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'; |
8fcbe7fb |
7 | use Mouse::Util 'blessed'; |
8 | use Scalar::Util '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} } |
c3398f5b |
40 | |
ccea8101 |
41 | sub has_default { exists $_[0]->{default} } |
42 | sub has_predicate { exists $_[0]->{predicate} } |
43 | sub has_clearer { exists $_[0]->{clearer} } |
44 | sub has_handles { exists $_[0]->{handles} } |
ccea8101 |
45 | sub has_type_constraint { exists $_[0]->{type_constraint} } |
de9a434a |
46 | sub has_trigger { exists $_[0]->{trigger} } |
47 | sub has_builder { exists $_[0]->{builder} } |
ccea8101 |
48 | |
1bfebf5f |
49 | sub _create_args { |
50 | $_[0]->{_create_args} = $_[1] if @_ > 1; |
51 | $_[0]->{_create_args} |
52 | } |
53 | |
c3398f5b |
54 | sub generate_accessor { |
55 | my $attribute = shift; |
56 | |
2434d21b |
57 | my $name = $attribute->name; |
f3c1ccc8 |
58 | my $key = $name; |
2434d21b |
59 | my $default = $attribute->default; |
2434d21b |
60 | my $type = $attribute->type_constraint; |
5aa30ced |
61 | my $constraint = $attribute->find_type_constraint; |
9367e029 |
62 | my $builder = $attribute->builder; |
a08e715f |
63 | my $trigger = $attribute->trigger; |
4e757c98 |
64 | |
c3398f5b |
65 | my $accessor = 'sub { |
66 | my $self = shift;'; |
67 | |
2434d21b |
68 | if ($attribute->_is_metadata eq 'rw') { |
c3398f5b |
69 | $accessor .= 'if (@_) { |
a707f587 |
70 | local $_ = $_[0];'; |
71 | |
a08e715f |
72 | if ($constraint) { |
73 | $accessor .= 'unless ($constraint->()) { |
74 | my $display = defined($_) ? overload::StrVal($_) : "undef"; |
75 | Carp::confess("Attribute ($name) does not pass the type constraint because: Validation failed for \'$type\' failed with value $display"); |
76 | }' |
a707f587 |
77 | } |
78 | |
a08e715f |
79 | $accessor .= '$self->{$key} = $_;'; |
c3398f5b |
80 | |
a08e715f |
81 | if ($attribute->is_weak_ref) { |
82 | $accessor .= 'Scalar::Util::weaken($self->{$key}) if ref($self->{$key});'; |
c3398f5b |
83 | } |
84 | |
a08e715f |
85 | if ($trigger) { |
86 | $accessor .= '$trigger->($self, $_, $attribute);'; |
c3398f5b |
87 | } |
88 | |
89 | $accessor .= '}'; |
90 | } |
91 | else { |
636c002e |
92 | $accessor .= 'confess "Cannot assign a value to a read-only accessor" if @_;'; |
c3398f5b |
93 | } |
94 | |
2434d21b |
95 | if ($attribute->is_lazy) { |
c3398f5b |
96 | $accessor .= '$self->{$key} = '; |
9367e029 |
97 | |
98 | $accessor .= $attribute->has_builder |
99 | ? '$self->$builder' |
100 | : ref($default) eq 'CODE' |
101 | ? '$default->($self)' |
102 | : '$default'; |
103 | |
c3398f5b |
104 | $accessor .= ' if !exists($self->{$key});'; |
105 | } |
106 | |
3cf68001 |
107 | if ($attribute->should_auto_deref) { |
108 | if ($attribute->type_constraint eq 'ArrayRef') { |
109 | $accessor .= 'if (wantarray) { |
110 | return @{ $self->{$key} || [] }; |
111 | }'; |
112 | } |
113 | else { |
114 | $accessor .= 'if (wantarray) { |
115 | return %{ $self->{$key} || {} }; |
116 | }'; |
117 | } |
118 | } |
119 | |
120 | $accessor .= 'return $self->{$key}; |
c3398f5b |
121 | }'; |
122 | |
123 | return eval $accessor; |
124 | } |
125 | |
126 | sub generate_predicate { |
127 | my $attribute = shift; |
f3c1ccc8 |
128 | my $key = $attribute->name; |
c3398f5b |
129 | |
130 | my $predicate = 'sub { exists($_[0]->{$key}) }'; |
131 | |
132 | return eval $predicate; |
133 | } |
134 | |
135 | sub generate_clearer { |
136 | my $attribute = shift; |
f3c1ccc8 |
137 | my $key = $attribute->name; |
c3398f5b |
138 | |
