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'; |
04dd7510 |
12 | use Scalar::Util 'blessed', 'reftype', 'weaken', 'refaddr'; |
8b978dd5 |
13 | use Sub::Name 'subname'; |
96ceced8 |
14 | use B 'svref_2object'; |
8b978dd5 |
15 | |
c0fcd6ab |
16 | our $VERSION = '0.22'; |
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"; |
c23184fc |
32 | $class->construct_class_instance('package' => $package_name, @_); |
be7677c7 |
33 | } |
34 | |
35 | sub reinitialize { |
36 | my $class = shift; |
37 | my $package_name = shift; |
38 | (defined $package_name && $package_name && !blessed($package_name)) |
0ac992ee |
39 | || confess "You must pass a package name and it cannot be blessed"; |
be7677c7 |
40 | Class::MOP::remove_metaclass_by_name($package_name); |
c23184fc |
41 | $class->construct_class_instance('package' => $package_name, @_); |
0ac992ee |
42 | } |
43 | |
44 | # NOTE: (meta-circularity) |
45 | # this is a special form of &construct_instance |
be7677c7 |
46 | # (see below), which is used to construct class |
0ac992ee |
47 | # meta-object instances for any Class::MOP::* |
48 | # class. All other classes will use the more |
be7677c7 |
49 | # normal &construct_instance. |
50 | sub construct_class_instance { |
51 | my $class = shift; |
52 | my %options = @_; |
c23184fc |
53 | my $package_name = $options{'package'}; |
be7677c7 |
54 | (defined $package_name && $package_name) |
0ac992ee |
55 | || confess "You must pass a package name"; |
be7677c7 |
56 | # NOTE: |
0ac992ee |
57 | # return the metaclass if we have it cached, |
58 | # and it is still defined (it has not been |
59 | # reaped by DESTROY yet, which can happen |
be7677c7 |
60 | # annoyingly enough during global destruction) |
61 | return Class::MOP::get_metaclass_by_name($package_name) |
0ac992ee |
62 | if Class::MOP::does_metaclass_exist($package_name); |
be7677c7 |
63 | |
64 | # NOTE: |
0ac992ee |
65 | # we need to deal with the possibility |
66 | # of class immutability here, and then |
be7677c7 |
67 | # get the name of the class appropriately |
68 | $class = (blessed($class) |
69 | ? ($class->is_immutable |
70 | ? $class->get_mutable_metaclass_name() |
71 | : blessed($class)) |
72 | : $class); |
73 | |
be7677c7 |
74 | # now create the metaclass |
75 | my $meta; |
76 | if ($class =~ /^Class::MOP::Class$/) { |
0ac992ee |
77 | no strict 'refs'; |
78 | $meta = bless { |
be7677c7 |
79 | # inherited from Class::MOP::Package |
0ac992ee |
80 | '$!package' => $package_name, |
81 | |
c4260b45 |
82 | # NOTE: |
0ac992ee |
83 | # since the following attributes will |
84 | # actually be loaded from the symbol |
c4260b45 |
85 | # table, and actually bypass the instance |
86 | # entirely, we can just leave these things |
87 | # listed here for reference, because they |
0ac992ee |
88 | # should not actually have a value associated |
c4260b45 |
89 | # with the slot. |
0ac992ee |
90 | '%!namespace' => \undef, |
be7677c7 |
91 | # inherited from Class::MOP::Module |
c23184fc |
92 | '$!version' => \undef, |
93 | '$!authority' => \undef, |
c4260b45 |
94 | # defined in Class::MOP::Class |
c23184fc |
95 | '@!superclasses' => \undef, |
0ac992ee |
96 | |
c23184fc |
97 | '%!methods' => {}, |
0ac992ee |
98 | '%!attributes' => {}, |
c23184fc |
99 | '$!attribute_metaclass' => $options{'attribute_metaclass'} || 'Class::MOP::Attribute', |
100 | '$!method_metaclass' => $options{'method_metaclass'} || 'Class::MOP::Method', |
101 | '$!instance_metaclass' => $options{'instance_metaclass'} || 'Class::MOP::Instance', |
be7677c7 |
102 | } => $class; |
103 | } |
104 | else { |
105 | # NOTE: |
106 | # it is safe to use meta here because |
0ac992ee |
107 | # class will always be a subclass of |
be7677c7 |
108 | # Class::MOP::Class, which defines meta |
109 | $meta = $class->meta->construct_instance(%options) |
727919c5 |
110 | } |
0ac992ee |
111 | |
be7677c7 |
112 | # and check the metaclass compatibility |
113 | $meta->check_metaclass_compatability(); |
0ac992ee |
114 | |
be7677c7 |
115 | Class::MOP::store_metaclass_by_name($package_name, $meta); |
0ac992ee |
116 | |
be7677c7 |
117 | # NOTE: |
118 | # we need to weaken any anon classes |
119 | # so that they can call DESTROY properly |
b9d9fc0b |
120 | Class::MOP::weaken_metaclass($package_name) if $meta->is_anon_class; |
0ac992ee |
121 | |
122 | $meta; |
123 | } |
124 | |
be7677c7 |
125 | sub check_metaclass_compatability { |
126 | my $self = shift; |
127 | |
128 | # this is always okay ... |
0ac992ee |
129 | return if blessed($self) eq 'Class::MOP::Class' && |
be7677c7 |
130 | $self->instance_metaclass eq 'Class::MOP::Instance'; |
131 | |
132 | my @class_list = $self->class_precedence_list; |
133 | shift @class_list; # shift off $self->name |
373a16ae |
134 | |
0ac992ee |
135 | foreach my $class_name (@class_list) { |
be7677c7 |
136 | my $meta = Class::MOP::get_metaclass_by_name($class_name) || next; |
0ac992ee |
137 | |
373a16ae |
138 | # NOTE: |
0ac992ee |
139 | # we need to deal with the possibility |
140 | # of class immutability here, and then |
141 | # get the name of the class appropriately |
be7677c7 |
142 | my $meta_type = ($meta->is_immutable |
143 | ? $meta->get_mutable_metaclass_name() |
0ac992ee |
144 | : blessed($meta)); |
145 | |
be7677c7 |
146 | ($self->isa($meta_type)) |
0ac992ee |
147 | || confess $self->name . "->meta => (" . (blessed($self)) . ")" . |
148 | " is not compatible with the " . |
be7677c7 |
149 | $class_name . "->meta => (" . ($meta_type) . ")"; |
77e5fce4 |
150 | # NOTE: |
be7677c7 |
151 | # we also need to check that instance metaclasses |
152 | # are compatabile in the same the class. |
153 | ($self->instance_metaclass->isa($meta->instance_metaclass)) |
0ac992ee |
154 | || confess $self->name . "->meta => (" . ($self->instance_metaclass) . ")" . |
155 | " is not compatible with the " . |
156 | $class_name . "->meta => (" . ($meta->instance_metaclass) . ")"; |
157 | } |
158 | } |
8b978dd5 |
159 | |
6d5355c3 |
160 | ## ANON classes |
161 | |
162 | { |
163 | # NOTE: |
0ac992ee |
164 | # this should be sufficient, if you have a |
165 | # use case where it is not, write a test and |
6d5355c3 |
166 | # I will change it. |
167 | my $ANON_CLASS_SERIAL = 0; |
0ac992ee |
168 | |
b9d9fc0b |
169 | # NOTE: |
170 | # we need a sufficiently annoying prefix |
0ac992ee |
171 | # this should suffice for now, this is |
172 | # used in a couple of places below, so |
b9d9fc0b |
173 | # need to put it up here for now. |
0ac992ee |
174 | my $ANON_CLASS_PREFIX = 'Class::MOP::Class::__ANON__::SERIAL::'; |
b9d9fc0b |
175 | |
176 | sub is_anon_class { |
177 | my $self = shift; |
a651e249 |
178 | no warnings 'uninitialized'; |
0ac992ee |
179 | $self->name =~ /^$ANON_CLASS_PREFIX/ ? 1 : 0; |
b9d9fc0b |
180 | } |
6d5355c3 |
181 | |
182 | sub create_anon_class { |
0ac992ee |
183 | my ($class, %options) = @_; |
6d5355c3 |
184 | my $package_name = $ANON_CLASS_PREFIX . ++$ANON_CLASS_SERIAL; |
88dd563c |
185 | return $class->create($package_name, %options); |
0ac992ee |
186 | } |
6d5355c3 |
187 | |
b9d9fc0b |
188 | # NOTE: |
0ac992ee |
189 | # this will only get called for |
190 | # anon-classes, all other calls |
191 | # are assumed to occur during |
b9d9fc0b |
192 | # global destruction and so don't |
193 | # really need to be handled explicitly |
194 | sub DESTROY { |
195 | my $self = shift; |
0ac992ee |
196 | no warnings 'uninitialized'; |
b9d9fc0b |
197 | return unless $self->name =~ /^$ANON_CLASS_PREFIX/; |
198 | my ($serial_id) = ($self->name =~ /^$ANON_CLASS_PREFIX(\d+)/); |
0ac992ee |
199 | no strict 'refs'; |
b9d9fc0b |
200 | foreach my $key (keys %{$ANON_CLASS_PREFIX . $serial_id}) { |
201 | delete ${$ANON_CLASS_PREFIX . $serial_id}{$key}; |
