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 | |
b817e248 |
12 | our $VERSION = '0.02'; |
c23184fc |
13 | our $AUTHORITY = 'cpan:STEVAN'; |
14 | |
0ac992ee |
15 | sub new { |
c23184fc |
16 | my ($class, $metaclass, $options) = @_; |
0ac992ee |
17 | |
c23184fc |
18 | my $self = bless { |
19 | '$!metaclass' => $metaclass, |
20 | '%!options' => $options, |
21 | '$!immutable_metaclass' => undef, |
22 | } => $class; |
0ac992ee |
23 | |
c23184fc |
24 | # NOTE: |
0ac992ee |
25 | # we initialize the immutable |
c23184fc |
26 | # version of the metaclass here |
27 | $self->create_immutable_metaclass; |
0ac992ee |
28 | |
c23184fc |
29 | return $self; |
30 | } |
31 | |
32 | sub immutable_metaclass { (shift)->{'$!immutable_metaclass'} } |
33 | sub metaclass { (shift)->{'$!metaclass'} } |
34 | sub options { (shift)->{'%!options'} } |
35 | |
36 | sub create_immutable_metaclass { |
37 | my $self = shift; |
38 | |
39 | # NOTE: |
0ac992ee |
40 | # The immutable version of the |
c23184fc |
41 | # metaclass is just a anon-class |
0ac992ee |
42 | # which shadows the methods |
c23184fc |
43 | # appropriately |
44 | $self->{'$!immutable_metaclass'} = Class::MOP::Class->create_anon_class( |
45 | superclasses => [ blessed($self->metaclass) ], |
46 | methods => $self->create_methods_for_immutable_metaclass, |
0ac992ee |
47 | ); |
c23184fc |
48 | } |
49 | |
d9586da2 |
50 | |
c23184fc |
51 | my %DEFAULT_METHODS = ( |
d9586da2 |
52 | # I don't really understand this, but removing it breaks tests (groditi) |
0ac992ee |
53 | meta => sub { |
c23184fc |
54 | my $self = shift; |
0ac992ee |
55 | # if it is not blessed, then someone is asking |
c23184fc |
56 | # for the meta of Class::MOP::Class::Immutable |
57 | return Class::MOP::Class->initialize($self) unless blessed($self); |
0ac992ee |
58 | # otherwise, they are asking for the metaclass |
c23184fc |
59 | # which has been made immutable, which is itself |
60 | return $self; |
61 | }, |
d9586da2 |
62 | is_mutable => sub { 0 }, |
63 | is_immutable => sub { 1 }, |
64 | make_immutable => sub { () }, |
c23184fc |
65 | ); |
66 | |
67 | # NOTE: |
0ac992ee |
68 | # this will actually convert the |
69 | # existing metaclass to an immutable |
c23184fc |
70 | # version of itself |
71 | sub make_metaclass_immutable { |
72 | my ($self, $metaclass, %options) = @_; |
0ac992ee |
73 | |
c23184fc |
74 | $options{inline_accessors} = 1 unless exists $options{inline_accessors}; |
75 | $options{inline_constructor} = 1 unless exists $options{inline_constructor}; |
0ac992ee |
76 | $options{inline_destructor} = 0 unless exists $options{inline_destructor}; |
c23184fc |
77 | $options{constructor_name} = 'new' unless exists $options{constructor_name}; |
0ac992ee |
78 | $options{debug} = 0 unless exists $options{debug}; |
79 | |
c23184fc |
80 | if ($options{inline_accessors}) { |
81 | foreach my $attr_name ($metaclass->get_attribute_list) { |
82 | # inline the accessors |
83 | $metaclass->get_attribute($attr_name) |
0ac992ee |
84 | ->install_accessors(1); |
85 | } |
c23184fc |
86 | } |
87 | |
0ac992ee |
88 | if ($options{inline_constructor}) { |
c23184fc |
89 | my $constructor_class = $options{constructor_class} || 'Class::MOP::Method::Constructor'; |
c23184fc |
