Commit | Line | Data |
c3398f5b |
1 | #!/usr/bin/env perl |
306290e8 |
2 | package Mouse::Meta::Attribute; |
c3398f5b |
3 | use strict; |
4 | use warnings; |
3b8fe109 |
5 | require overload; |
c3398f5b |
6 | |
7 | use Carp 'confess'; |
626cd940 |
8 | use Mouse::Util qw/blessed weaken/; |
c3398f5b |
9 | |
10 | sub new { |
11 | my $class = shift; |
12 | my %args = @_; |
13 | |
2e7e86c6 |
14 | my $name = $args{name}; |
15 | |
16 | $args{init_arg} = $name |
7ee01d77 |
17 | unless exists $args{init_arg}; |
45959ffa |
18 | |
c3398f5b |
19 | $args{is} ||= ''; |
20 | |
21 | bless \%args, $class; |
22 | } |
23 | |
181502b9 |
24 | sub name { $_[0]->{name} } |
25 | sub associated_class { $_[0]->{associated_class} } |
26 | sub _is_metadata { $_[0]->{is} } |
27 | sub is_required { $_[0]->{required} } |
28 | sub default { $_[0]->{default} } |
29 | sub is_lazy { $_[0]->{lazy} } |
30 | sub is_lazy_build { $_[0]->{lazy_build} } |
31 | sub predicate { $_[0]->{predicate} } |
32 | sub clearer { $_[0]->{clearer} } |
33 | sub handles { $_[0]->{handles} } |
34 | sub is_weak_ref { $_[0]->{weak_ref} } |
35 | sub init_arg { $_[0]->{init_arg} } |
36 | sub type_constraint { $_[0]->{type_constraint} } |
37 | sub trigger { $_[0]->{trigger} } |
38 | sub builder { $_[0]->{builder} } |
39 | sub should_auto_deref { $_[0]->{auto_deref} } |
32af3489 |
40 | sub should_coerce { $_[0]->{should_coerce} } |
c3398f5b |
41 | |
ccea8101 |
42 | sub has_default { exists $_[0]->{default} } |
43 | sub has_predicate { exists $_[0]->{predicate} } |
44 | sub has_clearer { exists $_[0]->{clearer} } |
45 | sub has_handles { exists $_[0]->{handles} } |
ccea8101 |
46 | sub has_type_constraint { exists $_[0]->{type_constraint} } |
de9a434a |
47 | sub has_trigger { exists $_[0]->{trigger} } |
48 | sub has_builder { exists $_[0]->{builder} } |
ccea8101 |
49 | |
1bfebf5f |
50 | sub _create_args { |
51 | $_[0]->{_create_args} = $_[1] if @_ > 1; |
52 | $_[0]->{_create_args} |
53 | } |
54 | |
7f7406a5 |
55 | sub inlined_name { |
56 | my $self = shift; |
57 | my $name = $self->name; |
58 | my $key = "'" . $name . "'"; |
59 | return $key; |
60 | } |
61 | |
c3398f5b |
62 | sub generate_accessor { |
63 | my $attribute = shift; |
64 | |
32af3489 |
65 | my $name = $attribute->name; |
66 | my $default = $attribute->default; |
67 | my $type = $attribute->type_constraint; |
68 | my $constraint = $attribute->find_type_constraint; |
69 | my $builder = $attribute->builder; |
70 | my $trigger = $attribute->trigger; |
71 | my $is_weak = $attribute->is_weak_ref; |
72 | my $should_deref = $attribute->should_auto_deref; |
73 | my $should_coerce = $attribute->should_coerce; |
4e757c98 |
74 | |
85ccd3e9 |
75 | my $self = '$_[0]'; |
85ccd3e9 |
76 | my $key = $attribute->inlined_name; |
c3398f5b |
77 | |
85ccd3e9 |
78 | my $accessor = "sub {\n"; |
2434d21b |
79 | if ($attribute->_is_metadata eq 'rw') { |
7de13475 |
80 | $accessor .= 'if (scalar(@_) >= 2) {' . "\n"; |
81 | |
82 | my $value = '$_[1]'; |
a707f587 |
83 | |
a08e715f |
84 | if ($constraint) { |
32af3489 |
85 | if ($should_coerce) { |
4188b837 |
86 | $accessor .= $value.' = $attribute->coerce_constraint('.$value.');'; |
87 | } |
88 | $accessor .= 'local $_ = '.$value.';'; |
89 | $accessor .= ' |
ed1eec39 |
90 | unless ($constraint->()) { |
a08e715f |
91 | my $display = defined($_) ? overload::StrVal($_) : "undef"; |