202 | } |
0ac992ee |
203 | delete ${'main::' . $ANON_CLASS_PREFIX}{$serial_id . '::'}; |
6d5355c3 |
204 | } |
b9d9fc0b |
205 | |
6d5355c3 |
206 | } |
207 | |
208 | # creating classes with MOP ... |
209 | |
8b978dd5 |
210 | sub create { |
88dd563c |
211 | my $class = shift; |
212 | my $package_name = shift; |
0ac992ee |
213 | |
bfe4d0fc |
214 | (defined $package_name && $package_name) |
8b978dd5 |
215 | || confess "You must pass a package name"; |
88dd563c |
216 | |
217 | (scalar @_ % 2 == 0) |
0ac992ee |
218 | || confess "You much pass all parameters as name => value pairs " . |
88dd563c |
219 | "(I found an uneven number of params in \@_)"; |
220 | |
221 | my (%options) = @_; |
0ac992ee |
222 | |
8b978dd5 |
223 | my $code = "package $package_name;"; |
0ac992ee |
224 | $code .= "\$$package_name\:\:VERSION = '" . $options{version} . "';" |
88dd563c |
225 | if exists $options{version}; |
0ac992ee |
226 | $code .= "\$$package_name\:\:AUTHORITY = '" . $options{authority} . "';" |
227 | if exists $options{authority}; |
228 | |
8b978dd5 |
229 | eval $code; |
0ac992ee |
230 | confess "creation of $package_name failed : $@" if $@; |
231 | |
bfe4d0fc |
232 | my $meta = $class->initialize($package_name); |
0ac992ee |
233 | |
234 | $meta->add_method('meta' => sub { |
df7b4119 |
235 | $class->initialize(blessed($_[0]) || $_[0]); |
aa448b16 |
236 | }); |
0ac992ee |
237 | |
8b978dd5 |
238 | $meta->superclasses(@{$options{superclasses}}) |
239 | if exists $options{superclasses}; |
2eb717d5 |
240 | # NOTE: |
0ac992ee |
241 | # process attributes first, so that they can |
2eb717d5 |
242 | # install accessors, but locally defined methods |
243 | # can then overwrite them. It is maybe a little odd, but |
244 | # I think this should be the order of things. |
245 | if (exists $options{attributes}) { |
cbd9f942 |
246 | foreach my $attr (@{$options{attributes}}) { |
247 | $meta->add_attribute($attr); |
2eb717d5 |
248 | } |
0ac992ee |
249 | } |
bfe4d0fc |
250 | if (exists $options{methods}) { |
251 | foreach my $method_name (keys %{$options{methods}}) { |
252 | $meta->add_method($method_name, $options{methods}->{$method_name}); |
253 | } |
0ac992ee |
254 | } |
8b978dd5 |
255 | return $meta; |
256 | } |
257 | |
7b31baf4 |
258 | ## Attribute readers |
259 | |
260 | # NOTE: |
0ac992ee |
261 | # all these attribute readers will be bootstrapped |
7b31baf4 |
262 | # away in the Class::MOP bootstrap section |
263 | |
c23184fc |
264 | sub get_attribute_map { $_[0]->{'%!attributes'} } |
265 | sub attribute_metaclass { $_[0]->{'$!attribute_metaclass'} } |
266 | sub method_metaclass { $_[0]->{'$!method_metaclass'} } |
267 | sub instance_metaclass { $_[0]->{'$!instance_metaclass'} } |
7b31baf4 |
268 | |
0f71bc80 |
269 | # FIXME: |
270 | # this is a prime canidate for conversion to XS |
0ac992ee |
271 | sub get_method_map { |
c4260b45 |
272 | my $self = shift; |
0ac992ee |
273 | my $map = $self->{'%!methods'}; |
274 | |
0f71bc80 |
275 | my $class_name = $self->name; |
276 | my $method_metaclass = $self->method_metaclass; |
0ac992ee |
277 | |
92330ee2 |
278 | foreach my $symbol ($self->list_all_package_symbols('CODE')) { |
91e0eb4a |
279 | my $code = $self->get_package_symbol('&' . $symbol); |
0ac992ee |
280 | |
281 | next if exists $map->{$symbol} && |
282 | defined $map->{$symbol} && |
283 | $map->{$symbol}->body == $code; |
284 | |
0f71bc80 |
285 | my $gv = svref_2object($code)->GV; |
286 | next if ($gv->STASH->NAME || '') ne $class_name && |
0ac992ee |
287 | ($gv->NAME || '') ne '__ANON__'; |
288 | |
0f71bc80 |
289 | $map->{$symbol} = $method_metaclass->wrap($code); |
7855ddba |
290 | } |
0ac992ee |
291 | |
7855ddba |
292 | return $map; |
c4260b45 |
293 | } |
294 | |
c9e77dbb |
295 | # Instance Construction & Cloning |
296 | |
5f3c057a |
297 | sub new_object { |
298 | my $class = shift; |
651955fb |
299 | # NOTE: |
0ac992ee |
300 | # we need to protect the integrity of the |
651955fb |
301 | # Class::MOP::Class singletons here, so we |
302 | # delegate this to &construct_class_instance |
303 | # which will deal with the singletons |
304 | return $class->construct_class_instance(@_) |
305 | if $class->name->isa('Class::MOP::Class'); |
24869f62 |
306 | return $class->construct_instance(@_); |
5f3c057a |
307 | } |
e16da3e6 |
308 | |
309 | sub construct_instance { |
cbd9f942 |
310 | my ($class, %params) = @_; |
0e76a376 |
311 | my $meta_instance = $class->get_meta_instance(); |
312 | my $instance = $meta_instance->create_instance(); |
c9e77dbb |
313 | foreach my $attr ($class->compute_all_applicable_attributes()) { |
f892c0f0 |
314 | $attr->initialize_instance_slot($meta_instance, $instance, \%params); |
cbd9f942 |
315 | } |
0ac992ee |
316 | # NOTE: |
d4ba1677 |
317 | # this will only work for a HASH instance type |
318 | if ($class->is_anon_class) { |
319 | (reftype($instance) eq 'HASH') |
320 | || confess "Currently only HASH based instances are supported with instance of anon-classes"; |
321 | # NOTE: |
322 | # At some point we should make this official |
0ac992ee |
323 | # as a reserved slot name, but right now I am |
d4ba1677 |
324 | # going to keep it here. |
325 | # my $RESERVED_MOP_SLOT = '__MOP__'; |
326 | $instance->{'__MOP__'} = $class; |
327 | } |
2d711cc8 |
328 | return $instance; |
329 | } |
330 | |
331 | sub get_meta_instance { |
332 | my $class = shift; |
052c2a1a |
333 | return $class->instance_metaclass->new( |
0ac992ee |
334 | $class, |
052c2a1a |
335 | $class->compute_all_applicable_attributes() |
336 | ); |
e16da3e6 |
337 | } |
338 | |
5f3c057a |
339 | sub clone_object { |
340 | my $class = shift; |
0ac992ee |
341 | my $instance = shift; |
651955fb |
342 | (blessed($instance) && $instance->isa($class->name)) |
343 | || confess "You must pass an instance ($instance) of the metaclass (" . $class->name . ")"; |
344 | # NOTE: |
0ac992ee |
345 | # we need to protect the integrity of the |
346 | # Class::MOP::Class singletons here, they |
a740253a |
347 | # should not be cloned. |
0ac992ee |
348 | return $instance if $instance->isa('Class::MOP::Class'); |
f7259199 |
349 | $class->clone_instance($instance, @_); |
5f3c057a |
350 | } |
351 | |
c9e77dbb |
352 | sub clone_instance { |
651955fb |
353 | my ($class, $instance, %params) = @_; |
354 | (blessed($instance)) |
c9e77dbb |
355 | || confess "You can only clone instances, \$self is not a blessed instance"; |
f7259199 |
356 | my $meta_instance = $class->get_meta_instance(); |
0ac992ee |
357 | my $clone = $meta_instance->clone_instance($instance); |
c23184fc |
358 | foreach my $attr ($class->compute_all_applicable_attributes()) { |
795a0c8b |
359 | if (exists $params{$attr->init_arg}) { |
0ac992ee |
360 | $meta_instance->set_slot_value($clone, $attr->name, $params{$attr->init_arg}); |
c23184fc |
361 | } |
0ac992ee |
362 | } |
363 | return $clone; |
c9e77dbb |
364 | } |
365 | |
8b978dd5 |
366 | # Inheritance |
367 | |
368 | sub superclasses { |
369 | my $self = shift; |
8b978dd5 |
370 | if (@_) { |
371 | my @supers = @_; |
9d6dce77 |
372 | @{$self->get_package_symbol('@ISA')} = @supers; |
d82060fe |
373 | # NOTE: |
0ac992ee |
374 | # we need to check the metaclass |
375 | # compatability here so that we can |
376 | # be sure that the superclass is |
377 | # not potentially creating an issues |
d82060fe |
378 | # we don't know about |
379 | $self->check_metaclass_compatability(); |
8b978dd5 |
380 | } |
9d6dce77 |
381 | @{$self->get_package_symbol('@ISA')}; |
8b978dd5 |
382 | } |
383 | |
384 | sub class_precedence_list { |
385 | my $self = shift; |
bfe4d0fc |
386 | # NOTE: |
387 | # We need to check for ciruclar inheirtance here. |
388 | # This will do nothing if all is well, and blow |
