Commit | Line | Data |
c3398f5b |
1 | #!/usr/bin/env perl |
306290e8 |
2 | package Mouse::Meta::Attribute; |
c3398f5b |
3 | use strict; |
4 | use warnings; |
5 | |
6 | use Carp 'confess'; |
626cd940 |
7 | use Mouse::Util qw/blessed weaken/; |
c3398f5b |
8 | |
9 | sub new { |
10 | my $class = shift; |
11 | my %args = @_; |
12 | |
2e7e86c6 |
13 | my $name = $args{name}; |
14 | |
15 | $args{init_arg} = $name |
7ee01d77 |
16 | unless exists $args{init_arg}; |
45959ffa |
17 | |
c3398f5b |
18 | $args{is} ||= ''; |
19 | |
20 | bless \%args, $class; |
21 | } |
22 | |
181502b9 |
23 | sub name { $_[0]->{name} } |
24 | sub associated_class { $_[0]->{associated_class} } |
25 | sub _is_metadata { $_[0]->{is} } |
26 | sub is_required { $_[0]->{required} } |
27 | sub default { $_[0]->{default} } |
28 | sub is_lazy { $_[0]->{lazy} } |
29 | sub is_lazy_build { $_[0]->{lazy_build} } |
30 | sub predicate { $_[0]->{predicate} } |
31 | sub clearer { $_[0]->{clearer} } |
32 | sub handles { $_[0]->{handles} } |
33 | sub is_weak_ref { $_[0]->{weak_ref} } |
34 | sub init_arg { $_[0]->{init_arg} } |
35 | sub type_constraint { $_[0]->{type_constraint} } |
36 | sub trigger { $_[0]->{trigger} } |
37 | sub builder { $_[0]->{builder} } |
38 | sub should_auto_deref { $_[0]->{auto_deref} } |
c3398f5b |
39 | |
ccea8101 |
40 | sub has_default { exists $_[0]->{default} } |
41 | sub has_predicate { exists $_[0]->{predicate} } |
42 | sub has_clearer { exists $_[0]->{clearer} } |
43 | sub has_handles { exists $_[0]->{handles} } |
ccea8101 |
44 | sub has_type_constraint { exists $_[0]->{type_constraint} } |
de9a434a |
45 | sub has_trigger { exists $_[0]->{trigger} } |
46 | sub has_builder { exists $_[0]->{builder} } |
ccea8101 |
47 | |
1bfebf5f |
48 | sub _create_args { |
49 | $_[0]->{_create_args} = $_[1] if @_ > 1; |
50 | $_[0]->{_create_args} |
51 | } |
52 | |
7f7406a5 |
53 | sub inlined_name { |
54 | my $self = shift; |
55 | my $name = $self->name; |
56 | my $key = "'" . $name . "'"; |
57 | return $key; |
58 | } |
59 | |
c3398f5b |
60 | sub generate_accessor { |
61 | my $attribute = shift; |
62 | |
ccd73de7 |
63 | my $name = $attribute->name; |
64 | my $default = $attribute->default; |
65 | my $type = $attribute->type_constraint; |
66 | my $constraint = $attribute->find_type_constraint; |
67 | my $builder = $attribute->builder; |
68 | my $trigger = $attribute->trigger; |
69 | my $is_weak = $attribute->is_weak_ref; |
70 | my $should_deref = $attribute->should_auto_deref; |
4e757c98 |
71 | |
85ccd3e9 |
72 | my $self = '$_[0]'; |
85ccd3e9 |
73 | my $key = $attribute->inlined_name; |
c3398f5b |
74 | |
85ccd3e9 |
75 | my $accessor = "sub {\n"; |
2434d21b |
76 | if ($attribute->_is_metadata eq 'rw') { |
7de13475 |
77 | $accessor .= 'if (scalar(@_) >= 2) {' . "\n"; |
78 | |
79 | my $value = '$_[1]'; |
a707f587 |
80 | |
a08e715f |
81 | if ($constraint) { |
7de13475 |
82 | $accessor .= 'local $_ = '.$value.'; |
ed1eec39 |
83 | unless ($constraint->()) { |
a08e715f |
84 | my $display = defined($_) ? overload::StrVal($_) : "undef"; |
85 | Carp::confess("Attribute ($name) does not pass the type constraint because: Validation failed for \'$type\' failed with value $display"); |
85ccd3e9 |
86 | }' . "\n" |
a707f587 |
87 | } |
88 | |
ccd73de7 |
