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 | |
2434d21b |
63 | my $name = $attribute->name; |
2434d21b |
64 | my $default = $attribute->default; |
2434d21b |
65 | my $type = $attribute->type_constraint; |
5aa30ced |
66 | my $constraint = $attribute->find_type_constraint; |
9367e029 |
67 | my $builder = $attribute->builder; |
a08e715f |
68 | my $trigger = $attribute->trigger; |
4e757c98 |
69 | |
85ccd3e9 |
70 | my $self = '$_[0]'; |
71 | my $value = '$_[1]'; |
72 | my $key = $attribute->inlined_name; |
c3398f5b |
73 | |
85ccd3e9 |
74 | my $accessor = "sub {\n"; |
2434d21b |
75 | if ($attribute->_is_metadata eq 'rw') { |
85ccd3e9 |
76 | $accessor .= 'if (scalar(@_) >= 2) { |
ed1eec39 |
77 | '; |
a707f587 |
78 | |
a08e715f |
79 | if ($constraint) { |
85ccd3e9 |
80 | $accessor .= 'local $_ = ' . $value . '; |
ed1eec39 |
81 | unless ($constraint->()) { |
a08e715f |
82 | my $display = defined($_) ? overload::StrVal($_) : "undef"; |
83 | Carp::confess("Attribute ($name) does not pass the type constraint because: Validation failed for \'$type\' failed with value $display"); |
85ccd3e9 |
84 | }' . "\n" |
a707f587 |
85 | } |
86 | |
35e1cb90 |
87 | $accessor .= 'return ' |
88 | if !$attribute->is_weak_ref |
89 | && !$trigger |
90 | && !$attribute->should_auto_deref; |
c3398f5b |
91 | |
a08e715f |
92 | if ($attribute->is_weak_ref) { |
85ccd3e9 |
93 | $accessor .= 'weaken('.$self.'->{'.$key.'}) if ref('.$self.'->{'.$key.'});' . "\n"; |
c3398f5b |
94 | } |
95 | |
a08e715f |
96 | if ($trigger) { |
85ccd3e9 |
97 | $accessor .= '$trigger->('.$self.', '.$value.', $attribute);' . "\n"; |
c3398f5b |
98 | } |
99 | |
85ccd3e9 |
100 | $accessor .= "}\n"; |
c3398f5b |
101 | } |
102 | else { |
85ccd3e9 |
103 | $accessor .= 'confess "Cannot assign a value to a read-only accessor" if scalar(@_) >= 2;' . "\n"; |
c3398f5b |
104 | } |
105 | |
2434d21b |
106 | if ($attribute->is_lazy) { |
85ccd3e9 |
107 | $accessor .= $self.'->{'.$key.'} = '; |
9367e029 |
108 | |
109 | $accessor .= $attribute->has_builder |
85ccd3e9 |
110 | ? $self.'->$builder' |
111 | : ref($default) eq 'CODE' |
112 | ? '$default->('.$self.')' |
113 | : '$default'; |
114 | $accessor .= ' if !exists '.$self.'->{'.$key.'};' . "\n"; |
c3398f5b |
115 | } |
116 | |
3cf68001 |
117 | if ($attribute->should_auto_deref) { |
118 | if ($attribute->type_constraint eq 'ArrayRef') { |
119 | $accessor .= 'if (wantarray) { |
85ccd3e9 |
120 | return @{ '.$self.'->{'.$key.'} || [] }; |
121 | }' . "\n"; |
3cf68001 |
122 | } |
123 | else { |
124 | $accessor .= 'if (wantarray) { |
85ccd3e9 |
125 | return %{ '.$self.'->{'.$key.'} || {} }; |
126 | }' . "\n"; |
3cf68001 |
127 | } |
128 | } |
129 | |
85ccd3e9 |
130 | $accessor .= 'return '.$self.'->{'.$key.'}; |
c3398f5b |
131 | }'; |
132 | |
71b948d1 |
133 | my $sub = eval $accessor; |
134 | confess $@ if $@; |
135 | return $sub; |
c3398f5b |
136 | } |
137 | |
138 | sub generate_predicate { |
139 | my $attribute = shift; |
d10fd510 |
140 | my $key = $attribute->inlined_name; |
c3398f5b |
141 | |
d10fd510 |
142 | my $predicate = 'sub { exists($_[0]->{'.$key.'}) }'; |
c3398f5b |
143 | |
71b948d1 |
144 | my $sub = eval $predicate; |
145 | confess $@ if $@; |
146 | return $sub; |
c3398f5b |
147 | } |
148 | |
149 | sub generate_clearer { |
150 | my $attribute = shift; |
d10fd510 |
151 | my $key = $attribute->inlined_name; |
c3398f5b |
152 | |
d10fd510 |
153 | my $clearer = 'sub { delete($_[0]->{'.$key.'}) }'; |
c3398f5b |
154 | |
71b948d1 |
155 | my $sub = eval $clearer; |
156 | confess $@ if $@; |