0ac992ee |
389 | # up otherwise. Yes, it's an ugly hack, better |
bfe4d0fc |
390 | # suggestions are welcome. |
93b4e576 |
391 | { ($self->name || return)->isa('This is a test for circular inheritance') } |
0ac992ee |
392 | |
8b978dd5 |
393 | ( |
0ac992ee |
394 | $self->name, |
395 | map { |
f7259199 |
396 | $self->initialize($_)->class_precedence_list() |
8b978dd5 |
397 | } $self->superclasses() |
0ac992ee |
398 | ); |
8b978dd5 |
399 | } |
400 | |
0882828e |
401 | ## Methods |
402 | |
403 | sub add_method { |
404 | my ($self, $method_name, $method) = @_; |
405 | (defined $method_name && $method_name) |
406 | || confess "You must define a method name"; |
0ac992ee |
407 | |
7855ddba |
408 | my $body; |
7855ddba |
409 | if (blessed($method)) { |
0ac992ee |
410 | $body = $method->body; |
7855ddba |
411 | } |
0ac992ee |
412 | else { |
7855ddba |
413 | $body = $method; |
7855ddba |
414 | ('CODE' eq (reftype($body) || '')) |
0ac992ee |
415 | || confess "Your code block must be a CODE reference"; |
416 | $method = $self->method_metaclass->wrap($body); |
7855ddba |
417 | } |
0f71bc80 |
418 | $self->get_method_map->{$method_name} = $method; |
0ac992ee |
419 | |
420 | my $full_method_name = ($self->name . '::' . $method_name); |
7855ddba |
421 | $self->add_package_symbol("&${method_name}" => subname $full_method_name => $body); |
0882828e |
422 | } |
423 | |
a4258ffd |
424 | { |
2d711cc8 |
425 | my $fetch_and_prepare_method = sub { |
426 | my ($self, $method_name) = @_; |
427 | # fetch it locally |
428 | my $method = $self->get_method($method_name); |
429 | # if we dont have local ... |
430 | unless ($method) { |
195f5bf8 |
431 | # try to find the next method |
432 | $method = $self->find_next_method_by_name($method_name); |
433 | # die if it does not exist |
434 | (defined $method) |
804f7d24 |
435 | || confess "The method '$method_name' is not found in the inheritance hierarchy for class " . $self->name; |
0ac992ee |
436 | # and now make sure to wrap it |
195f5bf8 |
437 | # even if it is already wrapped |
438 | # because we need a new sub ref |
2d711cc8 |
439 | $method = Class::MOP::Method::Wrapped->wrap($method); |
195f5bf8 |
440 | } |
441 | else { |
0ac992ee |
442 | # now make sure we wrap it properly |
195f5bf8 |
443 | $method = Class::MOP::Method::Wrapped->wrap($method) |
0ac992ee |
444 | unless $method->isa('Class::MOP::Method::Wrapped'); |
445 | } |
446 | $self->add_method($method_name => $method); |
2d711cc8 |
447 | return $method; |
448 | }; |
449 | |
450 | sub add_before_method_modifier { |
451 | my ($self, $method_name, $method_modifier) = @_; |
452 | (defined $method_name && $method_name) |
0ac992ee |
453 | || confess "You must pass in a method name"; |
2d711cc8 |
454 | my $method = $fetch_and_prepare_method->($self, $method_name); |
455 | $method->add_before_modifier(subname ':before' => $method_modifier); |
456 | } |
457 | |
458 | sub add_after_method_modifier { |
459 | my ($self, $method_name, $method_modifier) = @_; |
460 | (defined $method_name && $method_name) |
0ac992ee |
461 | || confess "You must pass in a method name"; |
2d711cc8 |
462 | my $method = $fetch_and_prepare_method->($self, $method_name); |
463 | $method->add_after_modifier(subname ':after' => $method_modifier); |
464 | } |
0ac992ee |
465 | |
2d711cc8 |
466 | sub add_around_method_modifier { |
467 | my ($self, $method_name, $method_modifier) = @_; |
468 | (defined $method_name && $method_name) |
469 | || confess "You must pass in a method name"; |
470 | my $method = $fetch_and_prepare_method->($self, $method_name); |
471 | $method->add_around_modifier(subname ':around' => $method_modifier); |
0ac992ee |
472 | } |
a4258ffd |
473 | |
0ac992ee |
474 | # NOTE: |
8c936afc |
475 | # the methods above used to be named like this: |
476 | # ${pkg}::${method}:(before|after|around) |
477 | # but this proved problematic when using one modifier |
478 | # to wrap multiple methods (something which is likely |
479 | # to happen pretty regularly IMO). So instead of naming |
0ac992ee |
480 | # it like this, I have chosen to just name them purely |
8c936afc |
481 | # with their modifier names, like so: |
482 | # :(before|after|around) |
0ac992ee |
483 | # The fact is that in a stack trace, it will be fairly |
8c936afc |
484 | # evident from the context what method they are attached |
485 | # to, and so don't need the fully qualified name. |
ee5e71d4 |
486 | } |
487 | |
663f8198 |
488 | sub alias_method { |
489 | my ($self, $method_name, $method) = @_; |
490 | (defined $method_name && $method_name) |
491 | || confess "You must define a method name"; |
de19f115 |
492 | |
0f71bc80 |
493 | my $body = (blessed($method) ? $method->body : $method); |
494 | ('CODE' eq (reftype($body) || '')) |
0ac992ee |
495 | || confess "Your code block must be a CODE reference"; |
496 | |
7855ddba |
497 | $self->add_package_symbol("&${method_name}" => $body); |
16e960bd |
498 | } |
499 | |
de19f115 |
500 | sub has_method { |
501 | my ($self, $method_name) = @_; |
502 | (defined $method_name && $method_name) |
0ac992ee |
503 | || confess "You must define a method name"; |
504 | |
505 | return 0 unless exists $self->get_method_map->{$method_name}; |
de19f115 |
506 | return 1; |
0882828e |
507 | } |
508 | |
509 | sub get_method { |
c9b8b7f9 |
510 | my ($self, $method_name) = @_; |
0882828e |
511 | (defined $method_name && $method_name) |
512 | || confess "You must define a method name"; |
0ac992ee |
513 | |
0f71bc80 |
514 | # NOTE: |
515 | # I don't really need this here, because |
0ac992ee |
516 | # if the method_map is missing a key it |
0f71bc80 |
517 | # will just return undef for me now |
518 | # return unless $self->has_method($method_name); |
0ac992ee |
519 | |
7855ddba |
520 | return $self->get_method_map->{$method_name}; |
c9b8b7f9 |
521 | } |
522 | |
523 | sub remove_method { |
524 | my ($self, $method_name) = @_; |
525 | (defined $method_name && $method_name) |
526 | || confess "You must define a method name"; |
0ac992ee |
527 | |
528 | my $removed_method = $self->get_method($method_name); |
529 | |
530 | do { |
0f71bc80 |
531 | $self->remove_package_symbol("&${method_name}"); |
532 | delete $self->get_method_map->{$method_name}; |
533 | } if defined $removed_method; |
0ac992ee |
534 | |
c9b8b7f9 |
535 | return $removed_method; |
536 | } |
537 | |
538 | sub get_method_list { |
539 | my $self = shift; |
0f71bc80 |
540 | keys %{$self->get_method_map}; |
7855ddba |
541 | } |
542 | |
543 | sub find_method_by_name { |
544 | my ($self, $method_name) = @_; |
b9575695 |
545 | (defined $method_name && $method_name) |
0ac992ee |
546 | || confess "You must define a method name to find"; |
b9575695 |
547 | # keep a record of what we have seen |
0ac992ee |
548 | # here, this will handle all the |
549 | # inheritence issues because we are |
b9575695 |
550 | # using the &class_precedence_list |
551 | my %seen_class; |
552 | my @cpl = $self->class_precedence_list(); |
553 | foreach my $class (@cpl) { |
554 | next if $seen_class{$class}; |
555 | $seen_class{$class}++; |
556 | # fetch the meta-class ... |
557 | my $meta = $self->initialize($class); |
0ac992ee |
558 | return $meta->get_method($method_name) |
b9575695 |
559 | if $meta->has_method($method_name); |
560 | } |
561 | return; |
a5eca695 |
562 | } |
563 | |
564 | sub compute_all_applicable_methods { |
565 | my $self = shift; |
566 | my @methods; |
567 | # keep a record of what we have seen |
0ac992ee |
568 | # here, this will handle all the |
569 | # inheritence issues because we are |
a5eca695 |
570 | # using the &class_precedence_list |
571 | my (%seen_class, %seen_method); |
