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'; |
3301fa54 |
7 | use Scalar::Util 'blessed'; |
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 | |
3cf68001 |
23 | sub name { $_[0]->{name} } |
24 | sub class { $_[0]->{class} } |
25 | sub _is_metadata { $_[0]->{is} } |
26 | sub is_required { $_[0]->{required} } |
27 | sub default { $_[0]->{default} } |
28 | sub is_lazy { $_[0]->{lazy} } |
a5fe4015 |
29 | sub is_lazy_build { $_[0]->{lazy_build} } |
3cf68001 |
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 | |
c3398f5b |
53 | sub generate_accessor { |
54 | my $attribute = shift; |
55 | |
2434d21b |
56 | my $name = $attribute->name; |
f3c1ccc8 |
57 | my $key = $name; |
2434d21b |
58 | my $default = $attribute->default; |
2434d21b |
59 | my $type = $attribute->type_constraint; |
5aa30ced |
60 | my $constraint = $attribute->find_type_constraint; |
9367e029 |
61 | my $builder = $attribute->builder; |
c3398f5b |
62 | |
4e757c98 |
63 | my $trigger = $attribute->trigger; |
64 | my $before = $trigger->{before}; |
65 | my $after = $trigger->{after}; |
66 | my $around = $trigger->{around}; |
67 | |
c3398f5b |
68 | my $accessor = 'sub { |
69 | my $self = shift;'; |
70 | |
2434d21b |
71 | if ($attribute->_is_metadata eq 'rw') { |
c3398f5b |
72 | $accessor .= 'if (@_) { |
a707f587 |
73 | local $_ = $_[0];'; |
74 | |
4e757c98 |
75 | if ($before) { |
76 | $accessor .= '$before->($self, $_, $attribute);'; |
77 | } |
78 | |
a707f587 |
79 | if ($constraint) { |
1f2b4780 |
80 | $accessor .= 'do { |
e8b3db47 |
81 | my $display = defined($_) ? overload::StrVal($_) : "undef"; |
1f2b4780 |
82 | Carp::confess("Attribute ($name) does not pass the type constraint because: Validation failed for \'$type\' failed with value $display") unless $constraint->(); |
83 | };' |
a707f587 |
84 | } |
85 | |
86 | $accessor .= '$self->{$key} = $_;'; |
c3398f5b |
87 | |
3645b316 |
88 | if ($attribute->is_weak_ref) { |
89 | $accessor .= 'Scalar::Util::weaken($self->{$key}) if ref($self->{$key});'; |
c3398f5b |
90 | } |
91 | |
4e757c98 |
92 | if ($after) { |
93 | $accessor .= '$after->($self, $_, $attribute);'; |
c3398f5b |
94 | } |
95 | |
96 | $accessor .= '}'; |
97 | } |
98 | else { |
636c002e |
99 | $accessor .= 'confess "Cannot assign a value to a read-only accessor" if @_;'; |
c3398f5b |
100 | } |
101 | |
2434d21b |
102 | if ($attribute->is_lazy) { |
c3398f5b |
103 | $accessor .= '$self->{$key} = '; |
9367e029 |
104 | |
105 | $accessor .= $attribute->has_builder |
106 | ? '$self->$builder' |
107 | : ref($default) eq 'CODE' |
108 | ? '$default->($self)' |
109 | : '$default'; |
110 | |
c3398f5b |
111 | $accessor .= ' if !exists($self->{$key});'; |
112 | } |
113 | |
3cf68001 |
114 | if ($attribute->should_auto_deref) { |
115 | if ($attribute->type_constraint eq 'ArrayRef') { |
116 | $accessor .= 'if (wantarray) { |
117 | return @{ $self->{$key} || [] }; |
118 | }'; |
119 | } |
120 | else { |
121 | $accessor .= 'if (wantarray) { |
122 | return %{ $self->{$key} || {} }; |
123 | }'; |
124 | } |
125 | } |
126 | |
127 | $accessor .= 'return $self->{$key}; |
c3398f5b |
128 | }'; |
129 | |
130 | return eval $accessor; |
131 | } |
132 | |
133 | sub generate_predicate { |
134 | my $attribute = shift; |
f3c1ccc8 |
135 | my $key = $attribute->name; |
c3398f5b |
136 | |
137 | my $predicate = 'sub { exists($_[0]->{$key}) }'; |
138 | |
139 | return eval $predicate; |
140 | } |
141 | |
142 | sub generate_clearer { |
143 | my $attribute = shift; |
f3c1ccc8 |
144 | my $key = $attribute->name; |