89 | # if there's nothing left to do for the attribute we can return during |
90 | # this setter |
91 | $accessor .= 'return ' if !$is_weak && !$trigger && !$should_deref; |
c3398f5b |
92 | |
7de13475 |
93 | $accessor .= $self.'->{'.$key.'} = '.$value.';' . "\n"; |
94 | |
ccd73de7 |
95 | if ($is_weak) { |
85ccd3e9 |
96 | $accessor .= 'weaken('.$self.'->{'.$key.'}) if ref('.$self.'->{'.$key.'});' . "\n"; |
c3398f5b |
97 | } |
98 | |
a08e715f |
99 | if ($trigger) { |
85ccd3e9 |
100 | $accessor .= '$trigger->('.$self.', '.$value.', $attribute);' . "\n"; |
c3398f5b |
101 | } |
102 | |
85ccd3e9 |
103 | $accessor .= "}\n"; |
c3398f5b |
104 | } |
105 | else { |
85ccd3e9 |
106 | $accessor .= 'confess "Cannot assign a value to a read-only accessor" if scalar(@_) >= 2;' . "\n"; |
c3398f5b |
107 | } |
108 | |
2434d21b |
109 | if ($attribute->is_lazy) { |
85ccd3e9 |
110 | $accessor .= $self.'->{'.$key.'} = '; |
9367e029 |
111 | |
112 | $accessor .= $attribute->has_builder |
85ccd3e9 |
113 | ? $self.'->$builder' |
114 | : ref($default) eq 'CODE' |
115 | ? '$default->('.$self.')' |
116 | : '$default'; |
117 | $accessor .= ' if !exists '.$self.'->{'.$key.'};' . "\n"; |
c3398f5b |
118 | } |
119 | |
ccd73de7 |
120 | if ($should_deref) { |
3cf68001 |
121 | if ($attribute->type_constraint eq 'ArrayRef') { |
122 | $accessor .= 'if (wantarray) { |
85ccd3e9 |
123 | return @{ '.$self.'->{'.$key.'} || [] }; |
7de13475 |
124 | }'; |
3cf68001 |
125 | } |
126 | else { |
127 | $accessor .= 'if (wantarray) { |
85ccd3e9 |
128 | return %{ '.$self.'->{'.$key.'} || {} }; |
7de13475 |
129 | }'; |
3cf68001 |
130 | } |
131 | } |
132 | |
85ccd3e9 |
133 | $accessor .= 'return '.$self.'->{'.$key.'}; |
c3398f5b |
134 | }'; |
135 | |
71b948d1 |
136 | my $sub = eval $accessor; |
137 | confess $@ if $@; |
138 | return $sub; |
c3398f5b |
139 | } |
140 | |
141 | sub generate_predicate { |
142 | my $attribute = shift; |
d10fd510 |
143 | my $key = $attribute->inlined_name; |
c3398f5b |
144 | |
d10fd510 |
145 | my $predicate = 'sub { exists($_[0]->{'.$key.'}) }'; |
c3398f5b |
146 | |
71b948d1 |
147 | my $sub = eval $predicate; |
148 | confess $@ if $@; |
149 | return $sub; |
c3398f5b |
150 | } |
151 | |
152 | sub generate_clearer { |
153 | my $attribute = shift; |
d10fd510 |
154 | my $key = $attribute->inlined_name; |
c3398f5b |
155 | |
d10fd510 |
156 | my $clearer = 'sub { delete($_[0]->{'.$key.'}) }'; |
c3398f5b |
157 | |
71b948d1 |
158 | my $sub = eval $clearer; |
159 | confess $@ if $@; |
160 | return $sub; |
c3398f5b |
161 | } |
162 | |
163 | sub generate_handles { |
164 | my $attribute = shift; |
2434d21b |
165 | my $reader = $attribute->name; |
c3cc3642 |
166 | my %handles = $attribute->_canonicalize_handles($attribute->handles); |
c3398f5b |
167 | |
168 | my %method_map; |
169 | |
c3cc3642 |
170 | for my $local_method (keys %handles) { |
171 | my $remote_method = $handles{$local_method}; |
c3398f5b |
172 | |
173 | my $method = 'sub { |
174 | my $self = shift; |
175 | $self->$reader->$remote_method(@_) |
176 | }'; |
177 | |
178 | $method_map{$local_method} = eval $method; |
71b948d1 |
179 | confess $@ if $@; |
c3398f5b |
180 | } |
181 | |
182 | return \%method_map; |
183 | } |
184 | |
185 | sub create { |
186 | my ($self, $class, $name, %args) = @_; |
187 | |
