Commit | Line | Data |
8b978dd5 |
1 | |
2 | package Class::MOP::Class; |
3 | |
4 | use strict; |
5 | use warnings; |
6 | |
c23184fc |
7 | use Class::MOP::Immutable; |
ba38bf08 |
8 | use Class::MOP::Instance; |
9 | use Class::MOP::Method::Wrapped; |
10 | |
8b978dd5 |
11 | use Carp 'confess'; |
7f63694d |
12 | use Scalar::Util 'blessed', 'reftype', 'weaken'; |
8b978dd5 |
13 | use Sub::Name 'subname'; |
96ceced8 |
14 | use B 'svref_2object'; |
8b978dd5 |
15 | |
6c9f390e |
16 | our $VERSION = '0.25'; |
f0480c45 |
17 | our $AUTHORITY = 'cpan:STEVAN'; |
8b978dd5 |
18 | |
2243a22b |
19 | use base 'Class::MOP::Module'; |
20 | |
0ac992ee |
21 | # Self-introspection |
2eb717d5 |
22 | |
aa448b16 |
23 | sub meta { Class::MOP::Class->initialize(blessed($_[0]) || $_[0]) } |
2eb717d5 |
24 | |
8b978dd5 |
25 | # Creation |
0ac992ee |
26 | |
be7677c7 |
27 | sub initialize { |
28 | my $class = shift; |
29 | my $package_name = shift; |
30 | (defined $package_name && $package_name && !blessed($package_name)) |
0ac992ee |
31 | || confess "You must pass a package name and it cannot be blessed"; |
3af3cbbd |
32 | if (defined(my $meta = Class::MOP::get_metaclass_by_name($package_name))) { |
33 | return $meta; |
34 | } |
c23184fc |
35 | $class->construct_class_instance('package' => $package_name, @_); |
be7677c7 |
36 | } |
37 | |
38 | sub reinitialize { |
39 | my $class = shift; |
40 | my $package_name = shift; |
41 | (defined $package_name && $package_name && !blessed($package_name)) |
0ac992ee |
42 | || confess "You must pass a package name and it cannot be blessed"; |
be7677c7 |
43 | Class::MOP::remove_metaclass_by_name($package_name); |
c23184fc |
44 | $class->construct_class_instance('package' => $package_name, @_); |
0ac992ee |
45 | } |
46 | |
47 | # NOTE: (meta-circularity) |
48 | # this is a special form of &construct_instance |
be7677c7 |
49 | # (see below), which is used to construct class |
0ac992ee |
50 | # meta-object instances for any Class::MOP::* |
51 | # class. All other classes will use the more |
be7677c7 |
52 | # normal &construct_instance. |
53 | sub construct_class_instance { |
54 | my $class = shift; |
55 | my %options = @_; |
c23184fc |
56 | my $package_name = $options{'package'}; |
be7677c7 |
57 | (defined $package_name && $package_name) |
0ac992ee |
58 | || confess "You must pass a package name"; |
be7677c7 |
59 | # NOTE: |
0ac992ee |
60 | # return the metaclass if we have it cached, |
61 | # and it is still defined (it has not been |
62 | # reaped by DESTROY yet, which can happen |
be7677c7 |
63 | # annoyingly enough during global destruction) |
3af3cbbd |
64 | |
65 | if (defined(my $meta = Class::MOP::get_metaclass_by_name($package_name))) { |
66 | return $meta; |
67 | } |
be7677c7 |
68 | |
69 | # NOTE: |
0ac992ee |
70 | # we need to deal with the possibility |
71 | # of class immutability here, and then |
be7677c7 |
72 | # get the name of the class appropriately |
73 | $class = (blessed($class) |
74 | ? ($class->is_immutable |
75 | ? $class->get_mutable_metaclass_name() |
76 | : blessed($class)) |
77 | : $class); |
78 | |
be7677c7 |
79 | # now create the metaclass |
80 | my $meta; |
9c6877f4 |
81 | if ($class eq 'Class::MOP::Class') { |
0ac992ee |
82 | no strict 'refs'; |
83 | $meta = bless { |
be7677c7 |
84 | # inherited from Class::MOP::Package |
0ac992ee |
85 | '$!package' => $package_name, |
86 | |
c4260b45 |
87 | # NOTE: |
0ac992ee |
88 | # since the following attributes will |
89 | # actually be loaded from the symbol |
c4260b45 |
90 | # table, and actually bypass the instance |
91 | # entirely, we can just leave these things |
92 | # listed here for reference, because they |
0ac992ee |
93 | # should not actually have a value associated |
c4260b45 |
94 | # with the slot. |
0ac992ee |
95 | '%!namespace' => \undef, |
be7677c7 |
96 | # inherited from Class::MOP::Module |
c23184fc |
97 | '$!version' => \undef, |
98 | '$!authority' => \undef, |
c4260b45 |
99 | # defined in Class::MOP::Class |
c23184fc |
100 | '@!superclasses' => \undef, |
0ac992ee |
101 | |
c23184fc |
102 | '%!methods' => {}, |
0ac992ee |
103 | '%!attributes' => {}, |
c23184fc |
104 | '$!attribute_metaclass' => $options{'attribute_metaclass'} || 'Class::MOP::Attribute', |
105 | '$!method_metaclass' => $options{'method_metaclass'} || 'Class::MOP::Method', |
106 | '$!instance_metaclass' => $options{'instance_metaclass'} || 'Class::MOP::Instance', |
be7677c7 |
107 | } => $class; |
108 | } |
109 | else { |
110 | # NOTE: |
111 | # it is safe to use meta here because |
0ac992ee |
112 | # class will always be a subclass of |
be7677c7 |
113 | # Class::MOP::Class, which defines meta |
114 | $meta = $class->meta->construct_instance(%options) |
727919c5 |
115 | } |
0ac992ee |
116 | |
be7677c7 |
117 | # and check the metaclass compatibility |
118 | $meta->check_metaclass_compatability(); |
0ac992ee |
119 | |
be7677c7 |
120 | Class::MOP::store_metaclass_by_name($package_name, $meta); |
0ac992ee |
121 | |
be7677c7 |
122 | # NOTE: |
123 | # we need to weaken any anon classes |
124 | # so that they can call DESTROY properly |
b9d9fc0b |
125 | Class::MOP::weaken_metaclass($package_name) if $meta->is_anon_class; |
0ac992ee |
126 | |
127 | $meta; |
128 | } |
129 | |
be7677c7 |
130 | sub check_metaclass_compatability { |
131 | my $self = shift; |
132 | |
133 | # this is always okay ... |
0ac992ee |
134 | return if blessed($self) eq 'Class::MOP::Class' && |
be7677c7 |
135 | $self->instance_metaclass eq 'Class::MOP::Instance'; |
136 | |
b7bdffc3 |
137 | my @class_list = $self->linearized_isa; |
be7677c7 |
138 | shift @class_list; # shift off $self->name |
373a16ae |
139 | |
0ac992ee |
140 | foreach my $class_name (@class_list) { |
be7677c7 |
141 | my $meta = Class::MOP::get_metaclass_by_name($class_name) || next; |
0ac992ee |
142 | |
373a16ae |
143 | # NOTE: |
0ac992ee |
144 | # we need to deal with the possibility |
145 | # of class immutability here, and then |
146 | # get the name of the class appropriately |
be7677c7 |
147 | my $meta_type = ($meta->is_immutable |
148 | ? $meta->get_mutable_metaclass_name() |
0ac992ee |
149 | : blessed($meta)); |
150 | |
be7677c7 |
151 | ($self->isa($meta_type)) |
0ac992ee |
152 | || confess $self->name . "->meta => (" . (blessed($self)) . ")" . |
153 | " is not compatible with the " . |
be7677c7 |
154 | $class_name . "->meta => (" . ($meta_type) . ")"; |
77e5fce4 |
155 | # NOTE: |
be7677c7 |
156 | # we also need to check that instance metaclasses |
157 | # are compatabile in the same the class. |
158 | ($self->instance_metaclass->isa($meta->instance_metaclass)) |
0ac992ee |
159 | || confess $self->name . "->meta => (" . ($self->instance_metaclass) . ")" . |
160 | " is not compatible with the " . |
161 | $class_name . "->meta => (" . ($meta->instance_metaclass) . ")"; |
162 | } |
163 | } |
8b978dd5 |
164 | |
6d5355c3 |
165 | ## ANON classes |
166 | |
167 | { |
168 | # NOTE: |
0ac992ee |
169 | # this should be sufficient, if you have a |
170 | # use case where it is not, write a test and |
6d5355c3 |
171 | # I will change it. |
172 | my $ANON_CLASS_SERIAL = 0; |
0ac992ee |
173 | |
b9d9fc0b |
174 | # NOTE: |
175 | # we need a sufficiently annoying prefix |
0ac992ee |
176 | # this should suffice for now, this is |
177 | # used in a couple of places below, so |
b9d9fc0b |
178 | # need to put it up here for now. |
0ac992ee |
179 | my $ANON_CLASS_PREFIX = 'Class::MOP::Class::__ANON__::SERIAL::'; |
b9d9fc0b |
180 | |
181 | sub is_anon_class { |
182 | my $self = shift; |
a651e249 |
183 | no warnings 'uninitialized'; |
0ac992ee |
184 | $self->name =~ /^$ANON_CLASS_PREFIX/ ? 1 : 0; |
b9d9fc0b |
185 | } |
6d5355c3 |
186 | |
187 | sub create_anon_class { |
0ac992ee |
188 | my ($class, %options) = @_; |
6d5355c3 |
189 | my $package_name = $ANON_CLASS_PREFIX . ++$ANON_CLASS_SERIAL; |
