Commit | Line | Data |
c0e30cf5 |
1 | |
2 | package Moose::Meta::Attribute; |
3 | |
4 | use strict; |
5 | use warnings; |
6 | |
78cd1d3b |
7 | use Scalar::Util 'blessed', 'weaken', 'reftype'; |
a15dff8d |
8 | use Carp 'confess'; |
9 | |
4fd69d6c |
10 | our $VERSION = '0.08'; |
78cd1d3b |
11 | |
8ee73eeb |
12 | use Moose::Meta::Method::Accessor; |
a3c7e2fe |
13 | use Moose::Util::TypeConstraints (); |
bc1e29b5 |
14 | |
c0e30cf5 |
15 | use base 'Class::MOP::Attribute'; |
16 | |
452bac1b |
17 | # options which are not directly used |
18 | # but we store them for metadata purposes |
98aae381 |
19 | __PACKAGE__->meta->add_attribute('isa' => (reader => '_isa_metadata')); |
20 | __PACKAGE__->meta->add_attribute('does' => (reader => '_does_metadata')); |
21 | __PACKAGE__->meta->add_attribute('is' => (reader => '_is_metadata')); |
452bac1b |
22 | |
23 | # these are actual options for the attrs |
1a563243 |
24 | __PACKAGE__->meta->add_attribute('required' => (reader => 'is_required' )); |
25 | __PACKAGE__->meta->add_attribute('lazy' => (reader => 'is_lazy' )); |
26 | __PACKAGE__->meta->add_attribute('coerce' => (reader => 'should_coerce' )); |
27 | __PACKAGE__->meta->add_attribute('weak_ref' => (reader => 'is_weak_ref' )); |
28 | __PACKAGE__->meta->add_attribute('auto_deref' => (reader => 'should_auto_deref')); |
82168dbb |
29 | __PACKAGE__->meta->add_attribute('type_constraint' => ( |
30 | reader => 'type_constraint', |
31 | predicate => 'has_type_constraint', |
32 | )); |
8c9d74e7 |
33 | __PACKAGE__->meta->add_attribute('trigger' => ( |
34 | reader => 'trigger', |
35 | predicate => 'has_trigger', |
36 | )); |
452bac1b |
37 | __PACKAGE__->meta->add_attribute('handles' => ( |
38 | reader => 'handles', |
39 | predicate => 'has_handles', |
40 | )); |
82168dbb |
41 | |
78cd1d3b |
42 | sub new { |
43 | my ($class, $name, %options) = @_; |
1d768fb1 |
44 | $class->_process_options($name, \%options); |
98aae381 |
45 | return $class->SUPER::new($name, %options); |
1d768fb1 |
46 | } |
47 | |
ce0e8d63 |
48 | sub clone_and_inherit_options { |
49 | my ($self, %options) = @_; |
50 | # you can change default, required and coerce |
51 | my %actual_options; |
52 | foreach my $legal_option (qw(default coerce required)) { |
53 | if (exists $options{$legal_option}) { |
54 | $actual_options{$legal_option} = $options{$legal_option}; |
55 | delete $options{$legal_option}; |
56 | } |
57 | } |
fcb7afc2 |
58 | # isa can be changed, but only if the |
59 | # new type is a subtype |
ce0e8d63 |
60 | if ($options{isa}) { |
61 | my $type_constraint; |
62 | if (blessed($options{isa}) && $options{isa}->isa('Moose::Meta::TypeConstraint')) { |
63 | $type_constraint = $options{isa}; |
64 | } |
65 | else { |
66 | $type_constraint = Moose::Util::TypeConstraints::find_type_constraint($options{isa}); |
67 | (defined $type_constraint) |
68 | || confess "Could not find the type constraint '" . $options{isa} . "'"; |
69 | } |
2a0f3bd3 |
70 | # NOTE: |
71 | # check here to see if the new type |
72 | # is a subtype of the old one |
ce0e8d63 |
73 | ($type_constraint->is_subtype_of($self->type_constraint->name)) |
74 | || confess "New type constraint setting must be a subtype of inherited one" |
2a0f3bd3 |
75 | # iff we have a type constraint that is ... |
ce0e8d63 |
76 | if $self->has_type_constraint; |
2a0f3bd3 |
77 | # then we use it :) |
ce0e8d63 |
78 | $actual_options{type_constraint} = $type_constraint; |
79 | delete $options{isa}; |
80 | } |
81 | (scalar keys %options == 0) |
