Commit | Line | Data |
8b978dd5 |
1 | |
2 | package Class::MOP::Class; |
3 | |
4 | use strict; |
5 | use warnings; |
6 | |
7 | use Carp 'confess'; |
0882828e |
8 | use Scalar::Util 'blessed', 'reftype'; |
8b978dd5 |
9 | use Sub::Name 'subname'; |
10 | use B 'svref_2object'; |
11 | |
12 | our $VERSION = '0.01'; |
13 | |
2eb717d5 |
14 | # Self-introspection |
15 | |
16 | sub meta { $_[0]->initialize($_[0]) } |
17 | |
8b978dd5 |
18 | # Creation |
19 | |
bfe4d0fc |
20 | { |
21 | # Metaclasses are singletons, so we cache them here. |
22 | # there is no need to worry about destruction though |
23 | # because they should die only when the program dies. |
24 | # After all, do package definitions even get reaped? |
25 | my %METAS; |
26 | sub initialize { |
27 | my ($class, $package_name) = @_; |
28 | (defined $package_name && $package_name) |
29 | || confess "You must pass a package name"; |
e16da3e6 |
30 | $METAS{$package_name} ||= bless { |
31 | '$:pkg' => $package_name, |
32 | '%:attrs' => {} |
33 | } => blessed($class) || $class; |
bfe4d0fc |
34 | } |
8b978dd5 |
35 | } |
36 | |
37 | sub create { |
38 | my ($class, $package_name, $package_version, %options) = @_; |
bfe4d0fc |
39 | (defined $package_name && $package_name) |
8b978dd5 |
40 | || confess "You must pass a package name"; |
41 | my $code = "package $package_name;"; |
42 | $code .= "\$$package_name\:\:VERSION = '$package_version';" |
43 | if defined $package_version; |
44 | eval $code; |
45 | confess "creation of $package_name failed : $@" if $@; |
bfe4d0fc |
46 | my $meta = $class->initialize($package_name); |
8b978dd5 |
47 | $meta->superclasses(@{$options{superclasses}}) |
48 | if exists $options{superclasses}; |
2eb717d5 |
49 | # NOTE: |
50 | # process attributes first, so that they can |
51 | # install accessors, but locally defined methods |
52 | # can then overwrite them. It is maybe a little odd, but |
53 | # I think this should be the order of things. |
54 | if (exists $options{attributes}) { |
55 | foreach my $attr_name (keys %{$options{attributes}}) { |
56 | $meta->add_attribute($attr_name, $options{attributes}->{$attr_name}); |
57 | } |
58 | } |
bfe4d0fc |
59 | if (exists $options{methods}) { |
60 | foreach my $method_name (keys %{$options{methods}}) { |
61 | $meta->add_method($method_name, $options{methods}->{$method_name}); |
62 | } |
2eb717d5 |
63 | } |
8b978dd5 |
64 | return $meta; |
65 | } |
66 | |
e16da3e6 |
67 | # Instance Construction |
68 | |
69 | sub construct_instance { |
70 | my ($canidate, %params) = @_; |
71 | # ... |
72 | } |
73 | |
8b978dd5 |
74 | # Informational |
75 | |
e16da3e6 |
76 | sub name { $_[0]->{'$:pkg'} } |
8b978dd5 |
77 | |
78 | sub version { |
79 | my $self = shift; |
80 | no strict 'refs'; |
81 | ${$self->name . '::VERSION'}; |
82 | } |
83 | |
84 | # Inheritance |
85 | |
86 | sub superclasses { |
87 | my $self = shift; |
88 | no strict 'refs'; |
89 | if (@_) { |
90 | my @supers = @_; |
91 | @{$self->name . '::ISA'} = @supers; |
92 | } |
93 | @{$self->name . '::ISA'}; |
94 | } |
95 | |
96 | sub class_precedence_list { |
97 | my $self = shift; |
bfe4d0fc |
98 | # NOTE: |
99 | # We need to check for ciruclar inheirtance here. |
100 | # This will do nothing if all is well, and blow |
101 | # up otherwise. Yes, it's an ugly hack, better |
102 | # suggestions are welcome. |
103 | { $self->name->isa('This is a test for circular inheritance') } |
104 | # ... and no back to our regularly scheduled program |
8b978dd5 |
105 | ( |
106 | $self->name, |
107 | map { |
bfe4d0fc |
108 | $self->initialize($_)->class_precedence_list() |
8b978dd5 |
109 | } $self->superclasses() |
110 | ); |
111 | } |
112 | |
0882828e |
113 | ## Methods |
114 | |
115 | sub add_method { |
116 | my ($self, $method_name, $method) = @_; |
117 | (defined $method_name && $method_name) |
118 | || confess "You must define a method name"; |
a5eca695 |
119 | # use reftype here to allow for blessed subs ... |
0882828e |
120 | (reftype($method) && reftype($method) eq 'CODE') |