88dd563c |
190 | return $class->create($package_name, %options); |
0ac992ee |
191 | } |
6d5355c3 |
192 | |
b9d9fc0b |
193 | # NOTE: |
0ac992ee |
194 | # this will only get called for |
195 | # anon-classes, all other calls |
196 | # are assumed to occur during |
b9d9fc0b |
197 | # global destruction and so don't |
198 | # really need to be handled explicitly |
199 | sub DESTROY { |
200 | my $self = shift; |
0ac992ee |
201 | no warnings 'uninitialized'; |
b9d9fc0b |
202 | return unless $self->name =~ /^$ANON_CLASS_PREFIX/; |
203 | my ($serial_id) = ($self->name =~ /^$ANON_CLASS_PREFIX(\d+)/); |
0ac992ee |
204 | no strict 'refs'; |
b9d9fc0b |
205 | foreach my $key (keys %{$ANON_CLASS_PREFIX . $serial_id}) { |
206 | delete ${$ANON_CLASS_PREFIX . $serial_id}{$key}; |
207 | } |
0ac992ee |
208 | delete ${'main::' . $ANON_CLASS_PREFIX}{$serial_id . '::'}; |
6d5355c3 |
209 | } |
b9d9fc0b |
210 | |
6d5355c3 |
211 | } |
212 | |
213 | # creating classes with MOP ... |
214 | |
8b978dd5 |
215 | sub create { |
88dd563c |
216 | my $class = shift; |
217 | my $package_name = shift; |
0ac992ee |
218 | |
bfe4d0fc |
219 | (defined $package_name && $package_name) |
8b978dd5 |
220 | || confess "You must pass a package name"; |
88dd563c |
221 | |
222 | (scalar @_ % 2 == 0) |
0ac992ee |
223 | || confess "You much pass all parameters as name => value pairs " . |
88dd563c |
224 | "(I found an uneven number of params in \@_)"; |
225 | |
226 | my (%options) = @_; |
0ac992ee |
227 | |
8b978dd5 |
228 | my $code = "package $package_name;"; |
0ac992ee |
229 | $code .= "\$$package_name\:\:VERSION = '" . $options{version} . "';" |
88dd563c |
230 | if exists $options{version}; |
0ac992ee |
231 | $code .= "\$$package_name\:\:AUTHORITY = '" . $options{authority} . "';" |
232 | if exists $options{authority}; |
233 | |
8b978dd5 |
234 | eval $code; |
0ac992ee |
235 | confess "creation of $package_name failed : $@" if $@; |
236 | |
bfe4d0fc |
237 | my $meta = $class->initialize($package_name); |
0ac992ee |
238 | |
239 | $meta->add_method('meta' => sub { |
df7b4119 |
240 | $class->initialize(blessed($_[0]) || $_[0]); |
aa448b16 |
241 | }); |
0ac992ee |
242 | |
8b978dd5 |
243 | $meta->superclasses(@{$options{superclasses}}) |
244 | if exists $options{superclasses}; |
2eb717d5 |
245 | # NOTE: |
0ac992ee |
246 | # process attributes first, so that they can |
2eb717d5 |
247 | # install accessors, but locally defined methods |
248 | # can then overwrite them. It is maybe a little odd, but |
249 | # I think this should be the order of things. |
250 | if (exists $options{attributes}) { |
cbd9f942 |
251 | foreach my $attr (@{$options{attributes}}) { |
252 | $meta->add_attribute($attr); |
2eb717d5 |
253 | } |
0ac992ee |
254 | } |
bfe4d0fc |
255 | if (exists $options{methods}) { |
256 | foreach my $method_name (keys %{$options{methods}}) { |
257 | $meta->add_method($method_name, $options{methods}->{$method_name}); |
258 | } |
0ac992ee |
259 | } |
8b978dd5 |
260 | return $meta; |
261 | } |
262 | |
7b31baf4 |
263 | ## Attribute readers |
264 | |
265 | # NOTE: |
0ac992ee |
266 | # all these attribute readers will be bootstrapped |
7b31baf4 |
267 | # away in the Class::MOP bootstrap section |
268 | |
c23184fc |
269 | sub get_attribute_map { $_[0]->{'%!attributes'} } |
270 | sub attribute_metaclass { $_[0]->{'$!attribute_metaclass'} } |
271 | sub method_metaclass { $_[0]->{'$!method_metaclass'} } |
272 | sub instance_metaclass { $_[0]->{'$!instance_metaclass'} } |
7b31baf4 |
273 | |
0f71bc80 |
274 | # FIXME: |
275 | # this is a prime canidate for conversion to XS |
0ac992ee |
276 | sub get_method_map { |
c4260b45 |
277 | my $self = shift; |
0ac992ee |
278 | my $map = $self->{'%!methods'}; |
279 | |
0f71bc80 |
280 | my $class_name = $self->name; |
281 | my $method_metaclass = $self->method_metaclass; |
0ac992ee |
282 | |
92330ee2 |
283 | foreach my $symbol ($self->list_all_package_symbols('CODE')) { |
91e0eb4a |
284 | my $code = $self->get_package_symbol('&' . $symbol); |
0ac992ee |
285 | |
286 | next if exists $map->{$symbol} && |
287 | defined $map->{$symbol} && |
288 | $map->{$symbol}->body == $code; |
289 | |
0f71bc80 |
290 | my $gv = svref_2object($code)->GV; |
291 | next if ($gv->STASH->NAME || '') ne $class_name && |
0ac992ee |
292 | ($gv->NAME || '') ne '__ANON__'; |
293 | |
0f71bc80 |
294 | $map->{$symbol} = $method_metaclass->wrap($code); |
7855ddba |
295 | } |
0ac992ee |
296 | |
7855ddba |
297 | return $map; |
c4260b45 |
298 | } |
299 | |
c9e77dbb |
300 | # Instance Construction & Cloning |
301 | |
5f3c057a |
302 | sub new_object { |
303 | my $class = shift; |
651955fb |
304 | # NOTE: |
0ac992ee |
305 | # we need to protect the integrity of the |
651955fb |
306 | # Class::MOP::Class singletons here, so we |
307 | # delegate this to &construct_class_instance |
308 | # which will deal with the singletons |
309 | return $class->construct_class_instance(@_) |
310 | if $class->name->isa('Class::MOP::Class'); |
24869f62 |
311 | return $class->construct_instance(@_); |
5f3c057a |
312 | } |
e16da3e6 |
313 | |
314 | sub construct_instance { |
cbd9f942 |
315 | my ($class, %params) = @_; |
0e76a376 |
316 | my $meta_instance = $class->get_meta_instance(); |
317 | my $instance = $meta_instance->create_instance(); |
c9e77dbb |
318 | foreach my $attr ($class->compute_all_applicable_attributes()) { |
f892c0f0 |
319 | $attr->initialize_instance_slot($meta_instance, $instance, \%params); |
cbd9f942 |
320 | } |
0ac992ee |
321 | # NOTE: |
d4ba1677 |
322 | # this will only work for a HASH instance type |
323 | if ($class->is_anon_class) { |
324 | (reftype($instance) eq 'HASH') |
325 | || confess "Currently only HASH based instances are supported with instance of anon-classes"; |
326 | # NOTE: |
327 | # At some point we should make this official |
0ac992ee |
328 | # as a reserved slot name, but right now I am |
d4ba1677 |
329 | # going to keep it here. |
330 | # my $RESERVED_MOP_SLOT = '__MOP__'; |
331 | $instance->{'__MOP__'} = $class; |
332 | } |
2d711cc8 |
333 | return $instance; |
334 | } |
335 | |
336 | sub get_meta_instance { |
337 | my $class = shift; |
052c2a1a |
338 | return $class->instance_metaclass->new( |
0ac992ee |
339 | $class, |
052c2a1a |
340 | $class->compute_all_applicable_attributes() |
341 | ); |
e16da3e6 |
342 | } |
343 | |
5f3c057a |
344 | sub clone_object { |
345 | my $class = shift; |
0ac992ee |
346 | my $instance = shift; |
651955fb |
347 | (blessed($instance) && $instance->isa($class->name)) |
348 | || confess "You must pass an instance ($instance) of the metaclass (" . $class->name . ")"; |
349 | # NOTE: |
0ac992ee |
350 | # we need to protect the integrity of the |
351 | # Class::MOP::Class singletons here, they |
a740253a |
352 | # should not be cloned. |
0ac992ee |
353 | return $instance if $instance->isa('Class::MOP::Class'); |
f7259199 |
354 | $class->clone_instance($instance, @_); |
5f3c057a |
355 | } |
356 | |
c9e77dbb |
357 | sub clone_instance { |
651955fb |
358 | my ($class, $instance, %params) = @_; |
359 | (blessed($instance)) |
c9e77dbb |
360 | || confess "You can only clone instances, \$self is not a blessed instance"; |
f7259199 |
361 | my $meta_instance = $class->get_meta_instance(); |
0ac992ee |
362 | my $clone = $meta_instance->clone_instance($instance); |
c23184fc |
363 | foreach my $attr ($class->compute_all_applicable_attributes()) { |
795a0c8b |
364 | if (exists $params{$attr->init_arg}) { |
0ac992ee |
365 | $meta_instance->set_slot_value($clone, $attr->name, $params{$attr->init_arg}); |
c23184fc |
366 | } |
0ac992ee |
367 | } |
368 | return $clone; |
c9e77dbb |
369 | } |
370 | |
8b978dd5 |
371 | # Inheritance |
372 | |
373 | sub superclasses { |
374 | my $self = shift; |
8b978dd5 |
375 | if (@_) { |
376 | my @supers = @_; |
9d6dce77 |