1bfebf5f |
188 | $args{name} = $name; |
181502b9 |
189 | $args{associated_class} = $class; |
1bfebf5f |
190 | |
93d190e0 |
191 | %args = $self->canonicalize_args($name, %args); |
1bbaa8ed |
192 | $self->validate_args($name, \%args); |
45ea8620 |
193 | |
c021207d |
194 | $args{type_constraint} = delete $args{isa} |
195 | if exists $args{isa}; |
186657a9 |
196 | |
1bfebf5f |
197 | my $attribute = $self->new(%args); |
1bfebf5f |
198 | |
724c77c0 |
199 | $attribute->_create_args(\%args); |
c3398f5b |
200 | |
724c77c0 |
201 | $class->add_attribute($attribute); |
b2500191 |
202 | |
c3398f5b |
203 | # install an accessor |
2434d21b |
204 | if ($attribute->_is_metadata eq 'rw' || $attribute->_is_metadata eq 'ro') { |
c3398f5b |
205 | my $accessor = $attribute->generate_accessor; |
724c77c0 |
206 | $class->add_method($name => $accessor); |
c3398f5b |
207 | } |
208 | |
c3398f5b |
209 | for my $method (qw/predicate clearer/) { |
2434d21b |
210 | my $predicate = "has_$method"; |
211 | if ($attribute->$predicate) { |
c3398f5b |
212 | my $generator = "generate_$method"; |
213 | my $coderef = $attribute->$generator; |
724c77c0 |
214 | $class->add_method($attribute->$method => $coderef); |
c3398f5b |
215 | } |
216 | } |
217 | |
2434d21b |
218 | if ($attribute->has_handles) { |
c3398f5b |
219 | my $method_map = $attribute->generate_handles; |
220 | for my $method_name (keys %$method_map) { |
724c77c0 |
221 | $class->add_method($method_name => $method_map->{$method_name}); |
c3398f5b |
222 | } |
223 | } |
224 | |
225 | return $attribute; |
226 | } |
227 | |
93d190e0 |
228 | sub canonicalize_args { |
229 | my $self = shift; |
230 | my $name = shift; |
231 | my %args = @_; |
232 | |
233 | if ($args{lazy_build}) { |
234 | $args{lazy} = 1; |
235 | $args{required} = 1; |
236 | $args{builder} = "_build_${name}" |
237 | if !exists($args{builder}); |
238 | if ($name =~ /^_/) { |
239 | $args{clearer} = "_clear${name}" if !exists($args{clearer}); |
240 | $args{predicate} = "_has${name}" if !exists($args{predicate}); |
241 | } |
242 | else { |
243 | $args{clearer} = "clear_${name}" if !exists($args{clearer}); |
244 | $args{predicate} = "has_${name}" if !exists($args{predicate}); |
245 | } |
246 | } |
247 | |
248 | return %args; |
249 | } |
250 | |
8fd9e611 |
251 | sub validate_args { |
252 | my $self = shift; |
253 | my $name = shift; |
1bbaa8ed |
254 | my $args = shift; |
8fd9e611 |
255 | |
93d190e0 |
256 | confess "You can not use lazy_build and default for the same attribute ($name)" |
1bbaa8ed |
257 | if $args->{lazy_build} && exists $args->{default}; |
93d190e0 |
258 | |
8fd9e611 |
259 | confess "You cannot have lazy attribute ($name) without specifying a default value for it" |
1bbaa8ed |
260 | if $args->{lazy} |
261 | && !exists($args->{default}) |
262 | && !exists($args->{builder}); |
8fd9e611 |
263 | |
264 | confess "References are not allowed as default values, you must wrap the default of '$name' in a CODE reference (ex: sub { [] } and not [])" |
1bbaa8ed |
265 | if ref($args->{default}) |
266 | && ref($args->{default}) ne 'CODE'; |
8fd9e611 |
267 | |
97661b77 |
268 | confess "You cannot auto-dereference without specifying a type constraint on attribute ($name)" |
1bbaa8ed |
269 | if $args->{auto_deref} && !exists($args->{isa}); |
