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 | |
f0480c45 |
9 | our $VERSION = '0.03'; |
10 | our $AUTHORITY = 'cpan:STEVAN'; |
24869f62 |
11 | |
12 | sub meta { |
13 | require Class::MOP::Class; |
14 | Class::MOP::Class->initialize(blessed($_[0]) || $_[0]); |
15 | } |
16 | |
17 | sub new { |
052c2a1a |
18 | my ($class, $meta, @attrs) = @_; |
c57c8b10 |
19 | my @slots = map { $_->slots } @attrs; |
c23184fc |
20 | my $instance = bless { |
fc3ddd1d |
21 | # NOTE: |
22 | # I am not sure that it makes |
23 | # sense to pass in the meta |
24 | # The ideal would be to just |
25 | # pass in the class name, but |
26 | # that is placing too much of |
27 | # an assumption on bless(), |
28 | # which is *probably* a safe |
29 | # assumption,.. but you can |
30 | # never tell <:) |
c23184fc |
31 | '$!meta' => $meta, |
32 | '@!slots' => { map { $_ => undef } @slots }, |
24869f62 |
33 | } => $class; |
c23184fc |
34 | |
35 | weaken($instance->{'$!meta'}); |
36 | |
37 | return $instance; |
24869f62 |
38 | } |
39 | |
c23184fc |
40 | sub associated_metaclass { (shift)->{'$!meta'} } |
41 | |
49c93440 |
42 | sub create_instance { |
43 | my $self = shift; |
44 | $self->bless_instance_structure({}); |
2d711cc8 |
45 | } |
46 | |
49c93440 |
47 | sub bless_instance_structure { |
48 | my ($self, $instance_structure) = @_; |
c23184fc |
49 | bless $instance_structure, $self->associated_metaclass->name; |
2d711cc8 |
50 | } |
51 | |
f7259199 |
52 | sub clone_instance { |
53 | my ($self, $instance) = @_; |
54 | $self->bless_instance_structure({ %$instance }); |
55 | } |
56 | |
2d711cc8 |
57 | # operations on meta instance |
58 | |
eb49acde |
59 | sub get_all_slots { |
60 | my $self = shift; |
c23184fc |
61 | return keys %{$self->{'@!slots'}}; |
f7259199 |
62 | } |
63 | |
64 | sub is_valid_slot { |
65 | my ($self, $slot_name) = @_; |
c23184fc |
66 | exists $self->{'@!slots'}->{$slot_name} ? 1 : 0; |
839ea973 |
67 | } |
68 | |
2d711cc8 |
69 | # operations on created instances |
70 | |
839ea973 |
71 | sub get_slot_value { |
2bab2be6 |
72 | my ($self, $instance, $slot_name) = @_; |
73 | return $instance->{$slot_name}; |
839ea973 |
74 | } |
75 | |
2bab2be6 |
76 | sub set_slot_value { |
77 | my ($self, $instance, $slot_name, $value) = @_; |
78 | $instance->{$slot_name} = $value; |
79 | } |
80 | |
2d711cc8 |
81 | sub initialize_slot { |
49c93440 |
82 | my ($self, $instance, $slot_name) = @_; |
d82060fe |
83 | $self->set_slot_value($instance, $slot_name, undef); |
2d711cc8 |
84 | } |
85 | |
7d28758b |
86 | sub deinitialize_slot { |
87 | my ( $self, $instance, $slot_name ) = @_; |
88 | delete $instance->{$slot_name}; |
89 | } |
90 | |
c174112e |
91 | sub initialize_all_slots { |
92 | my ($self, $instance) = @_; |
93 | foreach my $slot_name ($self->get_all_slots) { |
94 | $self->initialize_slot($instance, $slot_name); |
95 | } |
96 | } |
97 | |
7d28758b |
98 | sub deinitialize_all_slots { |
99 | my ($self, $instance) = @_; |
100 | foreach my $slot_name ($self->get_all_slots) { |
101 | $self->deinitialize_slot($instance, $slot_name); |
102 | } |
103 | } |
104 | |
49c93440 |
105 | sub is_slot_initialized { |
106 | my ($self, $instance, $slot_name, $value) = @_; |
2d711cc8 |
107 | exists $instance->{$slot_name} ? 1 : 0; |
2bab2be6 |
108 | } |
839ea973 |
109 | |
5582521c |
110 | sub weaken_slot_value { |
111 | my ($self, $instance, $slot_name) = @_; |
112 | weaken $instance->{$slot_name}; |
113 | } |
114 | |
115 | sub strengthen_slot_value { |
116 | my ($self, $instance, $slot_name) = @_; |
117 | $self->set_slot_value($instance, $slot_name, $self->get_slot_value($instance, $slot_name)); |
118 | } |
119 | |
ee7c0467 |
120 | # inlinable operation snippets |
121 | |
c0cbf4d9 |
122 | sub is_inlinable { 1 } |
123 | |
124 | sub inline_create_instance { |
125 | my ($self, $class_variable) = @_; |
