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'; |
11 | |
d7b2249e |
12 | our $VERSION = '0.05'; |
c23184fc |
13 | our $AUTHORITY = 'cpan:STEVAN'; |
14 | |
d7b2249e |
15 | use base 'Class::MOP::Object'; |
16 | |
0ac992ee |
17 | sub new { |
c23184fc |
18 | my ($class, $metaclass, $options) = @_; |
0ac992ee |
19 | |
c23184fc |
20 | my $self = bless { |
21 | '$!metaclass' => $metaclass, |
22 | '%!options' => $options, |
23 | '$!immutable_metaclass' => undef, |
24 | } => $class; |
0ac992ee |
25 | |
c23184fc |
26 | # NOTE: |
0ac992ee |
27 | # we initialize the immutable |
c23184fc |
28 | # version of the metaclass here |
29 | $self->create_immutable_metaclass; |
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30 | |
c23184fc |
31 | return $self; |
32 | } |
33 | |
34 | sub immutable_metaclass { (shift)->{'$!immutable_metaclass'} } |
35 | sub metaclass { (shift)->{'$!metaclass'} } |
36 | sub options { (shift)->{'%!options'} } |
37 | |
38 | sub create_immutable_metaclass { |
39 | my $self = shift; |
40 | |
41 | # NOTE: |
0ac992ee |
42 | # The immutable version of the |
c23184fc |
43 | # metaclass is just a anon-class |
0ac992ee |
44 | # which shadows the methods |
c23184fc |
45 | # appropriately |
46 | $self->{'$!immutable_metaclass'} = Class::MOP::Class->create_anon_class( |
47 | superclasses => [ blessed($self->metaclass) ], |
48 | methods => $self->create_methods_for_immutable_metaclass, |
0ac992ee |
49 | ); |
c23184fc |
50 | } |
51 | |
d9586da2 |
52 | |
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53 | my %DEFAULT_METHODS = ( |
d9586da2 |
54 | # I don't really understand this, but removing it breaks tests (groditi) |
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55 | meta => sub { |
c23184fc |
56 | my $self = shift; |
0ac992ee |
57 | # if it is not blessed, then someone is asking |
127d39a7 |
58 | # for the meta of Class::MOP::Immutable |
c23184fc |
59 | return Class::MOP::Class->initialize($self) unless blessed($self); |
0ac992ee |
60 | # otherwise, they are asking for the metaclass |
c23184fc |
61 | # which has been made immutable, which is itself |
62 | return $self; |
63 | }, |
d9586da2 |
64 | is_mutable => sub { 0 }, |
65 | is_immutable => sub { 1 }, |
66 | make_immutable => sub { () }, |
c23184fc |
67 | ); |
68 | |
69 | # NOTE: |
0ac992ee |
70 | # this will actually convert the |
71 | # existing metaclass to an immutable |
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72 | # version of itself |
73 | sub make_metaclass_immutable { |
229910b5 |
74 | my ($self, $metaclass, $options) = @_; |
75 | |
76 | foreach my $pair ( |
77 | [ inline_accessors => 1 ], |
78 | [ inline_constructor => 1 ], |
79 | [ inline_destructor => 0 ], |
80 | [ constructor_name => 'new' ], |
81 | [ debug => 0 ], |
82 | ) { |
83 | $options->{$pair->[0]} = $pair->[1] unless exists $options->{$pair->[0]}; |
84 | } |
0ac992ee |
85 | |
229910b5 |
86 | my %options = %$options; |
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87 | |
c23184fc |
88 | if ($options{inline_accessors}) { |
89 | foreach my $attr_name ($metaclass->get_attribute_list) { |
90 | # inline the accessors |
91 | $metaclass->get_attribute($attr_name) |
0ac992ee |
92 | ->install_accessors(1); |
93 | } |
c23184fc |
94 | } |
95 | |
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96 | if ($options{inline_constructor}) { |
c23184fc |
