Commit | Line | Data |
24869f62 |
1 | |
2 | package Class::MOP::Instance; |
3 | |
4 | use strict; |
5 | use warnings; |
6 | |
fa16e528 |
7 | use Scalar::Util 'weaken', 'blessed'; |
24869f62 |
8 | |
f3ddcd1a |
9 | our $VERSION = '0.80'; |
d519662a |
10 | $VERSION = eval $VERSION; |
f0480c45 |
11 | our $AUTHORITY = 'cpan:STEVAN'; |
24869f62 |
12 | |
d7b2249e |
13 | use base 'Class::MOP::Object'; |
24869f62 |
14 | |
63d08a9e |
15 | sub BUILDARGS { |
d43737b3 |
16 | my ($class, @args) = @_; |
17 | |
18 | if ( @args == 1 ) { |
63d08a9e |
19 | unshift @args, "associated_metaclass"; |
d43737b3 |
20 | } elsif ( @args >= 2 && blessed($args[0]) && $args[0]->isa("Class::MOP::Class") ) { |
21 | # compat mode |
22 | my ( $meta, @attrs ) = @args; |
63d08a9e |
23 | @args = ( associated_metaclass => $meta, attributes => \@attrs ); |
d43737b3 |
24 | } |
25 | |
26 | my %options = @args; |
7c7fd869 |
27 | # FIXME lazy_build |
d43737b3 |
28 | $options{slots} ||= [ map { $_->slots } @{ $options{attributes} || [] } ]; |
63d08a9e |
29 | $options{slot_hash} = { map { $_ => undef } @{ $options{slots} } }; # FIXME lazy_build |
30 | |
31 | return \%options; |
32 | } |
33 | |
34 | sub new { |
35 | my $class = shift; |
36 | my $options = $class->BUILDARGS(@_); |
d43737b3 |
37 | |
38 | # FIXME replace with a proper constructor |
b4b5d65a |
39 | my $instance = $class->_new(%$options); |
40 | |
41 | # FIXME weak_ref => 1, |
42 | weaken($instance->{'associated_metaclass'}); |
43 | |
44 | return $instance; |
45 | } |
46 | |
47 | sub _new { |
48 | my ( $class, %options ) = @_; |
49 | bless { |
fc3ddd1d |
50 | # NOTE: |
51 | # I am not sure that it makes |
52 | # sense to pass in the meta |
8d2d4c67 |
53 | # The ideal would be to just |
54 | # pass in the class name, but |
55 | # that is placing too much of |
56 | # an assumption on bless(), |
fc3ddd1d |
57 | # which is *probably* a safe |
8d2d4c67 |
58 | # assumption,.. but you can |
fc3ddd1d |
59 | # never tell <:) |
b4b5d65a |
60 | 'associated_metaclass' => $options{associated_metaclass}, |
61 | 'attributes' => $options{attributes}, |
62 | 'slots' => $options{slots}, |
63 | 'slot_hash' => $options{slot_hash}, |
8d2d4c67 |
64 | } => $class; |
24869f62 |
65 | } |
66 | |
74890687 |
67 | sub _class_name { $_[0]->{_class_name} ||= $_[0]->associated_metaclass->name } |
68 | |
69 | sub associated_metaclass { $_[0]{'associated_metaclass'} } |
c23184fc |
70 | |
49c93440 |
71 | sub create_instance { |
72 | my $self = shift; |
becd03c6 |
73 | bless {}, $self->_class_name; |
2d711cc8 |
74 | } |
75 | |
becd03c6 |
76 | # for compatibility |
49c93440 |
77 | sub bless_instance_structure { |
78 | my ($self, $instance_structure) = @_; |
74890687 |
79 | bless $instance_structure, $self->_class_name; |
2d711cc8 |
80 | } |
81 | |
f7259199 |
82 | sub clone_instance { |
83 | my ($self, $instance) = @_; |
becd03c6 |
84 | bless { %$instance }, $self->_class_name; |
f7259199 |
85 | } |
86 | |
2d711cc8 |
87 | # operations on meta instance |
88 | |
eb49acde |
89 | sub get_all_slots { |
90 | my $self = shift; |
7c7fd869 |
91 | return @{$self->{'slots'}}; |
f7259199 |
92 | } |
93 | |
0b5d46da |