82 | || confess "Illegal inherited options => (" . (join ', ' => keys %options) . ")"; |
83 | $self->clone(%actual_options); |
1d768fb1 |
84 | } |
85 | |
86 | sub _process_options { |
87 | my ($class, $name, $options) = @_; |
452bac1b |
88 | |
1d768fb1 |
89 | if (exists $options->{is}) { |
90 | if ($options->{is} eq 'ro') { |
91 | $options->{reader} = $name; |
92 | (!exists $options->{trigger}) |
8c9d74e7 |
93 | || confess "Cannot have a trigger on a read-only attribute"; |
78cd1d3b |
94 | } |
1d768fb1 |
95 | elsif ($options->{is} eq 'rw') { |
452bac1b |
96 | $options->{accessor} = $name; |
98aae381 |
97 | ((reftype($options->{trigger}) || '') eq 'CODE') |
98 | || confess "Trigger must be a CODE ref" |
99 | if exists $options->{trigger}; |
452bac1b |
100 | } |
101 | else { |
102 | confess "I do not understand this option (is => " . $options->{is} . ")" |
78cd1d3b |
103 | } |
104 | } |
105 | |
1d768fb1 |
106 | if (exists $options->{isa}) { |
02a0fb52 |
107 | |
1d768fb1 |
108 | if (exists $options->{does}) { |
109 | if (eval { $options->{isa}->can('does') }) { |
110 | ($options->{isa}->does($options->{does})) |
02a0fb52 |
111 | || confess "Cannot have an isa option and a does option if the isa does not do the does"; |
112 | } |
7eaef7ad |
113 | else { |
114 | confess "Cannot have an isa option which cannot ->does()"; |
115 | } |
02a0fb52 |
116 | } |
117 | |
78cd1d3b |
118 | # allow for anon-subtypes here ... |
1d768fb1 |
119 | if (blessed($options->{isa}) && $options->{isa}->isa('Moose::Meta::TypeConstraint')) { |
120 | $options->{type_constraint} = $options->{isa}; |
78cd1d3b |
121 | } |
122 | else { |
c07af9d2 |
123 | |
1d768fb1 |
124 | if ($options->{isa} =~ /\|/) { |
125 | my @type_constraints = split /\s*\|\s*/ => $options->{isa}; |
126 | $options->{type_constraint} = Moose::Util::TypeConstraints::create_type_constraint_union( |
c07af9d2 |
127 | @type_constraints |
78cd1d3b |
128 | ); |
c07af9d2 |
129 | } |
130 | else { |
131 | # otherwise assume it is a constraint |
1d768fb1 |
132 | my $constraint = Moose::Util::TypeConstraints::find_type_constraint($options->{isa}); |
c07af9d2 |
133 | # if the constraing it not found .... |
134 | unless (defined $constraint) { |
135 | # assume it is a foreign class, and make |
136 | # an anon constraint for it |
137 | $constraint = Moose::Util::TypeConstraints::subtype( |
138 | 'Object', |
1d768fb1 |
139 | Moose::Util::TypeConstraints::where { $_->isa($options->{isa}) } |
c07af9d2 |
140 | ); |
141 | } |
1d768fb1 |
142 | $options->{type_constraint} = $constraint; |
c07af9d2 |
143 | } |
78cd1d3b |
144 | } |
145 | } |
1d768fb1 |
146 | elsif (exists $options->{does}) { |
02a0fb52 |
147 | # allow for anon-subtypes here ... |
1d768fb1 |
148 | if (blessed($options->{does}) && $options->{does}->isa('Moose::Meta::TypeConstraint')) { |
149 | $options->{type_constraint} = $options->{isa}; |
02a0fb52 |
150 | } |
151 | else { |
152 | # otherwise assume it is a constraint |
1d768fb1 |
153 | my $constraint = Moose::Util::TypeConstraints::find_type_constraint($options->{does}); |
02a0fb52 |
154 | # if the constraing it not found .... |
155 | unless (defined $constraint) { |
156 | # assume it is a foreign class, and make |
157 | # an anon constraint for it |
158 | $constraint = Moose::Util::TypeConstraints::subtype( |
159 | 'Role', |
1d768fb1 |
160 | Moose::Util::TypeConstraints::where { $_->does($options->{does}) } |
02a0fb52 |
161 | ); |
162 | } |
1d768fb1 |
163 | $options->{type_constraint} = $constraint; |
02a0fb52 |
164 | } |
165 | } |
78cd1d3b |
166 | |
1d768fb1 |