377 | @{$self->get_package_symbol('@ISA')} = @supers; |
d82060fe |
378 | # NOTE: |
0ac992ee |
379 | # we need to check the metaclass |
84086365 |
380 | # compatibility here so that we can |
0ac992ee |
381 | # be sure that the superclass is |
382 | # not potentially creating an issues |
d82060fe |
383 | # we don't know about |
384 | $self->check_metaclass_compatability(); |
8b978dd5 |
385 | } |
9d6dce77 |
386 | @{$self->get_package_symbol('@ISA')}; |
8b978dd5 |
387 | } |
388 | |
7160cad4 |
389 | sub subclasses { |
390 | my $self = shift; |
391 | |
392 | my $super_class = $self->name; |
393 | my @derived_classes; |
394 | |
395 | my $find_derived_classes; |
396 | $find_derived_classes = sub { |
397 | my ($outer_class) = @_; |
398 | |
399 | my $symbol_table_hashref = do { no strict 'refs'; \%{"${outer_class}::"} }; |
400 | |
401 | SYMBOL: |
402 | for my $symbol ( keys %$symbol_table_hashref ) { |
403 | next SYMBOL if $symbol !~ /\A (\w+):: \z/x; |
404 | my $inner_class = $1; |
405 | |
406 | next SYMBOL if $inner_class eq 'SUPER'; # skip '*::SUPER' |
407 | |
408 | my $class = |
409 | $outer_class |
410 | ? "${outer_class}::$inner_class" |
411 | : $inner_class; |
412 | |
413 | if ( $class->isa($super_class) and $class ne $super_class ) { |
414 | push @derived_classes, $class; |
415 | } |
416 | |
417 | next SYMBOL if $class eq 'main'; # skip 'main::*' |
418 | |
419 | $find_derived_classes->($class); |
420 | } |
421 | }; |
422 | |
423 | my $root_class = q{}; |
424 | $find_derived_classes->($root_class); |
425 | |
426 | undef $find_derived_classes; |
427 | |
428 | @derived_classes = sort { $a->isa($b) ? 1 : $b->isa($a) ? -1 : 0 } @derived_classes; |
429 | |
430 | return @derived_classes; |
431 | } |
432 | |
433 | |
b7bdffc3 |
434 | sub linearized_isa { |
435 | my %seen; |
436 | grep { !($seen{$_}++) } (shift)->class_precedence_list |
437 | } |
438 | |
8b978dd5 |
439 | sub class_precedence_list { |
440 | my $self = shift; |
bfe4d0fc |
441 | # NOTE: |
84086365 |
442 | # We need to check for circular inheritance here. |
bfe4d0fc |
443 | # This will do nothing if all is well, and blow |
0ac992ee |
444 | # up otherwise. Yes, it's an ugly hack, better |
bfe4d0fc |
445 | # suggestions are welcome. |
93b4e576 |
446 | { ($self->name || return)->isa('This is a test for circular inheritance') } |
0ac992ee |
447 | |
8b978dd5 |
448 | ( |
0ac992ee |
449 | $self->name, |
450 | map { |
f7259199 |
451 | $self->initialize($_)->class_precedence_list() |
8b978dd5 |
452 | } $self->superclasses() |
0ac992ee |
453 | ); |
8b978dd5 |
454 | } |
455 | |
0882828e |
456 | ## Methods |
457 | |
458 | sub add_method { |
459 | my ($self, $method_name, $method) = @_; |
460 | (defined $method_name && $method_name) |
461 | || confess "You must define a method name"; |
0ac992ee |
462 | |
7855ddba |
463 | my $body; |
7855ddba |
464 | if (blessed($method)) { |
0ac992ee |
465 | $body = $method->body; |
7855ddba |
466 | } |
0ac992ee |
467 | else { |
7855ddba |
468 | $body = $method; |
7855ddba |
469 | ('CODE' eq (reftype($body) || '')) |
0ac992ee |
470 | || confess "Your code block must be a CODE reference"; |
471 | $method = $self->method_metaclass->wrap($body); |
7855ddba |
472 | } |
0f71bc80 |
473 | $self->get_method_map->{$method_name} = $method; |
0ac992ee |
474 | |
475 | my $full_method_name = ($self->name . '::' . $method_name); |
7855ddba |
476 | $self->add_package_symbol("&${method_name}" => subname $full_method_name => $body); |
0882828e |
477 | } |
478 | |
a4258ffd |
479 | { |
2d711cc8 |
480 | my $fetch_and_prepare_method = sub { |
481 | my ($self, $method_name) = @_; |
482 | # fetch it locally |
483 | my $method = $self->get_method($method_name); |
484 | # if we dont have local ... |
485 | unless ($method) { |
195f5bf8 |
486 | # try to find the next method |
487 | $method = $self->find_next_method_by_name($method_name); |
488 | # die if it does not exist |
489 | (defined $method) |
804f7d24 |
490 | || confess "The method '$method_name' is not found in the inheritance hierarchy for class " . $self->name; |
0ac992ee |
491 | # and now make sure to wrap it |
195f5bf8 |
492 | # even if it is already wrapped |
493 | # because we need a new sub ref |
2d711cc8 |
494 | $method = Class::MOP::Method::Wrapped->wrap($method); |
195f5bf8 |
495 | } |
496 | else { |
0ac992ee |
497 | # now make sure we wrap it properly |
195f5bf8 |
498 | $method = Class::MOP::Method::Wrapped->wrap($method) |
0ac992ee |
499 | unless $method->isa('Class::MOP::Method::Wrapped'); |
500 | } |
501 | $self->add_method($method_name => $method); |
2d711cc8 |
502 | return $method; |
503 | }; |
504 | |
505 | sub add_before_method_modifier { |
506 | my ($self, $method_name, $method_modifier) = @_; |
507 | (defined $method_name && $method_name) |
0ac992ee |
508 | || confess "You must pass in a method name"; |
2d711cc8 |
509 | my $method = $fetch_and_prepare_method->($self, $method_name); |
510 | $method->add_before_modifier(subname ':before' => $method_modifier); |
511 | } |
512 | |
513 | sub add_after_method_modifier { |
514 | my ($self, $method_name, $method_modifier) = @_; |
515 | (defined $method_name && $method_name) |
0ac992ee |
516 | || confess "You must pass in a method name"; |
2d711cc8 |
517 | my $method = $fetch_and_prepare_method->($self, $method_name); |
518 | $method->add_after_modifier(subname ':after' => $method_modifier); |
519 | } |
0ac992ee |
520 | |
2d711cc8 |
521 | sub add_around_method_modifier { |
522 | my ($self, $method_name, $method_modifier) = @_; |
523 | (defined $method_name && $method_name) |
524 | || confess "You must pass in a method name"; |
525 | my $method = $fetch_and_prepare_method->($self, $method_name); |
526 | $method->add_around_modifier(subname ':around' => $method_modifier); |
0ac992ee |
527 | } |
a4258ffd |
528 | |
0ac992ee |
529 | # NOTE: |
8c936afc |
530 | # the methods above used to be named like this: |
531 | # ${pkg}::${method}:(before|after|around) |
532 | # but this proved problematic when using one modifier |
533 | # to wrap multiple methods (something which is likely |
534 | # to happen pretty regularly IMO). So instead of naming |
0ac992ee |
535 | # it like this, I have chosen to just name them purely |
8c936afc |
536 | # with their modifier names, like so: |
537 | # :(before|after|around) |
0ac992ee |
538 | # The fact is that in a stack trace, it will be fairly |
8c936afc |
539 | # evident from the context what method they are attached |
540 | # to, and so don't need the fully qualified name. |
ee5e71d4 |
541 | } |
542 | |
663f8198 |
543 | sub alias_method { |
544 | my ($self, $method_name, $method) = @_; |
545 | (defined $method_name && $method_name) |
546 | || confess "You must define a method name"; |
de19f115 |
547 | |
0f71bc80 |
548 | my $body = (blessed($method) ? $method->body : $method); |
549 | ('CODE' eq (reftype($body) || '')) |
0ac992ee |
550 | || confess "Your code block must be a CODE reference"; |
551 | |
7855ddba |
552 | $self->add_package_symbol("&${method_name}" => $body); |
16e960bd |
553 | } |
554 | |
de19f115 |
555 | sub has_method { |
556 | my ($self, $method_name) = @_; |
557 | (defined $method_name && $method_name) |
0ac992ee |
558 | || confess "You must define a method name"; |
559 | |
560 | return 0 unless exists $self->get_method_map->{$method_name}; |
de19f115 |
561 | return 1; |
0882828e |
562 | } |
563 | |
564 | sub get_method { |
c9b8b7f9 |
565 | my ($self, $method_name) = @_; |
0882828e |
566 | (defined $method_name && $method_name) |
567 | || confess "You must define a method name"; |
0ac992ee |
568 | |
0f71bc80 |
569 | # NOTE: |
570 | # I don't really need this here, because |
0ac992ee |
571 | # if the method_map is missing a key it |
0f71bc80 |
572 | # will just return undef for me now |
573 | # return unless $self->has_method($method_name); |