94 | sub get_all_attributes { |
95 | my $self = shift; |
96 | return @{$self->{attributes}}; |
97 | } |
98 | |
f7259199 |
99 | sub is_valid_slot { |
100 | my ($self, $slot_name) = @_; |
7c7fd869 |
101 | exists $self->{'slot_hash'}->{$slot_name}; |
839ea973 |
102 | } |
103 | |
2d711cc8 |
104 | # operations on created instances |
105 | |
839ea973 |
106 | sub get_slot_value { |
2bab2be6 |
107 | my ($self, $instance, $slot_name) = @_; |
230472a7 |
108 | $instance->{$slot_name}; |
839ea973 |
109 | } |
110 | |
2bab2be6 |
111 | sub set_slot_value { |
112 | my ($self, $instance, $slot_name, $value) = @_; |
113 | $instance->{$slot_name} = $value; |
114 | } |
115 | |
2d711cc8 |
116 | sub initialize_slot { |
49c93440 |
117 | my ($self, $instance, $slot_name) = @_; |
a007159d |
118 | return; |
2d711cc8 |
119 | } |
120 | |
7d28758b |
121 | sub deinitialize_slot { |
122 | my ( $self, $instance, $slot_name ) = @_; |
123 | delete $instance->{$slot_name}; |
124 | } |
125 | |
c174112e |
126 | sub initialize_all_slots { |
127 | my ($self, $instance) = @_; |
128 | foreach my $slot_name ($self->get_all_slots) { |
129 | $self->initialize_slot($instance, $slot_name); |
130 | } |
131 | } |
132 | |
7d28758b |
133 | sub deinitialize_all_slots { |
134 | my ($self, $instance) = @_; |
135 | foreach my $slot_name ($self->get_all_slots) { |
136 | $self->deinitialize_slot($instance, $slot_name); |
137 | } |
138 | } |
139 | |
49c93440 |
140 | sub is_slot_initialized { |
141 | my ($self, $instance, $slot_name, $value) = @_; |
230472a7 |
142 | exists $instance->{$slot_name}; |
2bab2be6 |
143 | } |
839ea973 |
144 | |
5582521c |
145 | sub weaken_slot_value { |
69e3ab0a |
146 | my ($self, $instance, $slot_name) = @_; |
147 | weaken $instance->{$slot_name}; |
5582521c |
148 | } |
149 | |
150 | sub strengthen_slot_value { |
69e3ab0a |
151 | my ($self, $instance, $slot_name) = @_; |
152 | $self->set_slot_value($instance, $slot_name, $self->get_slot_value($instance, $slot_name)); |
5582521c |
153 | } |
154 | |
3d9e4646 |
155 | sub rebless_instance_structure { |
156 | my ($self, $instance, $metaclass) = @_; |
feb93c85 |
157 | |
158 | # we use $_[1] here because of t/306_rebless_overload.t regressions on 5.8.8 |
159 | bless $_[1], $metaclass->name; |
3d9e4646 |
160 | } |
161 | |
da5680be |
162 | sub is_dependent_on_superclasses { |
163 | return; # for meta instances that require updates on inherited slot changes |
164 | } |
165 | |
ee7c0467 |
166 | # inlinable operation snippets |
167 | |
c0cbf4d9 |
168 | sub is_inlinable { 1 } |
169 | |
170 | sub inline_create_instance { |
171 | my ($self, $class_variable) = @_; |
172 | 'bless {} => ' . $class_variable; |
173 | } |
174 | |
ee7c0467 |
175 | sub inline_slot_access { |
176 | my ($self, $instance, $slot_name) = @_; |
e9a19694 |
177 | sprintf q[%s->{"%s"}], $instance, quotemeta($slot_name); |
ee7c0467 |
178 | } |
179 | |
180 | sub inline_get_slot_value { |
181 | my ($self, $instance, $slot_name) = @_; |
230472a7 |
182 | $self->inline_slot_access($instance, $slot_name); |
ee7c0467 |
183 | } |
184 | |
185 | sub inline_set_slot_value { |
186 | my ($self, $instance, $slot_name, $value) = @_; |
8d2d4c67 |