167 | if (exists $options->{coerce} && $options->{coerce}) { |
168 | (exists $options->{type_constraint}) |
3ec7b7a3 |
169 | || confess "You cannot have coercion without specifying a type constraint"; |
4b598ea3 |
170 | confess "You cannot have a weak reference to a coerced value" |
1d768fb1 |
171 | if $options->{weak_ref}; |
ca01a97b |
172 | } |
78cd1d3b |
173 | |
536f0b17 |
174 | if (exists $options->{auto_deref} && $options->{auto_deref}) { |
175 | (exists $options->{type_constraint}) |
176 | || confess "You cannot auto-dereference without specifying a type constraint"; |
94b8bbb8 |
177 | ($options->{type_constraint}->is_a_type_of('ArrayRef') || |
178 | $options->{type_constraint}->is_a_type_of('HashRef')) |
536f0b17 |
179 | || confess "You cannot auto-dereference anything other than a ArrayRef or HashRef"; |
180 | } |
181 | |
1d768fb1 |
182 | if (exists $options->{lazy} && $options->{lazy}) { |
183 | (exists $options->{default}) |
ca01a97b |
184 | || confess "You cannot have lazy attribute without specifying a default value for it"; |
1d768fb1 |
185 | } |
78cd1d3b |
186 | } |
c0e30cf5 |
187 | |
d500266f |
188 | sub initialize_instance_slot { |
ddd0ec20 |
189 | my ($self, $meta_instance, $instance, $params) = @_; |
d500266f |
190 | my $init_arg = $self->init_arg(); |
191 | # try to fetch the init arg from the %params ... |
ddd0ec20 |
192 | |
d500266f |
193 | my $val; |
194 | if (exists $params->{$init_arg}) { |
195 | $val = $params->{$init_arg}; |
196 | } |
197 | else { |
198 | # skip it if it's lazy |
199 | return if $self->is_lazy; |
200 | # and die if it's required and doesn't have a default value |
201 | confess "Attribute (" . $self->name . ") is required" |
202 | if $self->is_required && !$self->has_default; |
203 | } |
ddd0ec20 |
204 | |
d500266f |
205 | # if nothing was in the %params, we can use the |
206 | # attribute's default value (if it has one) |
207 | if (!defined $val && $self->has_default) { |
208 | $val = $self->default($instance); |
209 | } |
210 | if (defined $val) { |
211 | if ($self->has_type_constraint) { |
c07af9d2 |
212 | my $type_constraint = $self->type_constraint; |
213 | if ($self->should_coerce && $type_constraint->has_coercion) { |
0a5bd159 |
214 | $val = $type_constraint->coerce($val); |
d500266f |
215 | } |
c07af9d2 |
216 | (defined($type_constraint->check($val))) |
217 | || confess "Attribute (" . |
218 | $self->name . |
8449e6e7 |
219 | ") does not pass the type constraint (" . |
c07af9d2 |
220 | $type_constraint->name . |
221 | ") with '$val'"; |
d500266f |
222 | } |
223 | } |
ddd0ec20 |
224 | |
ac1ef2f9 |
225 | $meta_instance->set_slot_value($instance, $self->name, $val); |
226 | $meta_instance->weaken_slot_value($instance, $self->name) |
227 | if ref $val && $self->is_weak_ref; |
d500266f |
228 | } |
229 | |
d617b644 |
230 | ## Slot management |
9e93dd19 |
231 | |
946289d1 |
232 | sub set_value { |
233 | my ($self, $instance, $value) = @_; |
234 | |
235 | my $attr_name = $self->name; |
236 | |
237 | if ($self->is_required) { |
238 | defined($value) |
239 | || confess "Attribute ($attr_name) is required, so cannot be set to undef"; |
240 | } |
241 | |
242 | if ($self->has_type_constraint) { |
243 | |
244 | my $type_constraint = $self->type_constraint; |
245 | |
246 | if ($self->should_coerce) { |
247 | $value = $type_constraint->coerce($value); |
248 | } |
249 | defined($type_constraint->_compiled_type_constraint->($value)) |
250 | || confess "Attribute ($attr_name) does not pass the type constraint (" |