0ac992ee |
574 | |
7855ddba |
575 | return $self->get_method_map->{$method_name}; |
c9b8b7f9 |
576 | } |
577 | |
578 | sub remove_method { |
579 | my ($self, $method_name) = @_; |
580 | (defined $method_name && $method_name) |
581 | || confess "You must define a method name"; |
0ac992ee |
582 | |
583 | my $removed_method = $self->get_method($method_name); |
584 | |
585 | do { |
0f71bc80 |
586 | $self->remove_package_symbol("&${method_name}"); |
587 | delete $self->get_method_map->{$method_name}; |
588 | } if defined $removed_method; |
0ac992ee |
589 | |
c9b8b7f9 |
590 | return $removed_method; |
591 | } |
592 | |
593 | sub get_method_list { |
594 | my $self = shift; |
0f71bc80 |
595 | keys %{$self->get_method_map}; |
7855ddba |
596 | } |
597 | |
598 | sub find_method_by_name { |
599 | my ($self, $method_name) = @_; |
b9575695 |
600 | (defined $method_name && $method_name) |
0ac992ee |
601 | || confess "You must define a method name to find"; |
b7bdffc3 |
602 | foreach my $class ($self->linearized_isa) { |
b9575695 |
603 | # fetch the meta-class ... |
604 | my $meta = $self->initialize($class); |
0ac992ee |
605 | return $meta->get_method($method_name) |
b9575695 |
606 | if $meta->has_method($method_name); |
607 | } |
608 | return; |
a5eca695 |
609 | } |
610 | |
611 | sub compute_all_applicable_methods { |
612 | my $self = shift; |
b7bdffc3 |
613 | my (@methods, %seen_method); |
614 | foreach my $class ($self->linearized_isa) { |
a5eca695 |
615 | # fetch the meta-class ... |
616 | my $meta = $self->initialize($class); |
0ac992ee |
617 | foreach my $method_name ($meta->get_method_list()) { |
a5eca695 |
618 | next if exists $seen_method{$method_name}; |
619 | $seen_method{$method_name}++; |
620 | push @methods => { |
0ac992ee |
621 | name => $method_name, |
a5eca695 |
622 | class => $class, |
623 | code => $meta->get_method($method_name) |
624 | }; |
625 | } |
626 | } |
627 | return @methods; |
628 | } |
629 | |
a5eca695 |
630 | sub find_all_methods_by_name { |
631 | my ($self, $method_name) = @_; |
632 | (defined $method_name && $method_name) |
0ac992ee |
633 | || confess "You must define a method name to find"; |
a5eca695 |
634 | my @methods; |
b7bdffc3 |
635 | foreach my $class ($self->linearized_isa) { |
a5eca695 |
636 | # fetch the meta-class ... |
96ceced8 |
637 | my $meta = $self->initialize($class); |
a5eca695 |
638 | push @methods => { |
0ac992ee |
639 | name => $method_name, |
a5eca695 |
640 | class => $class, |
641 | code => $meta->get_method($method_name) |
642 | } if $meta->has_method($method_name); |
643 | } |
644 | return @methods; |
8b978dd5 |
645 | } |
646 | |
96ceced8 |
647 | sub find_next_method_by_name { |
648 | my ($self, $method_name) = @_; |
649 | (defined $method_name && $method_name) |
0ac992ee |
650 | || confess "You must define a method name to find"; |
b7bdffc3 |
651 | my @cpl = $self->linearized_isa; |
2d711cc8 |
652 | shift @cpl; # discard ourselves |
96ceced8 |
653 | foreach my $class (@cpl) { |
96ceced8 |
654 | # fetch the meta-class ... |
655 | my $meta = $self->initialize($class); |
0ac992ee |
656 | return $meta->get_method($method_name) |
2d711cc8 |
657 | if $meta->has_method($method_name); |
96ceced8 |
658 | } |
2d711cc8 |
659 | return; |
96ceced8 |
660 | } |
661 | |
552e3d24 |
662 | ## Attributes |
663 | |
e16da3e6 |
664 | sub add_attribute { |
2e41896e |
665 | my $self = shift; |
666 | # either we have an attribute object already |
667 | # or we need to create one from the args provided |
668 | my $attribute = blessed($_[0]) ? $_[0] : $self->attribute_metaclass->new(@_); |
669 | # make sure it is derived from the correct type though |
670 | ($attribute->isa('Class::MOP::Attribute')) |
0ac992ee |
671 | || confess "Your attribute must be an instance of Class::MOP::Attribute (or a subclass)"; |
b1897d4d |
672 | |
673 | # first we attach our new attribute |
0ac992ee |
674 | # because it might need certain information |
b1897d4d |
675 | # about the class which it is attached to |
9ec169fe |
676 | $attribute->attach_to_class($self); |
0ac992ee |
677 | |
678 | # then we remove attributes of a conflicting |
679 | # name here so that we can properly detach |
680 | # the old attr object, and remove any |
b1897d4d |
681 | # accessors it would have generated |
682 | $self->remove_attribute($attribute->name) |
683 | if $self->has_attribute($attribute->name); |
0ac992ee |
684 | |
b1897d4d |
685 | # then onto installing the new accessors |
2d711cc8 |
686 | $attribute->install_accessors(); |
291073fc |
687 | $self->get_attribute_map->{$attribute->name} = $attribute; |
e16da3e6 |
688 | } |
689 | |
690 | sub has_attribute { |
691 | my ($self, $attribute_name) = @_; |
692 | (defined $attribute_name && $attribute_name) |
693 | || confess "You must define an attribute name"; |
0ac992ee |
694 | exists $self->get_attribute_map->{$attribute_name} ? 1 : 0; |
695 | } |
e16da3e6 |
696 | |
697 | sub get_attribute { |
698 | my ($self, $attribute_name) = @_; |
699 | (defined $attribute_name && $attribute_name) |
700 | || confess "You must define an attribute name"; |
0ac992ee |
701 | return $self->get_attribute_map->{$attribute_name} |
b1897d4d |
702 | # NOTE: |
703 | # this will return undef anyway, so no need ... |
0ac992ee |
704 | # if $self->has_attribute($attribute_name); |
705 | #return; |
706 | } |
e16da3e6 |
707 | |
708 | sub remove_attribute { |
709 | my ($self, $attribute_name) = @_; |
710 | (defined $attribute_name && $attribute_name) |
711 | || confess "You must define an attribute name"; |
0ac992ee |
712 | my $removed_attribute = $self->get_attribute_map->{$attribute_name}; |
22286063 |
713 | return unless defined $removed_attribute; |
0ac992ee |
714 | delete $self->get_attribute_map->{$attribute_name}; |
715 | $removed_attribute->remove_accessors(); |
2d711cc8 |
716 | $removed_attribute->detach_from_class(); |
e16da3e6 |
717 | return $removed_attribute; |
0ac992ee |
718 | } |
e16da3e6 |
719 | |
720 | sub get_attribute_list { |
721 | my $self = shift; |
f7259199 |
722 | keys %{$self->get_attribute_map}; |
0ac992ee |
723 | } |
e16da3e6 |
724 | |
725 | sub compute_all_applicable_attributes { |
726 | my $self = shift; |
b7bdffc3 |
727 | my (@attrs, %seen_attr); |
728 | foreach my $class ($self->linearized_isa) { |
e16da3e6 |
729 | # fetch the meta-class ... |
f7259199 |
730 | my $meta = $self->initialize($class); |
0ac992ee |
731 | foreach my $attr_name ($meta->get_attribute_list()) { |
e16da3e6 |
732 | next if exists $seen_attr{$attr_name}; |
733 | $seen_attr{$attr_name}++; |
c9e77dbb |
734 | push @attrs => $meta->get_attribute($attr_name); |
e16da3e6 |
735 | } |
736 | } |
0ac992ee |
737 | return @attrs; |
e16da3e6 |
738 | } |
2eb717d5 |
739 | |
058c1cf5 |
740 | sub find_attribute_by_name { |
741 | my ($self, $attr_name) = @_; |
b7bdffc3 |
742 | foreach my $class ($self->linearized_isa) { |
058c1cf5 |
743 | # fetch the meta-class ... |
744 | my $meta = $self->initialize($class); |
745 | return $meta->get_attribute($attr_name) |
746 | if $meta->has_attribute($attr_name); |
747 | } |
748 | return; |
749 | } |
750 | |
857f87a7 |
751 | ## Class closing |
752 | |
753 | sub is_mutable { 1 } |
754 | sub is_immutable { 0 } |
755 | |
b817e248 |
756 | # NOTE: |
757 | # Why I changed this (groditi) |
758 | # - One Metaclass may have many Classes through many Metaclass instances |
759 | # - One Metaclass should only have one Immutable Transformer instance |
760 | # - Each Class may have different Immutabilizing options |
761 | # - Therefore each Metaclass instance may have different Immutabilizing options |
762 | # - We need to store one Immutable Transformer instance per Metaclass |
763 | # - We need to store one set of Immutable Transformer options per Class |
764 | # - Upon make_mutable we may delete the Immutabilizing options |
