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'; |
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8 | |
9 | sub new { |
10 | my $class = shift; |
11 | my %args = @_; |
12 | |
7ee01d77 |
13 | $args{init_arg} = $args{name} |
14 | unless exists $args{init_arg}; |
45959ffa |
15 | |
c3398f5b |
16 | $args{is} ||= ''; |
17 | |
45959ffa |
18 | if ( $args{lazy_build} ) { |
19 | $args{lazy} = 1; |
20 | $args{builder} ||= "_build_$args{name}"; |
21 | } |
22 | |
c3398f5b |
23 | bless \%args, $class; |
24 | } |
25 | |
3cf68001 |
26 | sub name { $_[0]->{name} } |
27 | sub class { $_[0]->{class} } |
28 | sub _is_metadata { $_[0]->{is} } |
29 | sub is_required { $_[0]->{required} } |
30 | sub default { $_[0]->{default} } |
31 | sub is_lazy { $_[0]->{lazy} } |
32 | sub predicate { $_[0]->{predicate} } |
33 | sub clearer { $_[0]->{clearer} } |
34 | sub handles { $_[0]->{handles} } |
35 | sub is_weak_ref { $_[0]->{weak_ref} } |
36 | sub init_arg { $_[0]->{init_arg} } |
37 | sub type_constraint { $_[0]->{type_constraint} } |
38 | sub trigger { $_[0]->{trigger} } |
39 | sub builder { $_[0]->{builder} } |
40 | sub should_auto_deref { $_[0]->{auto_deref} } |
c3398f5b |
41 | |
ccea8101 |
42 | sub has_default { exists $_[0]->{default} } |
43 | sub has_predicate { exists $_[0]->{predicate} } |
44 | sub has_clearer { exists $_[0]->{clearer} } |
45 | sub has_handles { exists $_[0]->{handles} } |
ccea8101 |
46 | sub has_type_constraint { exists $_[0]->{type_constraint} } |
de9a434a |
47 | sub has_trigger { exists $_[0]->{trigger} } |
48 | sub has_builder { exists $_[0]->{builder} } |
ccea8101 |
49 | |
1bfebf5f |
50 | sub _create_args { |
51 | $_[0]->{_create_args} = $_[1] if @_ > 1; |
52 | $_[0]->{_create_args} |
53 | } |
54 | |
c3398f5b |
55 | sub generate_accessor { |
56 | my $attribute = shift; |
57 | |
2434d21b |
58 | my $name = $attribute->name; |
f3c1ccc8 |
59 | my $key = $name; |
2434d21b |
60 | my $default = $attribute->default; |
61 | my $trigger = $attribute->trigger; |
62 | my $type = $attribute->type_constraint; |
5aa30ced |
63 | my $constraint = $attribute->find_type_constraint; |
9367e029 |
64 | my $builder = $attribute->builder; |
c3398f5b |
65 | |
66 | my $accessor = 'sub { |
67 | my $self = shift;'; |
68 | |
2434d21b |
69 | if ($attribute->_is_metadata eq 'rw') { |
c3398f5b |
70 | $accessor .= 'if (@_) { |
a707f587 |
71 | local $_ = $_[0];'; |
72 | |
73 | if ($constraint) { |
1f2b4780 |
74 | $accessor .= 'do { |
e8b3db47 |
75 | my $display = defined($_) ? overload::StrVal($_) : "undef"; |
1f2b4780 |
76 | Carp::confess("Attribute ($name) does not pass the type constraint because: Validation failed for \'$type\' failed with value $display") unless $constraint->(); |
77 | };' |
a707f587 |
78 | } |
79 | |
80 | $accessor .= '$self->{$key} = $_;'; |
c3398f5b |
81 | |
3645b316 |
82 | if ($attribute->is_weak_ref) { |
83 | $accessor .= 'Scalar::Util::weaken($self->{$key}) if ref($self->{$key});'; |
c3398f5b |
84 | } |
85 | |
86 | if ($trigger) { |
a707f587 |
87 | $accessor .= '$trigger->($self, $_, $attribute);'; |
c3398f5b |
88 | } |
89 | |