90 | $metaclass->add_method( |
91 | $options{constructor_name}, |
92 | $constructor_class->new( |
0ac992ee |
93 | options => \%options, |
94 | metaclass => $metaclass, |
565f0cbb |
95 | is_inline => 1, |
c23184fc |
96 | ) |
97 | ) unless $metaclass->has_method($options{constructor_name}); |
0ac992ee |
98 | } |
99 | |
100 | if ($options{inline_destructor}) { |
c23184fc |
101 | (exists $options{destructor_class}) |
102 | || confess "The 'inline_destructor' option is present, but " |
103 | . "no destructor class was specified"; |
0ac992ee |
104 | |
c23184fc |
105 | my $destructor_class = $options{destructor_class}; |
0ac992ee |
106 | |
c23184fc |
107 | my $destructor = $destructor_class->new( |
108 | options => \%options, |
109 | metaclass => $metaclass, |
110 | ); |
0ac992ee |
111 | |
112 | $metaclass->add_method('DESTROY' => $destructor) |
c23184fc |
113 | # NOTE: |
0ac992ee |
114 | # we allow the destructor to determine |
c23184fc |
115 | # if it is needed or not, it can perform |
0ac992ee |
116 | # all sorts of checks because it has the |
117 | # metaclass instance |
c23184fc |
118 | if $destructor->is_needed; |
0ac992ee |
119 | } |
120 | |
c23184fc |
121 | my $memoized_methods = $self->options->{memoize}; |
122 | foreach my $method_name (keys %{$memoized_methods}) { |
123 | my $type = $memoized_methods->{$method_name}; |
0ac992ee |
124 | |
c23184fc |
125 | ($metaclass->can($method_name)) |
0ac992ee |
126 | || confess "Could not find the method '$method_name' in " . $metaclass->name; |
127 | |
c23184fc |
128 | if ($type eq 'ARRAY') { |
129 | $metaclass->{'___' . $method_name} = [ $metaclass->$method_name ]; |
130 | } |
131 | elsif ($type eq 'HASH') { |
0ac992ee |
132 | $metaclass->{'___' . $method_name} = { $metaclass->$method_name }; |
c23184fc |
133 | } |
134 | elsif ($type eq 'SCALAR') { |
135 | $metaclass->{'___' . $method_name} = $metaclass->$method_name; |
136 | } |
0ac992ee |
137 | } |
138 | |
0ac992ee |
139 | $metaclass->{'___original_class'} = blessed($metaclass); |
c23184fc |
140 | bless $metaclass => $self->immutable_metaclass->name; |
141 | } |
142 | |
0ac992ee |
143 | sub make_metaclass_mutable { |
144 | my ($self, $immutable, %options) = @_; |
145 | |
146 | my $original_class = $immutable->get_mutable_metaclass_name; |
147 | delete $immutable->{'___original_class'} ; |
148 | bless $immutable => $original_class; |
149 | |
150 | my $memoized_methods = $self->options->{memoize}; |
151 | foreach my $method_name (keys %{$memoized_methods}) { |
152 | my $type = $memoized_methods->{$method_name}; |
153 | |
154 | ($immutable->can($method_name)) |
155 | || confess "Could not find the method '$method_name' in " . $immutable->name; |
156 | if ($type eq 'SCALAR' || $type eq 'ARRAY' || $type eq 'HASH' ) { |
157 | delete $immutable->{'___' . $method_name}; |
158 | } |
159 | } |
160 | |
161 | if ($options{inline_destructor} && $immutable->has_method('DESTROY')) { |
162 | $immutable->remove_method('DESTROY') |
163 | if $immutable->get_method('DESTROY')->blessed eq $options{destructor_class}; |
164 | } |
165 | |
b817e248 |
166 | # NOTE: |
167 | # 14:01 <@stevan> nah,. you shouldnt |
168 | # 14:01 <@stevan> they are just inlined |
169 | # 14:01 <@stevan> which is the default in Moose anyway |