765 | # - We could clean the immutable Transformer instance when there is no more |
766 | # immutable Classes of that type, but we can also keep it in case |
767 | # another class with this same Metaclass becomes immutable. It is a case |
768 | # of trading of storing an instance to avoid unnecessary instantiations of |
769 | # Immutable Transformers. You may view this as a memory leak, however |
770 | # Because we have few Metaclasses, in practice it seems acceptable |
771 | # - To allow Immutable Transformers instances to be cleaned up we could weaken |
772 | # the reference stored in $IMMUTABLE_TRANSFORMERS{$class} and ||= should DWIM |
04dd7510 |
773 | |
c23184fc |
774 | { |
d9586da2 |
775 | my %IMMUTABLE_TRANSFORMERS; |
0ac992ee |
776 | my %IMMUTABLE_OPTIONS; |
c23184fc |
777 | sub make_immutable { |
0ac992ee |
778 | my $self = shift; |
04dd7510 |
779 | my %options = @_; |
d9586da2 |
780 | my $class = blessed $self || $self; |
781 | |
782 | $IMMUTABLE_TRANSFORMERS{$class} ||= $self->create_immutable_transformer; |
783 | my $transformer = $IMMUTABLE_TRANSFORMERS{$class}; |
784 | |
785 | $transformer->make_metaclass_immutable($self, %options); |
7f63694d |
786 | $IMMUTABLE_OPTIONS{$self->name} = |
d9586da2 |
787 | { %options, IMMUTABLE_TRANSFORMER => $transformer }; |
04dd7510 |
788 | |
789 | if( exists $options{debug} && $options{debug} ){ |
d9586da2 |
790 | print STDERR "# of Metaclass options: ", keys %IMMUTABLE_OPTIONS; |
791 | print STDERR "# of Immutable transformers: ", keys %IMMUTABLE_TRANSFORMERS; |
04dd7510 |
792 | } |
c23184fc |
793 | } |
0ac992ee |
794 | |
795 | sub make_mutable{ |
796 | my $self = shift; |
797 | return if $self->is_mutable; |
7f63694d |
798 | my $options = delete $IMMUTABLE_OPTIONS{$self->name}; |
1d68af04 |
799 | confess "unable to find immutabilizing options" unless ref $options; |
d9586da2 |
800 | my $transformer = delete $options->{IMMUTABLE_TRANSFORMER}; |
801 | $transformer->make_metaclass_mutable($self, %$options); |
0ac992ee |
802 | } |
d9586da2 |
803 | } |
0ac992ee |
804 | |
d9586da2 |
805 | sub create_immutable_transformer { |
806 | my $self = shift; |
807 | my $class = Class::MOP::Immutable->new($self, { |
808 | read_only => [qw/superclasses/], |
809 | cannot_call => [qw/ |
810 | add_method |
811 | alias_method |
812 | remove_method |
813 | add_attribute |
814 | remove_attribute |
815 | add_package_symbol |
816 | remove_package_symbol |
817 | /], |
818 | memoize => { |
819 | class_precedence_list => 'ARRAY', |
b7bdffc3 |
820 | linearized_isa => 'ARRAY', |
d9586da2 |
821 | compute_all_applicable_attributes => 'ARRAY', |
822 | get_meta_instance => 'SCALAR', |
823 | get_method_map => 'SCALAR', |
824 | } |
825 | }); |
826 | return $class; |
857f87a7 |
827 | } |
828 | |
8b978dd5 |
829 | 1; |
830 | |
831 | __END__ |
832 | |
833 | =pod |
834 | |
0ac992ee |
835 | =head1 NAME |
8b978dd5 |
836 | |
837 | Class::MOP::Class - Class Meta Object |
838 | |
839 | =head1 SYNOPSIS |
840 | |
0ac992ee |
841 | # assuming that class Foo |
8c936afc |
842 | # has been defined, you can |
0ac992ee |
843 | |
fe122940 |
844 | # use this for introspection ... |
0ac992ee |
845 | |
fe122940 |
846 | # add a method to Foo ... |
847 | Foo->meta->add_method('bar' => sub { ... }) |
0ac992ee |
848 | |
849 | # get a list of all the classes searched |
850 | # the method dispatcher in the correct order |
fe122940 |
851 | Foo->meta->class_precedence_list() |
0ac992ee |
852 | |
fe122940 |
853 | # remove a method from Foo |
854 | Foo->meta->remove_method('bar'); |
0ac992ee |
855 | |
fe122940 |
856 | # or use this to actually create classes ... |
0ac992ee |
857 | |
88dd563c |
858 | Class::MOP::Class->create('Bar' => ( |
859 | version => '0.01', |
fe122940 |
860 | superclasses => [ 'Foo' ], |
861 | attributes => [ |
862 | Class::MOP:::Attribute->new('$bar'), |
0ac992ee |
863 | Class::MOP:::Attribute->new('$baz'), |
fe122940 |
864 | ], |
865 | methods => { |
866 | calculate_bar => sub { ... }, |
0ac992ee |
867 | construct_baz => sub { ... } |
fe122940 |
868 | } |
869 | )); |
870 | |
8b978dd5 |
871 | =head1 DESCRIPTION |
872 | |
0ac992ee |
873 | This is the largest and currently most complex part of the Perl 5 |
874 | meta-object protocol. It controls the introspection and |
875 | manipulation of Perl 5 classes (and it can create them too). The |
876 | best way to understand what this module can do, is to read the |
fe122940 |
877 | documentation for each of it's methods. |
878 | |
552e3d24 |
879 | =head1 METHODS |
880 | |
2eb717d5 |
881 | =head2 Self Introspection |
882 | |
883 | =over 4 |
884 | |
885 | =item B<meta> |
886 | |
0ac992ee |
887 | This will return a B<Class::MOP::Class> instance which is related |
888 | to this class. Thereby allowing B<Class::MOP::Class> to actually |
fe122940 |
889 | introspect itself. |
890 | |
0ac992ee |
891 | As with B<Class::MOP::Attribute>, B<Class::MOP> will actually |
892 | bootstrap this module by installing a number of attribute meta-objects |
893 | into it's metaclass. This will allow this class to reap all the benifits |
894 | of the MOP when subclassing it. |
2eb717d5 |
895 | |
896 | =back |
897 | |
552e3d24 |
898 | =head2 Class construction |
899 | |
0ac992ee |
900 | These methods will handle creating B<Class::MOP::Class> objects, |
901 | which can be used to both create new classes, and analyze |
902 | pre-existing classes. |
552e3d24 |
903 | |
0ac992ee |
904 | This module will internally store references to all the instances |
905 | you create with these methods, so that they do not need to be |
552e3d24 |
906 | created any more than nessecary. Basically, they are singletons. |
907 | |
908 | =over 4 |
909 | |
0ac992ee |
910 | =item B<create ($package_name, |
911 | version =E<gt> ?$version, |
912 | authority =E<gt> ?$authority, |
913 | superclasses =E<gt> ?@superclasses, |
914 | methods =E<gt> ?%methods, |
a2e85e6c |
915 | attributes =E<gt> ?%attributes)> |
552e3d24 |
916 | |
0ac992ee |
917 | This returns a B<Class::MOP::Class> object, bringing the specified |
918 | C<$package_name> into existence and adding any of the C<$version>, |
919 | C<$authority>, C<@superclasses>, C<%methods> and C<%attributes> to |
88dd563c |
920 | it. |
552e3d24 |
921 | |
0ac992ee |
922 | =item B<create_anon_class (superclasses =E<gt> ?@superclasses, |
923 | methods =E<gt> ?%methods, |
587aca23 |
924 | attributes =E<gt> ?%attributes)> |
925 | |
0ac992ee |
926 | This will create an anonymous class, it works much like C<create> but |
927 | it does not need a C<$package_name>. Instead it will create a suitably |
587aca23 |
928 | unique package name for you to stash things into. |
929 | |
0ac992ee |
930 | On very important distinction is that anon classes are destroyed once |
931 | the metaclass they are attached to goes out of scope. In the DESTROY |
932 | method, the created package will be removed from the symbol table. |
823a5d31 |
933 | |
d4ba1677 |
934 | It is also worth noting that any instances created with an anon-class |
0ac992ee |
935 | will keep a special reference to the anon-meta which will prevent the |
936 | anon-class from going out of scope until all instances of it have also |
937 | been destroyed. This however only works for HASH based instance types, |
938 | as we use a special reserved slot (C<__MOP__>) to store this. |
d4ba1677 |
939 | |
66b3dded |
940 | =item B<initialize ($package_name, %options)> |
552e3d24 |
941 | |
0ac992ee |
942 | This initializes and returns returns a B<Class::MOP::Class> object |
a2e85e6c |
943 | for a given a C<$package_name>. |
944 | |
66b3dded |
945 | =item B<reinitialize ($package_name, %options)> |
946 | |
947 | This removes the old metaclass, and creates a new one in it's place. |
0ac992ee |
948 | Do B<not> use this unless you really know what you are doing, it could |