92 | Carp::confess("Attribute ($name) does not pass the type constraint because: Validation failed for \'$type\' failed with value $display"); |
85ccd3e9 |
93 | }' . "\n" |
a707f587 |
94 | } |
95 | |
ccd73de7 |
96 | # if there's nothing left to do for the attribute we can return during |
97 | # this setter |
98 | $accessor .= 'return ' if !$is_weak && !$trigger && !$should_deref; |
c3398f5b |
99 | |
7de13475 |
100 | $accessor .= $self.'->{'.$key.'} = '.$value.';' . "\n"; |
101 | |
ccd73de7 |
102 | if ($is_weak) { |
85ccd3e9 |
103 | $accessor .= 'weaken('.$self.'->{'.$key.'}) if ref('.$self.'->{'.$key.'});' . "\n"; |
c3398f5b |
104 | } |
105 | |
a08e715f |
106 | if ($trigger) { |
85ccd3e9 |
107 | $accessor .= '$trigger->('.$self.', '.$value.', $attribute);' . "\n"; |
c3398f5b |
108 | } |
109 | |
85ccd3e9 |
110 | $accessor .= "}\n"; |
c3398f5b |
111 | } |
112 | else { |
85ccd3e9 |
113 | $accessor .= 'confess "Cannot assign a value to a read-only accessor" if scalar(@_) >= 2;' . "\n"; |
c3398f5b |
114 | } |
115 | |
2434d21b |
116 | if ($attribute->is_lazy) { |
85ccd3e9 |
117 | $accessor .= $self.'->{'.$key.'} = '; |
9367e029 |
118 | |
119 | $accessor .= $attribute->has_builder |
85ccd3e9 |
120 | ? $self.'->$builder' |
121 | : ref($default) eq 'CODE' |
122 | ? '$default->('.$self.')' |
123 | : '$default'; |
124 | $accessor .= ' if !exists '.$self.'->{'.$key.'};' . "\n"; |
c3398f5b |
125 | } |
126 | |
ccd73de7 |
127 | if ($should_deref) { |
3cf68001 |
128 | if ($attribute->type_constraint eq 'ArrayRef') { |
129 | $accessor .= 'if (wantarray) { |
85ccd3e9 |
130 | return @{ '.$self.'->{'.$key.'} || [] }; |
7de13475 |
131 | }'; |
3cf68001 |
132 | } |
133 | else { |
134 | $accessor .= 'if (wantarray) { |
85ccd3e9 |
135 | return %{ '.$self.'->{'.$key.'} || {} }; |
7de13475 |
136 | }'; |
3cf68001 |
137 | } |
138 | } |
139 | |
85ccd3e9 |
140 | $accessor .= 'return '.$self.'->{'.$key.'}; |
c3398f5b |
141 | }'; |
142 | |
71b948d1 |
143 | my $sub = eval $accessor; |
144 | confess $@ if $@; |
145 | return $sub; |
c3398f5b |
146 | } |
147 | |
148 | sub generate_predicate { |
149 | my $attribute = shift; |
d10fd510 |
150 | my $key = $attribute->inlined_name; |
c3398f5b |
151 | |
d10fd510 |
152 | my $predicate = 'sub { exists($_[0]->{'.$key.'}) }'; |
c3398f5b |
153 | |
71b948d1 |
154 | my $sub = eval $predicate; |
155 | confess $@ if $@; |
156 | return $sub; |
c3398f5b |
157 | } |
158 | |
159 | sub generate_clearer { |
160 | my $attribute = shift; |
d10fd510 |
161 | my $key = $attribute->inlined_name; |
c3398f5b |
162 | |
d10fd510 |
163 | my $clearer = 'sub { delete($_[0]->{'.$key.'}) }'; |
c3398f5b |
164 | |
71b948d1 |
165 | my $sub = eval $clearer; |
166 | confess $@ if $@; |
167 | return $sub; |
c3398f5b |
168 | } |
169 | |
170 | sub generate_handles { |
171 | my $attribute = shift; |
2434d21b |
172 | my $reader = $attribute->name; |
c3cc3642 |
173 | my %handles = $attribute->_canonicalize_handles($attribute->handles); |
c3398f5b |
174 | |
175 | my %method_map; |
176 | |
c3cc3642 |
177 | for my $local_method (keys %handles) { |
178 | my $remote_method = $handles{$local_method}; |
c3398f5b |
179 | |
180 | my $method = 'sub { |
181 | my $self = shift; |
182 | $self->$reader->$remote_method(@_) |
183 | }'; |
184 | |
185 | $method_map{$local_method} = eval $method; |
71b948d1 |
186 | confess $@ if $@; |
c3398f5b |
187 | } |
188 | |
189 | return \%method_map; |
190 | } |
191 | |
192 | sub create { |
193 | my ($self, $class, $name, %args) = @_; |