121 | || confess "Your code block must be a CODE reference"; |
122 | my $full_method_name = ($self->name . '::' . $method_name); |
123 | |
124 | no strict 'refs'; |
c9b8b7f9 |
125 | no warnings 'redefine'; |
0882828e |
126 | *{$full_method_name} = subname $full_method_name => $method; |
127 | } |
128 | |
bfe4d0fc |
129 | { |
130 | |
131 | ## private utility functions for has_method |
2eb717d5 |
132 | my $_find_subroutine_package_name = sub { eval { svref_2object($_[0])->GV->STASH->NAME } || '' }; |
133 | my $_find_subroutine_name = sub { eval { svref_2object($_[0])->GV->NAME } || '' }; |
bfe4d0fc |
134 | |
135 | sub has_method { |
c9b8b7f9 |
136 | my ($self, $method_name) = @_; |
bfe4d0fc |
137 | (defined $method_name && $method_name) |
138 | || confess "You must define a method name"; |
0882828e |
139 | |
bfe4d0fc |
140 | my $sub_name = ($self->name . '::' . $method_name); |
0882828e |
141 | |
bfe4d0fc |
142 | no strict 'refs'; |
143 | return 0 if !defined(&{$sub_name}); |
144 | return 0 if $_find_subroutine_package_name->(\&{$sub_name}) ne $self->name && |
145 | $_find_subroutine_name->(\&{$sub_name}) ne '__ANON__'; |
146 | return 1; |
147 | } |
148 | |
0882828e |
149 | } |
150 | |
151 | sub get_method { |
c9b8b7f9 |
152 | my ($self, $method_name) = @_; |
0882828e |
153 | (defined $method_name && $method_name) |
154 | || confess "You must define a method name"; |
155 | |
156 | no strict 'refs'; |
157 | return \&{$self->name . '::' . $method_name} |
bfe4d0fc |
158 | if $self->has_method($method_name); |
c9b8b7f9 |
159 | return; # <- make sure to return undef |
160 | } |
161 | |
162 | sub remove_method { |
163 | my ($self, $method_name) = @_; |
164 | (defined $method_name && $method_name) |
165 | || confess "You must define a method name"; |
166 | |
167 | my $removed_method = $self->get_method($method_name); |
168 | |
169 | no strict 'refs'; |
170 | delete ${$self->name . '::'}{$method_name} |
171 | if defined $removed_method; |
172 | |
173 | return $removed_method; |
174 | } |
175 | |
176 | sub get_method_list { |
177 | my $self = shift; |
178 | no strict 'refs'; |
a5eca695 |
179 | grep { $self->has_method($_) } %{$self->name . '::'}; |
180 | } |
181 | |
182 | sub compute_all_applicable_methods { |
183 | my $self = shift; |
184 | my @methods; |
185 | # keep a record of what we have seen |
186 | # here, this will handle all the |
187 | # inheritence issues because we are |
188 | # using the &class_precedence_list |
189 | my (%seen_class, %seen_method); |
190 | foreach my $class ($self->class_precedence_list()) { |
191 | next if $seen_class{$class}; |
192 | $seen_class{$class}++; |
193 | # fetch the meta-class ... |
194 | my $meta = $self->initialize($class); |
195 | foreach my $method_name ($meta->get_method_list()) { |
196 | next if exists $seen_method{$method_name}; |
197 | $seen_method{$method_name}++; |
198 | push @methods => { |
199 | name => $method_name, |
200 | class => $class, |
201 | code => $meta->get_method($method_name) |
202 | }; |
203 | } |
204 | } |
205 | return @methods; |
206 | } |
207 | |
a5eca695 |
208 | sub find_all_methods_by_name { |
209 | my ($self, $method_name) = @_; |
210 | (defined $method_name && $method_name) |
211 | || confess "You must define a method name to find"; |
212 | my @methods; |
213 | # keep a record of what we have seen |
214 | # here, this will handle all the |
215 | # inheritence issues because we are |
216 | # using the &class_precedence_list |
217 | my %seen_class; |
218 | foreach my $class ($self->class_precedence_list()) { |
219 | next if $seen_class{$class}; |
220 | $seen_class{$class}++; |
221 | # fetch the meta-class ... |
222 | my $meta = $self->initialize($class); |
223 | push @methods => { |
224 | name => $method_name, |
225 | class => $class, |
226 | code => $meta->get_method($method_name) |
227 | } if $meta->has_method($method_name); |
228 | } |
229 | return @methods; |
230 | |
8b978dd5 |
231 | } |
232 | |
552e3d24 |
