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1 | #!/usr/bin/env perl |
306290e8 |
2 | package Mouse::Meta::Attribute; |
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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}; |
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15 | $args{is} ||= ''; |
16 | |
17 | bless \%args, $class; |
18 | } |
19 | |
3cf68001 |
20 | sub name { $_[0]->{name} } |
21 | sub class { $_[0]->{class} } |
22 | sub _is_metadata { $_[0]->{is} } |
23 | sub is_required { $_[0]->{required} } |
24 | sub default { $_[0]->{default} } |
25 | sub is_lazy { $_[0]->{lazy} } |
26 | sub predicate { $_[0]->{predicate} } |
27 | sub clearer { $_[0]->{clearer} } |
28 | sub handles { $_[0]->{handles} } |
29 | sub is_weak_ref { $_[0]->{weak_ref} } |
30 | sub init_arg { $_[0]->{init_arg} } |
31 | sub type_constraint { $_[0]->{type_constraint} } |
32 | sub trigger { $_[0]->{trigger} } |
33 | sub builder { $_[0]->{builder} } |
34 | sub should_auto_deref { $_[0]->{auto_deref} } |
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35 | |
ccea8101 |
36 | sub has_default { exists $_[0]->{default} } |
37 | sub has_predicate { exists $_[0]->{predicate} } |
38 | sub has_clearer { exists $_[0]->{clearer} } |
39 | sub has_handles { exists $_[0]->{handles} } |
ccea8101 |
40 | sub has_type_constraint { exists $_[0]->{type_constraint} } |
de9a434a |
41 | sub has_trigger { exists $_[0]->{trigger} } |
42 | sub has_builder { exists $_[0]->{builder} } |
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43 | |
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44 | sub generate_accessor { |
45 | my $attribute = shift; |
46 | |
2434d21b |
47 | my $name = $attribute->name; |
f3c1ccc8 |
48 | my $key = $name; |
2434d21b |
49 | my $default = $attribute->default; |
50 | my $trigger = $attribute->trigger; |
51 | my $type = $attribute->type_constraint; |
5aa30ced |
52 | my $constraint = $attribute->find_type_constraint; |
9367e029 |
53 | my $builder = $attribute->builder; |
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54 | |
55 | my $accessor = 'sub { |
56 | my $self = shift;'; |
57 | |
2434d21b |
58 | if ($attribute->_is_metadata eq 'rw') { |
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59 | $accessor .= 'if (@_) { |
a707f587 |
60 | local $_ = $_[0];'; |
61 | |
62 | if ($constraint) { |
1f2b4780 |
63 | $accessor .= 'do { |
e8b3db47 |
64 | my $display = defined($_) ? overload::StrVal($_) : "undef"; |
1f2b4780 |
65 | Carp::confess("Attribute ($name) does not pass the type constraint because: Validation failed for \'$type\' failed with value $display") unless $constraint->(); |
66 | };' |
a707f587 |
67 | } |
68 | |
69 | $accessor .= '$self->{$key} = $_;'; |
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70 | |
3645b316 |
71 | if ($attribute->is_weak_ref) { |
72 | $accessor .= 'Scalar::Util::weaken($self->{$key}) if ref($self->{$key});'; |
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73 | } |
74 | |
75 | if ($trigger) { |
a707f587 |
76 | $accessor .= '$trigger->($self, $_, $attribute);'; |
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77 | } |
78 | |
79 | $accessor .= '}'; |
80 | } |
81 | else { |
636c002e |
82 | $accessor .= 'confess "Cannot assign a value to a read-only accessor" if @_;'; |
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83 | } |
84 | |
2434d21b |
85 | if ($attribute->is_lazy) { |
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86 | $accessor .= '$self->{$key} = '; |
9367e029 |
87 | |
88 | $accessor .= $attribute->has_builder |
89 | ? '$self->$builder' |
90 | : ref($default) eq 'CODE' |
91 | ? '$default->($self)' |
92 | : '$default'; |
93 | |
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94 | $accessor .= ' if !exists($self->{$key});'; |
95 | } |
96 | |
3cf68001 |
97 | if ($attribute->should_auto_deref) { |
98 | if ($attribute->type_constraint eq 'ArrayRef') { |
99 | $accessor .= 'if (wantarray) { |
100 | return @{ $self->{$key} || [] }; |
101 | }'; |
102 | } |
103 | else { |
104 | $accessor .= 'if (wantarray) { |
105 | return %{ $self->{$key} || {} }; |
106 | }'; |
107 | } |
108 | } |
109 | |
110 | $accessor .= 'return $self->{$key}; |
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111 | }'; |
112 | |
113 | return eval $accessor; |
114 | } |
115 | |
116 | sub generate_predicate { |
117 | my $attribute = shift; |