194 | |
1bfebf5f |
195 | $args{name} = $name; |
181502b9 |
196 | $args{associated_class} = $class; |
1bfebf5f |
197 | |
93d190e0 |
198 | %args = $self->canonicalize_args($name, %args); |
1bbaa8ed |
199 | $self->validate_args($name, \%args); |
45ea8620 |
200 | |
32af3489 |
201 | $args{should_coerce} = delete $args{coerce} |
4188b837 |
202 | if exists $args{coerce}; |
203 | |
c021207d |
204 | $args{type_constraint} = delete $args{isa} |
205 | if exists $args{isa}; |
186657a9 |
206 | |
1bfebf5f |
207 | my $attribute = $self->new(%args); |
1bfebf5f |
208 | |
724c77c0 |
209 | $attribute->_create_args(\%args); |
c3398f5b |
210 | |
724c77c0 |
211 | $class->add_attribute($attribute); |
b2500191 |
212 | |
c3398f5b |
213 | # install an accessor |
2434d21b |
214 | if ($attribute->_is_metadata eq 'rw' || $attribute->_is_metadata eq 'ro') { |
c3398f5b |
215 | my $accessor = $attribute->generate_accessor; |
724c77c0 |
216 | $class->add_method($name => $accessor); |
c3398f5b |
217 | } |
218 | |
c3398f5b |
219 | for my $method (qw/predicate clearer/) { |
2434d21b |
220 | my $predicate = "has_$method"; |
221 | if ($attribute->$predicate) { |
c3398f5b |
222 | my $generator = "generate_$method"; |
223 | my $coderef = $attribute->$generator; |
724c77c0 |
224 | $class->add_method($attribute->$method => $coderef); |
c3398f5b |
225 | } |
226 | } |
227 | |
2434d21b |
228 | if ($attribute->has_handles) { |
c3398f5b |
229 | my $method_map = $attribute->generate_handles; |
230 | for my $method_name (keys %$method_map) { |
724c77c0 |
231 | $class->add_method($method_name => $method_map->{$method_name}); |
c3398f5b |
232 | } |
233 | } |
234 | |
235 | return $attribute; |
236 | } |
237 | |
93d190e0 |
238 | sub canonicalize_args { |
239 | my $self = shift; |
240 | my $name = shift; |
241 | my %args = @_; |
242 | |
243 | if ($args{lazy_build}) { |
244 | $args{lazy} = 1; |
245 | $args{required} = 1; |
246 | $args{builder} = "_build_${name}" |
247 | if !exists($args{builder}); |
248 | if ($name =~ /^_/) { |
249 | $args{clearer} = "_clear${name}" if !exists($args{clearer}); |
250 | $args{predicate} = "_has${name}" if !exists($args{predicate}); |
251 | } |
252 | else { |
253 | $args{clearer} = "clear_${name}" if !exists($args{clearer}); |
254 | $args{predicate} = "has_${name}" if !exists($args{predicate}); |
255 | } |
256 | } |
257 | |
258 | return %args; |
259 | } |
260 | |
8fd9e611 |
261 | sub validate_args { |
262 | my $self = shift; |
263 | my $name = shift; |
1bbaa8ed |
264 | my $args = shift; |
8fd9e611 |
265 | |
93d190e0 |
266 | confess "You can not use lazy_build and default for the same attribute ($name)" |
1bbaa8ed |
267 | if $args->{lazy_build} && exists $args->{default}; |
93d190e0 |
268 | |
8fd9e611 |
269 | confess "You cannot have lazy attribute ($name) without specifying a default value for it" |
1bbaa8ed |
270 | if $args->{lazy} |
271 | && !exists($args->{default}) |
272 | && !exists($args->{builder}); |
8fd9e611 |
273 | |
274 | confess "References are not allowed as default values, you must wrap the default of '$name' in a CODE reference (ex: sub { [] } and not [])" |
1bbaa8ed |
275 | if ref($args->{default}) |
276 | && ref($args->{default}) ne 'CODE'; |
8fd9e611 |
277 | |
97661b77 |
278 | confess "You cannot auto-dereference without specifying a type constraint on attribute ($name)" |
1bbaa8ed |
279 | if $args->{auto_deref} && !exists($args->{isa}); |
8fd9e611 |
280 | |
