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1 | package ## Hide from PAUSE |
2 | MooseX::Meta::TypeConstraint::Dependent; |
3 | |
4 | use Moose; |
5 | use Moose::Util::TypeConstraints (); |
6 | use MooseX::Meta::TypeCoercion::Dependent; |
7 | extends 'Moose::Meta::TypeConstraint'; |
8 | |
9 | =head1 NAME |
10 | |
11 | MooseX::Meta::TypeConstraint::Dependent - Metaclass for Dependent type constraints. |
12 | |
13 | =head1 DESCRIPTION |
14 | |
15 | see L<MooseX::Types::Dependent> for examples and details of how to use dependent |
16 | types. This class is a subclass of L<Moose::Meta::TypeConstraint> which |
17 | provides the gut functionality to enable dependent type constraints. |
18 | |
19 | =head1 ATTRIBUTES |
20 | |
21 | This class defines the following attributes. |
22 | |
23 | =head2 dependent_type_constraint |
24 | |
25 | The type constraint whose validity is being made dependent on a value that is a |
26 | L</constraining_type_constraint> |
27 | |
28 | =cut |
29 | |
30 | has 'dependent_type_constraint' => ( |
31 | is=>'ro', |
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32 | isa=>'Object', |
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33 | predicate=>'has_dependent_type_constraint', |
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34 | required=>1, |
35 | handles=>{ |
36 | check_dependent=>'check', |
37 | }, |
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38 | ); |
39 | |
40 | =head2 constraining_type_constraint |
41 | |
42 | This is a type constraint which defines what kind of value is allowed to be the |
43 | constraining value of the depending type. |
44 | |
45 | =cut |
46 | |
47 | has 'constraining_type_constraint' => ( |
48 | is=>'ro', |
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49 | isa=>'Object', |
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50 | predicate=>'has_constraining_type_constraint', |
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51 | required=>1, |
52 | handles=>{ |
53 | check_constraining=>'check', |
54 | }, |
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55 | ); |
56 | |
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57 | =head2 comparison_callback |
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58 | |
59 | This is a callback which returns a boolean value. It get's passed the value |
60 | L</constraining_type_constraint> validates as well as the check value. |
61 | |
62 | This callback is executed in addition to anything you put into a 'where' clause. |
63 | However, the 'where' clause only get's the check value. |
64 | |
65 | Exercise some sanity, this should be limited to actual comparision operations, |
66 | not as a sneaky way to mess with the constraining value. |
67 | |
68 | =cut |
69 | |
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70 | has 'comparison_callback' => ( |
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71 | is=>'ro', |
72 | isa=>'CodeRef', |
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73 | predicate=>'has_comparison_callback', |
74 | required=>1, |
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75 | ); |
76 | |
77 | =head2 constraint_generator |
78 | |
79 | A subref or closure that contains the way we validate incoming values against |
80 | a set of type constraints. |
81 | |
82 | =cut |
83 | |
84 | has 'constraint_generator' => ( |
85 | is=>'ro', |
86 | isa=>'CodeRef', |
87 | predicate=>'has_constraint_generator', |
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88 | required=>1, |
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89 | ); |
90 | |
91 | =head1 METHODS |
92 | |
93 | This class defines the following methods. |
94 | |
95 | =head2 new |
96 | |
97 | Initialization stuff. |
98 | |
99 | =cut |
100 | |
101 | around 'new' => sub { |
102 | my ($new, $class, @args) = @_; |
103 | my $self = $class->$new(@args); |
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104 | $self->coercion(MooseX::Meta::TypeCoercion::Dependent->new( |
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105 | type_constraint => $self, |
106 | )); |
107 | return $self; |
108 | }; |
109 | |
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110 | =head2 check($check_value, $constraining_value) |
111 | |
112 | Make sure when properly dispatch all the right values to the right spots |
113 | |
114 | =cut |
115 | |
116 | around 'check' => sub { |
117 | my ($check, $self, $check_value, $constraining_value) = @_; |
118 | |
119 | unless($self->check_dependent($check_value)) { |
120 | return; |
121 | } |
122 | |
123 | unless($self->check_constraining($constraining_value)) { |
124 | return; |
125 | } |
126 | |
127 | return $self->$check($check_value, $constraining_value); |
128 | }; |
129 | |
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130 | =head2 generate_constraint_for ($type_constraints) |
131 | |
132 | Given some type constraints, use them to generate validation rules for an ref |
133 | of values (to be passed at check time) |
134 | |
135 | =cut |
136 | |
137 | sub generate_constraint_for { |
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138 | my ($self, $callback, $constraining) = @_; |
139 | return sub { |
140 | my ($check_value, $constraining_value) = @_; |
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141 | my $constraint_generator = $self->constraint_generator; |
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142 | return $constraint_generator->( |
143 | $callback, |
144 | $check_value, |
145 | $constraining_value, |
146 | ); |
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147 | }; |
148 | } |
149 | |
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150 | =head2 parameterize ($dependent, $callback, $constraining) |
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151 | |
152 | Given a ref of type constraints, create a structured type. |
153 | |
154 | =cut |
155 | |
156 | sub parameterize { |
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157 | my ($self, $dependent, $callback, $constraining) = @_; |
158 | my $class = ref $self; |
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159 | my $name = $self->_generate_subtype_name($dependent, $callback, $constraining); |