187 | $self->inline_slot_access($instance, $slot_name) . " = $value", |
ee7c0467 |
188 | } |
189 | |
190 | sub inline_initialize_slot { |
191 | my ($self, $instance, $slot_name) = @_; |
a007159d |
192 | return ''; |
ee7c0467 |
193 | } |
194 | |
7d28758b |
195 | sub inline_deinitialize_slot { |
196 | my ($self, $instance, $slot_name) = @_; |
197 | "delete " . $self->inline_slot_access($instance, $slot_name); |
198 | } |
ee7c0467 |
199 | sub inline_is_slot_initialized { |
200 | my ($self, $instance, $slot_name) = @_; |
230472a7 |
201 | "exists " . $self->inline_slot_access($instance, $slot_name); |
ee7c0467 |
202 | } |
203 | |
204 | sub inline_weaken_slot_value { |
205 | my ($self, $instance, $slot_name) = @_; |
206 | sprintf "Scalar::Util::weaken( %s )", $self->inline_slot_access($instance, $slot_name); |
207 | } |
208 | |
209 | sub inline_strengthen_slot_value { |
210 | my ($self, $instance, $slot_name) = @_; |
211 | $self->inline_set_slot_value($instance, $slot_name, $self->inline_slot_access($instance, $slot_name)); |
212 | } |
213 | |
24869f62 |
214 | 1; |
215 | |
216 | __END__ |
217 | |
218 | =pod |
219 | |
8d2d4c67 |
220 | =head1 NAME |
24869f62 |
221 | |
222 | Class::MOP::Instance - Instance Meta Object |
223 | |
24869f62 |
224 | =head1 DESCRIPTION |
225 | |
ba1b8aa2 |
226 | The Instance Protocol controls the creation of object instances, and |
20315887 |
227 | the storage of attribute values in those instances. |
228 | |
229 | Using this API directly in your own code violates encapsulation, and |
230 | we recommend that you use the appropriate APIs in L<Class::MOP::Class> |
231 | and L<Class::MOP::Attribute> instead. Those APIs in turn call the |
232 | methods in this class as appropriate. |
233 | |
234 | This class also participates in generating inlined code by providing |
235 | snippets of code to access an object instance. |
9fa4d0b4 |
236 | |
24869f62 |
237 | =head1 METHODS |
238 | |
20315887 |
239 | =head2 Object construction |
240 | |
24869f62 |
241 | =over 4 |
242 | |
20315887 |
243 | =item B<< Class::MOP::Instance->new(%options) >> |
9fa4d0b4 |
244 | |
20315887 |
245 | This method creates a new meta-instance object. |
9fa4d0b4 |
246 | |
20315887 |
247 | It accepts the following keys in C<%options>: |
63d08a9e |
248 | |
20315887 |
249 | =over 8 |
63d08a9e |
250 | |
20315887 |
251 | =item * associated_metaclass |
9fa4d0b4 |
252 | |
20315887 |
253 | The L<Class::MOP::Class> object for which instances will be created. |
9fa4d0b4 |
254 | |
20315887 |
255 | =item * attributes |
9fa4d0b4 |
256 | |
20315887 |
257 | An array reference of L<Class::MOP::Attribute> objects. These are the |
258 | attributes which can be stored in each instance. |
9fa4d0b4 |
259 | |
20315887 |
260 | =back |
24869f62 |
261 | |
20315887 |
262 | =back |
58287a97 |
263 | |
20315887 |
264 | =head2 Creating and altering instances |
0e76a376 |
265 | |
20315887 |
266 | =over 4 |
839ea973 |
267 | |
20315887 |
268 | =item B<< $metainstance->create_instance >> |
0e76a376 |
269 | |
20315887 |
270 | This method returns a reference blessed into the associated |
271 | metaclass's class. |
becd03c6 |
272 | |
20315887 |