170 | # 14:02 <@stevan> and adding new attributes will just DWIM |
171 | # 14:02 <@stevan> and you really cant change an attribute anyway |
172 | # if ($options{inline_accessors}) { |
173 | # foreach my $attr_name ($immutable->get_attribute_list) { |
174 | # my $attr = $immutable->get_attribute($attr_name); |
175 | # $attr->remove_accessors; |
176 | # $attr->install_accessors(0); |
177 | # } |
178 | # } |
179 | |
180 | # 14:26 <@stevan> the only user of ::Method::Constructor is immutable |
181 | # 14:27 <@stevan> if someone uses it outside of immutable,.. they are either: mst or groditi |
182 | # 14:27 <@stevan> so I am not worried |
0ac992ee |
183 | $options{constructor_name} = 'new' unless exists $options{constructor_name}; |
184 | if ($options{inline_constructor}) { |
185 | my $constructor_class = $options{constructor_class} || 'Class::MOP::Method::Constructor'; |
186 | $immutable->remove_method( $options{constructor_name} ) |
187 | if $immutable->get_method($options{constructor_name})->blessed eq $constructor_class; |
188 | } |
189 | } |
190 | |
c23184fc |
191 | sub create_methods_for_immutable_metaclass { |
192 | my $self = shift; |
0ac992ee |
193 | |
c23184fc |
194 | my %methods = %DEFAULT_METHODS; |
0ac992ee |
195 | |
c23184fc |
196 | foreach my $read_only_method (@{$self->options->{read_only}}) { |
197 | my $method = $self->metaclass->meta->find_method_by_name($read_only_method); |
0ac992ee |
198 | |
c23184fc |
199 | (defined $method) |
200 | || confess "Could not find the method '$read_only_method' in " . $self->metaclass->name; |
0ac992ee |
201 | |
c23184fc |
202 | $methods{$read_only_method} = sub { |
203 | confess "This method is read-only" if scalar @_ > 1; |
204 | goto &{$method->body} |
205 | }; |
206 | } |
0ac992ee |
207 | |
c23184fc |
208 | foreach my $cannot_call_method (@{$self->options->{cannot_call}}) { |
209 | $methods{$cannot_call_method} = sub { |
210 | confess "This method ($cannot_call_method) cannot be called on an immutable instance"; |
211 | }; |
0ac992ee |
212 | } |
213 | |
c23184fc |
214 | my $memoized_methods = $self->options->{memoize}; |
c23184fc |
215 | foreach my $method_name (keys %{$memoized_methods}) { |
216 | my $type = $memoized_methods->{$method_name}; |
217 | if ($type eq 'ARRAY') { |
218 | $methods{$method_name} = sub { @{$_[0]->{'___' . $method_name}} }; |
219 | } |
220 | elsif ($type eq 'HASH') { |
221 | $methods{$method_name} = sub { %{$_[0]->{'___' . $method_name}} }; |
222 | } |
223 | elsif ($type eq 'SCALAR') { |
224 | $methods{$method_name} = sub { $_[0]->{'___' . $method_name} }; |
0ac992ee |
225 | } |
226 | } |
227 | |
228 | $methods{get_mutable_metaclass_name} = sub { (shift)->{'___original_class'} }; |
229 | |
c23184fc |
230 | return \%methods; |
231 | } |
232 | |
233 | 1; |
234 | |
235 | __END__ |
236 | |
237 | =pod |
238 | |
0ac992ee |
239 | =head1 NAME |
c23184fc |
240 | |
241 | Class::MOP::Immutable - A class to transform Class::MOP::Class metaclasses |
242 | |
243 | =head1 SYNOPSIS |
244 | |
96e38ba6 |
245 | use Class::MOP::Immutable; |
0ac992ee |
246 | |
96e38ba6 |
247 | my $immutable_metaclass = Class::MOP::Immutable->new($metaclass, { |
248 | read_only => [qw/superclasses/], |
249 | cannot_call => [qw/ |
