Commit | Line | Data |
c23184fc |
1 | |
2 | package Class::MOP::Immutable; |
3 | |
4 | use strict; |
5 | use warnings; |
6 | |
7 | use Class::MOP::Method::Constructor; |
8 | |
9 | use Carp 'confess'; |
10 | use Scalar::Util 'blessed'; |
53299a7b |
11 | use Sub::Name 'subname'; |
c23184fc |
12 | |
5f3efd66 |
13 | our $VERSION = '0.06'; |
c23184fc |
14 | our $AUTHORITY = 'cpan:STEVAN'; |
15 | |
d7b2249e |
16 | use base 'Class::MOP::Object'; |
17 | |
0ac992ee |
18 | sub new { |
c23184fc |
19 | my ($class, $metaclass, $options) = @_; |
0ac992ee |
20 | |
c23184fc |
21 | my $self = bless { |
22 | '$!metaclass' => $metaclass, |
23 | '%!options' => $options, |
24 | '$!immutable_metaclass' => undef, |
25 | } => $class; |
0ac992ee |
26 | |
c23184fc |
27 | # NOTE: |
0ac992ee |
28 | # we initialize the immutable |
c23184fc |
29 | # version of the metaclass here |
30 | $self->create_immutable_metaclass; |
0ac992ee |
31 | |
c23184fc |
32 | return $self; |
33 | } |
34 | |
35 | sub immutable_metaclass { (shift)->{'$!immutable_metaclass'} } |
36 | sub metaclass { (shift)->{'$!metaclass'} } |
37 | sub options { (shift)->{'%!options'} } |
38 | |
39 | sub create_immutable_metaclass { |
40 | my $self = shift; |
41 | |
42 | # NOTE: |
0ac992ee |
43 | # The immutable version of the |
c23184fc |
44 | # metaclass is just a anon-class |
0ac992ee |
45 | # which shadows the methods |
c23184fc |
46 | # appropriately |
47 | $self->{'$!immutable_metaclass'} = Class::MOP::Class->create_anon_class( |
48 | superclasses => [ blessed($self->metaclass) ], |
49 | methods => $self->create_methods_for_immutable_metaclass, |
0ac992ee |
50 | ); |
c23184fc |
51 | } |
52 | |
d9586da2 |
53 | |
c23184fc |
54 | my %DEFAULT_METHODS = ( |
d9586da2 |
55 | # I don't really understand this, but removing it breaks tests (groditi) |
0ac992ee |
56 | meta => sub { |
c23184fc |
57 | my $self = shift; |
0ac992ee |
58 | # if it is not blessed, then someone is asking |
127d39a7 |
59 | # for the meta of Class::MOP::Immutable |
c23184fc |
60 | return Class::MOP::Class->initialize($self) unless blessed($self); |
0ac992ee |
61 | # otherwise, they are asking for the metaclass |
c23184fc |
62 | # which has been made immutable, which is itself |
63 | return $self; |
64 | }, |
d9586da2 |
65 | is_mutable => sub { 0 }, |
66 | is_immutable => sub { 1 }, |
67 | make_immutable => sub { () }, |
c23184fc |
68 | ); |
69 | |
70 | # NOTE: |
0ac992ee |
71 | # this will actually convert the |
72 | # existing metaclass to an immutable |
c23184fc |
73 | # version of itself |
74 | sub make_metaclass_immutable { |
229910b5 |
75 | my ($self, $metaclass, $options) = @_; |
76 | |
77 | foreach my $pair ( |
78 | [ inline_accessors => 1 ], |
79 | [ inline_constructor => 1 ], |
80 | [ inline_destructor => 0 ], |
81 | [ constructor_name => 'new' ], |
82 | [ debug => 0 ], |
83 | ) { |
84 | $options->{$pair->[0]} = $pair->[1] unless exists $options->{$pair->[0]}; |
85 | } |
0ac992ee |
86 | |
229910b5 |
87 | my %options = %$options; |
0ac992ee |
88 | |
c23184fc |
89 | if ($options{inline_accessors}) { |
90 | foreach my $attr_name ($metaclass->get_attribute_list) { |
91 | # inline the accessors |
92 | $metaclass->get_attribute($attr_name) |
0ac992ee |
93 | ->install_accessors(1); |
94 | } |
c23184fc |
95 | } |
96 | |
0ac992ee |
97 | if ($options{inline_constructor}) { |
c23184fc |
98 | my $constructor_class = $options{constructor_class} || 'Class::MOP::Method::Constructor'; |
c23184fc |
99 | $metaclass->add_method( |