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160 | my $constraint_generator = $self->__infer_constraint_generator; |
161 | |
162 | return $class->new( |
163 | name => $name, |
164 | parent => $self, |
165 | dependent_type_constraint=>$dependent, |
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166 | comparison_callback=>$callback, |
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167 | constraint_generator => $constraint_generator, |
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168 | constraining_type_constraint => $constraining, |
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169 | ); |
170 | } |
171 | |
172 | =head2 _generate_subtype_name |
173 | |
174 | Returns a name for the dependent type that should be unique |
175 | |
176 | =cut |
177 | |
178 | sub _generate_subtype_name { |
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179 | my ($self, $dependent, $callback, $constraining) = @_; |
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180 | return sprintf( |
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181 | "%s_depends_on_%s_via_%s", |
182 | $dependent, $constraining, $callback |
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183 | ); |
184 | } |
185 | |
186 | =head2 __infer_constraint_generator |
187 | |
188 | This returns a CODEREF which generates a suitable constraint generator. Not |
189 | user servicable, you'll never call this directly. |
190 | |
191 | TBD, this is definitely going to need some work. |
192 | |
193 | =cut |
194 | |
195 | sub __infer_constraint_generator { |
196 | my ($self) = @_; |
197 | if($self->has_constraint_generator) { |
198 | return $self->constraint_generator; |
199 | } else { |
200 | return sub { |
201 | ## I'm not sure about this stuff but everything seems to work |
202 | my $tc = shift @_; |
203 | my $merged_tc = [ |
204 | @$tc, |
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205 | $self->comparison_callback, |
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206 | $self->constraining_type_constraint, |
207 | ]; |
208 | |
209 | $self->constraint->($merged_tc, @_); |
210 | }; |
211 | } |
212 | } |
213 | |
214 | =head2 compile_type_constraint |
215 | |
216 | hook into compile_type_constraint so we can set the correct validation rules. |
217 | |
218 | =cut |
219 | |
220 | around 'compile_type_constraint' => sub { |
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221 | my ($compile_type_constraint, $self) = @_; |
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222 | |
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223 | if($self->has_comparison_callback && |
224 | $self->has_constraining_type_constraint) { |
225 | my $generated_constraint = $self->generate_constraint_for( |
226 | $self->comparison_callback, |
227 | $self->constraining_type_constraint, |
228 | ); |
229 | $self->_set_constraint($generated_constraint); |
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230 | } |
231 | |
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232 | return $self->$compile_type_constraint; |
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233 | }; |
234 | |
235 | =head2 create_child_type |
236 | |
237 | modifier to make sure we get the constraint_generator |
238 | |
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239 | around 'create_child_type' => sub { |
240 | my ($create_child_type, $self, %opts) = @_; |
241 | return $self->$create_child_type( |
242 | %opts, |
243 | constraint_generator => $self->__infer_constraint_generator, |
244 | ); |
245 | }; |
246 | |
247 | =head2 is_a_type_of |
248 | |
249 | =head2 is_subtype_of |
250 | |
251 | =head2 equals |
252 | |
253 | Override the base class behavior. |
254 | |
255 | TBD |
256 | |
257 | sub equals { |
258 | my ( $self, $type_or_name ) = @_; |
259 | my $other = Moose::Util::TypeConstraints::find_type_constraint($type_or_name); |
260 | |
261 | return unless $other->isa(__PACKAGE__); |
262 | |
263 | return ( |
264 | $self->type_constraints_equals($other) |
265 | and |
266 | $self->parent->equals( $other->parent ) |
267 | ); |
268 | } |
269 | |
270 | =head2 type_constraints_equals |
271 | |
272 | Checks to see if the internal type contraints are equal. |
273 | |
274 | TBD |
275 | |
276 | sub type_constraints_equals { |
277 | my ($self, $other) = @_; |
278 | my @self_type_constraints = @{$self->type_constraints||[]}; |
279 | my @other_type_constraints = @{$other->type_constraints||[]}; |
280 | |
281 | ## Incoming ay be either arrayref or hashref, need top compare both |
282 | while(@self_type_constraints) { |
283 | my $self_type_constraint = shift @self_type_constraints; |
284 | my $other_type_constraint = shift @other_type_constraints |
285 | || return; ## $other needs the same number of children. |
286 | |
287 | if( ref $self_type_constraint) { |
288 | $self_type_constraint->equals($other_type_constraint) |
289 | || return; ## type constraints obviously need top be equal |
290 | } else { |
291 | $self_type_constraint eq $other_type_constraint |
292 | || return; ## strings should be equal |
293 | } |
294 | |
295 | } |
296 | |
297 | return 1; ##If we get this far, everything is good. |
298 | } |
299 | |
300 | =head2 get_message |
301 | |
302 | Give you a better peek into what's causing the error. For now we stringify the |
303 | incoming deep value with L<Devel::PartialDump> and pass that on to either your |
304 | custom error message or the default one. In the future we'll try to provide a |
305 | more complete stack trace of the actual offending elements |
306 | |
307 | TBD |
308 | |
309 | around 'get_message' => sub { |
310 | my ($get_message, $self, $value) = @_; |
311 | my $new_value = Devel::PartialDump::dump($value); |
312 | return $self->$get_message($new_value); |
313 | }; |
314 | |
315 | =head1 SEE ALSO |
316 | |
317 | The following modules or resources may be of interest. |
318 | |
319 | L<Moose>, L<Moose::Meta::TypeConstraint> |
320 | |
321 | =head1 AUTHOR |
322 | |
323 | John Napiorkowski, C<< <jjnapiork@cpan.org> >> |
324 | |
325 | =head1 COPYRIGHT & LICENSE |
326 | |
327 | This program is free software; you can redistribute it and/or modify |
328 | it under the same terms as Perl itself. |
329 | |
330 | =cut |
331 | |
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332 | __PACKAGE__->meta->make_immutable; |