126 | 'bless {} => ' . $class_variable; |
127 | } |
128 | |
ee7c0467 |
129 | sub inline_slot_access { |
130 | my ($self, $instance, $slot_name) = @_; |
131 | sprintf "%s->{%s}", $instance, $slot_name; |
132 | } |
133 | |
134 | sub inline_get_slot_value { |
135 | my ($self, $instance, $slot_name) = @_; |
136 | $self->inline_slot_access($instance, $slot_name); |
137 | } |
138 | |
139 | sub inline_set_slot_value { |
140 | my ($self, $instance, $slot_name, $value) = @_; |
141 | $self->inline_slot_access($instance, $slot_name) . " = $value", |
142 | } |
143 | |
144 | sub inline_initialize_slot { |
145 | my ($self, $instance, $slot_name) = @_; |
146 | $self->inline_set_slot_value($instance, $slot_name, 'undef'), |
147 | } |
148 | |
7d28758b |
149 | sub inline_deinitialize_slot { |
150 | my ($self, $instance, $slot_name) = @_; |
151 | "delete " . $self->inline_slot_access($instance, $slot_name); |
152 | } |
ee7c0467 |
153 | sub inline_is_slot_initialized { |
154 | my ($self, $instance, $slot_name) = @_; |
155 | "exists " . $self->inline_slot_access($instance, $slot_name) . " ? 1 : 0"; |
156 | } |
157 | |
158 | sub inline_weaken_slot_value { |
159 | my ($self, $instance, $slot_name) = @_; |
160 | sprintf "Scalar::Util::weaken( %s )", $self->inline_slot_access($instance, $slot_name); |
161 | } |
162 | |
163 | sub inline_strengthen_slot_value { |
164 | my ($self, $instance, $slot_name) = @_; |
165 | $self->inline_set_slot_value($instance, $slot_name, $self->inline_slot_access($instance, $slot_name)); |
166 | } |
167 | |
24869f62 |
168 | 1; |
169 | |
170 | __END__ |
171 | |
172 | =pod |
173 | |
174 | =head1 NAME |
175 | |
176 | Class::MOP::Instance - Instance Meta Object |
177 | |
178 | =head1 SYNOPSIS |
179 | |
9fa4d0b4 |
180 | # for the most part, this protocol is internal |
181 | # and not for public usage, but this how one |
182 | # might use it |
183 | |
184 | package Foo; |
185 | |
186 | use strict; |
187 | use warnings; |
1becdfcc |
188 | use metaclass ( |
9fa4d0b4 |
189 | ':instance_metaclass' => 'ArrayBasedStorage::Instance', |
190 | ); |
191 | |
192 | # now Foo->new produces blessed ARRAY ref based objects |
193 | |
24869f62 |
194 | =head1 DESCRIPTION |
195 | |
9fa4d0b4 |
196 | This is a sub-protocol which governs instance creation |
197 | and access to the slots of the instance structure. |
198 | |
199 | This may seem like over-abstraction, but by abstracting |
200 | this process into a sub-protocol we make it possible to |
201 | easily switch the details of how an object's instance is |
202 | stored with minimal impact. In most cases just subclassing |
1becdfcc |
203 | this class will be all you need to do (see the examples; |
204 | F<examples/ArrayBasedStorage.pod> and |
205 | F<examples/InsideOutClass.pod> for details). |
9fa4d0b4 |
206 | |
24869f62 |
207 | =head1 METHODS |
208 | |
209 | =over 4 |
210 | |
9fa4d0b4 |
211 | =item B<new ($meta, @attrs)> |
212 | |
213 | Creates a new instance meta-object and gathers all the slots from |
214 | the list of C<@attrs> given. |
215 | |
216 | =item B<meta> |
217 | |
218 | This will return a B<Class::MOP::Class> instance which is related |
219 | to this class. |
220 | |
221 | =back |
222 | |
223 | =head2 Creation of Instances |
224 | |
225 | =over 4 |
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226 | |
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227 | =item B<create_instance> |
228 | |
9fa4d0b4 |
229 | This creates the appropriate structure needed for the instance and |
230 | then calls C<bless_instance_structure> to bless it into the class. |
0e76a376 |
231 | |
9fa4d0b4 |
232 | =item B<bless_instance_structure ($instance_structure)> |
839ea973 |
233 | |
9fa4d0b4 |
234 | This does just exactly what it says it does. |
0e76a376 |
235 | |
f7259199 |