100 | $options{constructor_name}, |
101 | $constructor_class->new( |
0ac992ee |
102 | options => \%options, |
103 | metaclass => $metaclass, |
565f0cbb |
104 | is_inline => 1, |
c23184fc |
105 | ) |
106 | ) unless $metaclass->has_method($options{constructor_name}); |
0ac992ee |
107 | } |
108 | |
109 | if ($options{inline_destructor}) { |
c23184fc |
110 | (exists $options{destructor_class}) |
111 | || confess "The 'inline_destructor' option is present, but " |
112 | . "no destructor class was specified"; |
0ac992ee |
113 | |
c23184fc |
114 | my $destructor_class = $options{destructor_class}; |
0ac992ee |
115 | |
c23184fc |
116 | my $destructor = $destructor_class->new( |
117 | options => \%options, |
118 | metaclass => $metaclass, |
119 | ); |
0ac992ee |
120 | |
121 | $metaclass->add_method('DESTROY' => $destructor) |
c23184fc |
122 | # NOTE: |
0ac992ee |
123 | # we allow the destructor to determine |
c23184fc |
124 | # if it is needed or not, it can perform |
0ac992ee |
125 | # all sorts of checks because it has the |
126 | # metaclass instance |
c23184fc |
127 | if $destructor->is_needed; |
0ac992ee |
128 | } |
129 | |
c23184fc |
130 | my $memoized_methods = $self->options->{memoize}; |
131 | foreach my $method_name (keys %{$memoized_methods}) { |
132 | my $type = $memoized_methods->{$method_name}; |
0ac992ee |
133 | |
c23184fc |
134 | ($metaclass->can($method_name)) |
0ac992ee |
135 | || confess "Could not find the method '$method_name' in " . $metaclass->name; |
136 | |
c23184fc |
137 | if ($type eq 'ARRAY') { |
138 | $metaclass->{'___' . $method_name} = [ $metaclass->$method_name ]; |
139 | } |
140 | elsif ($type eq 'HASH') { |
0ac992ee |
141 | $metaclass->{'___' . $method_name} = { $metaclass->$method_name }; |
c23184fc |
142 | } |
143 | elsif ($type eq 'SCALAR') { |
144 | $metaclass->{'___' . $method_name} = $metaclass->$method_name; |
145 | } |
0ac992ee |
146 | } |
147 | |
0ac992ee |
148 | $metaclass->{'___original_class'} = blessed($metaclass); |
c23184fc |
149 | bless $metaclass => $self->immutable_metaclass->name; |
150 | } |
151 | |
0ac992ee |
152 | sub make_metaclass_mutable { |
229910b5 |
153 | my ($self, $immutable, $options) = @_; |
154 | |
155 | my %options = %$options; |
0ac992ee |
156 | |
157 | my $original_class = $immutable->get_mutable_metaclass_name; |
158 | delete $immutable->{'___original_class'} ; |
159 | bless $immutable => $original_class; |
160 | |
161 | my $memoized_methods = $self->options->{memoize}; |
162 | foreach my $method_name (keys %{$memoized_methods}) { |
163 | my $type = $memoized_methods->{$method_name}; |
164 | |
165 | ($immutable->can($method_name)) |
166 | || confess "Could not find the method '$method_name' in " . $immutable->name; |
167 | if ($type eq 'SCALAR' || $type eq 'ARRAY' || $type eq 'HASH' ) { |
168 | delete $immutable->{'___' . $method_name}; |
169 | } |
170 | } |
171 | |
172 | if ($options{inline_destructor} && $immutable->has_method('DESTROY')) { |
173 | $immutable->remove_method('DESTROY') |
11b56828 |
174 | if blessed($immutable->get_method('DESTROY')) eq $options{destructor_class}; |
0ac992ee |
175 | } |
176 | |
b817e248 |
177 | # NOTE: |
178 | # 14:01 <@stevan> nah,. you shouldnt |
179 | # 14:01 <@stevan> they are just inlined |
180 | # 14:01 <@stevan> which is the default in Moose anyway |
181 | # 14:02 <@stevan> and adding new attributes will just DWIM |
182 | # 14:02 <@stevan> and you really cant change an attribute anyway |
183 | # if ($options{inline_accessors}) { |