c3398f5b |
145 | |
146 | my $predicate = 'sub { delete($_[0]->{$key}) }'; |
147 | |
148 | return eval $predicate; |
149 | } |
150 | |
151 | sub generate_handles { |
152 | my $attribute = shift; |
2434d21b |
153 | my $reader = $attribute->name; |
c3cc3642 |
154 | my %handles = $attribute->_canonicalize_handles($attribute->handles); |
c3398f5b |
155 | |
156 | my %method_map; |
157 | |
c3cc3642 |
158 | for my $local_method (keys %handles) { |
159 | my $remote_method = $handles{$local_method}; |
c3398f5b |
160 | |
161 | my $method = 'sub { |
162 | my $self = shift; |
163 | $self->$reader->$remote_method(@_) |
164 | }'; |
165 | |
166 | $method_map{$local_method} = eval $method; |
167 | } |
168 | |
169 | return \%method_map; |
170 | } |
171 | |
172 | sub create { |
173 | my ($self, $class, $name, %args) = @_; |
174 | |
1bfebf5f |
175 | $args{name} = $name; |
176 | $args{class} = $class; |
177 | |
93d190e0 |
178 | %args = $self->canonicalize_args($name, %args); |
1bbaa8ed |
179 | $self->validate_args($name, \%args); |
45ea8620 |
180 | |
c021207d |
181 | $args{type_constraint} = delete $args{isa} |
182 | if exists $args{isa}; |
186657a9 |
183 | |
1bfebf5f |
184 | my $attribute = $self->new(%args); |
185 | $attribute->_create_args(\%args); |
186 | |
c3398f5b |
187 | my $meta = $class->meta; |
188 | |
b2500191 |
189 | $meta->add_attribute($attribute); |
190 | |
c3398f5b |
191 | # install an accessor |
2434d21b |
192 | if ($attribute->_is_metadata eq 'rw' || $attribute->_is_metadata eq 'ro') { |
c3398f5b |
193 | my $accessor = $attribute->generate_accessor; |
194 | no strict 'refs'; |
195 | *{ $class . '::' . $name } = $accessor; |
196 | } |
197 | |
c3398f5b |
198 | for my $method (qw/predicate clearer/) { |
2434d21b |
199 | my $predicate = "has_$method"; |
200 | if ($attribute->$predicate) { |
c3398f5b |
201 | my $generator = "generate_$method"; |
202 | my $coderef = $attribute->$generator; |
203 | no strict 'refs'; |
2434d21b |
204 | *{ $class . '::' . $attribute->$method } = $coderef; |
c3398f5b |
205 | } |
206 | } |
207 | |
2434d21b |
208 | if ($attribute->has_handles) { |
c3398f5b |
209 | my $method_map = $attribute->generate_handles; |
210 | for my $method_name (keys %$method_map) { |
211 | no strict 'refs'; |
212 | *{ $class . '::' . $method_name } = $method_map->{$method_name}; |
213 | } |
214 | } |
215 | |
216 | return $attribute; |
217 | } |
218 | |
93d190e0 |
219 | sub canonicalize_args { |
220 | my $self = shift; |
221 | my $name = shift; |
222 | my %args = @_; |
223 | |
224 | if ($args{lazy_build}) { |
225 | $args{lazy} = 1; |
226 | $args{required} = 1; |
227 | $args{builder} = "_build_${name}" |
228 | if !exists($args{builder}); |
229 | if ($name =~ /^_/) { |
230 | $args{clearer} = "_clear${name}" if !exists($args{clearer}); |
231 | $args{predicate} = "_has${name}" if !exists($args{predicate}); |
232 | } |
233 | else { |
234 | $args{clearer} = "clear_${name}" if !exists($args{clearer}); |
235 | $args{predicate} = "has_${name}" if !exists($args{predicate}); |
236 | } |
237 | } |
238 | |
239 | return %args; |
240 | } |
241 | |
8fd9e611 |
242 | sub validate_args { |
243 | my $self = shift; |
244 | my $name = shift; |
1bbaa8ed |
245 | my $args = shift; |
8fd9e611 |
246 | |
93d190e0 |
247 | confess "You can not use lazy_build and default for the same attribute ($name)" |
1bbaa8ed |
248 | if $args->{lazy_build} && exists $args->{default}; |
93d190e0 |
249 | |
8fd9e611 |
250 | confess "You cannot have lazy attribute ($name) without specifying a default value for it" |