8fd9e611 |
270 | |
97661b77 |
271 | confess "You cannot auto-dereference anything other than a ArrayRef or HashRef on attribute ($name)" |
1bbaa8ed |
272 | if $args->{auto_deref} |
273 | && $args->{isa} ne 'ArrayRef' |
274 | && $args->{isa} ne 'HashRef'; |
8fd9e611 |
275 | |
506db557 |
276 | if ($args->{trigger}) { |
a08e715f |
277 | if (ref($args->{trigger}) eq 'HASH') { |
278 | Carp::carp "HASH-based form of trigger has been removed. Only the coderef form of triggers are now supported."; |
844fa049 |
279 | } |
506db557 |
280 | |
844fa049 |
281 | confess "Trigger must be a CODE ref on attribute ($name)" |
a08e715f |
282 | if ref($args->{trigger}) ne 'CODE'; |
506db557 |
283 | } |
6c5498d0 |
284 | |
8fd9e611 |
285 | return 1; |
286 | } |
287 | |
5aa30ced |
288 | sub find_type_constraint { |
289 | my $self = shift; |
290 | my $type = $self->type_constraint; |
291 | |
292 | return unless $type; |
293 | |
294 | my $checker = Mouse::TypeRegistry->optimized_constraints->{$type}; |
295 | return $checker if $checker; |
296 | |
3fc40cff |
297 | return sub { blessed($_) && $_->isa($type) }; |
5aa30ced |
298 | } |
299 | |
300 | sub verify_type_constraint { |
301 | my $self = shift; |
302 | local $_ = shift; |
303 | |
304 | my $type = $self->type_constraint |
305 | or return 1; |
af745d5a |
306 | my $constraint = $self->find_type_constraint; |
5aa30ced |
307 | |
308 | return 1 if $constraint->($_); |
309 | |
310 | my $name = $self->name; |
f3e05dfd |
311 | my $display = defined($_) ? overload::StrVal($_) : 'undef'; |
312 | Carp::confess("Attribute ($name) does not pass the type constraint because: Validation failed for \'$type\' failed with value $display"); |
5aa30ced |
313 | } |
314 | |
af745d5a |
315 | sub _canonicalize_handles { |
316 | my $self = shift; |
317 | my $handles = shift; |
318 | |
319 | if (ref($handles) eq 'HASH') { |
320 | return %$handles; |
321 | } |
322 | elsif (ref($handles) eq 'ARRAY') { |
323 | return map { $_ => $_ } @$handles; |
324 | } |
325 | else { |
326 | confess "Unable to canonicalize the 'handles' option with $handles"; |
327 | } |
328 | } |
329 | |
1bfebf5f |
330 | sub clone_parent { |
331 | my $self = shift; |
332 | my $class = shift; |
333 | my $name = shift; |
334 | my %args = ($self->get_parent_args($class, $name), @_); |
335 | |
336 | $self->create($class, $name, %args); |
337 | } |
338 | |
339 | sub get_parent_args { |
340 | my $self = shift; |
341 | my $class = shift; |
342 | my $name = shift; |
343 | |
724c77c0 |
344 | for my $super ($class->linearized_isa) { |
bb733405 |
345 | my $super_attr = $super->can("meta") && $super->meta->get_attribute($name) |
1bfebf5f |
346 | or next; |
347 | return %{ $super_attr->_create_args }; |
348 | } |
349 | |
350 | confess "Could not find an attribute by the name of '$name' to inherit from"; |
351 | } |
352 | |
c3398f5b |
353 | 1; |
354 | |
355 | __END__ |
356 | |
357 | =head1 NAME |
358 | |
306290e8 |
359 | Mouse::Meta::Attribute - attribute metaclass |
c3398f5b |
360 | |
361 | =head1 METHODS |
362 | |
306290e8 |
363 | =head2 new %args -> Mouse::Meta::Attribute |
c3398f5b |
364 | |
306290e8 |
365 | Instantiates a new Mouse::Meta::Attribute. Does nothing else. |
c3398f5b |
366 | |
306290e8 |
367 | =head2 create OwnerClass, AttributeName, %args -> Mouse::Meta::Attribute |