251 | . $type_constraint->name . ") with " . (defined($value) ? ("'" . $value . "'") : "undef") |
252 | if defined($value); |
253 | } |
254 | |
255 | my $meta_instance = Class::MOP::Class->initialize(blessed($instance)) |
256 | ->get_meta_instance; |
257 | |
258 | $meta_instance->set_slot_value($instance, $attr_name, $value); |
259 | |
260 | if (ref $value && $self->is_weak_ref) { |
261 | $meta_instance->weaken_slot_value($instance, $attr_name); |
262 | } |
263 | |
264 | if ($self->has_trigger) { |
265 | $self->trigger->($instance, $value, $self); |
266 | } |
267 | } |
268 | |
269 | sub get_value { |
270 | my ($self, $instance) = @_; |
271 | |
272 | if ($self->is_lazy) { |
273 | unless ($self->has_value($instance)) { |
274 | if ($self->has_default) { |
275 | my $default = $self->default($instance); |
276 | $self->set_value($instance, $default); |
277 | } |
278 | else { |
279 | $self->set_value($instance, undef); |
280 | } |
281 | } |
282 | } |
283 | |
284 | if ($self->should_auto_deref) { |
285 | |
286 | my $type_constraint = $self->type_constraint; |
287 | |
288 | if ($type_constraint->is_a_type_of('ArrayRef')) { |
289 | my $rv = $self->SUPER::get_value($instance); |
290 | return unless defined $rv; |
291 | return wantarray ? @{ $rv } : $rv; |
292 | } |
293 | elsif ($type_constraint->is_a_type_of('HashRef')) { |
294 | my $rv = $self->SUPER::get_value($instance); |
295 | return unless defined $rv; |
296 | return wantarray ? %{ $rv } : $rv; |
297 | } |
298 | else { |
299 | confess "Can not auto de-reference the type constraint '" . $type_constraint->name . "'"; |
300 | } |
301 | |
302 | } |
303 | else { |
304 | |
305 | return $self->SUPER::get_value($instance); |
306 | } |
307 | } |
a15dff8d |
308 | |
d617b644 |
309 | ## installing accessors |
c0e30cf5 |
310 | |
d617b644 |
311 | sub accessor_metaclass { 'Moose::Meta::Method::Accessor' } |
d7f17ebb |
312 | |
452bac1b |
313 | sub install_accessors { |
314 | my $self = shift; |
315 | $self->SUPER::install_accessors(@_); |
316 | |
317 | if ($self->has_handles) { |
318 | |
319 | # NOTE: |
320 | # Here we canonicalize the 'handles' option |
321 | # this will sort out any details and always |
322 | # return an hash of methods which we want |
323 | # to delagate to, see that method for details |
324 | my %handles = $self->_canonicalize_handles(); |
325 | |
326 | # find the name of the accessor for this attribute |
327 | my $accessor_name = $self->reader || $self->accessor; |
328 | (defined $accessor_name) |
329 | || confess "You cannot install delegation without a reader or accessor for the attribute"; |
330 | |
331 | # make sure we handle HASH accessors correctly |
332 | ($accessor_name) = keys %{$accessor_name} |
333 | if ref($accessor_name) eq 'HASH'; |
334 | |
335 | # install the delegation ... |
336 | my $associated_class = $self->associated_class; |
337 | foreach my $handle (keys %handles) { |
338 | my $method_to_call = $handles{$handle}; |
339 | |
340 | (!$associated_class->has_method($handle)) |
341 | || confess "You cannot overwrite a locally defined method ($handle) with a delegation"; |
342 | |
343 | if ((reftype($method_to_call) || '') eq 'CODE') { |
344 | $associated_class->add_method($handle => $method_to_call); |
345 | } |
346 | else { |
347 | $associated_class->add_method($handle => sub { |
b805c70c |
348 | # FIXME |
349 | # we should check for lack of |
350 | # a callable return value from |
351 | # the accessor here |
452bac1b |
352 | ((shift)->$accessor_name())->$method_to_call(@_); |
353 | }); |
354 | } |
