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