97 | my $constructor_class = $options{constructor_class} || 'Class::MOP::Method::Constructor'; |
c23184fc |
98 | $metaclass->add_method( |
99 | $options{constructor_name}, |
100 | $constructor_class->new( |
0ac992ee |
101 | options => \%options, |
102 | metaclass => $metaclass, |
565f0cbb |
103 | is_inline => 1, |
c23184fc |
104 | ) |
105 | ) unless $metaclass->has_method($options{constructor_name}); |
0ac992ee |
106 | } |
107 | |
108 | if ($options{inline_destructor}) { |
c23184fc |
109 | (exists $options{destructor_class}) |
110 | || confess "The 'inline_destructor' option is present, but " |
111 | . "no destructor class was specified"; |
0ac992ee |
112 | |
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113 | my $destructor_class = $options{destructor_class}; |
0ac992ee |
114 | |
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115 | my $destructor = $destructor_class->new( |
116 | options => \%options, |
117 | metaclass => $metaclass, |
118 | ); |
0ac992ee |
119 | |
120 | $metaclass->add_method('DESTROY' => $destructor) |
c23184fc |
121 | # NOTE: |
0ac992ee |
122 | # we allow the destructor to determine |
c23184fc |
123 | # if it is needed or not, it can perform |
0ac992ee |
124 | # all sorts of checks because it has the |
125 | # metaclass instance |
c23184fc |
126 | if $destructor->is_needed; |
0ac992ee |
127 | } |
128 | |
c23184fc |
129 | my $memoized_methods = $self->options->{memoize}; |
130 | foreach my $method_name (keys %{$memoized_methods}) { |
131 | my $type = $memoized_methods->{$method_name}; |
0ac992ee |
132 | |
c23184fc |
133 | ($metaclass->can($method_name)) |
0ac992ee |
134 | || confess "Could not find the method '$method_name' in " . $metaclass->name; |
135 | |
c23184fc |
136 | if ($type eq 'ARRAY') { |
137 | $metaclass->{'___' . $method_name} = [ $metaclass->$method_name ]; |
138 | } |
139 | elsif ($type eq 'HASH') { |
0ac992ee |
140 | $metaclass->{'___' . $method_name} = { $metaclass->$method_name }; |
c23184fc |
141 | } |
142 | elsif ($type eq 'SCALAR') { |
143 | $metaclass->{'___' . $method_name} = $metaclass->$method_name; |
144 | } |
0ac992ee |
145 | } |
146 | |
0ac992ee |
147 | $metaclass->{'___original_class'} = blessed($metaclass); |
c23184fc |
148 | bless $metaclass => $self->immutable_metaclass->name; |
149 | } |
150 | |
0ac992ee |
151 | sub make_metaclass_mutable { |
229910b5 |
152 | my ($self, $immutable, $options) = @_; |
153 | |
154 | my %options = %$options; |
0ac992ee |
155 | |
156 | my $original_class = $immutable->get_mutable_metaclass_name; |
157 | delete $immutable->{'___original_class'} ; |
158 | bless $immutable => $original_class; |
159 | |
160 | my $memoized_methods = $self->options->{memoize}; |
161 | foreach my $method_name (keys %{$memoized_methods}) { |
162 | my $type = $memoized_methods->{$method_name}; |
163 | |
164 | ($immutable->can($method_name)) |
165 | || confess "Could not find the method '$method_name' in " . $immutable->name; |
166 | if ($type eq 'SCALAR' || $type eq 'ARRAY' || $type eq 'HASH' ) { |
167 | delete $immutable->{'___' . $method_name}; |
168 | } |
169 | } |
170 | |
171 | if ($options{inline_destructor} && $immutable->has_method('DESTROY')) { |
172 | $immutable->remove_method('DESTROY') |
173 | if $immutable->get_method('DESTROY')->blessed eq $options{destructor_class}; |
174 | } |
175 | |
b817e248 |
176 | # NOTE: |