572 | foreach my $class ($self->class_precedence_list()) { |
573 | next if $seen_class{$class}; |
574 | $seen_class{$class}++; |
575 | # fetch the meta-class ... |
576 | my $meta = $self->initialize($class); |
0ac992ee |
577 | foreach my $method_name ($meta->get_method_list()) { |
a5eca695 |
578 | next if exists $seen_method{$method_name}; |
579 | $seen_method{$method_name}++; |
580 | push @methods => { |
0ac992ee |
581 | name => $method_name, |
a5eca695 |
582 | class => $class, |
583 | code => $meta->get_method($method_name) |
584 | }; |
585 | } |
586 | } |
587 | return @methods; |
588 | } |
589 | |
a5eca695 |
590 | sub find_all_methods_by_name { |
591 | my ($self, $method_name) = @_; |
592 | (defined $method_name && $method_name) |
0ac992ee |
593 | || confess "You must define a method name to find"; |
a5eca695 |
594 | my @methods; |
595 | # keep a record of what we have seen |
0ac992ee |
596 | # here, this will handle all the |
597 | # inheritence issues because we are |
a5eca695 |
598 | # using the &class_precedence_list |
599 | my %seen_class; |
600 | foreach my $class ($self->class_precedence_list()) { |
601 | next if $seen_class{$class}; |
602 | $seen_class{$class}++; |
603 | # fetch the meta-class ... |
96ceced8 |
604 | my $meta = $self->initialize($class); |
a5eca695 |
605 | push @methods => { |
0ac992ee |
606 | name => $method_name, |
a5eca695 |
607 | class => $class, |
608 | code => $meta->get_method($method_name) |
609 | } if $meta->has_method($method_name); |
610 | } |
611 | return @methods; |
8b978dd5 |
612 | } |
613 | |
96ceced8 |
614 | sub find_next_method_by_name { |
615 | my ($self, $method_name) = @_; |
616 | (defined $method_name && $method_name) |
0ac992ee |
617 | || confess "You must define a method name to find"; |
96ceced8 |
618 | # keep a record of what we have seen |
0ac992ee |
619 | # here, this will handle all the |
620 | # inheritence issues because we are |
96ceced8 |
621 | # using the &class_precedence_list |
622 | my %seen_class; |
2d711cc8 |
623 | my @cpl = $self->class_precedence_list(); |
624 | shift @cpl; # discard ourselves |
96ceced8 |
625 | foreach my $class (@cpl) { |
626 | next if $seen_class{$class}; |
627 | $seen_class{$class}++; |
628 | # fetch the meta-class ... |
629 | my $meta = $self->initialize($class); |
0ac992ee |
630 | return $meta->get_method($method_name) |
2d711cc8 |
631 | if $meta->has_method($method_name); |
96ceced8 |
632 | } |
2d711cc8 |
633 | return; |
96ceced8 |
634 | } |
635 | |
552e3d24 |
636 | ## Attributes |
637 | |
e16da3e6 |
638 | sub add_attribute { |
2e41896e |
639 | my $self = shift; |
640 | # either we have an attribute object already |
641 | # or we need to create one from the args provided |
642 | my $attribute = blessed($_[0]) ? $_[0] : $self->attribute_metaclass->new(@_); |
643 | # make sure it is derived from the correct type though |
644 | ($attribute->isa('Class::MOP::Attribute')) |
0ac992ee |
645 | || confess "Your attribute must be an instance of Class::MOP::Attribute (or a subclass)"; |
b1897d4d |
646 | |
647 | # first we attach our new attribute |
0ac992ee |
648 | # because it might need certain information |
b1897d4d |
649 | # about the class which it is attached to |
9ec169fe |
650 | $attribute->attach_to_class($self); |
0ac992ee |
651 | |
652 | # then we remove attributes of a conflicting |
653 | # name here so that we can properly detach |
654 | # the old attr object, and remove any |
b1897d4d |
655 | # accessors it would have generated |
656 | $self->remove_attribute($attribute->name) |
657 | if $self->has_attribute($attribute->name); |
0ac992ee |
658 | |
b1897d4d |
659 | # then onto installing the new accessors |
2d711cc8 |
660 | $attribute->install_accessors(); |
291073fc |
661 | $self->get_attribute_map->{$attribute->name} = $attribute; |
e16da3e6 |
662 | } |
663 | |
664 | sub has_attribute { |
665 | my ($self, $attribute_name) = @_; |
666 | (defined $attribute_name && $attribute_name) |
667 | || confess "You must define an attribute name"; |
0ac992ee |
668 | exists $self->get_attribute_map->{$attribute_name} ? 1 : 0; |
669 | } |
e16da3e6 |
670 | |
671 | sub get_attribute { |
672 | my ($self, $attribute_name) = @_; |
673 | (defined $attribute_name && $attribute_name) |
674 | || confess "You must define an attribute name"; |
0ac992ee |
675 | return $self->get_attribute_map->{$attribute_name} |
b1897d4d |
676 | # NOTE: |
677 | # this will return undef anyway, so no need ... |
0ac992ee |
678 | # if $self->has_attribute($attribute_name); |
679 | #return; |
680 | } |
e16da3e6 |
681 | |
682 | sub remove_attribute { |
683 | my ($self, $attribute_name) = @_; |
684 | (defined $attribute_name && $attribute_name) |
685 | || confess "You must define an attribute name"; |
0ac992ee |
686 | my $removed_attribute = $self->get_attribute_map->{$attribute_name}; |
22286063 |
687 | return unless defined $removed_attribute; |
0ac992ee |
688 | delete $self->get_attribute_map->{$attribute_name}; |
689 | $removed_attribute->remove_accessors(); |
2d711cc8 |
690 | $removed_attribute->detach_from_class(); |
e16da3e6 |
691 | return $removed_attribute; |
0ac992ee |
692 | } |
e16da3e6 |
693 | |
694 | sub get_attribute_list { |
695 | my $self = shift; |
f7259199 |
696 | keys %{$self->get_attribute_map}; |
0ac992ee |
697 | } |
e16da3e6 |
698 | |
699 | sub compute_all_applicable_attributes { |
700 | my $self = shift; |
701 | my @attrs; |
702 | # keep a record of what we have seen |
0ac992ee |
703 | # here, this will handle all the |
704 | # inheritence issues because we are |
e16da3e6 |
705 | # using the &class_precedence_list |
706 | my (%seen_class, %seen_attr); |
707 | foreach my $class ($self->class_precedence_list()) { |
708 | next if $seen_class{$class}; |
709 | $seen_class{$class}++; |
710 | # fetch the meta-class ... |
f7259199 |
711 | my $meta = $self->initialize($class); |
0ac992ee |
712 | foreach my $attr_name ($meta->get_attribute_list()) { |
e16da3e6 |
713 | next if exists $seen_attr{$attr_name}; |
714 | $seen_attr{$attr_name}++; |
c9e77dbb |
715 | push @attrs => $meta->get_attribute($attr_name); |
e16da3e6 |
716 | } |
717 | } |
0ac992ee |
718 | return @attrs; |
e16da3e6 |
719 | } |
2eb717d5 |
720 | |
058c1cf5 |
721 | sub find_attribute_by_name { |
722 | my ($self, $attr_name) = @_; |
723 | # keep a record of what we have seen |
0ac992ee |
724 | # here, this will handle all the |
725 | # inheritence issues because we are |
058c1cf5 |
726 | # using the &class_precedence_list |
727 | my %seen_class; |
728 | foreach my $class ($self->class_precedence_list()) { |
729 | next if $seen_class{$class}; |
730 | $seen_class{$class}++; |
731 | # fetch the meta-class ... |
732 | my $meta = $self->initialize($class); |
733 | return $meta->get_attribute($attr_name) |
734 | if $meta->has_attribute($attr_name); |
735 | } |
736 | return; |
737 | } |
738 | |
857f87a7 |
739 | ## Class closing |
740 | |
741 | sub is_mutable { 1 } |
742 | sub is_immutable { 0 } |
743 | |
04dd7510 |
744 | #Why I changed this (groditi) |
745 | # - One Metaclass may have many Classes through many Metaclass instances |
d9586da2 |
746 | # - One Metaclass should only have one Immutable Transformer instance |
04dd7510 |
747 | # - Each Class may have different Immutabilizing options |
748 | # - Therefore each Metaclass instance may have different Immutabilizing options |
d9586da2 |
749 | # - We need to store one Immutable Transformer instance per Metaclass |
750 | # - We need to store one set of Immutable Transformer options per Class |
04dd7510 |
751 | # - Upon make_mutable we may delete the Immutabilizing options |
d9586da2 |
752 | # - We could clean the immutable Transformer instance when there is no more |