233 | ## Attributes |
234 | |
e16da3e6 |
235 | sub add_attribute { |
2eb717d5 |
236 | my ($self,$attribute) = @_; |
e16da3e6 |
237 | (blessed($attribute) && $attribute->isa('Class::MOP::Attribute')) |
238 | || confess "Your attribute must be an instance of Class::MOP::Attribute (or a subclass)"; |
2eb717d5 |
239 | $attribute->install_accessors($self); |
240 | $self->{'%:attrs'}->{$attribute->name} = $attribute; |
e16da3e6 |
241 | } |
242 | |
243 | sub has_attribute { |
244 | my ($self, $attribute_name) = @_; |
245 | (defined $attribute_name && $attribute_name) |
246 | || confess "You must define an attribute name"; |
247 | exists $self->{'%:attrs'}->{$attribute_name} ? 1 : 0; |
248 | } |
249 | |
250 | sub get_attribute { |
251 | my ($self, $attribute_name) = @_; |
252 | (defined $attribute_name && $attribute_name) |
253 | || confess "You must define an attribute name"; |
254 | return $self->{'%:attrs'}->{$attribute_name} |
255 | if $self->has_attribute($attribute_name); |
256 | } |
257 | |
258 | sub remove_attribute { |
259 | my ($self, $attribute_name) = @_; |
260 | (defined $attribute_name && $attribute_name) |
261 | || confess "You must define an attribute name"; |
262 | my $removed_attribute = $self->{'%:attrs'}->{$attribute_name}; |
263 | delete $self->{'%:attrs'}->{$attribute_name} |
264 | if defined $removed_attribute; |
2eb717d5 |
265 | $removed_attribute->remove_accessors($self); |
e16da3e6 |
266 | return $removed_attribute; |
267 | } |
268 | |
269 | sub get_attribute_list { |
270 | my $self = shift; |
271 | keys %{$self->{'%:attrs'}}; |
272 | } |
273 | |
274 | sub compute_all_applicable_attributes { |
275 | my $self = shift; |
276 | my @attrs; |
277 | # keep a record of what we have seen |
278 | # here, this will handle all the |
279 | # inheritence issues because we are |
280 | # using the &class_precedence_list |
281 | my (%seen_class, %seen_attr); |
282 | foreach my $class ($self->class_precedence_list()) { |
283 | next if $seen_class{$class}; |
284 | $seen_class{$class}++; |
285 | # fetch the meta-class ... |
286 | my $meta = $self->initialize($class); |
287 | foreach my $attr_name ($meta->get_attribute_list()) { |
288 | next if exists $seen_attr{$attr_name}; |
289 | $seen_attr{$attr_name}++; |
290 | push @attrs => { |
291 | name => $attr_name, |
292 | class => $class, |
293 | attribute => $meta->get_attribute($attr_name) |
294 | }; |
295 | } |
296 | } |
297 | return @attrs; |
298 | } |
2eb717d5 |
299 | |
552e3d24 |
300 | |
8b978dd5 |
301 | 1; |
302 | |
303 | __END__ |
304 | |
305 | =pod |
306 | |
307 | =head1 NAME |
308 | |
309 | Class::MOP::Class - Class Meta Object |
310 | |
311 | =head1 SYNOPSIS |
312 | |
313 | =head1 DESCRIPTION |
314 | |
552e3d24 |
315 | =head1 METHODS |
316 | |
2eb717d5 |
317 | =head2 Self Introspection |
318 | |
319 | =over 4 |
320 | |
321 | =item B<meta> |
322 | |
323 | This allows Class::MOP::Class to actually introspect itself. |
324 | |
325 | =back |
326 | |
552e3d24 |
327 | =head2 Class construction |
328 | |
329 | These methods handle creating Class objects, which can be used to |
330 | both create new classes, and analyze pre-existing ones. |
331 | |
332 | This module will internally store references to all the instances |
333 | you create with these methods, so that they do not need to be |
334 | created any more than nessecary. Basically, they are singletons. |
335 | |
336 | =over 4 |
337 | |
338 | =item B<create ($package_name, ?$package_version, |
339 | superclasses => ?@superclasses, |
340 | methods => ?%methods, |
341 | attributes => ?%attributes)> |
342 | |
343 | This returns the basic Class object, bringing the specified |
344 | C<$package_name> into existence and adding any of the |
345 | C<$package_version>, C<@superclasses>, C<%methods> and C<%attributes> |
346 | to it. |
347 | |
348 | =item B<initialize ($package_name)> |
349 | |
350 | This initializes a Class object for a given a C<$package_name>. |
351 | |
352 | =back |
353 | |