273 | The default is to use a hash reference. Subclasses can override this. |
f7259199 |
274 | |
20315887 |
275 | =item B<< $metainstance->clone_instance($instance) >> |
276 | |
277 | Given an instance, this method creates a new object by making |
278 | I<shallow> clone of the original. |
127d39a7 |
279 | |
9fa4d0b4 |
280 | =back |
839ea973 |
281 | |
98bf345b |
282 | =head2 Introspection |
58287a97 |
283 | |
9fa4d0b4 |
284 | =over 4 |
285 | |
20315887 |
286 | =item B<< $metainstance->associated_metaclass >> |
c23184fc |
287 | |
20315887 |
288 | This returns the L<Class::MOP::Class> object associated with the |
289 | meta-instance object. |
127d39a7 |
290 | |
20315887 |
291 | =item B<< $metainstance->get_all_slots >> |
9fa4d0b4 |
292 | |
20315887 |
293 | This returns a list of slot names stored in object instances. In |
294 | almost all cases, slot names correspond directly attribute names. |
58287a97 |
295 | |
20315887 |
296 | =item B<< $metainstance->is_valid_slot($slot_name) >> |
f7259199 |
297 | |
127d39a7 |
298 | This will return true if C<$slot_name> is a valid slot name. |
299 | |
20315887 |
300 | =item B<< $metainstance->get_all_attributes >> |
da5680be |
301 | |
20315887 |
302 | This returns a list of attributes corresponding to the attributes |
303 | passed to the constructor. |
0202ee96 |
304 | |
24869f62 |
305 | =back |
306 | |
9fa4d0b4 |
307 | =head2 Operations on Instance Structures |
308 | |
20315887 |
309 | It's important to understand that the meta-instance object is a |
310 | different entity from the actual instances it creates. For this |
311 | reason, any operations on the C<$instance_structure> always require |
312 | that the object instance be passed to the method. |
127d39a7 |
313 | |
24869f62 |
314 | =over 4 |
315 | |
20315887 |
316 | =item B<< $metainstance->get_slot_value($instance_structure, $slot_name) >> |
317 | |
318 | =item B<< $metainstance->set_slot_value($instance_structure, $slot_name, $value) >> |
24869f62 |
319 | |
20315887 |
320 | =item B<< $metainstance->initialize_slot($instance_structure, $slot_name) >> |
9fa4d0b4 |
321 | |
20315887 |
322 | =item B<< $metainstance->deinitialize_slot($instance_structure, $slot_name) >> |
9fa4d0b4 |
323 | |
20315887 |
324 | =item B<< $metainstance->initialize_all_slots($instance_structure) >> |
7d28758b |
325 | |
20315887 |
326 | =item B<< $metainstance->deinitialize_all_slots($instance_structure) >> |
9fa4d0b4 |
327 | |
20315887 |
328 | =item B<< $metainstance->is_slot_initialized($instance_structure, $slot_name) >> |
7d28758b |
329 | |
20315887 |
330 | =item B<< $metainstance->weaken_slot_value($instance_structure, $slot_name) >> |
24869f62 |
331 | |
20315887 |
332 | =item B<< $metainstance->strengthen_slot_value($instance_structure, $slot_name) >> |
ee7c0467 |
333 | |
20315887 |
334 | =item B<< $metainstance->rebless_instance_structure($instance_structure, $new_metaclass) >> |
ee7c0467 |
335 | |
20315887 |
336 | The exact details of what each method does should be fairly obvious |
337 | from the method name. |
5fdf066d |
338 | |
ee7c0467 |
339 | =back |
340 | |
20315887 |
341 | =head2 Inlinable Instance Operations |