177 | # 14:01 <@stevan> nah,. you shouldnt |
178 | # 14:01 <@stevan> they are just inlined |
179 | # 14:01 <@stevan> which is the default in Moose anyway |
180 | # 14:02 <@stevan> and adding new attributes will just DWIM |
181 | # 14:02 <@stevan> and you really cant change an attribute anyway |
182 | # if ($options{inline_accessors}) { |
183 | # foreach my $attr_name ($immutable->get_attribute_list) { |
184 | # my $attr = $immutable->get_attribute($attr_name); |
185 | # $attr->remove_accessors; |
186 | # $attr->install_accessors(0); |
187 | # } |
188 | # } |
189 | |
190 | # 14:26 <@stevan> the only user of ::Method::Constructor is immutable |
191 | # 14:27 <@stevan> if someone uses it outside of immutable,.. they are either: mst or groditi |
192 | # 14:27 <@stevan> so I am not worried |
0ac992ee |
193 | if ($options{inline_constructor}) { |
194 | my $constructor_class = $options{constructor_class} || 'Class::MOP::Method::Constructor'; |
195 | $immutable->remove_method( $options{constructor_name} ) |
196 | if $immutable->get_method($options{constructor_name})->blessed eq $constructor_class; |
197 | } |
198 | } |
199 | |
c23184fc |
200 | sub create_methods_for_immutable_metaclass { |
201 | my $self = shift; |
0ac992ee |
202 | |
c23184fc |
203 | my %methods = %DEFAULT_METHODS; |
0ac992ee |
204 | |
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205 | foreach my $read_only_method (@{$self->options->{read_only}}) { |
206 | my $method = $self->metaclass->meta->find_method_by_name($read_only_method); |
0ac992ee |
207 | |
c23184fc |
208 | (defined $method) |
209 | || confess "Could not find the method '$read_only_method' in " . $self->metaclass->name; |
0ac992ee |
210 | |
c23184fc |
211 | $methods{$read_only_method} = sub { |
212 | confess "This method is read-only" if scalar @_ > 1; |
213 | goto &{$method->body} |
214 | }; |
215 | } |
0ac992ee |
216 | |
c23184fc |
217 | foreach my $cannot_call_method (@{$self->options->{cannot_call}}) { |
218 | $methods{$cannot_call_method} = sub { |
219 | confess "This method ($cannot_call_method) cannot be called on an immutable instance"; |
220 | }; |
0ac992ee |
221 | } |
222 | |
c23184fc |
223 | my $memoized_methods = $self->options->{memoize}; |
c23184fc |
224 | foreach my $method_name (keys %{$memoized_methods}) { |
225 | my $type = $memoized_methods->{$method_name}; |
226 | if ($type eq 'ARRAY') { |
227 | $methods{$method_name} = sub { @{$_[0]->{'___' . $method_name}} }; |
228 | } |
229 | elsif ($type eq 'HASH') { |
230 | $methods{$method_name} = sub { %{$_[0]->{'___' . $method_name}} }; |
231 | } |
232 | elsif ($type eq 'SCALAR') { |
233 | $methods{$method_name} = sub { $_[0]->{'___' . $method_name} }; |
0ac992ee |
234 | } |
235 | } |
236 | |
237 | $methods{get_mutable_metaclass_name} = sub { (shift)->{'___original_class'} }; |
238 | |
9f3ff885 |
239 | $methods{immutable_transformer} = sub { $self }; |
240 | |
c23184fc |
241 | return \%methods; |
242 | } |
243 | |
244 | 1; |
245 | |
246 | __END__ |
247 | |
248 | =pod |
249 | |
0ac992ee |
250 | =head1 NAME |
c23184fc |
251 | |
252 | Class::MOP::Immutable - A class to transform Class::MOP::Class metaclasses |
253 | |
254 | =head1 SYNOPSIS |
255 | |
96e38ba6 |
256 | use Class::MOP::Immutable; |
0ac992ee |
257 | |
96e38ba6 |
258 | my $immutable_metaclass = Class::MOP::Immutable->new($metaclass, { |
259 | read_only => [qw/superclasses/], |