c3398f5b |
368 | |
369 | Creates a new attribute in OwnerClass. Accessors and helper methods are |
370 | installed. Some error checking is done. |
371 | |
372 | =head2 name -> AttributeName |
373 | |
181502b9 |
374 | =head2 associated_class -> OwnerClass |
c3398f5b |
375 | |
ab27a55e |
376 | =head2 is_required -> Bool |
c3398f5b |
377 | |
ab27a55e |
378 | =head2 default -> Item |
c3398f5b |
379 | |
ab27a55e |
380 | =head2 has_default -> Bool |
381 | |
382 | =head2 is_lazy -> Bool |
383 | |
384 | =head2 predicate -> MethodName | Undef |
385 | |
386 | =head2 has_predicate -> Bool |
387 | |
388 | =head2 clearer -> MethodName | Undef |
389 | |
390 | =head2 has_clearer -> Bool |
c3398f5b |
391 | |
392 | =head2 handles -> { LocalName => RemoteName } |
393 | |
ab27a55e |
394 | =head2 has_handles -> Bool |
395 | |
3645b316 |
396 | =head2 is_weak_ref -> Bool |
c3398f5b |
397 | |
398 | =head2 init_arg -> Str |
399 | |
ab27a55e |
400 | =head2 type_constraint -> Str |
401 | |
402 | =head2 has_type_constraint -> Bool |
403 | |
404 | =head2 trigger => CODE | Undef |
405 | |
406 | =head2 has_trigger -> Bool |
407 | |
408 | =head2 builder => MethodName | Undef |
409 | |
410 | =head2 has_builder -> Bool |
411 | |
93f08899 |
412 | =head2 is_lazy_build => Bool |
413 | |
0fff36e6 |
414 | =head2 should_auto_deref -> Bool |
415 | |
c3398f5b |
416 | Informational methods. |
417 | |
418 | =head2 generate_accessor -> CODE |
419 | |
420 | Creates a new code reference for the attribute's accessor. |
421 | |
422 | =head2 generate_predicate -> CODE |
423 | |
424 | Creates a new code reference for the attribute's predicate. |
425 | |
426 | =head2 generate_clearer -> CODE |
427 | |
428 | Creates a new code reference for the attribute's clearer. |
429 | |
430 | =head2 generate_handles -> { MethodName => CODE } |
431 | |
432 | Creates a new code reference for each of the attribute's handles methods. |
433 | |
fb706f5c |
434 | =head2 find_type_constraint -> CODE |
435 | |
436 | Returns a code reference which can be used to check that a given value passes |
437 | this attribute's type constraint; |
438 | |
439 | =head2 verify_type_constraint Item -> 1 | ERROR |
440 | |
441 | Checks that the given value passes this attribute's type constraint. Returns 1 |
442 | on success, otherwise C<confess>es. |
443 | |
93d190e0 |
444 | =head2 canonicalize_args Name, %args -> %args |
445 | |
446 | Canonicalizes some arguments to create. In particular, C<lazy_build> is |
447 | canonicalized into C<lazy>, C<builder>, etc. |
448 | |
1bbaa8ed |
449 | =head2 validate_args Name, \%args -> 1 | ERROR |
93d190e0 |
450 | |
451 | Checks that the arguments to create the attribute (ie those specified by |
452 | C<has>) are valid. |
453 | |
f7b11a21 |
454 | =head2 clone_parent OwnerClass, AttributeName, %args -> Mouse::Meta::Attribute |
455 | |
456 | Creates a new attribute in OwnerClass, inheriting options from parent classes. |
457 | Accessors and helper methods are installed. Some error checking is done. |
458 | |
459 | =head2 get_parent_args OwnerClass, AttributeName -> Hash |
460 | |
461 | Returns the options that the parent class of C<OwnerClass> used for attribute |
462 | C<AttributeName>. |
463 | |
c3398f5b |
464 | =cut |
465 | |