97661b77 |
281 | confess "You cannot auto-dereference anything other than a ArrayRef or HashRef on attribute ($name)" |
1bbaa8ed |
282 | if $args->{auto_deref} |
283 | && $args->{isa} ne 'ArrayRef' |
284 | && $args->{isa} ne 'HashRef'; |
8fd9e611 |
285 | |
506db557 |
286 | if ($args->{trigger}) { |
a08e715f |
287 | if (ref($args->{trigger}) eq 'HASH') { |
288 | Carp::carp "HASH-based form of trigger has been removed. Only the coderef form of triggers are now supported."; |
844fa049 |
289 | } |
506db557 |
290 | |
844fa049 |
291 | confess "Trigger must be a CODE ref on attribute ($name)" |
a08e715f |
292 | if ref($args->{trigger}) ne 'CODE'; |
506db557 |
293 | } |
6c5498d0 |
294 | |
8fd9e611 |
295 | return 1; |
296 | } |
297 | |
5aa30ced |
298 | sub find_type_constraint { |
299 | my $self = shift; |
300 | my $type = $self->type_constraint; |
301 | |
302 | return unless $type; |
303 | |
4188b837 |
304 | my $checker = Mouse::TypeRegistry->optimized_constraints($self->associated_class->name)->{$type}; |
5aa30ced |
305 | return $checker if $checker; |
306 | |
3301fa54 |
307 | return sub { blessed($_) && blessed($_) eq $type }; |
5aa30ced |
308 | } |
309 | |
310 | sub verify_type_constraint { |
311 | my $self = shift; |
312 | local $_ = shift; |
313 | |
314 | my $type = $self->type_constraint |
315 | or return 1; |
af745d5a |
316 | my $constraint = $self->find_type_constraint; |
5aa30ced |
317 | |
318 | return 1 if $constraint->($_); |
319 | |
320 | my $name = $self->name; |
f3e05dfd |
321 | my $display = defined($_) ? overload::StrVal($_) : 'undef'; |
322 | Carp::confess("Attribute ($name) does not pass the type constraint because: Validation failed for \'$type\' failed with value $display"); |
5aa30ced |
323 | } |
324 | |
4188b837 |
325 | sub coerce_constraint { |
326 | my($self, $value) = @_; |
327 | my $type = $self->type_constraint |
328 | or return $value; |
329 | return Mouse::TypeRegistry->typecast_constraints($self->associated_class->name, $type, $value); |
330 | } |
331 | |
af745d5a |
332 | sub _canonicalize_handles { |
333 | my $self = shift; |
334 | my $handles = shift; |
335 | |
336 | if (ref($handles) eq 'HASH') { |
337 | return %$handles; |
338 | } |
339 | elsif (ref($handles) eq 'ARRAY') { |
340 | return map { $_ => $_ } @$handles; |
341 | } |
342 | else { |
343 | confess "Unable to canonicalize the 'handles' option with $handles"; |
344 | } |
345 | } |
346 | |
1bfebf5f |
347 | sub clone_parent { |
348 | my $self = shift; |
349 | my $class = shift; |
350 | my $name = shift; |
351 | my %args = ($self->get_parent_args($class, $name), @_); |
352 | |
353 | $self->create($class, $name, %args); |
354 | } |
355 | |
356 | sub get_parent_args { |
357 | my $self = shift; |
358 | my $class = shift; |
359 | my $name = shift; |
360 | |
724c77c0 |
361 | for my $super ($class->linearized_isa) { |
bb733405 |
362 | my $super_attr = $super->can("meta") && $super->meta->get_attribute($name) |
1bfebf5f |
363 | or next; |
364 | return %{ $super_attr->_create_args }; |
365 | } |
366 | |
367 | confess "Could not find an attribute by the name of '$name' to inherit from"; |
368 | } |
369 | |
c3398f5b |
370 | 1; |
371 | |
372 | __END__ |
373 | |
374 | =head1 NAME |
375 | |
306290e8 |
376 | Mouse::Meta::Attribute - attribute metaclass |
c3398f5b |
377 | |
378 | =head1 METHODS |
379 | |
306290e8 |
380 | =head2 new %args -> Mouse::Meta::Attribute |
c3398f5b |
381 | |
306290e8 |