157 | return $sub; |
c3398f5b |
158 | } |
159 | |
160 | sub generate_handles { |
161 | my $attribute = shift; |
2434d21b |
162 | my $reader = $attribute->name; |
c3cc3642 |
163 | my %handles = $attribute->_canonicalize_handles($attribute->handles); |
c3398f5b |
164 | |
165 | my %method_map; |
166 | |
c3cc3642 |
167 | for my $local_method (keys %handles) { |
168 | my $remote_method = $handles{$local_method}; |
c3398f5b |
169 | |
170 | my $method = 'sub { |
171 | my $self = shift; |
172 | $self->$reader->$remote_method(@_) |
173 | }'; |
174 | |
175 | $method_map{$local_method} = eval $method; |
71b948d1 |
176 | confess $@ if $@; |
c3398f5b |
177 | } |
178 | |
179 | return \%method_map; |
180 | } |
181 | |
182 | sub create { |
183 | my ($self, $class, $name, %args) = @_; |
184 | |
1bfebf5f |
185 | $args{name} = $name; |
181502b9 |
186 | $args{associated_class} = $class; |
1bfebf5f |
187 | |
93d190e0 |
188 | %args = $self->canonicalize_args($name, %args); |
1bbaa8ed |
189 | $self->validate_args($name, \%args); |
45ea8620 |
190 | |
c021207d |
191 | $args{type_constraint} = delete $args{isa} |
192 | if exists $args{isa}; |
186657a9 |
193 | |
1bfebf5f |
194 | my $attribute = $self->new(%args); |
1bfebf5f |
195 | |
724c77c0 |
196 | $attribute->_create_args(\%args); |
c3398f5b |
197 | |
724c77c0 |
198 | $class->add_attribute($attribute); |
b2500191 |
199 | |
c3398f5b |
200 | # install an accessor |
2434d21b |
201 | if ($attribute->_is_metadata eq 'rw' || $attribute->_is_metadata eq 'ro') { |
c3398f5b |
202 | my $accessor = $attribute->generate_accessor; |
724c77c0 |
203 | $class->add_method($name => $accessor); |
c3398f5b |
204 | } |
205 | |
c3398f5b |
206 | for my $method (qw/predicate clearer/) { |
2434d21b |
207 | my $predicate = "has_$method"; |
208 | if ($attribute->$predicate) { |
c3398f5b |
209 | my $generator = "generate_$method"; |
210 | my $coderef = $attribute->$generator; |
724c77c0 |
211 | $class->add_method($attribute->$method => $coderef); |
c3398f5b |
212 | } |
213 | } |
214 | |
2434d21b |
215 | if ($attribute->has_handles) { |
c3398f5b |
216 | my $method_map = $attribute->generate_handles; |
217 | for my $method_name (keys %$method_map) { |
724c77c0 |
218 | $class->add_method($method_name => $method_map->{$method_name}); |
c3398f5b |
219 | } |
220 | } |
221 | |
222 | return $attribute; |
223 | } |
224 | |
93d190e0 |
225 | sub canonicalize_args { |
226 | my $self = shift; |
227 | my $name = shift; |
228 | my %args = @_; |
229 | |
230 | if ($args{lazy_build}) { |
231 | $args{lazy} = 1; |
232 | $args{required} = 1; |
233 | $args{builder} = "_build_${name}" |
234 | if !exists($args{builder}); |
235 | if ($name =~ /^_/) { |
236 | $args{clearer} = "_clear${name}" if !exists($args{clearer}); |
237 | $args{predicate} = "_has${name}" if !exists($args{predicate}); |
238 | } |
239 | else { |
240 | $args{clearer} = "clear_${name}" if !exists($args{clearer}); |
241 | $args{predicate} = "has_${name}" if !exists($args{predicate}); |
242 | } |
243 | } |
244 | |
245 | return %args; |
246 | } |
247 | |
8fd9e611 |
248 | sub validate_args { |
249 | my $self = shift; |
250 | my $name = shift; |
1bbaa8ed |
251 | my $args = shift; |
8fd9e611 |
252 | |
93d190e0 |
253 | confess "You can not use lazy_build and default for the same attribute ($name)" |
1bbaa8ed |
254 | if $args->{lazy_build} && exists $args->{default}; |
93d190e0 |
255 | |
8fd9e611 |
256 | confess "You cannot have lazy attribute ($name) without specifying a default value for it" |
1bbaa8ed |
257 | if $args->{lazy} |