90 | $accessor .= '}'; |
91 | } |
92 | else { |
636c002e |
93 | $accessor .= 'confess "Cannot assign a value to a read-only accessor" if @_;'; |
c3398f5b |
94 | } |
95 | |
2434d21b |
96 | if ($attribute->is_lazy) { |
c3398f5b |
97 | $accessor .= '$self->{$key} = '; |
9367e029 |
98 | |
99 | $accessor .= $attribute->has_builder |
100 | ? '$self->$builder' |
101 | : ref($default) eq 'CODE' |
102 | ? '$default->($self)' |
103 | : '$default'; |
104 | |
c3398f5b |
105 | $accessor .= ' if !exists($self->{$key});'; |
106 | } |
107 | |
3cf68001 |
108 | if ($attribute->should_auto_deref) { |
109 | if ($attribute->type_constraint eq 'ArrayRef') { |
110 | $accessor .= 'if (wantarray) { |
111 | return @{ $self->{$key} || [] }; |
112 | }'; |
113 | } |
114 | else { |
115 | $accessor .= 'if (wantarray) { |
116 | return %{ $self->{$key} || {} }; |
117 | }'; |
118 | } |
119 | } |
120 | |
121 | $accessor .= 'return $self->{$key}; |
c3398f5b |
122 | }'; |
123 | |
124 | return eval $accessor; |
125 | } |
126 | |
127 | sub generate_predicate { |
128 | my $attribute = shift; |
f3c1ccc8 |
129 | my $key = $attribute->name; |
c3398f5b |
130 | |
131 | my $predicate = 'sub { exists($_[0]->{$key}) }'; |
132 | |
133 | return eval $predicate; |
134 | } |
135 | |
136 | sub generate_clearer { |
137 | my $attribute = shift; |
f3c1ccc8 |
138 | my $key = $attribute->name; |
c3398f5b |
139 | |
140 | my $predicate = 'sub { delete($_[0]->{$key}) }'; |
141 | |
142 | return eval $predicate; |
143 | } |
144 | |
145 | sub generate_handles { |
146 | my $attribute = shift; |
2434d21b |
147 | my $reader = $attribute->name; |
c3cc3642 |
148 | my %handles = $attribute->_canonicalize_handles($attribute->handles); |
c3398f5b |
149 | |
150 | my %method_map; |
151 | |
c3cc3642 |
152 | for my $local_method (keys %handles) { |
153 | my $remote_method = $handles{$local_method}; |
c3398f5b |
154 | |
155 | my $method = 'sub { |
156 | my $self = shift; |
157 | $self->$reader->$remote_method(@_) |
158 | }'; |
159 | |
160 | $method_map{$local_method} = eval $method; |
161 | } |
162 | |
163 | return \%method_map; |
164 | } |
165 | |
166 | sub create { |
167 | my ($self, $class, $name, %args) = @_; |
168 | |
1bfebf5f |
169 | $args{name} = $name; |
170 | $args{class} = $class; |
171 | |
8fd9e611 |
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); |
178 | $attribute->_create_args(\%args); |
179 | |
c3398f5b |
180 | my $meta = $class->meta; |
181 | |
b2500191 |
182 | $meta->add_attribute($attribute); |
183 | |
c3398f5b |
184 | # install an accessor |
2434d21b |
185 | if ($attribute->_is_metadata eq 'rw' || $attribute->_is_metadata eq 'ro') { |
c3398f5b |
186 | my $accessor = $attribute->generate_accessor; |
187 | no strict 'refs'; |
188 | *{ $class . '::' . $name } = $accessor; |
189 | } |
190 | |
c3398f5b |
191 | for my $method (qw/predicate clearer/) { |
2434d21b |
192 | my $predicate = "has_$method"; |
193 | if ($attribute->$predicate) { |
c3398f5b |
194 | my $generator = "generate_$method"; |
195 | my $coderef = $attribute->$generator; |
196 | no strict 'refs'; |
2434d21b |