753 | # immutable Classes of that type, but we can also keep it in case |
04dd7510 |
754 | # another class with this same Metaclass becomes immutable. It is a case |
755 | # of trading of storing an instance to avoid unnecessary instantiations of |
d9586da2 |
756 | # Immutable Transformers. You may view this as a memory leak, however |
04dd7510 |
757 | # Because we have few Metaclasses, in practice it seems acceptable |
d9586da2 |
758 | # - To allow Immutable Transformers instances to be cleaned up we could weaken |
759 | # the reference stored in $IMMUTABLE_TRANSFORMERS{$class} and ||= should DWIM |
04dd7510 |
760 | |
c23184fc |
761 | { |
d9586da2 |
762 | my %IMMUTABLE_TRANSFORMERS; |
0ac992ee |
763 | my %IMMUTABLE_OPTIONS; |
c23184fc |
764 | sub make_immutable { |
0ac992ee |
765 | my $self = shift; |
04dd7510 |
766 | my %options = @_; |
d9586da2 |
767 | my $class = blessed $self || $self; |
768 | |
769 | $IMMUTABLE_TRANSFORMERS{$class} ||= $self->create_immutable_transformer; |
770 | my $transformer = $IMMUTABLE_TRANSFORMERS{$class}; |
771 | |
772 | $transformer->make_metaclass_immutable($self, %options); |
04dd7510 |
773 | $IMMUTABLE_OPTIONS{refaddr $self} = |
d9586da2 |
774 | { %options, IMMUTABLE_TRANSFORMER => $transformer }; |
04dd7510 |
775 | |
776 | if( exists $options{debug} && $options{debug} ){ |
d9586da2 |
777 | print STDERR "# of Metaclass options: ", keys %IMMUTABLE_OPTIONS; |
778 | print STDERR "# of Immutable transformers: ", keys %IMMUTABLE_TRANSFORMERS; |
04dd7510 |
779 | } |
c23184fc |
780 | } |
0ac992ee |
781 | |
782 | sub make_mutable{ |
783 | my $self = shift; |
784 | return if $self->is_mutable; |
04dd7510 |
785 | my $options = delete $IMMUTABLE_OPTIONS{refaddr $self}; |
d9586da2 |
786 | confess "unable to find immutabilizing options" unless $options; |
787 | my $transformer = delete $options->{IMMUTABLE_TRANSFORMER}; |
788 | $transformer->make_metaclass_mutable($self, %$options); |
0ac992ee |
789 | } |
d9586da2 |
790 | } |
0ac992ee |
791 | |
d9586da2 |
792 | sub create_immutable_transformer { |
793 | my $self = shift; |
794 | my $class = Class::MOP::Immutable->new($self, { |
795 | read_only => [qw/superclasses/], |
796 | cannot_call => [qw/ |
797 | add_method |
798 | alias_method |
799 | remove_method |
800 | add_attribute |
801 | remove_attribute |
802 | add_package_symbol |
803 | remove_package_symbol |
804 | /], |
805 | memoize => { |
806 | class_precedence_list => 'ARRAY', |
807 | compute_all_applicable_attributes => 'ARRAY', |
808 | get_meta_instance => 'SCALAR', |
809 | get_method_map => 'SCALAR', |
810 | } |
811 | }); |
812 | return $class; |
857f87a7 |
813 | } |
814 | |
8b978dd5 |
815 | 1; |
816 | |
817 | __END__ |
818 | |
819 | =pod |
820 | |
0ac992ee |
821 | =head1 NAME |
8b978dd5 |
822 | |
823 | Class::MOP::Class - Class Meta Object |
824 | |
825 | =head1 SYNOPSIS |
826 | |
0ac992ee |
827 | # assuming that class Foo |
8c936afc |
828 | # has been defined, you can |
0ac992ee |
829 | |
fe122940 |
830 | # use this for introspection ... |
0ac992ee |
831 | |
fe122940 |
832 | # add a method to Foo ... |
833 | Foo->meta->add_method('bar' => sub { ... }) |
0ac992ee |
834 | |
835 | # get a list of all the classes searched |
836 | # the method dispatcher in the correct order |
fe122940 |
837 | Foo->meta->class_precedence_list() |
0ac992ee |
838 | |
fe122940 |
839 | # remove a method from Foo |
840 | Foo->meta->remove_method('bar'); |
0ac992ee |
841 | |
fe122940 |
842 | # or use this to actually create classes ... |
0ac992ee |
843 | |
88dd563c |
844 | Class::MOP::Class->create('Bar' => ( |
845 | version => '0.01', |
fe122940 |
846 | superclasses => [ 'Foo' ], |
847 | attributes => [ |
848 | Class::MOP:::Attribute->new('$bar'), |
0ac992ee |
849 | Class::MOP:::Attribute->new('$baz'), |
fe122940 |
850 | ], |
851 | methods => { |
852 | calculate_bar => sub { ... }, |
0ac992ee |
853 | construct_baz => sub { ... } |
fe122940 |
854 | } |
855 | )); |
856 | |
8b978dd5 |
857 | =head1 DESCRIPTION |
858 | |
0ac992ee |
859 | This is the largest and currently most complex part of the Perl 5 |
860 | meta-object protocol. It controls the introspection and |
861 | manipulation of Perl 5 classes (and it can create them too). The |
862 | best way to understand what this module can do, is to read the |
fe122940 |
863 | documentation for each of it's methods. |
864 | |
552e3d24 |
865 | =head1 METHODS |
866 | |
2eb717d5 |
867 | =head2 Self Introspection |
868 | |
869 | =over 4 |
870 | |
871 | =item B<meta> |
872 | |
0ac992ee |
873 | This will return a B<Class::MOP::Class> instance which is related |
874 | to this class. Thereby allowing B<Class::MOP::Class> to actually |
fe122940 |
875 | introspect itself. |
876 | |
0ac992ee |
877 | As with B<Class::MOP::Attribute>, B<Class::MOP> will actually |
878 | bootstrap this module by installing a number of attribute meta-objects |
879 | into it's metaclass. This will allow this class to reap all the benifits |
880 | of the MOP when subclassing it. |
2eb717d5 |
881 | |
882 | =back |
883 | |
552e3d24 |
884 | =head2 Class construction |
885 | |
0ac992ee |
886 | These methods will handle creating B<Class::MOP::Class> objects, |
887 | which can be used to both create new classes, and analyze |
888 | pre-existing classes. |
552e3d24 |
889 | |
0ac992ee |
890 | This module will internally store references to all the instances |
891 | you create with these methods, so that they do not need to be |
552e3d24 |
892 | created any more than nessecary. Basically, they are singletons. |
893 | |
894 | =over 4 |
895 | |
0ac992ee |
896 | =item B<create ($package_name, |
897 | version =E<gt> ?$version, |
898 | authority =E<gt> ?$authority, |
899 | superclasses =E<gt> ?@superclasses, |
900 | methods =E<gt> ?%methods, |
a2e85e6c |
901 | attributes =E<gt> ?%attributes)> |
552e3d24 |
902 | |
0ac992ee |
903 | This returns a B<Class::MOP::Class> object, bringing the specified |
904 | C<$package_name> into existence and adding any of the C<$version>, |
905 | C<$authority>, C<@superclasses>, C<%methods> and C<%attributes> to |
88dd563c |
906 | it. |
552e3d24 |
907 | |
0ac992ee |
908 | =item B<create_anon_class (superclasses =E<gt> ?@superclasses, |
909 | methods =E<gt> ?%methods, |
587aca23 |
910 | attributes =E<gt> ?%attributes)> |
911 | |
0ac992ee |
912 | This will create an anonymous class, it works much like C<create> but |
913 | it does not need a C<$package_name>. Instead it will create a suitably |
587aca23 |
914 | unique package name for you to stash things into. |
915 | |
0ac992ee |
916 | On very important distinction is that anon classes are destroyed once |
917 | the metaclass they are attached to goes out of scope. In the DESTROY |
918 | method, the created package will be removed from the symbol table. |
823a5d31 |
919 | |
d4ba1677 |
920 | It is also worth noting that any instances created with an anon-class |
0ac992ee |
921 | will keep a special reference to the anon-meta which will prevent the |
922 | anon-class from going out of scope until all instances of it have also |
923 | been destroyed. This however only works for HASH based instance types, |
924 | as we use a special reserved slot (C<__MOP__>) to store this. |
d4ba1677 |
925 | |
66b3dded |
926 | =item B<initialize ($package_name, %options)> |
552e3d24 |
927 | |
0ac992ee |
928 | This initializes and returns returns a B<Class::MOP::Class> object |
a2e85e6c |
929 | for a given a C<$package_name>. |
930 | |
66b3dded |
931 | =item B<reinitialize ($package_name, %options)> |
932 | |
933 | This removes the old metaclass, and creates a new one in it's place. |
0ac992ee |
934 | Do B<not> use this unless you really know what you are doing, it could |