1bbaa8ed |
251 | if $args->{lazy} |
252 | && !exists($args->{default}) |
253 | && !exists($args->{builder}); |
8fd9e611 |
254 | |
255 | confess "References are not allowed as default values, you must wrap the default of '$name' in a CODE reference (ex: sub { [] } and not [])" |
1bbaa8ed |
256 | if ref($args->{default}) |
257 | && ref($args->{default}) ne 'CODE'; |
8fd9e611 |
258 | |
259 | confess "You cannot auto-dereference without specifying a type constraint on attribute $name" |
1bbaa8ed |
260 | if $args->{auto_deref} && !exists($args->{isa}); |
8fd9e611 |
261 | |
262 | confess "You cannot auto-dereference anything other than a ArrayRef or HashRef on attribute $name" |
1bbaa8ed |
263 | if $args->{auto_deref} |
264 | && $args->{isa} ne 'ArrayRef' |
265 | && $args->{isa} ne 'HashRef'; |
8fd9e611 |
266 | |
506db557 |
267 | if ($args->{trigger}) { |
268 | if (ref($args->{trigger}) eq 'CODE') { |
269 | $args->{trigger} = { |
270 | after => $args->{trigger}, |
271 | }; |
272 | } |
273 | |
274 | confess "Trigger must be a CODE or HASH ref on attribute ($name)" |
275 | if $args->{trigger} |
276 | && ref($args->{trigger}) ne 'HASH'; |
277 | } |
6c5498d0 |
278 | |
8fd9e611 |
279 | return 1; |
280 | } |
281 | |
5aa30ced |
282 | sub find_type_constraint { |
283 | my $self = shift; |
284 | my $type = $self->type_constraint; |
285 | |
286 | return unless $type; |
287 | |
288 | my $checker = Mouse::TypeRegistry->optimized_constraints->{$type}; |
289 | return $checker if $checker; |
290 | |
3301fa54 |
291 | return sub { blessed($_) && blessed($_) eq $type }; |
5aa30ced |
292 | } |
293 | |
294 | sub verify_type_constraint { |
295 | my $self = shift; |
296 | local $_ = shift; |
297 | |
298 | my $type = $self->type_constraint |
299 | or return 1; |
af745d5a |
300 | my $constraint = $self->find_type_constraint; |
5aa30ced |
301 | |
302 | return 1 if $constraint->($_); |
303 | |
304 | my $name = $self->name; |
f3e05dfd |
305 | my $display = defined($_) ? overload::StrVal($_) : 'undef'; |
306 | Carp::confess("Attribute ($name) does not pass the type constraint because: Validation failed for \'$type\' failed with value $display"); |
5aa30ced |
307 | } |
308 | |
af745d5a |
309 | sub _canonicalize_handles { |
310 | my $self = shift; |
311 | my $handles = shift; |
312 | |
313 | if (ref($handles) eq 'HASH') { |
314 | return %$handles; |
315 | } |
316 | elsif (ref($handles) eq 'ARRAY') { |
317 | return map { $_ => $_ } @$handles; |
318 | } |
319 | else { |
320 | confess "Unable to canonicalize the 'handles' option with $handles"; |
321 | } |
322 | } |
323 | |
1bfebf5f |
324 | sub clone_parent { |
325 | my $self = shift; |
326 | my $class = shift; |
327 | my $name = shift; |
328 | my %args = ($self->get_parent_args($class, $name), @_); |
329 | |
330 | $self->create($class, $name, %args); |
331 | } |
332 | |
333 | sub get_parent_args { |
334 | my $self = shift; |
335 | my $class = shift; |
336 | my $name = shift; |
337 | |
338 | for my $super ($class->meta->linearized_isa) { |
bb733405 |
339 | my $super_attr = $super->can("meta") && $super->meta->get_attribute($name) |
1bfebf5f |
340 | or next; |
341 | return %{ $super_attr->_create_args }; |
342 | } |
343 | |
344 | confess "Could not find an attribute by the name of '$name' to inherit from"; |
345 | } |
346 | |
c3398f5b |
347 | 1; |
348 | |
349 | __END__ |
350 | |
351 | =head1 NAME |
352 | |
306290e8 |
353 | Mouse::Meta::Attribute - attribute metaclass |
c3398f5b |
354 | |