258 | && !exists($args->{default}) |
259 | && !exists($args->{builder}); |
8fd9e611 |
260 | |
261 | confess "References are not allowed as default values, you must wrap the default of '$name' in a CODE reference (ex: sub { [] } and not [])" |
1bbaa8ed |
262 | if ref($args->{default}) |
263 | && ref($args->{default}) ne 'CODE'; |
8fd9e611 |
264 | |
97661b77 |
265 | confess "You cannot auto-dereference without specifying a type constraint on attribute ($name)" |
1bbaa8ed |
266 | if $args->{auto_deref} && !exists($args->{isa}); |
8fd9e611 |
267 | |
97661b77 |
268 | confess "You cannot auto-dereference anything other than a ArrayRef or HashRef on attribute ($name)" |
1bbaa8ed |
269 | if $args->{auto_deref} |
270 | && $args->{isa} ne 'ArrayRef' |
271 | && $args->{isa} ne 'HashRef'; |
8fd9e611 |
272 | |
506db557 |
273 | if ($args->{trigger}) { |
a08e715f |
274 | if (ref($args->{trigger}) eq 'HASH') { |
275 | Carp::carp "HASH-based form of trigger has been removed. Only the coderef form of triggers are now supported."; |
844fa049 |
276 | } |
506db557 |
277 | |
844fa049 |
278 | confess "Trigger must be a CODE ref on attribute ($name)" |
a08e715f |
279 | if ref($args->{trigger}) ne 'CODE'; |
506db557 |
280 | } |
6c5498d0 |
281 | |
8fd9e611 |
282 | return 1; |
283 | } |
284 | |
5aa30ced |
285 | sub find_type_constraint { |
286 | my $self = shift; |
287 | my $type = $self->type_constraint; |
288 | |
289 | return unless $type; |
290 | |
291 | my $checker = Mouse::TypeRegistry->optimized_constraints->{$type}; |
292 | return $checker if $checker; |
293 | |
3301fa54 |
294 | return sub { blessed($_) && blessed($_) eq $type }; |
5aa30ced |
295 | } |
296 | |
297 | sub verify_type_constraint { |
298 | my $self = shift; |
299 | local $_ = shift; |
300 | |
301 | my $type = $self->type_constraint |
302 | or return 1; |
af745d5a |
303 | my $constraint = $self->find_type_constraint; |
5aa30ced |
304 | |
305 | return 1 if $constraint->($_); |
306 | |
307 | my $name = $self->name; |
f3e05dfd |
308 | my $display = defined($_) ? overload::StrVal($_) : 'undef'; |
309 | Carp::confess("Attribute ($name) does not pass the type constraint because: Validation failed for \'$type\' failed with value $display"); |
5aa30ced |
310 | } |
311 | |
af745d5a |
312 | sub _canonicalize_handles { |
313 | my $self = shift; |
314 | my $handles = shift; |
315 | |
316 | if (ref($handles) eq 'HASH') { |
317 | return %$handles; |
318 | } |
319 | elsif (ref($handles) eq 'ARRAY') { |
320 | return map { $_ => $_ } @$handles; |
321 | } |
322 | else { |
323 | confess "Unable to canonicalize the 'handles' option with $handles"; |
324 | } |
325 | } |
326 | |
1bfebf5f |
327 | sub clone_parent { |
328 | my $self = shift; |
329 | my $class = shift; |
330 | my $name = shift; |
331 | my %args = ($self->get_parent_args($class, $name), @_); |
332 | |
333 | $self->create($class, $name, %args); |
334 | } |
335 | |
336 | sub get_parent_args { |
337 | my $self = shift; |
338 | my $class = shift; |
339 | my $name = shift; |
340 | |
724c77c0 |
341 | for my $super ($class->linearized_isa) { |
bb733405 |
342 | my $super_attr = $super->can("meta") && $super->meta->get_attribute($name) |
1bfebf5f |
343 | or next; |
344 | return %{ $super_attr->_create_args }; |
345 | } |
346 | |
347 | confess "Could not find an attribute by the name of '$name' to inherit from"; |
348 | } |
349 | |
c3398f5b |
350 | 1; |
351 | |
352 | __END__ |
353 | |
354 | =head1 NAME |
355 | |
306290e8 |
356 | Mouse::Meta::Attribute - attribute metaclass |
c3398f5b |
357 | |