935 | very easily make a very large mess of your program. |
66b3dded |
936 | |
651955fb |
937 | =item B<construct_class_instance (%options)> |
a2e85e6c |
938 | |
0ac992ee |
939 | This will construct an instance of B<Class::MOP::Class>, it is |
940 | here so that we can actually "tie the knot" for B<Class::MOP::Class> |
941 | to use C<construct_instance> once all the bootstrapping is done. This |
a2e85e6c |
942 | method is used internally by C<initialize> and should never be called |
943 | from outside of that method really. |
552e3d24 |
944 | |
550d56db |
945 | =item B<check_metaclass_compatability> |
946 | |
0ac992ee |
947 | This method is called as the very last thing in the |
948 | C<construct_class_instance> method. This will check that the |
949 | metaclass you are creating is compatible with the metaclasses of all |
950 | your ancestors. For more inforamtion about metaclass compatibility |
550d56db |
951 | see the C<About Metaclass compatibility> section in L<Class::MOP>. |
952 | |
552e3d24 |
953 | =back |
954 | |
c9e77dbb |
955 | =head2 Object instance construction and cloning |
a2e85e6c |
956 | |
0ac992ee |
957 | These methods are B<entirely optional>, it is up to you whether you want |
c9e77dbb |
958 | to use them or not. |
552e3d24 |
959 | |
960 | =over 4 |
961 | |
2bab2be6 |
962 | =item B<instance_metaclass> |
963 | |
2d711cc8 |
964 | =item B<get_meta_instance> |
965 | |
5f3c057a |
966 | =item B<new_object (%params)> |
967 | |
0ac992ee |
968 | This is a convience method for creating a new object of the class, and |
969 | blessing it into the appropriate package as well. Ideally your class |
5f3c057a |
970 | would call a C<new> this method like so: |
971 | |
0ac992ee |
972 | sub MyClass::new { |
5f3c057a |
973 | my ($class, %param) = @_; |
974 | $class->meta->new_object(%params); |
975 | } |
976 | |
0ac992ee |
977 | Of course the ideal place for this would actually be in C<UNIVERSAL::> |
5f3c057a |
978 | but that is considered bad style, so we do not do that. |
979 | |
cbd9f942 |
980 | =item B<construct_instance (%params)> |
552e3d24 |
981 | |
0ac992ee |
982 | This method is used to construct an instace structure suitable for |
983 | C<bless>-ing into your package of choice. It works in conjunction |
c9e77dbb |
984 | with the Attribute protocol to collect all applicable attributes. |
985 | |
0ac992ee |
986 | This will construct and instance using a HASH ref as storage |
987 | (currently only HASH references are supported). This will collect all |
988 | the applicable attributes and layout out the fields in the HASH ref, |
989 | it will then initialize them using either use the corresponding key |
990 | in C<%params> or any default value or initializer found in the |
a2e85e6c |
991 | attribute meta-object. |
727919c5 |
992 | |
5f3c057a |
993 | =item B<clone_object ($instance, %params)> |
994 | |
0ac992ee |
995 | This is a convience method for cloning an object instance, then |
996 | blessing it into the appropriate package. This method will call |
997 | C<clone_instance>, which performs a shallow copy of the object, |
998 | see that methods documentation for more details. Ideally your |
19d4b5b8 |
999 | class would call a C<clone> this method like so: |
5f3c057a |
1000 | |
1001 | sub MyClass::clone { |
1002 | my ($self, %param) = @_; |
1003 | $self->meta->clone_object($self, %params); |
1004 | } |
1005 | |
0ac992ee |
1006 | Of course the ideal place for this would actually be in C<UNIVERSAL::> |
5f3c057a |
1007 | but that is considered bad style, so we do not do that. |
1008 | |
c9e77dbb |
1009 | =item B<clone_instance($instance, %params)> |
1010 | |
0ac992ee |
1011 | This method is a compliment of C<construct_instance> (which means if |
1012 | you override C<construct_instance>, you need to override this one too), |
19d4b5b8 |
1013 | and clones the instance shallowly. |
a27ae83f |
1014 | |
0ac992ee |
1015 | The cloned structure returned is (like with C<construct_instance>) an |
1016 | unC<bless>ed HASH reference, it is your responsibility to then bless |
a27ae83f |
1017 | this cloned structure into the right class (which C<clone_object> will |
1018 | do for you). |
c9e77dbb |
1019 | |
0ac992ee |
1020 | As of 0.11, this method will clone the C<$instance> structure shallowly, |
1021 | as opposed to the deep cloning implemented in prior versions. After much |
1022 | thought, research and discussion, I have decided that anything but basic |
1023 | shallow cloning is outside the scope of the meta-object protocol. I |
1024 | think Yuval "nothingmuch" Kogman put it best when he said that cloning |
19d4b5b8 |
1025 | is too I<context-specific> to be part of the MOP. |
1026 | |
552e3d24 |
1027 | =back |
1028 | |
0ac992ee |
1029 | =head2 Informational |
552e3d24 |
1030 | |
b9d9fc0b |
1031 | These are a few predicate methods for asking information about the class. |
552e3d24 |
1032 | |
b9d9fc0b |
1033 | =over 4 |
552e3d24 |
1034 | |
b9d9fc0b |
1035 | =item B<is_anon_class> |
552e3d24 |
1036 | |
96e38ba6 |
1037 | This returns true if the class is a C<Class::MOP::Class> created anon class. |
1038 | |
b9d9fc0b |
1039 | =item B<is_mutable> |
552e3d24 |
1040 | |
96e38ba6 |
1041 | This returns true if the class is still mutable. |
1042 | |
b9d9fc0b |
1043 | =item B<is_immutable> |
552e3d24 |
1044 | |
96e38ba6 |
1045 | This returns true if the class has been made immutable. |
1046 | |
552e3d24 |
1047 | =back |
1048 | |
1049 | =head2 Inheritance Relationships |
1050 | |
1051 | =over 4 |
1052 | |
1053 | =item B<superclasses (?@superclasses)> |
1054 | |
0ac992ee |
1055 | This is a read-write attribute which represents the superclass |
a2e85e6c |
1056 | relationships of the class the B<Class::MOP::Class> instance is |
1057 | associated with. Basically, it can get and set the C<@ISA> for you. |
552e3d24 |
1058 | |
343203ee |
1059 | B<NOTE:> |
0ac992ee |
1060 | Perl will occasionally perform some C<@ISA> and method caching, if |
1061 | you decide to change your superclass relationship at runtime (which |
1062 | is quite insane and very much not recommened), then you should be |
1063 | aware of this and the fact that this module does not make any |
343203ee |
1064 | attempt to address this issue. |
1065 | |
552e3d24 |
1066 | =item B<class_precedence_list> |
1067 | |
0ac992ee |
1068 | This computes the a list of all the class's ancestors in the same order |
1069 | in which method dispatch will be done. This is similair to |
a2e85e6c |
1070 | what B<Class::ISA::super_path> does, but we don't remove duplicate names. |
552e3d24 |
1071 | |
1072 | =back |
1073 | |
1074 | =head2 Methods |
1075 | |
1076 | =over 4 |
1077 | |
c4260b45 |
1078 | =item B<get_method_map> |
1079 | |
2e41896e |
1080 | =item B<method_metaclass> |
1081 | |
552e3d24 |
1082 | =item B<add_method ($method_name, $method)> |
1083 | |
0ac992ee |
1084 | This will take a C<$method_name> and CODE reference to that |
1085 | C<$method> and install it into the class's package. |
552e3d24 |
1086 | |
0ac992ee |
1087 | B<NOTE>: |
1088 | This does absolutely nothing special to C<$method> |
1089 | other than use B<Sub::Name> to make sure it is tagged with the |
1090 | correct name, and therefore show up correctly in stack traces and |
552e3d24 |
1091 | such. |
1092 | |
663f8198 |
1093 | =item B<alias_method ($method_name, $method)> |
1094 | |
0ac992ee |
1095 | This will take a C<$method_name> and CODE reference to that |
1096 | C<$method> and alias the method into the class's package. |
663f8198 |
1097 | |
0ac992ee |
1098 | B<NOTE>: |
1099 | Unlike C<add_method>, this will B<not> try to name the |
1100 | C<$method> using B<Sub::Name>, it only aliases the method in |