355 | =head1 METHODS |
356 | |
306290e8 |
357 | =head2 new %args -> Mouse::Meta::Attribute |
c3398f5b |
358 | |
306290e8 |
359 | Instantiates a new Mouse::Meta::Attribute. Does nothing else. |
c3398f5b |
360 | |
306290e8 |
361 | =head2 create OwnerClass, AttributeName, %args -> Mouse::Meta::Attribute |
c3398f5b |
362 | |
363 | Creates a new attribute in OwnerClass. Accessors and helper methods are |
364 | installed. Some error checking is done. |
365 | |
366 | =head2 name -> AttributeName |
367 | |
368 | =head2 class -> OwnerClass |
369 | |
ab27a55e |
370 | =head2 is_required -> Bool |
c3398f5b |
371 | |
ab27a55e |
372 | =head2 default -> Item |
c3398f5b |
373 | |
ab27a55e |
374 | =head2 has_default -> Bool |
375 | |
376 | =head2 is_lazy -> Bool |
377 | |
378 | =head2 predicate -> MethodName | Undef |
379 | |
380 | =head2 has_predicate -> Bool |
381 | |
382 | =head2 clearer -> MethodName | Undef |
383 | |
384 | =head2 has_clearer -> Bool |
c3398f5b |
385 | |
386 | =head2 handles -> { LocalName => RemoteName } |
387 | |
ab27a55e |
388 | =head2 has_handles -> Bool |
389 | |
3645b316 |
390 | =head2 is_weak_ref -> Bool |
c3398f5b |
391 | |
392 | =head2 init_arg -> Str |
393 | |
ab27a55e |
394 | =head2 type_constraint -> Str |
395 | |
396 | =head2 has_type_constraint -> Bool |
397 | |
398 | =head2 trigger => CODE | Undef |
399 | |
400 | =head2 has_trigger -> Bool |
401 | |
402 | =head2 builder => MethodName | Undef |
403 | |
404 | =head2 has_builder -> Bool |
405 | |
93f08899 |
406 | =head2 is_lazy_build => Bool |
407 | |
0fff36e6 |
408 | =head2 should_auto_deref -> Bool |
409 | |
c3398f5b |
410 | Informational methods. |
411 | |
412 | =head2 generate_accessor -> CODE |
413 | |
414 | Creates a new code reference for the attribute's accessor. |
415 | |
416 | =head2 generate_predicate -> CODE |
417 | |
418 | Creates a new code reference for the attribute's predicate. |
419 | |
420 | =head2 generate_clearer -> CODE |
421 | |
422 | Creates a new code reference for the attribute's clearer. |
423 | |
424 | =head2 generate_handles -> { MethodName => CODE } |
425 | |
426 | Creates a new code reference for each of the attribute's handles methods. |
427 | |
fb706f5c |
428 | =head2 find_type_constraint -> CODE |
429 | |
430 | Returns a code reference which can be used to check that a given value passes |
431 | this attribute's type constraint; |
432 | |
433 | =head2 verify_type_constraint Item -> 1 | ERROR |
434 | |
435 | Checks that the given value passes this attribute's type constraint. Returns 1 |
436 | on success, otherwise C<confess>es. |
437 | |
93d190e0 |
438 | =head2 canonicalize_args Name, %args -> %args |
439 | |
440 | Canonicalizes some arguments to create. In particular, C<lazy_build> is |
441 | canonicalized into C<lazy>, C<builder>, etc. |
442 | |
1bbaa8ed |
443 | =head2 validate_args Name, \%args -> 1 | ERROR |
93d190e0 |
444 | |
445 | Checks that the arguments to create the attribute (ie those specified by |
446 | C<has>) are valid. |
447 | |
f7b11a21 |
448 | =head2 clone_parent OwnerClass, AttributeName, %args -> Mouse::Meta::Attribute |
449 | |
450 | Creates a new attribute in OwnerClass, inheriting options from parent classes. |
451 | Accessors and helper methods are installed. Some error checking is done. |
452 | |
453 | =head2 get_parent_args OwnerClass, AttributeName -> Hash |
454 | |
455 | Returns the options that the parent class of C<OwnerClass> used for attribute |
456 | C<AttributeName>. |
457 | |
c3398f5b |
458 | =cut |
459 | |