ee7c0467 |
342 | |
343 | =over 4 |
344 | |
20315887 |
345 | =item B<< $metainstance->is_inlinable >> |
c0cbf4d9 |
346 | |
20315887 |
347 | This is a boolean that indicates whether or not slot access operations |
348 | can be inlined. By default it is true, but subclasses can override |
349 | this. |
c0cbf4d9 |
350 | |
20315887 |
351 | =item B<< $metainstance->inline_create_instance($class_variable) >> |
495af518 |
352 | |
20315887 |
353 | This method expects a string that, I<when inlined>, will become a |
354 | class name. This would literally be something like C<'$class'>, not an |
355 | actual class name. |
ee7c0467 |
356 | |
20315887 |
357 | It returns a snippet of code that creates a new object for the |
358 | class. This is something like C< bless {}, $class_name >. |
ee7c0467 |
359 | |
20315887 |
360 | =item B<< $metainstance->inline_slot_access($instance_variable, $slot_name) >> |
ee7c0467 |
361 | |
20315887 |
362 | =item B<< $metainstance->inline_get_slot_value($instance_variable, $slot_name) >> |
ee7c0467 |
363 | |
20315887 |
364 | =item B<< $metainstance->inline_set_slot_value($instance_variable, $slot_name, $value) >> |
365 | |
366 | =item B<< $metainstance->inline_initialize_slot($instance_variable, $slot_name) >> |
367 | |
368 | =item B<< $metainstance->inline_deinitialize_slot($instance_variable, $slot_name) >> |
369 | |
370 | =item B<< $metainstance->inline_is_slot_initialized($instance_variable, $slot_name) >> |
371 | |
372 | =item B<< $metainstance->inline_weaken_slot_value($instance_variable, $slot_name) >> |
373 | |
374 | =item B<< $metainstance->inline_strengthen_slot_value($instance_variable, $slot_name) >> |
375 | |
376 | These methods all expect two arguments. The first is the name of a |
377 | variable, than when inlined, will represent the object |
378 | instance. Typically this will be a literal string like C<'$_[0]'>. |
379 | |
380 | The second argument is a slot name. |
381 | |
382 | The method returns a snippet of code that, when inlined, performs some |
383 | operation on the instance. |
384 | |
385 | =back |
386 | |
387 | =head2 Introspection |
388 | |
389 | =over 4 |
7d28758b |
390 | |
20315887 |
391 | =item B<< Class::MOP::Instance->meta >> |
5582521c |
392 | |
20315887 |
393 | This will return a L<Class::MOP::Class> instance for this class. |
5582521c |
394 | |
20315887 |
395 | It should also be noted that L<Class::MOP> will actually bootstrap |
396 | this module by installing a number of attribute meta-objects into its |
397 | metaclass. |
5582521c |
398 | |
24869f62 |
399 | =back |
400 | |
1a09d9cc |
401 | =head1 AUTHORS |
24869f62 |
402 | |
9fa4d0b4 |
403 | Yuval Kogman E<lt>nothingmuch@woobling.comE<gt> |
404 | |
24869f62 |
405 | Stevan Little E<lt>stevan@iinteractive.comE<gt> |
406 | |
407 | =head1 COPYRIGHT AND LICENSE |
408 | |
070bb6c9 |
409 | Copyright 2006-2009 by Infinity Interactive, Inc. |
24869f62 |
410 | |
411 | L<http://www.iinteractive.com> |
412 | |
413 | This library is free software; you can redistribute it and/or modify |
8d2d4c67 |
414 | it under the same terms as Perl itself. |
24869f62 |
415 | |
84ef30d1 |
416 | =cut |
5582521c |
417 | |