184 | # foreach my $attr_name ($immutable->get_attribute_list) { |
185 | # my $attr = $immutable->get_attribute($attr_name); |
186 | # $attr->remove_accessors; |
187 | # $attr->install_accessors(0); |
188 | # } |
189 | # } |
190 | |
191 | # 14:26 <@stevan> the only user of ::Method::Constructor is immutable |
192 | # 14:27 <@stevan> if someone uses it outside of immutable,.. they are either: mst or groditi |
193 | # 14:27 <@stevan> so I am not worried |
11b56828 |
194 | if ($options{inline_constructor} && $immutable->has_method($options{constructor_name})) { |
0ac992ee |
195 | my $constructor_class = $options{constructor_class} || 'Class::MOP::Method::Constructor'; |
196 | $immutable->remove_method( $options{constructor_name} ) |
11b56828 |
197 | if blessed($immutable->get_method($options{constructor_name})) eq $constructor_class; |
0ac992ee |
198 | } |
199 | } |
200 | |
c23184fc |
201 | sub create_methods_for_immutable_metaclass { |
202 | my $self = shift; |
0ac992ee |
203 | |
c23184fc |
204 | my %methods = %DEFAULT_METHODS; |
0ac992ee |
205 | |
c23184fc |
206 | foreach my $read_only_method (@{$self->options->{read_only}}) { |
207 | my $method = $self->metaclass->meta->find_method_by_name($read_only_method); |
0ac992ee |
208 | |
c23184fc |
209 | (defined $method) |
210 | || confess "Could not find the method '$read_only_method' in " . $self->metaclass->name; |
0ac992ee |
211 | |
c23184fc |
212 | $methods{$read_only_method} = sub { |
213 | confess "This method is read-only" if scalar @_ > 1; |
214 | goto &{$method->body} |
215 | }; |
216 | } |
0ac992ee |
217 | |
c23184fc |
218 | foreach my $cannot_call_method (@{$self->options->{cannot_call}}) { |
219 | $methods{$cannot_call_method} = sub { |
220 | confess "This method ($cannot_call_method) cannot be called on an immutable instance"; |
221 | }; |
0ac992ee |
222 | } |
223 | |
c23184fc |
224 | my $memoized_methods = $self->options->{memoize}; |
c23184fc |
225 | foreach my $method_name (keys %{$memoized_methods}) { |
226 | my $type = $memoized_methods->{$method_name}; |
227 | if ($type eq 'ARRAY') { |
228 | $methods{$method_name} = sub { @{$_[0]->{'___' . $method_name}} }; |
229 | } |
230 | elsif ($type eq 'HASH') { |
231 | $methods{$method_name} = sub { %{$_[0]->{'___' . $method_name}} }; |
232 | } |
233 | elsif ($type eq 'SCALAR') { |
234 | $methods{$method_name} = sub { $_[0]->{'___' . $method_name} }; |
0ac992ee |
235 | } |
236 | } |
53299a7b |
237 | |
5f3efd66 |
238 | my $wrapped_methods = $self->options->{wrapped}; |
239 | |
240 | foreach my $method_name (keys %{ $wrapped_methods }) { |
53299a7b |
241 | my $method = $self->metaclass->meta->find_method_by_name($method_name); |
5f3efd66 |
242 | |
243 | (defined $method) |
244 | || confess "Could not find the method '$method_name' in " . $self->metaclass->name; |
245 | |
246 | my $wrapper = $wrapped_methods->{$method_name}; |
247 | |
248 | $methods{$method_name} = sub { $wrapper->($method, @_) }; |
53299a7b |
249 | } |
0ac992ee |
250 | |
251 | $methods{get_mutable_metaclass_name} = sub { (shift)->{'___original_class'} }; |
252 | |
9f3ff885 |
253 | $methods{immutable_transformer} = sub { $self }; |
254 | |
c23184fc |
255 | return \%methods; |
256 | } |
257 | |
258 | 1; |
259 | |
260 | __END__ |
261 | |
262 | =pod |
263 | |
0ac992ee |
264 | =head1 NAME |
c23184fc |
265 | |
266 | Class::MOP::Immutable - A class to transform Class::MOP::Class metaclasses |
267 | |
268 | =head1 SYNOPSIS |
269 | |
96e38ba6 |
270 | use Class::MOP::Immutable; |