236 | =item B<clone_instance ($instance_structure)> |
237 | |
9fa4d0b4 |
238 | =back |
839ea973 |
239 | |
9fa4d0b4 |
240 | =head2 Instrospection |
58287a97 |
241 | |
9fa4d0b4 |
242 | NOTE: There might be more methods added to this part of the API, |
243 | we will add then when we need them basically. |
58287a97 |
244 | |
9fa4d0b4 |
245 | =over 4 |
246 | |
c23184fc |
247 | =item B<associated_metaclass> |
248 | |
9fa4d0b4 |
249 | =item B<get_all_slots> |
250 | |
251 | This will return the current list of slots based on what was |
252 | given to this object in C<new>. |
58287a97 |
253 | |
f7259199 |
254 | =item B<is_valid_slot ($slot_name)> |
255 | |
24869f62 |
256 | =back |
257 | |
9fa4d0b4 |
258 | =head2 Operations on Instance Structures |
259 | |
260 | An important distinction of this sub-protocol is that the |
261 | instance meta-object is a different entity from the actual |
262 | instance it creates. For this reason, any actions on slots |
263 | require that the C<$instance_structure> is passed into them. |
24869f62 |
264 | |
265 | =over 4 |
266 | |
9fa4d0b4 |
267 | =item B<get_slot_value ($instance_structure, $slot_name)> |
24869f62 |
268 | |
9fa4d0b4 |
269 | =item B<set_slot_value ($instance_structure, $slot_name, $value)> |
270 | |
271 | =item B<initialize_slot ($instance_structure, $slot_name)> |
272 | |
7d28758b |
273 | =item B<deinitialize_slot ($instance_structure, $slot_name)> |
274 | |
9fa4d0b4 |
275 | =item B<initialize_all_slots ($instance_structure)> |
276 | |
7d28758b |
277 | =item B<deinitialize_all_slots ($instance_structure)> |
278 | |
9fa4d0b4 |
279 | =item B<is_slot_initialized ($instance_structure, $slot_name)> |
24869f62 |
280 | |
ee7c0467 |
281 | =item B<weaken_slot_value ($instance_structure, $slot_name)> |
282 | |
283 | =item B<strengthen_slot_value ($instance_structure, $slot_name)> |
284 | |
285 | =back |
286 | |
287 | =head2 Inlineable Instance Operations |
288 | |
f7259199 |
289 | This part of the API is currently un-used. It is there for use |
290 | in future experiments in class finailization mostly. Best to |
291 | ignore this for now. |
292 | |
ee7c0467 |
293 | =over 4 |
294 | |
c0cbf4d9 |
295 | =item B<is_inlinable> |
296 | |
297 | Each meta-instance should override this method to tell Class::MOP if it's |
298 | possible to inline the slot access. |
299 | |
300 | This is currently only used by Class::MOP::Class::Immutable when performing |
301 | optimizations. |
302 | |
495af518 |
303 | =item B<inline_create_instance> |
304 | |
ee7c0467 |
305 | =item B<inline_slot_access ($instance_structure, $slot_name)> |
306 | |
307 | =item B<inline_get_slot_value ($instance_structure, $slot_name)> |
308 | |
309 | =item B<inline_set_slot_value ($instance_structure, $slot_name, $value)> |
310 | |
311 | =item B<inline_initialize_slot ($instance_structure, $slot_name)> |
312 | |
7d28758b |
313 | =item B<inline_deinitialize_slot ($instance_structure, $slot_name)> |
314 | |
ee7c0467 |
315 | =item B<inline_is_slot_initialized ($instance_structure, $slot_name)> |
5582521c |
316 | |
ee7c0467 |
317 | =item B<inline_weaken_slot_value ($instance_structure, $slot_name)> |
5582521c |
318 | |
ee7c0467 |
319 | =item B<inline_strengthen_slot_value ($instance_structure, $slot_name)> |
5582521c |
320 | |
24869f62 |
321 | =back |
322 | |
1a09d9cc |
323 | =head1 AUTHORS |
24869f62 |
324 | |
9fa4d0b4 |
325 | Yuval Kogman E<lt>nothingmuch@woobling.comE<gt> |
326 | |
24869f62 |
327 | Stevan Little E<lt>stevan@iinteractive.comE<gt> |
328 | |
329 | =head1 COPYRIGHT AND LICENSE |
330 | |
331 | Copyright 2006 by Infinity Interactive, Inc. |
332 | |
333 | L<http://www.iinteractive.com> |
334 | |
335 | This library is free software; you can redistribute it and/or modify |
336 | it under the same terms as Perl itself. |
337 | |
84ef30d1 |
338 | =cut |
5582521c |
339 | |