949 | very easily make a very large mess of your program. |
66b3dded |
950 | |
651955fb |
951 | =item B<construct_class_instance (%options)> |
a2e85e6c |
952 | |
0ac992ee |
953 | This will construct an instance of B<Class::MOP::Class>, it is |
954 | here so that we can actually "tie the knot" for B<Class::MOP::Class> |
955 | to use C<construct_instance> once all the bootstrapping is done. This |
a2e85e6c |
956 | method is used internally by C<initialize> and should never be called |
957 | from outside of that method really. |
552e3d24 |
958 | |
550d56db |
959 | =item B<check_metaclass_compatability> |
960 | |
0ac992ee |
961 | This method is called as the very last thing in the |
962 | C<construct_class_instance> method. This will check that the |
963 | metaclass you are creating is compatible with the metaclasses of all |
964 | your ancestors. For more inforamtion about metaclass compatibility |
550d56db |
965 | see the C<About Metaclass compatibility> section in L<Class::MOP>. |
966 | |
552e3d24 |
967 | =back |
968 | |
c9e77dbb |
969 | =head2 Object instance construction and cloning |
a2e85e6c |
970 | |
0ac992ee |
971 | These methods are B<entirely optional>, it is up to you whether you want |
c9e77dbb |
972 | to use them or not. |
552e3d24 |
973 | |
974 | =over 4 |
975 | |
2bab2be6 |
976 | =item B<instance_metaclass> |
977 | |
2d711cc8 |
978 | =item B<get_meta_instance> |
979 | |
5f3c057a |
980 | =item B<new_object (%params)> |
981 | |
0ac992ee |
982 | This is a convience method for creating a new object of the class, and |
983 | blessing it into the appropriate package as well. Ideally your class |
5f3c057a |
984 | would call a C<new> this method like so: |
985 | |
0ac992ee |
986 | sub MyClass::new { |
5f3c057a |
987 | my ($class, %param) = @_; |
988 | $class->meta->new_object(%params); |
989 | } |
990 | |
0ac992ee |
991 | Of course the ideal place for this would actually be in C<UNIVERSAL::> |
5f3c057a |
992 | but that is considered bad style, so we do not do that. |
993 | |
cbd9f942 |
994 | =item B<construct_instance (%params)> |
552e3d24 |
995 | |
0ac992ee |
996 | This method is used to construct an instace structure suitable for |
997 | C<bless>-ing into your package of choice. It works in conjunction |
c9e77dbb |
998 | with the Attribute protocol to collect all applicable attributes. |
999 | |
0ac992ee |
1000 | This will construct and instance using a HASH ref as storage |
1001 | (currently only HASH references are supported). This will collect all |
1002 | the applicable attributes and layout out the fields in the HASH ref, |
1003 | it will then initialize them using either use the corresponding key |
1004 | in C<%params> or any default value or initializer found in the |
a2e85e6c |
1005 | attribute meta-object. |
727919c5 |
1006 | |
5f3c057a |
1007 | =item B<clone_object ($instance, %params)> |
1008 | |
0ac992ee |
1009 | This is a convience method for cloning an object instance, then |
1010 | blessing it into the appropriate package. This method will call |
1011 | C<clone_instance>, which performs a shallow copy of the object, |
1012 | see that methods documentation for more details. Ideally your |
19d4b5b8 |
1013 | class would call a C<clone> this method like so: |
5f3c057a |
1014 | |
1015 | sub MyClass::clone { |
1016 | my ($self, %param) = @_; |
1017 | $self->meta->clone_object($self, %params); |
1018 | } |
1019 | |
0ac992ee |
1020 | Of course the ideal place for this would actually be in C<UNIVERSAL::> |
5f3c057a |
1021 | but that is considered bad style, so we do not do that. |
1022 | |
c9e77dbb |
1023 | =item B<clone_instance($instance, %params)> |
1024 | |
0ac992ee |
1025 | This method is a compliment of C<construct_instance> (which means if |
1026 | you override C<construct_instance>, you need to override this one too), |
19d4b5b8 |
1027 | and clones the instance shallowly. |
a27ae83f |
1028 | |
0ac992ee |
1029 | The cloned structure returned is (like with C<construct_instance>) an |
1030 | unC<bless>ed HASH reference, it is your responsibility to then bless |
a27ae83f |
1031 | this cloned structure into the right class (which C<clone_object> will |
1032 | do for you). |
c9e77dbb |
1033 | |
0ac992ee |
1034 | As of 0.11, this method will clone the C<$instance> structure shallowly, |
1035 | as opposed to the deep cloning implemented in prior versions. After much |
1036 | thought, research and discussion, I have decided that anything but basic |
1037 | shallow cloning is outside the scope of the meta-object protocol. I |
1038 | think Yuval "nothingmuch" Kogman put it best when he said that cloning |
19d4b5b8 |
1039 | is too I<context-specific> to be part of the MOP. |
1040 | |
552e3d24 |
1041 | =back |
1042 | |
0ac992ee |
1043 | =head2 Informational |
552e3d24 |
1044 | |
b9d9fc0b |
1045 | These are a few predicate methods for asking information about the class. |
552e3d24 |
1046 | |
b9d9fc0b |
1047 | =over 4 |
552e3d24 |
1048 | |
b9d9fc0b |
1049 | =item B<is_anon_class> |
552e3d24 |
1050 | |
96e38ba6 |
1051 | This returns true if the class is a C<Class::MOP::Class> created anon class. |
1052 | |
b9d9fc0b |
1053 | =item B<is_mutable> |
552e3d24 |
1054 | |
96e38ba6 |
1055 | This returns true if the class is still mutable. |
1056 | |
b9d9fc0b |
1057 | =item B<is_immutable> |
552e3d24 |
1058 | |
96e38ba6 |
1059 | This returns true if the class has been made immutable. |
1060 | |
552e3d24 |
1061 | =back |
1062 | |
1063 | =head2 Inheritance Relationships |
1064 | |
1065 | =over 4 |
1066 | |
1067 | =item B<superclasses (?@superclasses)> |
1068 | |
0ac992ee |
1069 | This is a read-write attribute which represents the superclass |
a2e85e6c |
1070 | relationships of the class the B<Class::MOP::Class> instance is |
1071 | associated with. Basically, it can get and set the C<@ISA> for you. |
552e3d24 |
1072 | |
343203ee |
1073 | B<NOTE:> |
0ac992ee |
1074 | Perl will occasionally perform some C<@ISA> and method caching, if |
1075 | you decide to change your superclass relationship at runtime (which |
1076 | is quite insane and very much not recommened), then you should be |
1077 | aware of this and the fact that this module does not make any |
343203ee |
1078 | attempt to address this issue. |
1079 | |
552e3d24 |
1080 | =item B<class_precedence_list> |
1081 | |
0ac992ee |
1082 | This computes the a list of all the class's ancestors in the same order |
1083 | in which method dispatch will be done. This is similair to |
a2e85e6c |
1084 | what B<Class::ISA::super_path> does, but we don't remove duplicate names. |
552e3d24 |
1085 | |
b7bdffc3 |
1086 | =item B<linearized_isa> |
1087 | |
1088 | This returns a list based on C<class_precedence_list> but with all |
1089 | duplicates removed. |
1090 | |
6c9f390e |
1091 | =item B<subclasses> |
1092 | |
1093 | This returns a list of subclasses for this class. |
1094 | |
552e3d24 |
1095 | =back |
1096 | |
1097 | =head2 Methods |
1098 | |
1099 | =over 4 |
1100 | |
c4260b45 |
1101 | =item B<get_method_map> |
1102 | |
2e41896e |
1103 | =item B<method_metaclass> |
1104 | |
552e3d24 |
1105 | =item B<add_method ($method_name, $method)> |
1106 | |
0ac992ee |
1107 | This will take a C<$method_name> and CODE reference to that |
1108 | C<$method> and install it into the class's package. |
552e3d24 |
1109 | |
0ac992ee |
1110 | B<NOTE>: |
1111 | This does absolutely nothing special to C<$method> |
1112 | other than use B<Sub::Name> to make sure it is tagged with the |
1113 | correct name, and therefore show up correctly in stack traces and |
552e3d24 |
1114 | such. |
1115 | |
663f8198 |
1116 | =item B<alias_method ($method_name, $method)> |
1117 | |
0ac992ee |
1118 | This will take a C<$method_name> and CODE reference to that |
1119 | C<$method> and alias the method into the class's package. |
663f8198 |
1120 | |
0ac992ee |