197 | *{ $class . '::' . $attribute->$method } = $coderef; |
c3398f5b |
198 | } |
199 | } |
200 | |
2434d21b |
201 | if ($attribute->has_handles) { |
c3398f5b |
202 | my $method_map = $attribute->generate_handles; |
203 | for my $method_name (keys %$method_map) { |
204 | no strict 'refs'; |
205 | *{ $class . '::' . $method_name } = $method_map->{$method_name}; |
206 | } |
207 | } |
208 | |
209 | return $attribute; |
210 | } |
211 | |
8fd9e611 |
212 | sub validate_args { |
213 | my $self = shift; |
214 | my $name = shift; |
215 | my %args = @_; |
216 | |
217 | confess "You cannot have lazy attribute ($name) without specifying a default value for it" |
218 | if $args{lazy} && !exists($args{default}) && !exists($args{builder}); |
219 | |
220 | confess "References are not allowed as default values, you must wrap the default of '$name' in a CODE reference (ex: sub { [] } and not [])" |
221 | if ref($args{default}) |
222 | && ref($args{default}) ne 'CODE'; |
223 | |
224 | confess "You cannot auto-dereference without specifying a type constraint on attribute $name" |
225 | if $args{auto_deref} && !exists($args{isa}); |
226 | |
227 | confess "You cannot auto-dereference anything other than a ArrayRef or HashRef on attribute $name" |
228 | if $args{auto_deref} |
229 | && $args{isa} ne 'ArrayRef' |
230 | && $args{isa} ne 'HashRef'; |
231 | |
232 | return 1; |
233 | } |
234 | |
5aa30ced |
235 | sub find_type_constraint { |
236 | my $self = shift; |
237 | my $type = $self->type_constraint; |
238 | |
239 | return unless $type; |
240 | |
241 | my $checker = Mouse::TypeRegistry->optimized_constraints->{$type}; |
242 | return $checker if $checker; |
243 | |
3301fa54 |
244 | return sub { blessed($_) && blessed($_) eq $type }; |
5aa30ced |
245 | } |
246 | |
247 | sub verify_type_constraint { |
248 | my $self = shift; |
249 | local $_ = shift; |
250 | |
251 | my $type = $self->type_constraint |
252 | or return 1; |
af745d5a |
253 | my $constraint = $self->find_type_constraint; |
5aa30ced |
254 | |
255 | return 1 if $constraint->($_); |
256 | |
257 | my $name = $self->name; |
f3e05dfd |
258 | my $display = defined($_) ? overload::StrVal($_) : 'undef'; |
259 | Carp::confess("Attribute ($name) does not pass the type constraint because: Validation failed for \'$type\' failed with value $display"); |
5aa30ced |
260 | } |
261 | |
af745d5a |
262 | sub _canonicalize_handles { |
263 | my $self = shift; |
264 | my $handles = shift; |
265 | |
266 | if (ref($handles) eq 'HASH') { |
267 | return %$handles; |
268 | } |
269 | elsif (ref($handles) eq 'ARRAY') { |
270 | return map { $_ => $_ } @$handles; |
271 | } |
272 | else { |
273 | confess "Unable to canonicalize the 'handles' option with $handles"; |
274 | } |
275 | } |
276 | |
1bfebf5f |
277 | sub clone_parent { |
278 | my $self = shift; |
279 | my $class = shift; |
280 | my $name = shift; |
281 | my %args = ($self->get_parent_args($class, $name), @_); |
282 | |
283 | $self->create($class, $name, %args); |
284 | } |
285 | |
286 | sub get_parent_args { |
287 | my $self = shift; |
288 | my $class = shift; |
289 | my $name = shift; |