139 | my $predicate = 'sub { delete($_[0]->{$key}) }'; |
140 | |
141 | return eval $predicate; |
142 | } |
143 | |
144 | sub generate_handles { |
145 | my $attribute = shift; |
2434d21b |
146 | my $reader = $attribute->name; |
c3cc3642 |
147 | my %handles = $attribute->_canonicalize_handles($attribute->handles); |
c3398f5b |
148 | |
149 | my %method_map; |
150 | |
c3cc3642 |
151 | for my $local_method (keys %handles) { |
152 | my $remote_method = $handles{$local_method}; |
c3398f5b |
153 | |
154 | my $method = 'sub { |
155 | my $self = shift; |
156 | $self->$reader->$remote_method(@_) |
157 | }'; |
158 | |
159 | $method_map{$local_method} = eval $method; |
160 | } |
161 | |
162 | return \%method_map; |
163 | } |
164 | |
165 | sub create { |
166 | my ($self, $class, $name, %args) = @_; |
167 | |
1bfebf5f |
168 | $args{name} = $name; |
181502b9 |
169 | $args{associated_class} = $class; |
1bfebf5f |
170 | |
93d190e0 |
171 | %args = $self->canonicalize_args($name, %args); |
1bbaa8ed |
172 | $self->validate_args($name, \%args); |
45ea8620 |
173 | |
c021207d |
174 | $args{type_constraint} = delete $args{isa} |
175 | if exists $args{isa}; |
186657a9 |
176 | |
1bfebf5f |
177 | my $attribute = $self->new(%args); |
1bfebf5f |
178 | |
724c77c0 |
179 | $attribute->_create_args(\%args); |
c3398f5b |
180 | |
724c77c0 |
181 | $class->add_attribute($attribute); |
b2500191 |
182 | |
c3398f5b |
183 | # install an accessor |
2434d21b |
184 | if ($attribute->_is_metadata eq 'rw' || $attribute->_is_metadata eq 'ro') { |
c3398f5b |
185 | my $accessor = $attribute->generate_accessor; |
724c77c0 |
186 | $class->add_method($name => $accessor); |
c3398f5b |
187 | } |
188 | |
c3398f5b |
189 | for my $method (qw/predicate clearer/) { |
2434d21b |
190 | my $predicate = "has_$method"; |
191 | if ($attribute->$predicate) { |
c3398f5b |
192 | my $generator = "generate_$method"; |
193 | my $coderef = $attribute->$generator; |
724c77c0 |
194 | $class->add_method($attribute->$method => $coderef); |
c3398f5b |
195 | } |
196 | } |
197 | |
2434d21b |
198 | if ($attribute->has_handles) { |
c3398f5b |
199 | my $method_map = $attribute->generate_handles; |
200 | for my $method_name (keys %$method_map) { |
724c77c0 |
201 | $class->add_method($method_name => $method_map->{$method_name}); |
c3398f5b |
202 | } |
203 | } |
204 | |
205 | return $attribute; |
206 | } |
207 | |
93d190e0 |
208 | sub canonicalize_args { |
209 | my $self = shift; |
210 | my $name = shift; |
211 | my %args = @_; |
212 | |
213 | if ($args{lazy_build}) { |
214 | $args{lazy} = 1; |
215 | $args{required} = 1; |
216 | $args{builder} = "_build_${name}" |
217 | if !exists($args{builder}); |
218 | if ($name =~ /^_/) { |
219 | $args{clearer} = "_clear${name}" if !exists($args{clearer}); |
220 | $args{predicate} = "_has${name}" if !exists($args{predicate}); |
221 | } |
222 | else { |
223 | $args{clearer} = "clear_${name}" if !exists($args{clearer}); |
224 | $args{predicate} = "has_${name}" if !exists($args{predicate}); |
225 | } |
226 | } |
227 | |
228 | return %args; |
229 | } |
230 | |
8fd9e611 |
231 | sub validate_args { |
232 | my $self = shift; |
233 | my $name = shift; |
1bbaa8ed |
234 | my $args = shift; |
8fd9e611 |
235 | |
93d190e0 |
236 | confess "You can not use lazy_build and default for the same attribute ($name)" |
1bbaa8ed |
237 | if $args->{lazy_build} && exists $args->{default}; |
93d190e0 |
238 | |
8fd9e611 |
239 | confess "You cannot have lazy attribute ($name) without specifying a default value for it" |
1bbaa8ed |
240 | if $args->{lazy} |