1121 | B<NOTE>: |
1122 | Unlike C<add_method>, this will B<not> try to name the |
1123 | C<$method> using B<Sub::Name>, it only aliases the method in |
1124 | the class's package. |
663f8198 |
1125 | |
552e3d24 |
1126 | =item B<has_method ($method_name)> |
1127 | |
0ac992ee |
1128 | This just provides a simple way to check if the class implements |
1129 | a specific C<$method_name>. It will I<not> however, attempt to check |
a2e85e6c |
1130 | if the class inherits the method (use C<UNIVERSAL::can> for that). |
552e3d24 |
1131 | |
0ac992ee |
1132 | This will correctly handle functions defined outside of the package |
552e3d24 |
1133 | that use a fully qualified name (C<sub Package::name { ... }>). |
1134 | |
0ac992ee |
1135 | This will correctly handle functions renamed with B<Sub::Name> and |
1136 | installed using the symbol tables. However, if you are naming the |
1137 | subroutine outside of the package scope, you must use the fully |
1138 | qualified name, including the package name, for C<has_method> to |
1139 | correctly identify it. |
552e3d24 |
1140 | |
0ac992ee |
1141 | This will attempt to correctly ignore functions imported from other |
1142 | packages using B<Exporter>. It breaks down if the function imported |
1143 | is an C<__ANON__> sub (such as with C<use constant>), which very well |
1144 | may be a valid method being applied to the class. |
552e3d24 |
1145 | |
0ac992ee |
1146 | In short, this method cannot always be trusted to determine if the |
1147 | C<$method_name> is actually a method. However, it will DWIM about |
a2e85e6c |
1148 | 90% of the time, so it's a small trade off I think. |
552e3d24 |
1149 | |
1150 | =item B<get_method ($method_name)> |
1151 | |
0ac992ee |
1152 | This will return a Class::MOP::Method instance related to the specified |
86482605 |
1153 | C<$method_name>, or return undef if that method does not exist. |
1154 | |
0ac992ee |
1155 | The Class::MOP::Method is codifiable, so you can use it like a normal |
86482605 |
1156 | CODE reference, see L<Class::MOP::Method> for more information. |
552e3d24 |
1157 | |
16e960bd |
1158 | =item B<find_method_by_name ($method_name> |
1159 | |
1160 | This will return a CODE reference of the specified C<$method_name>, |
1161 | or return undef if that method does not exist. |
1162 | |
1163 | Unlike C<get_method> this will also look in the superclasses. |
1164 | |
552e3d24 |
1165 | =item B<remove_method ($method_name)> |
1166 | |
0ac992ee |
1167 | This will attempt to remove a given C<$method_name> from the class. |
1168 | It will return the CODE reference that it has removed, and will |
552e3d24 |
1169 | attempt to use B<Sub::Name> to clear the methods associated name. |
1170 | |
1171 | =item B<get_method_list> |
1172 | |
0ac992ee |
1173 | This will return a list of method names for all I<locally> defined |
1174 | methods. It does B<not> provide a list of all applicable methods, |
1175 | including any inherited ones. If you want a list of all applicable |
552e3d24 |
1176 | methods, use the C<compute_all_applicable_methods> method. |
1177 | |
1178 | =item B<compute_all_applicable_methods> |
1179 | |
0ac992ee |
1180 | This will return a list of all the methods names this class will |
1181 | respond to, taking into account inheritance. The list will be a list of |
1182 | HASH references, each one containing the following information; method |
1183 | name, the name of the class in which the method lives and a CODE |
552e3d24 |
1184 | reference for the actual method. |
1185 | |
1186 | =item B<find_all_methods_by_name ($method_name)> |
1187 | |
0ac992ee |
1188 | This will traverse the inheritence hierarchy and locate all methods |
1189 | with a given C<$method_name>. Similar to |
1190 | C<compute_all_applicable_methods> it returns a list of HASH references |
1191 | with the following information; method name (which will always be the |
1192 | same as C<$method_name>), the name of the class in which the method |
552e3d24 |
1193 | lives and a CODE reference for the actual method. |
1194 | |
0ac992ee |
1195 | The list of methods produced is a distinct list, meaning there are no |
1196 | duplicates in it. This is especially useful for things like object |
1197 | initialization and destruction where you only want the method called |
552e3d24 |
1198 | once, and in the correct order. |
1199 | |
96ceced8 |
1200 | =item B<find_next_method_by_name ($method_name)> |
1201 | |
0ac992ee |
1202 | This will return the first method to match a given C<$method_name> in |
1203 | the superclasses, this is basically equivalent to calling |
96ceced8 |
1204 | C<SUPER::$method_name>, but it can be dispatched at runtime. |
1205 | |
552e3d24 |
1206 | =back |
1207 | |
a4258ffd |
1208 | =head2 Method Modifiers |
1209 | |
0ac992ee |
1210 | Method modifiers are a concept borrowed from CLOS, in which a method |
1211 | can be wrapped with I<before>, I<after> and I<around> method modifiers |
1212 | that will be called everytime the method is called. |
96ceced8 |
1213 | |
1214 | =head3 How method modifiers work? |
1215 | |
0ac992ee |
1216 | Method modifiers work by wrapping the original method and then replacing |
1217 | it in the classes symbol table. The wrappers will handle calling all the |
1218 | modifiers in the appropariate orders and preserving the calling context |
1219 | for the original method. |
1220 | |
1221 | Each method modifier serves a particular purpose, which may not be |
1222 | obvious to users of other method wrapping modules. To start with, the |
1223 | return values of I<before> and I<after> modifiers are ignored. This is |
1224 | because thier purpose is B<not> to filter the input and output of the |
1225 | primary method (this is done with an I<around> modifier). This may seem |
1226 | like an odd restriction to some, but doing this allows for simple code |
1227 | to be added at the begining or end of a method call without jeapordizing |
1228 | the normal functioning of the primary method or placing any extra |
1229 | responsibility on the code of the modifier. Of course if you have more |
1230 | complex needs, then use the I<around> modifier, which uses a variation |
1231 | of continutation passing style to allow for a high degree of flexibility. |
1232 | |
1233 | Before and around modifiers are called in last-defined-first-called order, |
1234 | while after modifiers are called in first-defined-first-called order. So |
96ceced8 |
1235 | the call tree might looks something like this: |
0ac992ee |
1236 | |
96ceced8 |
1237 | before 2 |
1238 | before 1 |
1239 | around 2 |
1240 | around 1 |
1241 | primary |
1242 | after 1 |
1243 | after 2 |
1244 | |
0ac992ee |
1245 | To see examples of using method modifiers, see the following examples |
1246 | included in the distribution; F<InstanceCountingClass>, F<Perl6Attribute>, |
1247 | F<AttributesWithHistory> and F<C3MethodDispatchOrder>. There is also a |
96ceced8 |
1248 | classic CLOS usage example in the test F<017_add_method_modifier.t>. |
1249 | |
1250 | =head3 What is the performance impact? |
1251 | |
0ac992ee |
1252 | Of course there is a performance cost associated with method modifiers, |
1253 | but we have made every effort to make that cost be directly proportional |
96ceced8 |
1254 | to the amount of modifier features you utilize. |
1255 | |
0ac992ee |
1256 | The wrapping method does it's best to B<only> do as much work as it |
1257 | absolutely needs to. In order to do this we have moved some of the |
96ceced8 |
1258 | performance costs to set-up time, where they are easier to amortize. |
1259 | |
1260 | All this said, my benchmarks have indicated the following: |
1261 | |
1262 | simple wrapper with no modifiers 100% slower |
1263 | simple wrapper with simple before modifier 400% slower |
1264 | simple wrapper with simple after modifier 450% slower |