250 | add_method |
251 | alias_method |
252 | remove_method |
253 | add_attribute |
254 | remove_attribute |
255 | add_package_symbol |
0ac992ee |
256 | remove_package_symbol |
96e38ba6 |
257 | /], |
258 | memoize => { |
259 | class_precedence_list => 'ARRAY', |
0ac992ee |
260 | compute_all_applicable_attributes => 'ARRAY', |
261 | get_meta_instance => 'SCALAR', |
262 | get_method_map => 'SCALAR', |
96e38ba6 |
263 | } |
0ac992ee |
264 | }); |
96e38ba6 |
265 | |
266 | $immutable_metaclass->make_metaclass_immutable(@_) |
267 | |
c23184fc |
268 | =head1 DESCRIPTION |
269 | |
0ac992ee |
270 | This is basically a module for applying a transformation on a given |
271 | metaclass. Current features include making methods read-only, |
96e38ba6 |
272 | making methods un-callable and memoizing methods (in a type specific |
0ac992ee |
273 | way too). |
96e38ba6 |
274 | |
0ac992ee |
275 | This module is fairly new to the MOP, and quite possibly will be |
96e38ba6 |
276 | expanded and further generalized as the need arises. |
277 | |
c23184fc |
278 | =head1 METHODS |
279 | |
280 | =over 4 |
281 | |
96e38ba6 |
282 | =item B<new ($metaclass, \%options)> |
283 | |
0ac992ee |
284 | Given a C<$metaclass> and a set of C<%options> this module will |
285 | prepare an immutable version of the C<$metaclass>, which can then |
286 | be applied to the C<$metaclass> using the C<make_metaclass_immutable> |
96e38ba6 |
287 | method. |
288 | |
c23184fc |
289 | =item B<options> |
290 | |
96e38ba6 |
291 | Returns the options HASH set in C<new>. |
292 | |
c23184fc |
293 | =item B<metaclass> |
294 | |
96e38ba6 |
295 | Returns the metaclass set in C<new>. |
296 | |
c23184fc |
297 | =item B<immutable_metaclass> |
298 | |
96e38ba6 |
299 | Returns the immutable metaclass created within C<new>. |
300 | |
c23184fc |
301 | =back |
302 | |
303 | =over 4 |
304 | |
305 | =item B<create_immutable_metaclass> |
306 | |
0ac992ee |
307 | This will create the immutable version of the C<$metaclass>, but will |
308 | not actually change the original metaclass. |
96e38ba6 |
309 | |
c23184fc |
310 | =item B<create_methods_for_immutable_metaclass> |
311 | |
0ac992ee |
312 | This will create all the methods for the immutable metaclass based |
96e38ba6 |
313 | on the C<%options> passed into C<new>. |
314 | |
0ac992ee |
315 | =item B<make_metaclass_immutable (%options)> |
c23184fc |
316 | |
96e38ba6 |
317 | This will actually change the C<$metaclass> into the immutable version. |
318 | |
0ac992ee |
319 | =item B<make_metaclass_mutable (%options)> |
320 | |
321 | This will change the C<$metaclass> into the mutable version by reversing |
322 | the immutable process. C<%options> should be the same options that were |
323 | given to make_metaclass_immutable. |
324 | |
c23184fc |
325 | =back |
326 | |
327 | =head1 AUTHORS |
328 | |
329 | Stevan Little E<lt>stevan@iinteractive.comE<gt> |
330 | |
331 | =head1 COPYRIGHT AND LICENSE |
332 | |
2367814a |
333 | Copyright 2006, 2007 by Infinity Interactive, Inc. |
c23184fc |
334 | |
335 | L<http://www.iinteractive.com> |
336 | |
337 | This library is free software; you can redistribute it and/or modify |
0ac992ee |
338 | it under the same terms as Perl itself. |
c23184fc |
339 | |
340 | =cut |