0ac992ee |
271 | |
96e38ba6 |
272 | my $immutable_metaclass = Class::MOP::Immutable->new($metaclass, { |
273 | read_only => [qw/superclasses/], |
274 | cannot_call => [qw/ |
275 | add_method |
276 | alias_method |
277 | remove_method |
278 | add_attribute |
279 | remove_attribute |
280 | add_package_symbol |
0ac992ee |
281 | remove_package_symbol |
96e38ba6 |
282 | /], |
283 | memoize => { |
284 | class_precedence_list => 'ARRAY', |
0ac992ee |
285 | compute_all_applicable_attributes => 'ARRAY', |
286 | get_meta_instance => 'SCALAR', |
287 | get_method_map => 'SCALAR', |
96e38ba6 |
288 | } |
0ac992ee |
289 | }); |
96e38ba6 |
290 | |
291 | $immutable_metaclass->make_metaclass_immutable(@_) |
292 | |
c23184fc |
293 | =head1 DESCRIPTION |
294 | |
0ac992ee |
295 | This is basically a module for applying a transformation on a given |
296 | metaclass. Current features include making methods read-only, |
96e38ba6 |
297 | making methods un-callable and memoizing methods (in a type specific |
0ac992ee |
298 | way too). |
96e38ba6 |
299 | |
127d39a7 |
300 | This module is not for the feint of heart, it does some whacky things |
301 | to the metaclass in order to make it immutable. If you are just curious, |
302 | I suggest you turn back now, there is nothing to see here. |
96e38ba6 |
303 | |
c23184fc |
304 | =head1 METHODS |
305 | |
306 | =over 4 |
307 | |
96e38ba6 |
308 | =item B<new ($metaclass, \%options)> |
309 | |
0ac992ee |
310 | Given a C<$metaclass> and a set of C<%options> this module will |
311 | prepare an immutable version of the C<$metaclass>, which can then |
312 | be applied to the C<$metaclass> using the C<make_metaclass_immutable> |
96e38ba6 |
313 | method. |
314 | |
c23184fc |
315 | =item B<options> |
316 | |
96e38ba6 |
317 | Returns the options HASH set in C<new>. |
318 | |
c23184fc |
319 | =item B<metaclass> |
320 | |
96e38ba6 |
321 | Returns the metaclass set in C<new>. |
322 | |
c23184fc |
323 | =item B<immutable_metaclass> |
324 | |
96e38ba6 |
325 | Returns the immutable metaclass created within C<new>. |
326 | |
c23184fc |
327 | =back |
328 | |
329 | =over 4 |
330 | |
331 | =item B<create_immutable_metaclass> |
332 | |
0ac992ee |
333 | This will create the immutable version of the C<$metaclass>, but will |
334 | not actually change the original metaclass. |
96e38ba6 |
335 | |
c23184fc |
336 | =item B<create_methods_for_immutable_metaclass> |
337 | |
0ac992ee |
338 | This will create all the methods for the immutable metaclass based |
96e38ba6 |
339 | on the C<%options> passed into C<new>. |
340 | |
0ac992ee |
341 | =item B<make_metaclass_immutable (%options)> |
c23184fc |
342 | |
96e38ba6 |
343 | This will actually change the C<$metaclass> into the immutable version. |
344 | |
0ac992ee |
345 | =item B<make_metaclass_mutable (%options)> |
346 | |
347 | This will change the C<$metaclass> into the mutable version by reversing |
348 | the immutable process. C<%options> should be the same options that were |
349 | given to make_metaclass_immutable. |
350 | |
c23184fc |
351 | =back |
352 | |
353 | =head1 AUTHORS |
354 | |
355 | Stevan Little E<lt>stevan@iinteractive.comE<gt> |
356 | |
357 | =head1 COPYRIGHT AND LICENSE |
358 | |
69e3ab0a |
359 | Copyright 2006-2008 by Infinity Interactive, Inc. |
c23184fc |
360 | |
361 | L<http://www.iinteractive.com> |
362 | |
363 | This library is free software; you can redistribute it and/or modify |
0ac992ee |
364 | it under the same terms as Perl itself. |
c23184fc |
365 | |
366 | =cut |