1265 | simple wrapper with simple around modifier 500-550% slower |
1266 | simple wrapper with all 3 modifiers 1100% slower |
1267 | |
0ac992ee |
1268 | These numbers may seem daunting, but you must remember, every feature |
1269 | comes with some cost. To put things in perspective, just doing a simple |
96ceced8 |
1270 | C<AUTOLOAD> which does nothing but extract the name of the method called |
0ac992ee |
1271 | and return it costs about 400% over a normal method call. |
96ceced8 |
1272 | |
a4258ffd |
1273 | =over 4 |
1274 | |
1275 | =item B<add_before_method_modifier ($method_name, $code)> |
1276 | |
0ac992ee |
1277 | This will wrap the method at C<$method_name> and the supplied C<$code> |
1278 | will be passed the C<@_> arguments, and called before the original |
1279 | method is called. As specified above, the return value of the I<before> |
1280 | method modifiers is ignored, and it's ability to modify C<@_> is |
1281 | fairly limited. If you need to do either of these things, use an |
96ceced8 |
1282 | C<around> method modifier. |
1283 | |
a4258ffd |
1284 | =item B<add_after_method_modifier ($method_name, $code)> |
1285 | |
0ac992ee |
1286 | This will wrap the method at C<$method_name> so that the original |
1287 | method will be called, it's return values stashed, and then the |
96ceced8 |
1288 | supplied C<$code> will be passed the C<@_> arguments, and called. |
0ac992ee |
1289 | As specified above, the return value of the I<after> method |
1290 | modifiers is ignored, and it cannot modify the return values of |
1291 | the original method. If you need to do either of these things, use an |
96ceced8 |
1292 | C<around> method modifier. |
1293 | |
a4258ffd |
1294 | =item B<add_around_method_modifier ($method_name, $code)> |
1295 | |
0ac992ee |
1296 | This will wrap the method at C<$method_name> so that C<$code> |
1297 | will be called and passed the original method as an extra argument |
1298 | at the begining of the C<@_> argument list. This is a variation of |
1299 | continuation passing style, where the function prepended to C<@_> |
1300 | can be considered a continuation. It is up to C<$code> if it calls |
1301 | the original method or not, there is no restriction on what the |
96ceced8 |
1302 | C<$code> can or cannot do. |
1303 | |
a4258ffd |
1304 | =back |
1305 | |
552e3d24 |
1306 | =head2 Attributes |
1307 | |
0ac992ee |
1308 | It should be noted that since there is no one consistent way to define |
1309 | the attributes of a class in Perl 5. These methods can only work with |
1310 | the information given, and can not easily discover information on |
a2e85e6c |
1311 | their own. See L<Class::MOP::Attribute> for more details. |
552e3d24 |
1312 | |
1313 | =over 4 |
1314 | |
2e41896e |
1315 | =item B<attribute_metaclass> |
1316 | |
7b31baf4 |
1317 | =item B<get_attribute_map> |
1318 | |
8203616d |
1319 | =item B<add_attribute ($attribute_meta_object | $attribute_name, %attribute_spec)> |
552e3d24 |
1320 | |
8203616d |
1321 | This stores the C<$attribute_meta_object> (or creates one from the |
0ac992ee |
1322 | C<$attribute_name> and C<%attribute_spec>) in the B<Class::MOP::Class> |
1323 | instance associated with the given class. Unlike methods, attributes |
1324 | within the MOP are stored as meta-information only. They will be used |
8203616d |
1325 | later to construct instances from (see C<construct_instance> above). |
0ac992ee |
1326 | More details about the attribute meta-objects can be found in the |
a2e85e6c |
1327 | L<Class::MOP::Attribute> or the L<Class::MOP/The Attribute protocol> |
1328 | section. |
1329 | |
0ac992ee |
1330 | It should be noted that any accessor, reader/writer or predicate |
1331 | methods which the C<$attribute_meta_object> has will be installed |
a2e85e6c |
1332 | into the class at this time. |
552e3d24 |
1333 | |
86482605 |
1334 | B<NOTE> |
0ac992ee |
1335 | If an attribute already exists for C<$attribute_name>, the old one |
1336 | will be removed (as well as removing all it's accessors), and then |
86482605 |
1337 | the new one added. |
1338 | |
552e3d24 |
1339 | =item B<has_attribute ($attribute_name)> |
1340 | |
0ac992ee |
1341 | Checks to see if this class has an attribute by the name of |
552e3d24 |
1342 | C<$attribute_name> and returns a boolean. |
1343 | |
1344 | =item B<get_attribute ($attribute_name)> |
1345 | |
0ac992ee |
1346 | Returns the attribute meta-object associated with C<$attribute_name>, |
1347 | if none is found, it will return undef. |
552e3d24 |
1348 | |
1349 | =item B<remove_attribute ($attribute_name)> |
1350 | |
0ac992ee |
1351 | This will remove the attribute meta-object stored at |
1352 | C<$attribute_name>, then return the removed attribute meta-object. |
552e3d24 |
1353 | |
0ac992ee |
1354 | B<NOTE:> |
1355 | Removing an attribute will only affect future instances of |
1356 | the class, it will not make any attempt to remove the attribute from |
552e3d24 |
1357 | any existing instances of the class. |
1358 | |
0ac992ee |
1359 | It should be noted that any accessor, reader/writer or predicate |
1360 | methods which the attribute meta-object stored at C<$attribute_name> |
1361 | has will be removed from the class at this time. This B<will> make |
1362 | these attributes somewhat inaccessable in previously created |
1363 | instances. But if you are crazy enough to do this at runtime, then |
a2e85e6c |
1364 | you are crazy enough to deal with something like this :). |
1365 | |
552e3d24 |
1366 | =item B<get_attribute_list> |
1367 | |
0ac992ee |
1368 | This returns a list of attribute names which are defined in the local |
1369 | class. If you want a list of all applicable attributes for a class, |
552e3d24 |
1370 | use the C<compute_all_applicable_attributes> method. |
1371 | |
1372 | =item B<compute_all_applicable_attributes> |
1373 | |
0ac992ee |
1374 | This will traverse the inheritance heirachy and return a list of all |
1375 | the applicable attributes for this class. It does not construct a |
1376 | HASH reference like C<compute_all_applicable_methods> because all |
1377 | that same information is discoverable through the attribute |
c9e77dbb |
1378 | meta-object itself. |
552e3d24 |
1379 | |
058c1cf5 |
1380 | =item B<find_attribute_by_name ($attr_name)> |
1381 | |
0ac992ee |
1382 | This method will traverse the inheritance heirachy and find the |
1383 | first attribute whose name matches C<$attr_name>, then return it. |
058c1cf5 |
1384 | It will return undef if nothing is found. |
1385 | |
552e3d24 |
1386 | =back |
1387 | |
96e38ba6 |
1388 | =head2 Class Immutability |
857f87a7 |
1389 | |
1390 | =over 4 |
1391 | |
96e38ba6 |
1392 | =item B<make_immutable (%options)> |
1393 | |
0ac992ee |
1394 | This method will invoke a tranforamtion upon the class which will |
1395 | make it immutable. Details of this transformation can be found in |
96e38ba6 |
1396 | the L<Class::MOP::Immutable> documentation. |
857f87a7 |
1397 | |
0ac992ee |
1398 | =item B<make_mutable> |
1399 | |
1400 | This method will reverse tranforamtion upon the class which |
1401 | made it immutable. |
1402 | |
b817e248 |
1403 | =item B<create_immutable_transformer> |
1404 | |
1405 | Create a transformer suitable for making this class immutable |
1406 | |
857f87a7 |
1407 | =back |
1408 | |
1a09d9cc |
1409 | =head1 AUTHORS |
8b978dd5 |
1410 | |
a2e85e6c |
1411 | Stevan Little E<lt>stevan@iinteractive.comE<gt> |
8b978dd5 |
1412 | |
1413 | =head1 COPYRIGHT AND LICENSE |
1414 | |
2367814a |
1415 | Copyright 2006, 2007 by Infinity Interactive, Inc. |
8b978dd5 |
1416 | |
1417 | L<http://www.iinteractive.com> |
1418 | |
1419 | This library is free software; you can redistribute it and/or modify |
0ac992ee |
1420 | it under the same terms as Perl itself. |
8b978dd5 |
1421 | |
798baea5 |
1422 | =cut |