355 | } |
356 | } |
357 | |
358 | return; |
359 | } |
360 | |
98aae381 |
361 | # private methods to help delegation ... |
362 | |
452bac1b |
363 | sub _canonicalize_handles { |
364 | my $self = shift; |
365 | my $handles = $self->handles; |
366 | if (ref($handles) eq 'HASH') { |
367 | return %{$handles}; |
368 | } |
369 | elsif (ref($handles) eq 'ARRAY') { |
370 | return map { $_ => $_ } @{$handles}; |
371 | } |
372 | elsif (ref($handles) eq 'Regexp') { |
373 | ($self->has_type_constraint) |
374 | || confess "Cannot delegate methods based on a RegExpr without a type constraint (isa)"; |
375 | return map { ($_ => $_) } |
376 | grep { $handles } $self->_get_delegate_method_list; |
377 | } |
378 | elsif (ref($handles) eq 'CODE') { |
379 | return $handles->($self, $self->_find_delegate_metaclass); |
380 | } |
381 | else { |
382 | confess "Unable to canonicalize the 'handles' option with $handles"; |
383 | } |
384 | } |
385 | |
386 | sub _find_delegate_metaclass { |
387 | my $self = shift; |
98aae381 |
388 | if (my $class = $self->_isa_metadata) { |
452bac1b |
389 | # if the class does have |
390 | # a meta method, use it |
391 | return $class->meta if $class->can('meta'); |
392 | # otherwise we might be |
393 | # dealing with a non-Moose |
394 | # class, and need to make |
395 | # our own metaclass |
396 | return Moose::Meta::Class->initialize($class); |
397 | } |
98aae381 |
398 | elsif (my $role = $self->_does_metadata) { |
452bac1b |
399 | # our role will always have |
400 | # a meta method |
98aae381 |
401 | return $role->meta; |
452bac1b |
402 | } |
403 | else { |
404 | confess "Cannot find delegate metaclass for attribute " . $self->name; |
405 | } |
406 | } |
407 | |
408 | sub _get_delegate_method_list { |
409 | my $self = shift; |
410 | my $meta = $self->_find_delegate_metaclass; |
411 | if ($meta->isa('Class::MOP::Class')) { |
093b12c2 |
412 | return map { $_->{name} } # NOTE: !never! delegate &meta |
413 | grep { $_->{class} ne 'Moose::Object' && $_->{name} ne 'meta' } |
452bac1b |
414 | $meta->compute_all_applicable_methods; |
415 | } |
416 | elsif ($meta->isa('Moose::Meta::Role')) { |
417 | return $meta->get_method_list; |
418 | } |
419 | else { |
420 | confess "Unable to recognize the delegate metaclass '$meta'"; |
421 | } |
422 | } |
423 | |
c0e30cf5 |
424 | 1; |
425 | |
426 | __END__ |
427 | |
428 | =pod |
429 | |
430 | =head1 NAME |
431 | |
6ba6d68c |
432 | Moose::Meta::Attribute - The Moose attribute metaclass |
c0e30cf5 |
433 | |
434 | =head1 DESCRIPTION |
435 | |
e522431d |
436 | This is a subclass of L<Class::MOP::Attribute> with Moose specific |
6ba6d68c |
437 | extensions. |
438 | |
439 | For the most part, the only time you will ever encounter an |
440 | instance of this class is if you are doing some serious deep |
441 | introspection. To really understand this class, you need to refer |
442 | to the L<Class::MOP::Attribute> documentation. |
e522431d |
443 | |
c0e30cf5 |
444 | =head1 METHODS |
445 | |
6ba6d68c |
446 | =head2 Overridden methods |
447 | |
448 | These methods override methods in L<Class::MOP::Attribute> and add |
449 | Moose specific features. You can safely assume though that they |
450 | will behave just as L<Class::MOP::Attribute> does. |
451 | |
c0e30cf5 |
452 | =over 4 |
453 | |
454 | =item B<new> |
455 | |
d500266f |
456 | =item B<initialize_instance_slot> |
457 | |
452bac1b |
458 | =item B<install_accessors> |
459 | |
39b3bc94 |
460 | =item B<accessor_metaclass> |
461 | |
946289d1 |
462 | =item B<get_value> |
463 | |