241 | && !exists($args->{default}) |
242 | && !exists($args->{builder}); |
8fd9e611 |
243 | |
244 | confess "References are not allowed as default values, you must wrap the default of '$name' in a CODE reference (ex: sub { [] } and not [])" |
1bbaa8ed |
245 | if ref($args->{default}) |
246 | && ref($args->{default}) ne 'CODE'; |
8fd9e611 |
247 | |
97661b77 |
248 | confess "You cannot auto-dereference without specifying a type constraint on attribute ($name)" |
1bbaa8ed |
249 | if $args->{auto_deref} && !exists($args->{isa}); |
8fd9e611 |
250 | |
97661b77 |
251 | confess "You cannot auto-dereference anything other than a ArrayRef or HashRef on attribute ($name)" |
1bbaa8ed |
252 | if $args->{auto_deref} |
253 | && $args->{isa} ne 'ArrayRef' |
254 | && $args->{isa} ne 'HashRef'; |
8fd9e611 |
255 | |
506db557 |
256 | if ($args->{trigger}) { |
a08e715f |
257 | if (ref($args->{trigger}) eq 'HASH') { |
258 | Carp::carp "HASH-based form of trigger has been removed. Only the coderef form of triggers are now supported."; |
844fa049 |
259 | } |
506db557 |
260 | |
844fa049 |
261 | confess "Trigger must be a CODE ref on attribute ($name)" |
a08e715f |
262 | if ref($args->{trigger}) ne 'CODE'; |
506db557 |
263 | } |
6c5498d0 |
264 | |
8fd9e611 |
265 | return 1; |
266 | } |
267 | |
5aa30ced |
268 | sub find_type_constraint { |
269 | my $self = shift; |
270 | my $type = $self->type_constraint; |
271 | |
272 | return unless $type; |
273 | |
274 | my $checker = Mouse::TypeRegistry->optimized_constraints->{$type}; |
275 | return $checker if $checker; |
276 | |
3301fa54 |
277 | return sub { blessed($_) && blessed($_) eq $type }; |
5aa30ced |
278 | } |
279 | |
280 | sub verify_type_constraint { |
281 | my $self = shift; |
282 | local $_ = shift; |
283 | |
284 | my $type = $self->type_constraint |
285 | or return 1; |
af745d5a |
286 | my $constraint = $self->find_type_constraint; |
5aa30ced |
287 | |
288 | return 1 if $constraint->($_); |
289 | |
290 | my $name = $self->name; |
f3e05dfd |
291 | my $display = defined($_) ? overload::StrVal($_) : 'undef'; |
292 | Carp::confess("Attribute ($name) does not pass the type constraint because: Validation failed for \'$type\' failed with value $display"); |
5aa30ced |
293 | } |
294 | |
af745d5a |
295 | sub _canonicalize_handles { |
296 | my $self = shift; |
297 | my $handles = shift; |
298 | |
299 | if (ref($handles) eq 'HASH') { |
300 | return %$handles; |
301 | } |
302 | elsif (ref($handles) eq 'ARRAY') { |
303 | return map { $_ => $_ } @$handles; |
304 | } |
305 | else { |
306 | confess "Unable to canonicalize the 'handles' option with $handles"; |
307 | } |
308 | } |
309 | |
1bfebf5f |
310 | sub clone_parent { |
311 | my $self = shift; |
312 | my $class = shift; |
313 | my $name = shift; |
314 | my %args = ($self->get_parent_args($class, $name), @_); |
315 | |
316 | $self->create($class, $name, %args); |
317 | } |
318 | |
319 | sub get_parent_args { |
320 | my $self = shift; |
321 | my $class = shift; |
322 | my $name = shift; |
323 | |
724c77c0 |
324 | for my $super ($class->linearized_isa) { |
bb733405 |
325 | my $super_attr = $super->can("meta") && $super->meta->get_attribute($name) |
1bfebf5f |
326 | or next; |
327 | return %{ $super_attr->_create_args }; |
328 | } |
329 | |
330 | confess "Could not find an attribute by the name of '$name' to inherit from"; |
331 | } |
332 | |
c3398f5b |
333 | 1; |
334 | |
335 | __END__ |
336 | |
337 | =head1 NAME |
338 | |
306290e8 |
339 | Mouse::Meta::Attribute - attribute metaclass |
c3398f5b |
340 | |