f3c1ccc8 |
118 | my $key = $attribute->name; |
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119 | |
120 | my $predicate = 'sub { exists($_[0]->{$key}) }'; |
121 | |
122 | return eval $predicate; |
123 | } |
124 | |
125 | sub generate_clearer { |
126 | my $attribute = shift; |
f3c1ccc8 |
127 | my $key = $attribute->name; |
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128 | |
129 | my $predicate = 'sub { delete($_[0]->{$key}) }'; |
130 | |
131 | return eval $predicate; |
132 | } |
133 | |
134 | sub generate_handles { |
135 | my $attribute = shift; |
2434d21b |
136 | my $reader = $attribute->name; |
c3cc3642 |
137 | my %handles = $attribute->_canonicalize_handles($attribute->handles); |
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138 | |
139 | my %method_map; |
140 | |
c3cc3642 |
141 | for my $local_method (keys %handles) { |
142 | my $remote_method = $handles{$local_method}; |
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143 | |
144 | my $method = 'sub { |
145 | my $self = shift; |
146 | $self->$reader->$remote_method(@_) |
147 | }'; |
148 | |
149 | $method_map{$local_method} = eval $method; |
150 | } |
151 | |
152 | return \%method_map; |
153 | } |
154 | |
155 | sub create { |
156 | my ($self, $class, $name, %args) = @_; |
157 | |
4eb1339a |
158 | confess "You cannot have lazy attribute ($name) without specifying a default value for it" |
9367e029 |
159 | if $args{lazy} && !exists($args{default}) && !exists($args{builder}); |
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160 | |
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161 | confess "References are not allowed as default values, you must wrap the default of '$name' in a CODE reference (ex: sub { [] } and not [])" |
162 | if ref($args{default}) |
163 | && ref($args{default}) ne 'CODE'; |
164 | |
45ea8620 |
165 | confess "You cannot auto-dereference without specifying a type constraint on attribute $name" |
166 | if $args{auto_deref} && !exists($args{isa}); |
167 | |
168 | confess "You cannot auto-dereference anything other than a ArrayRef or HashRef on attribute $name" |
169 | if $args{auto_deref} |
170 | && $args{isa} ne 'ArrayRef' |
171 | && $args{isa} ne 'HashRef'; |
172 | |
c021207d |
173 | $args{type_constraint} = delete $args{isa} |
174 | if exists $args{isa}; |
186657a9 |
175 | |
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176 | my $attribute = $self->new(%args, name => $name, class => $class); |
177 | my $meta = $class->meta; |
178 | |
b2500191 |
179 | $meta->add_attribute($attribute); |
180 | |
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181 | # install an accessor |
2434d21b |
182 | if ($attribute->_is_metadata eq 'rw' || $attribute->_is_metadata eq 'ro') { |
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183 | my $accessor = $attribute->generate_accessor; |
184 | no strict 'refs'; |
185 | *{ $class . '::' . $name } = $accessor; |
186 | } |
187 | |
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188 | for my $method (qw/predicate clearer/) { |
2434d21b |
189 | my $predicate = "has_$method"; |
190 | if ($attribute->$predicate) { |
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191 | my $generator = "generate_$method"; |
192 | my $coderef = $attribute->$generator; |
193 | no strict 'refs'; |
2434d21b |
194 | *{ $class . '::' . $attribute->$method } = $coderef; |
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195 | } |
196 | } |
197 | |
2434d21b |
198 | if ($attribute->has_handles) { |
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199 | my $method_map = $attribute->generate_handles; |
200 | for my $method_name (keys %$method_map) { |
201 | no strict 'refs'; |
202 | *{ $class . '::' . $method_name } = $method_map->{$method_name}; |
203 | } |
204 | } |
205 | |
206 | return $attribute; |
207 | } |
208 | |
5aa30ced |
209 | sub find_type_constraint { |
210 | my $self = shift; |
211 | my $type = $self->type_constraint; |
212 | |
213 | return unless $type; |
214 | |
215 | my $checker = Mouse::TypeRegistry->optimized_constraints->{$type}; |
216 | return $checker if $checker; |
217 | |
3301fa54 |
218 | return sub { blessed($_) && blessed($_) eq $type }; |
5aa30ced |
219 | } |
220 | |
221 | sub verify_type_constraint { |
222 | my $self = shift; |
223 | local $_ = shift; |
224 | |
225 | my $type = $self->type_constraint |
226 | or return 1; |
af745d5a |
