | Whitelist with options you can change. You can overload it in your custom |
801 | metaclass to allow your options be inheritable. |
802 | |
a15dff8d |
803 | =item B<has_type_constraint> |
804 | |
6ba6d68c |
805 | Returns true if this meta-attribute has a type constraint. |
806 | |
a15dff8d |
807 | =item B<type_constraint> |
808 | |
26fbace8 |
809 | A read-only accessor for this meta-attribute's type constraint. For |
810 | more information on what you can do with this, see the documentation |
6ba6d68c |
811 | for L<Moose::Meta::TypeConstraint>. |
a15dff8d |
812 | |
452bac1b |
813 | =item B<has_handles> |
814 | |
815 | Returns true if this meta-attribute performs delegation. |
816 | |
817 | =item B<handles> |
818 | |
819 | This returns the value which was passed into the handles option. |
820 | |
6ba6d68c |
821 | =item B<is_weak_ref> |
a15dff8d |
822 | |
02a0fb52 |
823 | Returns true if this meta-attribute produces a weak reference. |
4b598ea3 |
824 | |
ca01a97b |
825 | =item B<is_required> |
826 | |
02a0fb52 |
827 | Returns true if this meta-attribute is required to have a value. |
ca01a97b |
828 | |
829 | =item B<is_lazy> |
830 | |
02a0fb52 |
831 | Returns true if this meta-attribute should be initialized lazily. |
ca01a97b |
832 | |
26fbace8 |
833 | NOTE: lazy attributes, B<must> have a C<default> or C<builder> field set. |
834 | |
835 | =item B<is_lazy_build> |
836 | |
837 | Returns true if this meta-attribute should be initialized lazily through |
838 | the builder generated by lazy_build. Using C<lazy_build =E<gt> 1> will |
839 | make your attribute required and lazy. In addition it will set the builder, clearer |
840 | and predicate options for you using the following convention. |
841 | |
842 | #If your attribute name starts with an underscore: |
843 | has '_foo' => (lazy_build => 1); |
844 | #is the same as |
e606ae5f |
845 | has '_foo' => (lazy => 1, required => 1, predicate => '_has_foo', clearer => '_clear_foo', builder => '_build__foo'); |
26fbace8 |
846 | # or |
58f85113 |
847 | has '_foo' => (lazy => 1, required => 1, predicate => '_has_foo', clearer => '_clear_foo', default => sub{shift->_build__foo}); |
26fbace8 |
848 | |
849 | #If your attribute name does not start with an underscore: |
58f85113 |
850 | has 'foo' => (lazy_build => 1); |
851 | #is the same as |
e606ae5f |
852 | has 'foo' => (lazy => 1, required => 1, predicate => 'has_foo', clearer => 'clear_foo', builder => '_build_foo'); |
26fbace8 |
853 | # or |
58f85113 |
854 | has 'foo' => (lazy => 1, required => 1, predicate => 'has_foo', clearer => 'clear_foo', default => sub{shift->_build_foo}); |
855 | |
856 | The reason for the different naming of the C<builder> is that the C<builder> |
857 | method is a private method while the C<clearer> and C<predicate> methods |
858 | are public methods. |
26fbace8 |
859 | |
860 | NOTE: This means your class should provide a method whose name matches the value |
58f85113 |
861 | of the builder part, in this case _build__foo or _build_foo. |
ca01a97b |
862 | |
34a66aa3 |
863 | =item B<should_coerce> |
4b598ea3 |
864 | |
02a0fb52 |
865 | Returns true if this meta-attribute should perform type coercion. |
6ba6d68c |
866 | |
536f0b17 |
867 | =item B<should_auto_deref> |
868 | |
26fbace8 |
869 | Returns true if this meta-attribute should perform automatic |
870 | auto-dereferencing. |
536f0b17 |
871 | |
26fbace8 |
872 | NOTE: This can only be done for attributes whose type constraint is |
536f0b17 |
873 | either I<ArrayRef> or I<HashRef>. |
874 | |
8c9d74e7 |
875 | =item B<has_trigger> |
876 | |
02a0fb52 |
877 | Returns true if this meta-attribute has a trigger set. |
878 | |
8c9d74e7 |
879 | =item B<trigger> |
880 | |
26fbace8 |
881 | This is a CODE reference which will be executed every time the |
882 | value of an attribute is assigned. The CODE ref will get two values, |
883 | the invocant and the new value. This can be used to handle I<basic> |
02a0fb52 |
884 | bi-directional relations. |
885 | |
ddbdc0cb |
886 | =item B<documentation> |
887 | |
26fbace8 |
888 | This is a string which contains the documentation for this attribute. |
ddbdc0cb |
889 | It serves no direct purpose right now, but it might in the future |
890 | in some kind of automated documentation system perhaps. |
891 | |
892 | =item B<has_documentation> |
893 | |
894 | Returns true if this meta-attribute has any documentation. |
895 | |
88f23977 |
896 | =item B<applied_traits> |
897 | |
898 | This will return the ARRAY ref of all the traits applied to this |
899 | attribute, or if no traits have been applied, it returns C<undef>. |
900 | |
901 | =item B<has_applied_traits> |
902 | |
903 | Returns true if this meta-attribute has any traits applied. |
904 | |
c0e30cf5 |
905 | =back |
906 | |
907 | =head1 BUGS |
908 | |
26fbace8 |
909 | All complex software has bugs lurking in it, and this module is no |
c0e30cf5 |
910 | exception. If you find a bug please either email me, or add the bug |
911 | to cpan-RT. |
912 | |
c0e30cf5 |
913 | =head1 AUTHOR |
914 | |
915 | Stevan Little E<lt>stevan@iinteractive.comE<gt> |
916 | |
98aae381 |
917 | Yuval Kogman E<lt>nothingmuch@woobling.comE<gt> |
918 | |
c0e30cf5 |
919 | =head1 COPYRIGHT AND LICENSE |
920 | |
778db3ac |
921 | Copyright 2006-2008 by Infinity Interactive, Inc. |
c0e30cf5 |
922 | |
923 | L<http://www.iinteractive.com> |
924 | |
925 | This library is free software; you can redistribute it and/or modify |
26fbace8 |
926 | it under the same terms as Perl itself. |
c0e30cf5 |
927 | |
8a7a9c53 |
928 | =cut |