341 | =head1 METHODS |
342 | |
306290e8 |
343 | =head2 new %args -> Mouse::Meta::Attribute |
c3398f5b |
344 | |
306290e8 |
345 | Instantiates a new Mouse::Meta::Attribute. Does nothing else. |
c3398f5b |
346 | |
306290e8 |
347 | =head2 create OwnerClass, AttributeName, %args -> Mouse::Meta::Attribute |
c3398f5b |
348 | |
349 | Creates a new attribute in OwnerClass. Accessors and helper methods are |
350 | installed. Some error checking is done. |
351 | |
352 | =head2 name -> AttributeName |
353 | |
181502b9 |
354 | =head2 associated_class -> OwnerClass |
c3398f5b |
355 | |
ab27a55e |
356 | =head2 is_required -> Bool |
c3398f5b |
357 | |
ab27a55e |
358 | =head2 default -> Item |
c3398f5b |
359 | |
ab27a55e |
360 | =head2 has_default -> Bool |
361 | |
362 | =head2 is_lazy -> Bool |
363 | |
364 | =head2 predicate -> MethodName | Undef |
365 | |
366 | =head2 has_predicate -> Bool |
367 | |
368 | =head2 clearer -> MethodName | Undef |
369 | |
370 | =head2 has_clearer -> Bool |
c3398f5b |
371 | |
372 | =head2 handles -> { LocalName => RemoteName } |
373 | |
ab27a55e |
374 | =head2 has_handles -> Bool |
375 | |
3645b316 |
376 | =head2 is_weak_ref -> Bool |
c3398f5b |
377 | |
378 | =head2 init_arg -> Str |
379 | |
ab27a55e |
380 | =head2 type_constraint -> Str |
381 | |
382 | =head2 has_type_constraint -> Bool |
383 | |
384 | =head2 trigger => CODE | Undef |
385 | |
386 | =head2 has_trigger -> Bool |
387 | |
388 | =head2 builder => MethodName | Undef |
389 | |
390 | =head2 has_builder -> Bool |
391 | |
93f08899 |
392 | =head2 is_lazy_build => Bool |
393 | |
0fff36e6 |
394 | =head2 should_auto_deref -> Bool |
395 | |
c3398f5b |
396 | Informational methods. |
397 | |
398 | =head2 generate_accessor -> CODE |
399 | |
400 | Creates a new code reference for the attribute's accessor. |
401 | |
402 | =head2 generate_predicate -> CODE |
403 | |
404 | Creates a new code reference for the attribute's predicate. |
405 | |
406 | =head2 generate_clearer -> CODE |
407 | |
408 | Creates a new code reference for the attribute's clearer. |
409 | |
410 | =head2 generate_handles -> { MethodName => CODE } |
411 | |
412 | Creates a new code reference for each of the attribute's handles methods. |
413 | |
fb706f5c |
414 | =head2 find_type_constraint -> CODE |
415 | |
416 | Returns a code reference which can be used to check that a given value passes |
417 | this attribute's type constraint; |
418 | |
419 | =head2 verify_type_constraint Item -> 1 | ERROR |
420 | |
421 | Checks that the given value passes this attribute's type constraint. Returns 1 |
422 | on success, otherwise C<confess>es. |
423 | |
93d190e0 |
424 | =head2 canonicalize_args Name, %args -> %args |
425 | |
426 | Canonicalizes some arguments to create. In particular, C<lazy_build> is |
427 | canonicalized into C<lazy>, C<builder>, etc. |
428 | |
1bbaa8ed |
429 | =head2 validate_args Name, \%args -> 1 | ERROR |
93d190e0 |
430 | |
431 | Checks that the arguments to create the attribute (ie those specified by |
432 | C<has>) are valid. |
433 | |
f7b11a21 |
434 | =head2 clone_parent OwnerClass, AttributeName, %args -> Mouse::Meta::Attribute |
435 | |
436 | Creates a new attribute in OwnerClass, inheriting options from parent classes. |
437 | Accessors and helper methods are installed. Some error checking is done. |
438 | |
439 | =head2 get_parent_args OwnerClass, AttributeName -> Hash |
440 | |
441 | Returns the options that the parent class of C<OwnerClass> used for attribute |
442 | C<AttributeName>. |
443 | |
c3398f5b |
444 | =cut |
445 | |