354 | =head2 Instance construction |
355 | |
356 | =over 4 |
357 | |
358 | =item B<construct_instance ($canidate, %params)> |
359 | |
360 | This will construct and instance using the C<$canidate> as storage |
361 | (currently only HASH references are supported). This will collect all |
362 | the applicable attribute meta-objects and layout out the fields in the |
363 | C<$canidate>, it will then initialize them using either use the |
364 | corresponding key in C<%params> or any default value or initializer |
365 | found in the attribute meta-object. |
366 | |
367 | =back |
368 | |
369 | =head2 Informational |
370 | |
371 | =over 4 |
372 | |
373 | =item B<name> |
374 | |
375 | This is a read-only attribute which returns the package name that |
376 | the Class is stored in. |
377 | |
378 | =item B<version> |
379 | |
380 | This is a read-only attribute which returns the C<$VERSION> of the |
381 | package the Class is stored in. |
382 | |
383 | =back |
384 | |
385 | =head2 Inheritance Relationships |
386 | |
387 | =over 4 |
388 | |
389 | =item B<superclasses (?@superclasses)> |
390 | |
391 | This is a read-write attribute which represents the superclass |
392 | relationships of this Class. Basically, it can get and set the |
393 | C<@ISA> for you. |
394 | |
395 | =item B<class_precedence_list> |
396 | |
397 | This computes the a list of the Class's ancestors in the same order |
398 | in which method dispatch will be done. |
399 | |
400 | =back |
401 | |
402 | =head2 Methods |
403 | |
404 | =over 4 |
405 | |
406 | =item B<add_method ($method_name, $method)> |
407 | |
408 | This will take a C<$method_name> and CODE reference to that |
409 | C<$method> and install it into the Class. |
410 | |
411 | B<NOTE> : This does absolutely nothing special to C<$method> |
412 | other than use B<Sub::Name> to make sure it is tagged with the |
413 | correct name, and therefore show up correctly in stack traces and |
414 | such. |
415 | |
416 | =item B<has_method ($method_name)> |
417 | |
418 | This just provides a simple way to check if the Class implements |
419 | a specific C<$method_name>. It will I<not> however, attempt to check |
420 | if the class inherits the method. |
421 | |
422 | This will correctly handle functions defined outside of the package |
423 | that use a fully qualified name (C<sub Package::name { ... }>). |
424 | |
425 | This will correctly handle functions renamed with B<Sub::Name> and |
426 | installed using the symbol tables. However, if you are naming the |
427 | subroutine outside of the package scope, you must use the fully |
428 | qualified name, including the package name, for C<has_method> to |
429 | correctly identify it. |
430 | |
431 | This will attempt to correctly ignore functions imported from other |
432 | packages using B<Exporter>. It breaks down if the function imported |
433 | is an C<__ANON__> sub (such as with C<use constant>), which very well |
434 | may be a valid method being applied to the class. |
435 | |
436 | In short, this method cannot always be trusted to determine if the |
437 | C<$method_name> is actually a method. However, it will DWIM about |
438 | 90% of the time, so it's a small trade off IMO. |
439 | |
440 | =item B<get_method ($method_name)> |
441 | |
442 | This will return a CODE reference of the specified C<$method_name>, |
443 | or return undef if that method does not exist. |
444 | |
445 | =item B<remove_method ($method_name)> |
446 | |
447 | This will attempt to remove a given C<$method_name> from the Class. |
448 | It will return the CODE reference that it has removed, and will |
449 | attempt to use B<Sub::Name> to clear the methods associated name. |
450 | |
451 | =item B<get_method_list> |
452 | |
453 | This will return a list of method names for all I<locally> defined |
454 | methods. It does B<not> provide a list of all applicable methods, |
455 | including any inherited ones. If you want a list of all applicable |
456 | methods, use the C<compute_all_applicable_methods> method. |