260 | cannot_call => [qw/ |
261 | add_method |
262 | alias_method |
263 | remove_method |
264 | add_attribute |
265 | remove_attribute |
266 | add_package_symbol |
0ac992ee |
267 | remove_package_symbol |
96e38ba6 |
268 | /], |
269 | memoize => { |
270 | class_precedence_list => 'ARRAY', |
0ac992ee |
271 | compute_all_applicable_attributes => 'ARRAY', |
272 | get_meta_instance => 'SCALAR', |
273 | get_method_map => 'SCALAR', |
96e38ba6 |
274 | } |
0ac992ee |
275 | }); |
96e38ba6 |
276 | |
277 | $immutable_metaclass->make_metaclass_immutable(@_) |
278 | |
c23184fc |
279 | =head1 DESCRIPTION |
280 | |
0ac992ee |
281 | This is basically a module for applying a transformation on a given |
282 | metaclass. Current features include making methods read-only, |
96e38ba6 |
283 | making methods un-callable and memoizing methods (in a type specific |
0ac992ee |
284 | way too). |
96e38ba6 |
285 | |
127d39a7 |
286 | This module is not for the feint of heart, it does some whacky things |
287 | to the metaclass in order to make it immutable. If you are just curious, |
288 | I suggest you turn back now, there is nothing to see here. |
96e38ba6 |
289 | |
c23184fc |
290 | =head1 METHODS |
291 | |
292 | =over 4 |
293 | |
96e38ba6 |
294 | =item B<new ($metaclass, \%options)> |
295 | |
0ac992ee |
296 | Given a C<$metaclass> and a set of C<%options> this module will |
297 | prepare an immutable version of the C<$metaclass>, which can then |
298 | be applied to the C<$metaclass> using the C<make_metaclass_immutable> |
96e38ba6 |
299 | method. |
300 | |
c23184fc |
301 | =item B<options> |
302 | |
96e38ba6 |
303 | Returns the options HASH set in C<new>. |
304 | |
c23184fc |
305 | =item B<metaclass> |
306 | |
96e38ba6 |
307 | Returns the metaclass set in C<new>. |
308 | |
c23184fc |
309 | =item B<immutable_metaclass> |
310 | |
96e38ba6 |
311 | Returns the immutable metaclass created within C<new>. |
312 | |
c23184fc |
313 | =back |
314 | |
315 | =over 4 |
316 | |
317 | =item B<create_immutable_metaclass> |
318 | |
0ac992ee |
319 | This will create the immutable version of the C<$metaclass>, but will |
320 | not actually change the original metaclass. |
96e38ba6 |
321 | |
c23184fc |
322 | =item B<create_methods_for_immutable_metaclass> |
323 | |
0ac992ee |
324 | This will create all the methods for the immutable metaclass based |
96e38ba6 |
325 | on the C<%options> passed into C<new>. |
326 | |
0ac992ee |
327 | =item B<make_metaclass_immutable (%options)> |
c23184fc |
328 | |
96e38ba6 |
329 | This will actually change the C<$metaclass> into the immutable version. |
330 | |
0ac992ee |
331 | =item B<make_metaclass_mutable (%options)> |
332 | |
333 | This will change the C<$metaclass> into the mutable version by reversing |
334 | the immutable process. C<%options> should be the same options that were |
335 | given to make_metaclass_immutable. |
336 | |
c23184fc |
337 | =back |
338 | |
339 | =head1 AUTHORS |
340 | |
341 | Stevan Little E<lt>stevan@iinteractive.comE<gt> |
342 | |
343 | =head1 COPYRIGHT AND LICENSE |
344 | |
69e3ab0a |
345 | Copyright 2006-2008 by Infinity Interactive, Inc. |
c23184fc |
346 | |
347 | L<http://www.iinteractive.com> |
348 | |
349 | This library is free software; you can redistribute it and/or modify |
0ac992ee |
350 | it under the same terms as Perl itself. |
c23184fc |
351 | |
352 | =cut |