1101 | the class's package. |
663f8198 |
1102 | |
552e3d24 |
1103 | =item B<has_method ($method_name)> |
1104 | |
0ac992ee |
1105 | This just provides a simple way to check if the class implements |
1106 | a specific C<$method_name>. It will I<not> however, attempt to check |
a2e85e6c |
1107 | if the class inherits the method (use C<UNIVERSAL::can> for that). |
552e3d24 |
1108 | |
0ac992ee |
1109 | This will correctly handle functions defined outside of the package |
552e3d24 |
1110 | that use a fully qualified name (C<sub Package::name { ... }>). |
1111 | |
0ac992ee |
1112 | This will correctly handle functions renamed with B<Sub::Name> and |
1113 | installed using the symbol tables. However, if you are naming the |
1114 | subroutine outside of the package scope, you must use the fully |
1115 | qualified name, including the package name, for C<has_method> to |
1116 | correctly identify it. |
552e3d24 |
1117 | |
0ac992ee |
1118 | This will attempt to correctly ignore functions imported from other |
1119 | packages using B<Exporter>. It breaks down if the function imported |
1120 | is an C<__ANON__> sub (such as with C<use constant>), which very well |
1121 | may be a valid method being applied to the class. |
552e3d24 |
1122 | |
0ac992ee |
1123 | In short, this method cannot always be trusted to determine if the |
1124 | C<$method_name> is actually a method. However, it will DWIM about |
a2e85e6c |
1125 | 90% of the time, so it's a small trade off I think. |
552e3d24 |
1126 | |
1127 | =item B<get_method ($method_name)> |
1128 | |
0ac992ee |
1129 | This will return a Class::MOP::Method instance related to the specified |
86482605 |
1130 | C<$method_name>, or return undef if that method does not exist. |
1131 | |
0ac992ee |
1132 | The Class::MOP::Method is codifiable, so you can use it like a normal |
86482605 |
1133 | CODE reference, see L<Class::MOP::Method> for more information. |
552e3d24 |
1134 | |
16e960bd |
1135 | =item B<find_method_by_name ($method_name> |
1136 | |
1137 | This will return a CODE reference of the specified C<$method_name>, |
1138 | or return undef if that method does not exist. |
1139 | |
1140 | Unlike C<get_method> this will also look in the superclasses. |
1141 | |
552e3d24 |
1142 | =item B<remove_method ($method_name)> |
1143 | |
0ac992ee |
1144 | This will attempt to remove a given C<$method_name> from the class. |
1145 | It will return the CODE reference that it has removed, and will |
552e3d24 |
1146 | attempt to use B<Sub::Name> to clear the methods associated name. |
1147 | |
1148 | =item B<get_method_list> |
1149 | |
0ac992ee |
1150 | This will return a list of method names for all I<locally> defined |
1151 | methods. It does B<not> provide a list of all applicable methods, |
1152 | including any inherited ones. If you want a list of all applicable |
552e3d24 |
1153 | methods, use the C<compute_all_applicable_methods> method. |
1154 | |
1155 | =item B<compute_all_applicable_methods> |
1156 | |
0ac992ee |
1157 | This will return a list of all the methods names this class will |
1158 | respond to, taking into account inheritance. The list will be a list of |
1159 | HASH references, each one containing the following information; method |
1160 | name, the name of the class in which the method lives and a CODE |
552e3d24 |
1161 | reference for the actual method. |
1162 | |
1163 | =item B<find_all_methods_by_name ($method_name)> |
1164 | |
0ac992ee |
1165 | This will traverse the inheritence hierarchy and locate all methods |
1166 | with a given C<$method_name>. Similar to |
1167 | C<compute_all_applicable_methods> it returns a list of HASH references |
1168 | with the following information; method name (which will always be the |
1169 | same as C<$method_name>), the name of the class in which the method |
552e3d24 |
1170 | lives and a CODE reference for the actual method. |
1171 | |
0ac992ee |
1172 | The list of methods produced is a distinct list, meaning there are no |
1173 | duplicates in it. This is especially useful for things like object |
1174 | initialization and destruction where you only want the method called |
552e3d24 |
1175 | once, and in the correct order. |
1176 | |
96ceced8 |
1177 | =item B<find_next_method_by_name ($method_name)> |
1178 | |
0ac992ee |
1179 | This will return the first method to match a given C<$method_name> in |
1180 | the superclasses, this is basically equivalent to calling |
96ceced8 |
1181 | C<SUPER::$method_name>, but it can be dispatched at runtime. |
1182 | |
552e3d24 |
1183 | =back |
1184 | |
a4258ffd |
1185 | =head2 Method Modifiers |
1186 | |
0ac992ee |
1187 | Method modifiers are a concept borrowed from CLOS, in which a method |
1188 | can be wrapped with I<before>, I<after> and I<around> method modifiers |
1189 | that will be called everytime the method is called. |
96ceced8 |
1190 | |
1191 | =head3 How method modifiers work? |
1192 | |
0ac992ee |
1193 | Method modifiers work by wrapping the original method and then replacing |
1194 | it in the classes symbol table. The wrappers will handle calling all the |
1195 | modifiers in the appropariate orders and preserving the calling context |
1196 | for the original method. |
1197 | |
1198 | Each method modifier serves a particular purpose, which may not be |
1199 | obvious to users of other method wrapping modules. To start with, the |
1200 | return values of I<before> and I<after> modifiers are ignored. This is |
1201 | because thier purpose is B<not> to filter the input and output of the |
1202 | primary method (this is done with an I<around> modifier). This may seem |
1203 | like an odd restriction to some, but doing this allows for simple code |
1204 | to be added at the begining or end of a method call without jeapordizing |
1205 | the normal functioning of the primary method or placing any extra |
1206 | responsibility on the code of the modifier. Of course if you have more |
1207 | complex needs, then use the I<around> modifier, which uses a variation |
1208 | of continutation passing style to allow for a high degree of flexibility. |
1209 | |
1210 | Before and around modifiers are called in last-defined-first-called order, |
1211 | while after modifiers are called in first-defined-first-called order. So |
96ceced8 |
1212 | the call tree might looks something like this: |
0ac992ee |
1213 | |
96ceced8 |
1214 | before 2 |
1215 | before 1 |
1216 | around 2 |
1217 | around 1 |
1218 | primary |
1219 | after 1 |
1220 | after 2 |
1221 | |
0ac992ee |
1222 | To see examples of using method modifiers, see the following examples |
1223 | included in the distribution; F<InstanceCountingClass>, F<Perl6Attribute>, |
1224 | F<AttributesWithHistory> and F<C3MethodDispatchOrder>. There is also a |
96ceced8 |
1225 | classic CLOS usage example in the test F<017_add_method_modifier.t>. |
1226 | |
1227 | =head3 What is the performance impact? |
1228 | |
0ac992ee |
1229 | Of course there is a performance cost associated with method modifiers, |
1230 | but we have made every effort to make that cost be directly proportional |
96ceced8 |
1231 | to the amount of modifier features you utilize. |
1232 | |
0ac992ee |
1233 | The wrapping method does it's best to B<only> do as much work as it |
1234 | absolutely needs to. In order to do this we have moved some of the |
96ceced8 |
1235 | performance costs to set-up time, where they are easier to amortize. |
1236 | |
1237 | All this said, my benchmarks have indicated the following: |
1238 | |
1239 | simple wrapper with no modifiers 100% slower |
1240 | simple wrapper with simple before modifier 400% slower |
1241 | simple wrapper with simple after modifier 450% slower |