382 | Instantiates a new Mouse::Meta::Attribute. Does nothing else. |
c3398f5b |
383 | |
306290e8 |
384 | =head2 create OwnerClass, AttributeName, %args -> Mouse::Meta::Attribute |
c3398f5b |
385 | |
386 | Creates a new attribute in OwnerClass. Accessors and helper methods are |
387 | installed. Some error checking is done. |
388 | |
389 | =head2 name -> AttributeName |
390 | |
181502b9 |
391 | =head2 associated_class -> OwnerClass |
c3398f5b |
392 | |
ab27a55e |
393 | =head2 is_required -> Bool |
c3398f5b |
394 | |
ab27a55e |
395 | =head2 default -> Item |
c3398f5b |
396 | |
ab27a55e |
397 | =head2 has_default -> Bool |
398 | |
399 | =head2 is_lazy -> Bool |
400 | |
401 | =head2 predicate -> MethodName | Undef |
402 | |
403 | =head2 has_predicate -> Bool |
404 | |
405 | =head2 clearer -> MethodName | Undef |
406 | |
407 | =head2 has_clearer -> Bool |
c3398f5b |
408 | |
409 | =head2 handles -> { LocalName => RemoteName } |
410 | |
ab27a55e |
411 | =head2 has_handles -> Bool |
412 | |
3645b316 |
413 | =head2 is_weak_ref -> Bool |
c3398f5b |
414 | |
415 | =head2 init_arg -> Str |
416 | |
ab27a55e |
417 | =head2 type_constraint -> Str |
418 | |
419 | =head2 has_type_constraint -> Bool |
420 | |
421 | =head2 trigger => CODE | Undef |
422 | |
423 | =head2 has_trigger -> Bool |
424 | |
425 | =head2 builder => MethodName | Undef |
426 | |
427 | =head2 has_builder -> Bool |
428 | |
93f08899 |
429 | =head2 is_lazy_build => Bool |
430 | |
0fff36e6 |
431 | =head2 should_auto_deref -> Bool |
432 | |
c3398f5b |
433 | Informational methods. |
434 | |
435 | =head2 generate_accessor -> CODE |
436 | |
437 | Creates a new code reference for the attribute's accessor. |
438 | |
439 | =head2 generate_predicate -> CODE |
440 | |
441 | Creates a new code reference for the attribute's predicate. |
442 | |
443 | =head2 generate_clearer -> CODE |
444 | |
445 | Creates a new code reference for the attribute's clearer. |
446 | |
447 | =head2 generate_handles -> { MethodName => CODE } |
448 | |
449 | Creates a new code reference for each of the attribute's handles methods. |
450 | |
fb706f5c |
451 | =head2 find_type_constraint -> CODE |
452 | |
453 | Returns a code reference which can be used to check that a given value passes |
454 | this attribute's type constraint; |
455 | |
456 | =head2 verify_type_constraint Item -> 1 | ERROR |
457 | |
458 | Checks that the given value passes this attribute's type constraint. Returns 1 |
459 | on success, otherwise C<confess>es. |
460 | |
93d190e0 |
461 | =head2 canonicalize_args Name, %args -> %args |
462 | |
463 | Canonicalizes some arguments to create. In particular, C<lazy_build> is |
464 | canonicalized into C<lazy>, C<builder>, etc. |
465 | |
1bbaa8ed |
466 | =head2 validate_args Name, \%args -> 1 | ERROR |
93d190e0 |
467 | |
468 | Checks that the arguments to create the attribute (ie those specified by |
469 | C<has>) are valid. |
470 | |
f7b11a21 |
471 | =head2 clone_parent OwnerClass, AttributeName, %args -> Mouse::Meta::Attribute |
472 | |
473 | Creates a new attribute in OwnerClass, inheriting options from parent classes. |
474 | Accessors and helper methods are installed. Some error checking is done. |
475 | |
476 | =head2 get_parent_args OwnerClass, AttributeName -> Hash |
477 | |
478 | Returns the options that the parent class of C<OwnerClass> used for attribute |
479 | C<AttributeName>. |
480 | |
c3398f5b |
481 | =cut |
482 | |