290 | |
291 | for my $super ($class->meta->linearized_isa) { |
bb733405 |
292 | my $super_attr = $super->can("meta") && $super->meta->get_attribute($name) |
1bfebf5f |
293 | or next; |
294 | return %{ $super_attr->_create_args }; |
295 | } |
296 | |
297 | confess "Could not find an attribute by the name of '$name' to inherit from"; |
298 | } |
299 | |
c3398f5b |
300 | 1; |
301 | |
302 | __END__ |
303 | |
304 | =head1 NAME |
305 | |
306290e8 |
306 | Mouse::Meta::Attribute - attribute metaclass |
c3398f5b |
307 | |
308 | =head1 METHODS |
309 | |
306290e8 |
310 | =head2 new %args -> Mouse::Meta::Attribute |
c3398f5b |
311 | |
306290e8 |
312 | Instantiates a new Mouse::Meta::Attribute. Does nothing else. |
c3398f5b |
313 | |
306290e8 |
314 | =head2 create OwnerClass, AttributeName, %args -> Mouse::Meta::Attribute |
c3398f5b |
315 | |
316 | Creates a new attribute in OwnerClass. Accessors and helper methods are |
317 | installed. Some error checking is done. |
318 | |
319 | =head2 name -> AttributeName |
320 | |
321 | =head2 class -> OwnerClass |
322 | |
ab27a55e |
323 | =head2 is_required -> Bool |
c3398f5b |
324 | |
ab27a55e |
325 | =head2 default -> Item |
c3398f5b |
326 | |
ab27a55e |
327 | =head2 has_default -> Bool |
328 | |
329 | =head2 is_lazy -> Bool |
330 | |
331 | =head2 predicate -> MethodName | Undef |
332 | |
333 | =head2 has_predicate -> Bool |
334 | |
335 | =head2 clearer -> MethodName | Undef |
336 | |
337 | =head2 has_clearer -> Bool |
c3398f5b |
338 | |
339 | =head2 handles -> { LocalName => RemoteName } |
340 | |
ab27a55e |
341 | =head2 has_handles -> Bool |
342 | |
3645b316 |
343 | =head2 is_weak_ref -> Bool |
c3398f5b |
344 | |
345 | =head2 init_arg -> Str |
346 | |
ab27a55e |
347 | =head2 type_constraint -> Str |
348 | |
349 | =head2 has_type_constraint -> Bool |
350 | |
351 | =head2 trigger => CODE | Undef |
352 | |
353 | =head2 has_trigger -> Bool |
354 | |
355 | =head2 builder => MethodName | Undef |
356 | |
357 | =head2 has_builder -> Bool |
358 | |
0fff36e6 |
359 | =head2 should_auto_deref -> Bool |
360 | |
c3398f5b |
361 | Informational methods. |
362 | |
363 | =head2 generate_accessor -> CODE |
364 | |
365 | Creates a new code reference for the attribute's accessor. |
366 | |
367 | =head2 generate_predicate -> CODE |
368 | |
369 | Creates a new code reference for the attribute's predicate. |
370 | |
371 | =head2 generate_clearer -> CODE |
372 | |
373 | Creates a new code reference for the attribute's clearer. |
374 | |
375 | =head2 generate_handles -> { MethodName => CODE } |
376 | |
377 | Creates a new code reference for each of the attribute's handles methods. |
378 | |
fb706f5c |
379 | =head2 find_type_constraint -> CODE |
380 | |
381 | Returns a code reference which can be used to check that a given value passes |
382 | this attribute's type constraint; |
383 | |
384 | =head2 verify_type_constraint Item -> 1 | ERROR |
385 | |
386 | Checks that the given value passes this attribute's type constraint. Returns 1 |
387 | on success, otherwise C<confess>es. |
388 | |
c3398f5b |
389 | =cut |
390 | |