1242 | simple wrapper with simple around modifier 500-550% slower |
1243 | simple wrapper with all 3 modifiers 1100% slower |
1244 | |
0ac992ee |
1245 | These numbers may seem daunting, but you must remember, every feature |
1246 | comes with some cost. To put things in perspective, just doing a simple |
96ceced8 |
1247 | C<AUTOLOAD> which does nothing but extract the name of the method called |
0ac992ee |
1248 | and return it costs about 400% over a normal method call. |
96ceced8 |
1249 | |
a4258ffd |
1250 | =over 4 |
1251 | |
1252 | =item B<add_before_method_modifier ($method_name, $code)> |
1253 | |
0ac992ee |
1254 | This will wrap the method at C<$method_name> and the supplied C<$code> |
1255 | will be passed the C<@_> arguments, and called before the original |
1256 | method is called. As specified above, the return value of the I<before> |
1257 | method modifiers is ignored, and it's ability to modify C<@_> is |
1258 | fairly limited. If you need to do either of these things, use an |
96ceced8 |
1259 | C<around> method modifier. |
1260 | |
a4258ffd |
1261 | =item B<add_after_method_modifier ($method_name, $code)> |
1262 | |
0ac992ee |
1263 | This will wrap the method at C<$method_name> so that the original |
1264 | method will be called, it's return values stashed, and then the |
96ceced8 |
1265 | supplied C<$code> will be passed the C<@_> arguments, and called. |
0ac992ee |
1266 | As specified above, the return value of the I<after> method |
1267 | modifiers is ignored, and it cannot modify the return values of |
1268 | the original method. If you need to do either of these things, use an |
96ceced8 |
1269 | C<around> method modifier. |
1270 | |
a4258ffd |
1271 | =item B<add_around_method_modifier ($method_name, $code)> |
1272 | |
0ac992ee |
1273 | This will wrap the method at C<$method_name> so that C<$code> |
1274 | will be called and passed the original method as an extra argument |
1275 | at the begining of the C<@_> argument list. This is a variation of |
1276 | continuation passing style, where the function prepended to C<@_> |
1277 | can be considered a continuation. It is up to C<$code> if it calls |
1278 | the original method or not, there is no restriction on what the |
96ceced8 |
1279 | C<$code> can or cannot do. |
1280 | |
a4258ffd |
1281 | =back |
1282 | |
552e3d24 |
1283 | =head2 Attributes |
1284 | |
0ac992ee |
1285 | It should be noted that since there is no one consistent way to define |
1286 | the attributes of a class in Perl 5. These methods can only work with |
1287 | the information given, and can not easily discover information on |
a2e85e6c |
1288 | their own. See L<Class::MOP::Attribute> for more details. |
552e3d24 |
1289 | |
1290 | =over 4 |
1291 | |
2e41896e |
1292 | =item B<attribute_metaclass> |
1293 | |
7b31baf4 |
1294 | =item B<get_attribute_map> |
1295 | |
8203616d |
1296 | =item B<add_attribute ($attribute_meta_object | $attribute_name, %attribute_spec)> |
552e3d24 |
1297 | |
8203616d |
1298 | This stores the C<$attribute_meta_object> (or creates one from the |
0ac992ee |
1299 | C<$attribute_name> and C<%attribute_spec>) in the B<Class::MOP::Class> |
1300 | instance associated with the given class. Unlike methods, attributes |
1301 | within the MOP are stored as meta-information only. They will be used |
8203616d |
1302 | later to construct instances from (see C<construct_instance> above). |
0ac992ee |
1303 | More details about the attribute meta-objects can be found in the |
a2e85e6c |
1304 | L<Class::MOP::Attribute> or the L<Class::MOP/The Attribute protocol> |
1305 | section. |
1306 | |
0ac992ee |
1307 | It should be noted that any accessor, reader/writer or predicate |
1308 | methods which the C<$attribute_meta_object> has will be installed |
a2e85e6c |
1309 | into the class at this time. |
552e3d24 |
1310 | |
86482605 |
1311 | B<NOTE> |
0ac992ee |
1312 | If an attribute already exists for C<$attribute_name>, the old one |
1313 | will be removed (as well as removing all it's accessors), and then |
86482605 |
1314 | the new one added. |
1315 | |
552e3d24 |
1316 | =item B<has_attribute ($attribute_name)> |
1317 | |
0ac992ee |
1318 | Checks to see if this class has an attribute by the name of |
552e3d24 |
1319 | C<$attribute_name> and returns a boolean. |
1320 | |
1321 | =item B<get_attribute ($attribute_name)> |
1322 | |
0ac992ee |
1323 | Returns the attribute meta-object associated with C<$attribute_name>, |
1324 | if none is found, it will return undef. |
552e3d24 |
1325 | |
1326 | =item B<remove_attribute ($attribute_name)> |
1327 | |
0ac992ee |
1328 | This will remove the attribute meta-object stored at |
1329 | C<$attribute_name>, then return the removed attribute meta-object. |
552e3d24 |
1330 | |
0ac992ee |
1331 | B<NOTE:> |
1332 | Removing an attribute will only affect future instances of |
1333 | the class, it will not make any attempt to remove the attribute from |
552e3d24 |
1334 | any existing instances of the class. |
1335 | |
0ac992ee |
1336 | It should be noted that any accessor, reader/writer or predicate |
1337 | methods which the attribute meta-object stored at C<$attribute_name> |
1338 | has will be removed from the class at this time. This B<will> make |
1339 | these attributes somewhat inaccessable in previously created |
1340 | instances. But if you are crazy enough to do this at runtime, then |
a2e85e6c |
1341 | you are crazy enough to deal with something like this :). |
1342 | |
552e3d24 |
1343 | =item B<get_attribute_list> |
1344 | |
0ac992ee |
1345 | This returns a list of attribute names which are defined in the local |
1346 | class. If you want a list of all applicable attributes for a class, |
552e3d24 |
1347 | use the C<compute_all_applicable_attributes> method. |
1348 | |
1349 | =item B<compute_all_applicable_attributes> |
1350 | |
0ac992ee |
1351 | This will traverse the inheritance heirachy and return a list of all |
1352 | the applicable attributes for this class. It does not construct a |
1353 | HASH reference like C<compute_all_applicable_methods> because all |
1354 | that same information is discoverable through the attribute |
c9e77dbb |
1355 | meta-object itself. |
552e3d24 |
1356 | |
058c1cf5 |
1357 | =item B<find_attribute_by_name ($attr_name)> |
1358 | |
0ac992ee |
1359 | This method will traverse the inheritance heirachy and find the |
1360 | first attribute whose name matches C<$attr_name>, then return it. |
058c1cf5 |
1361 | It will return undef if nothing is found. |
1362 | |
552e3d24 |
1363 | =back |
1364 | |
96e38ba6 |
1365 | =head2 Class Immutability |
857f87a7 |
1366 | |
1367 | =over 4 |
1368 | |
96e38ba6 |
1369 | =item B<make_immutable (%options)> |
1370 | |
0ac992ee |
1371 | This method will invoke a tranforamtion upon the class which will |
1372 | make it immutable. Details of this transformation can be found in |
96e38ba6 |
1373 | the L<Class::MOP::Immutable> documentation. |
857f87a7 |
1374 | |
0ac992ee |
1375 | =item B<make_mutable> |
1376 | |
1377 | This method will reverse tranforamtion upon the class which |
1378 | made it immutable. |
1379 | |
857f87a7 |
1380 | =back |
1381 | |
1a09d9cc |
1382 | =head1 AUTHORS |
8b978dd5 |
1383 | |
a2e85e6c |
1384 | Stevan Little E<lt>stevan@iinteractive.comE<gt> |
8b978dd5 |
1385 | |
1386 | =head1 COPYRIGHT AND LICENSE |
1387 | |
2367814a |
1388 | Copyright 2006, 2007 by Infinity Interactive, Inc. |
8b978dd5 |
1389 | |
1390 | L<http://www.iinteractive.com> |
1391 | |
1392 | This library is free software; you can redistribute it and/or modify |
0ac992ee |
1393 | it under the same terms as Perl itself. |
8b978dd5 |
1394 | |
798baea5 |
1395 | =cut |