464 | =item B<set_value> |
465 | |
a15dff8d |
466 | =back |
467 | |
6ba6d68c |
468 | =head2 Additional Moose features |
469 | |
8449e6e7 |
470 | Moose attributes support type-constraint checking, weak reference |
6ba6d68c |
471 | creation and type coercion. |
472 | |
a15dff8d |
473 | =over 4 |
474 | |
9e93dd19 |
475 | =item B<clone_and_inherit_options> |
476 | |
477 | This is to support the C<has '+foo'> feature, it clones an attribute |
478 | from a superclass and allows a very specific set of changes to be made |
479 | to the attribute. |
480 | |
a15dff8d |
481 | =item B<has_type_constraint> |
482 | |
6ba6d68c |
483 | Returns true if this meta-attribute has a type constraint. |
484 | |
a15dff8d |
485 | =item B<type_constraint> |
486 | |
6ba6d68c |
487 | A read-only accessor for this meta-attribute's type constraint. For |
488 | more information on what you can do with this, see the documentation |
489 | for L<Moose::Meta::TypeConstraint>. |
a15dff8d |
490 | |
452bac1b |
491 | =item B<has_handles> |
492 | |
493 | Returns true if this meta-attribute performs delegation. |
494 | |
495 | =item B<handles> |
496 | |
497 | This returns the value which was passed into the handles option. |
498 | |
6ba6d68c |
499 | =item B<is_weak_ref> |
a15dff8d |
500 | |
02a0fb52 |
501 | Returns true if this meta-attribute produces a weak reference. |
4b598ea3 |
502 | |
ca01a97b |
503 | =item B<is_required> |
504 | |
02a0fb52 |
505 | Returns true if this meta-attribute is required to have a value. |
ca01a97b |
506 | |
507 | =item B<is_lazy> |
508 | |
02a0fb52 |
509 | Returns true if this meta-attribute should be initialized lazily. |
ca01a97b |
510 | |
511 | NOTE: lazy attributes, B<must> have a C<default> field set. |
512 | |
34a66aa3 |
513 | =item B<should_coerce> |
4b598ea3 |
514 | |
02a0fb52 |
515 | Returns true if this meta-attribute should perform type coercion. |
6ba6d68c |
516 | |
536f0b17 |
517 | =item B<should_auto_deref> |
518 | |
519 | Returns true if this meta-attribute should perform automatic |
520 | auto-dereferencing. |
521 | |
522 | NOTE: This can only be done for attributes whose type constraint is |
523 | either I<ArrayRef> or I<HashRef>. |
524 | |
8c9d74e7 |
525 | =item B<has_trigger> |
526 | |
02a0fb52 |
527 | Returns true if this meta-attribute has a trigger set. |
528 | |
8c9d74e7 |
529 | =item B<trigger> |
530 | |
02a0fb52 |
531 | This is a CODE reference which will be executed every time the |
532 | value of an attribute is assigned. The CODE ref will get two values, |
533 | the invocant and the new value. This can be used to handle I<basic> |
534 | bi-directional relations. |
535 | |
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536 | =back |
537 | |
538 | =head1 BUGS |
539 | |
540 | All complex software has bugs lurking in it, and this module is no |
541 | exception. If you find a bug please either email me, or add the bug |
542 | to cpan-RT. |
543 | |
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544 | =head1 AUTHOR |
545 | |
546 | Stevan Little E<lt>stevan@iinteractive.comE<gt> |
547 | |
98aae381 |
548 | Yuval Kogman E<lt>nothingmuch@woobling.comE<gt> |
549 | |
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550 | =head1 COPYRIGHT AND LICENSE |
551 | |
b77fdbed |
552 | Copyright 2006, 2007 by Infinity Interactive, Inc. |
c0e30cf5 |
553 | |
554 | L<http://www.iinteractive.com> |
555 | |
556 | This library is free software; you can redistribute it and/or modify |
557 | it under the same terms as Perl itself. |
558 | |
8a7a9c53 |
559 | =cut |