358 | =head1 METHODS |
359 | |
306290e8 |
360 | =head2 new %args -> Mouse::Meta::Attribute |
c3398f5b |
361 | |
306290e8 |
362 | Instantiates a new Mouse::Meta::Attribute. Does nothing else. |
c3398f5b |
363 | |
306290e8 |
364 | =head2 create OwnerClass, AttributeName, %args -> Mouse::Meta::Attribute |
c3398f5b |
365 | |
366 | Creates a new attribute in OwnerClass. Accessors and helper methods are |
367 | installed. Some error checking is done. |
368 | |
369 | =head2 name -> AttributeName |
370 | |
181502b9 |
371 | =head2 associated_class -> OwnerClass |
c3398f5b |
372 | |
ab27a55e |
373 | =head2 is_required -> Bool |
c3398f5b |
374 | |
ab27a55e |
375 | =head2 default -> Item |
c3398f5b |
376 | |
ab27a55e |
377 | =head2 has_default -> Bool |
378 | |
379 | =head2 is_lazy -> Bool |
380 | |
381 | =head2 predicate -> MethodName | Undef |
382 | |
383 | =head2 has_predicate -> Bool |
384 | |
385 | =head2 clearer -> MethodName | Undef |
386 | |
387 | =head2 has_clearer -> Bool |
c3398f5b |
388 | |
389 | =head2 handles -> { LocalName => RemoteName } |
390 | |
ab27a55e |
391 | =head2 has_handles -> Bool |
392 | |
3645b316 |
393 | =head2 is_weak_ref -> Bool |
c3398f5b |
394 | |
395 | =head2 init_arg -> Str |
396 | |
ab27a55e |
397 | =head2 type_constraint -> Str |
398 | |
399 | =head2 has_type_constraint -> Bool |
400 | |
401 | =head2 trigger => CODE | Undef |
402 | |
403 | =head2 has_trigger -> Bool |
404 | |
405 | =head2 builder => MethodName | Undef |
406 | |
407 | =head2 has_builder -> Bool |
408 | |
93f08899 |
409 | =head2 is_lazy_build => Bool |
410 | |
0fff36e6 |
411 | =head2 should_auto_deref -> Bool |
412 | |
c3398f5b |
413 | Informational methods. |
414 | |
415 | =head2 generate_accessor -> CODE |
416 | |
417 | Creates a new code reference for the attribute's accessor. |
418 | |
419 | =head2 generate_predicate -> CODE |
420 | |
421 | Creates a new code reference for the attribute's predicate. |
422 | |
423 | =head2 generate_clearer -> CODE |
424 | |
425 | Creates a new code reference for the attribute's clearer. |
426 | |
427 | =head2 generate_handles -> { MethodName => CODE } |
428 | |
429 | Creates a new code reference for each of the attribute's handles methods. |
430 | |
fb706f5c |
431 | =head2 find_type_constraint -> CODE |
432 | |
433 | Returns a code reference which can be used to check that a given value passes |
434 | this attribute's type constraint; |
435 | |
436 | =head2 verify_type_constraint Item -> 1 | ERROR |
437 | |
438 | Checks that the given value passes this attribute's type constraint. Returns 1 |
439 | on success, otherwise C<confess>es. |
440 | |
93d190e0 |
441 | =head2 canonicalize_args Name, %args -> %args |
442 | |
443 | Canonicalizes some arguments to create. In particular, C<lazy_build> is |
444 | canonicalized into C<lazy>, C<builder>, etc. |
445 | |
1bbaa8ed |
446 | =head2 validate_args Name, \%args -> 1 | ERROR |
93d190e0 |
447 | |
448 | Checks that the arguments to create the attribute (ie those specified by |
449 | C<has>) are valid. |
450 | |
f7b11a21 |
451 | =head2 clone_parent OwnerClass, AttributeName, %args -> Mouse::Meta::Attribute |
452 | |
453 | Creates a new attribute in OwnerClass, inheriting options from parent classes. |
454 | Accessors and helper methods are installed. Some error checking is done. |
455 | |
456 | =head2 get_parent_args OwnerClass, AttributeName -> Hash |
457 | |
458 | Returns the options that the parent class of C<OwnerClass> used for attribute |
459 | C<AttributeName>. |
460 | |
c3398f5b |
461 | =cut |
462 | |