457 | |
458 | =item B<compute_all_applicable_methods> |
459 | |
460 | This will return a list of all the methods names this Class will |
461 | support, taking into account inheritance. The list will be a list of |
462 | HASH references, each one containing the following information; method |
463 | name, the name of the class in which the method lives and a CODE |
464 | reference for the actual method. |
465 | |
466 | =item B<find_all_methods_by_name ($method_name)> |
467 | |
468 | This will traverse the inheritence hierarchy and locate all methods |
469 | with a given C<$method_name>. Similar to |
470 | C<compute_all_applicable_methods> it returns a list of HASH references |
471 | with the following information; method name (which will always be the |
472 | same as C<$method_name>), the name of the class in which the method |
473 | lives and a CODE reference for the actual method. |
474 | |
475 | The list of methods produced is a distinct list, meaning there are no |
476 | duplicates in it. This is especially useful for things like object |
477 | initialization and destruction where you only want the method called |
478 | once, and in the correct order. |
479 | |
480 | =back |
481 | |
482 | =head2 Attributes |
483 | |
484 | It should be noted that since there is no one consistent way to define |
485 | the attributes of a class in Perl 5. These methods can only work with |
486 | the information given, and can not easily discover information on |
487 | their own. |
488 | |
489 | =over 4 |
490 | |
491 | =item B<add_attribute ($attribute_name, $attribute_meta_object)> |
492 | |
493 | This stores a C<$attribute_meta_object> in the Class object and |
494 | associates it with the C<$attribute_name>. Unlike methods, attributes |
495 | within the MOP are stored as meta-information only. They will be used |
496 | later to construct instances from (see C<construct_instance> above). |
497 | More details about the attribute meta-objects can be found in the |
498 | L<The Attribute protocol> section of this document. |
499 | |
500 | =item B<has_attribute ($attribute_name)> |
501 | |
502 | Checks to see if this Class has an attribute by the name of |
503 | C<$attribute_name> and returns a boolean. |
504 | |
505 | =item B<get_attribute ($attribute_name)> |
506 | |
507 | Returns the attribute meta-object associated with C<$attribute_name>, |
508 | if none is found, it will return undef. |
509 | |
510 | =item B<remove_attribute ($attribute_name)> |
511 | |
512 | This will remove the attribute meta-object stored at |
513 | C<$attribute_name>, then return the removed attribute meta-object. |
514 | |
515 | B<NOTE:> Removing an attribute will only affect future instances of |
516 | the class, it will not make any attempt to remove the attribute from |
517 | any existing instances of the class. |
518 | |
519 | =item B<get_attribute_list> |
520 | |
521 | This returns a list of attribute names which are defined in the local |
522 | class. If you want a list of all applicable attributes for a class, |
523 | use the C<compute_all_applicable_attributes> method. |
524 | |
525 | =item B<compute_all_applicable_attributes> |
526 | |
527 | This will traverse the inheritance heirachy and return a list of HASH |
528 | references for all the applicable attributes for this class. The HASH |
529 | references will contain the following information; the attribute name, |
530 | the class which the attribute is associated with and the actual |
2eb717d5 |
531 | attribute meta-object. |
552e3d24 |
532 | |
533 | =back |
534 | |
8b978dd5 |
535 | =head1 AUTHOR |
536 | |
537 | Stevan Little E<gt>stevan@iinteractive.comE<lt> |
538 | |
539 | =head1 COPYRIGHT AND LICENSE |
540 | |
541 | Copyright 2006 by Infinity Interactive, Inc. |
542 | |
543 | L<http://www.iinteractive.com> |
544 | |
545 | This library is free software; you can redistribute it and/or modify |
546 | it under the same terms as Perl itself. |
547 | |
548 | =cut |