227 | my $constraint = $self->find_type_constraint; |
5aa30ced |
228 | |
229 | return 1 if $constraint->($_); |
230 | |
231 | my $name = $self->name; |
f3e05dfd |
232 | my $display = defined($_) ? overload::StrVal($_) : 'undef'; |
233 | Carp::confess("Attribute ($name) does not pass the type constraint because: Validation failed for \'$type\' failed with value $display"); |
5aa30ced |
234 | } |
235 | |
af745d5a |
236 | sub _canonicalize_handles { |
237 | my $self = shift; |
238 | my $handles = shift; |
239 | |
240 | if (ref($handles) eq 'HASH') { |
241 | return %$handles; |
242 | } |
243 | elsif (ref($handles) eq 'ARRAY') { |
244 | return map { $_ => $_ } @$handles; |
245 | } |
246 | else { |
247 | confess "Unable to canonicalize the 'handles' option with $handles"; |
248 | } |
249 | } |
250 | |
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251 | 1; |
252 | |
253 | __END__ |
254 | |
255 | =head1 NAME |
256 | |
306290e8 |
257 | Mouse::Meta::Attribute - attribute metaclass |
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258 | |
259 | =head1 METHODS |
260 | |
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261 | =head2 new %args -> Mouse::Meta::Attribute |
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262 | |
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263 | Instantiates a new Mouse::Meta::Attribute. Does nothing else. |
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264 | |
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265 | =head2 create OwnerClass, AttributeName, %args -> Mouse::Meta::Attribute |
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266 | |
267 | Creates a new attribute in OwnerClass. Accessors and helper methods are |
268 | installed. Some error checking is done. |
269 | |
270 | =head2 name -> AttributeName |
271 | |
272 | =head2 class -> OwnerClass |
273 | |
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274 | =head2 is_required -> Bool |
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275 | |
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276 | =head2 default -> Item |
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277 | |
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278 | =head2 has_default -> Bool |
279 | |
280 | =head2 is_lazy -> Bool |
281 | |
282 | =head2 predicate -> MethodName | Undef |
283 | |
284 | =head2 has_predicate -> Bool |
285 | |
286 | =head2 clearer -> MethodName | Undef |
287 | |
288 | =head2 has_clearer -> Bool |
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289 | |
290 | =head2 handles -> { LocalName => RemoteName } |
291 | |
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292 | =head2 has_handles -> Bool |
293 | |
3645b316 |
294 | =head2 is_weak_ref -> Bool |
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295 | |
296 | =head2 init_arg -> Str |
297 | |
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298 | =head2 type_constraint -> Str |
299 | |
300 | =head2 has_type_constraint -> Bool |
301 | |
302 | =head2 trigger => CODE | Undef |
303 | |
304 | =head2 has_trigger -> Bool |
305 | |
306 | =head2 builder => MethodName | Undef |
307 | |
308 | =head2 has_builder -> Bool |
309 | |
0fff36e6 |
310 | =head2 should_auto_deref -> Bool |
311 | |
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312 | Informational methods. |
313 | |
314 | =head2 generate_accessor -> CODE |
315 | |
316 | Creates a new code reference for the attribute's accessor. |
317 | |
318 | =head2 generate_predicate -> CODE |
319 | |
320 | Creates a new code reference for the attribute's predicate. |
321 | |
322 | =head2 generate_clearer -> CODE |
323 | |
324 | Creates a new code reference for the attribute's clearer. |
325 | |
326 | =head2 generate_handles -> { MethodName => CODE } |
327 | |
328 | Creates a new code reference for each of the attribute's handles methods. |
329 | |
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330 | =head2 find_type_constraint -> CODE |
331 | |
332 | Returns a code reference which can be used to check that a given value passes |
333 | this attribute's type constraint; |
334 | |
335 | =head2 verify_type_constraint Item -> 1 | ERROR |
336 | |
337 | Checks that the given value passes this attribute's type constraint. Returns 1 |
338 | on success, otherwise C<confess>es. |
339 | |
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340 | =cut |
341 | |