2 package Class::MOP::Immutable;
7 use Class::MOP::Method::Constructor;
10 use Scalar::Util 'blessed';
12 our $VERSION = '0.71';
13 $VERSION = eval $VERSION;
14 our $AUTHORITY = 'cpan:STEVAN';
16 use base 'Class::MOP::Object';
19 my ($class, @args) = @_;
21 my ( $metaclass, $options );
25 ( $metaclass, $options ) = @args;
27 unshift @args, "metaclass" if @args % 2 == 1;
32 $metaclass = $options{metaclass};
35 my $self = $class->_new(
36 'metaclass' => $metaclass,
37 'options' => $options,
38 'immutable_metaclass' => undef,
46 my $options = @_ == 1 ? $_[0] : {@_};
48 bless $options, $class;
51 sub immutable_metaclass {
54 $self->create_immutable_metaclass unless $self->{'immutable_metaclass'};
56 return $self->{'immutable_metaclass'};
59 sub metaclass { (shift)->{'metaclass'} }
60 sub options { (shift)->{'options'} }
62 sub create_immutable_metaclass {
66 # The immutable version of the
67 # metaclass is just a anon-class
68 # which shadows the methods
70 $self->{'immutable_metaclass'} = Class::MOP::Class->create_anon_class(
71 superclasses => [ blessed($self->metaclass) ],
72 methods => $self->create_methods_for_immutable_metaclass,
77 my %DEFAULT_METHODS = (
78 # I don't really understand this, but removing it breaks tests (groditi)
81 # if it is not blessed, then someone is asking
82 # for the meta of Class::MOP::Immutable
83 return Class::MOP::Class->initialize($self) unless blessed($self);
84 # otherwise, they are asking for the metaclass
85 # which has been made immutable, which is itself
86 # except in the cases where it is a metaclass itself
87 # that has been made immutable and for that we need
89 if ($self->isa('Class::MOP::Class')) {
90 return $self->{'___original_class'}->meta;
96 is_mutable => sub { 0 },
97 is_immutable => sub { 1 },
98 make_immutable => sub { () },
102 # this will actually convert the
103 # existing metaclass to an immutable
105 sub make_metaclass_immutable {
106 my ($self, $metaclass, $options) = @_;
109 inline_accessors => 1,
110 inline_constructor => 1,
111 inline_destructor => 0,
112 constructor_name => 'new',
117 %$options = %options; # FIXME who the hell is relying on this?!? tests fail =(
119 if ($options{inline_accessors}) {
120 foreach my $attr_name ($metaclass->get_attribute_list) {
121 # inline the accessors
122 $metaclass->get_attribute($attr_name)
123 ->install_accessors(1);
127 if ($options{inline_constructor}) {
128 my $constructor_class = $options{constructor_class} || 'Class::MOP::Method::Constructor';
129 $metaclass->add_method(
130 $options{constructor_name},
131 $constructor_class->new(
132 options => \%options,
133 metaclass => $metaclass,
135 package_name => $metaclass->name,
136 name => $options{constructor_name}
138 ) if $options{replace_constructor} or !$metaclass->has_method($options{constructor_name});
141 if ($options{inline_destructor}) {
142 (exists $options{destructor_class})
143 || confess "The 'inline_destructor' option is present, but "
144 . "no destructor class was specified";
146 my $destructor_class = $options{destructor_class};
149 # we allow the destructor to determine
150 # if it is needed or not before we actually
151 # create the destructor too
153 if ($destructor_class->is_needed($metaclass)) {
154 my $destructor = $destructor_class->new(
155 options => \%options,
156 metaclass => $metaclass,
157 package_name => $metaclass->name,
161 $metaclass->add_method('DESTROY' => $destructor)
163 # we allow the destructor to determine
164 # if it is needed or not, it can perform
165 # all sorts of checks because it has the
167 if $destructor->is_needed;
171 my $memoized_methods = $self->options->{memoize};
172 foreach my $method_name (keys %{$memoized_methods}) {
173 my $type = $memoized_methods->{$method_name};
175 ($metaclass->can($method_name))
176 || confess "Could not find the method '$method_name' in " . $metaclass->name;
178 if ($type eq 'ARRAY') {
179 $metaclass->{'___' . $method_name} = [ $metaclass->$method_name ];
181 elsif ($type eq 'HASH') {
182 $metaclass->{'___' . $method_name} = { $metaclass->$method_name };
184 elsif ($type eq 'SCALAR') {
185 $metaclass->{'___' . $method_name} = $metaclass->$method_name;
189 $metaclass->{'___original_class'} = blessed($metaclass);
190 bless $metaclass => $self->immutable_metaclass->name;
193 sub make_metaclass_mutable {
194 my ($self, $immutable, $options) = @_;
196 my %options = %$options;
198 my $original_class = $immutable->get_mutable_metaclass_name;
199 delete $immutable->{'___original_class'} ;
200 bless $immutable => $original_class;
202 my $memoized_methods = $self->options->{memoize};
203 foreach my $method_name (keys %{$memoized_methods}) {
204 my $type = $memoized_methods->{$method_name};
206 ($immutable->can($method_name))
207 || confess "Could not find the method '$method_name' in " . $immutable->name;
208 if ($type eq 'SCALAR' || $type eq 'ARRAY' || $type eq 'HASH' ) {
209 delete $immutable->{'___' . $method_name};
213 if ($options{inline_destructor} && $immutable->has_method('DESTROY')) {
214 $immutable->remove_method('DESTROY')
215 if blessed($immutable->get_method('DESTROY')) eq $options{destructor_class};
219 # 14:01 <@stevan> nah,. you shouldnt
220 # 14:01 <@stevan> they are just inlined
221 # 14:01 <@stevan> which is the default in Moose anyway
222 # 14:02 <@stevan> and adding new attributes will just DWIM
223 # 14:02 <@stevan> and you really cant change an attribute anyway
224 # if ($options{inline_accessors}) {
225 # foreach my $attr_name ($immutable->get_attribute_list) {
226 # my $attr = $immutable->get_attribute($attr_name);
227 # $attr->remove_accessors;
228 # $attr->install_accessors(0);
232 # 14:26 <@stevan> the only user of ::Method::Constructor is immutable
233 # 14:27 <@stevan> if someone uses it outside of immutable,.. they are either: mst or groditi
234 # 14:27 <@stevan> so I am not worried
235 if ($options{inline_constructor} && $immutable->has_method($options{constructor_name})) {
236 my $constructor_class = $options{constructor_class} || 'Class::MOP::Method::Constructor';
237 $immutable->remove_method( $options{constructor_name} )
238 if blessed($immutable->get_method($options{constructor_name})) eq $constructor_class;
242 sub create_methods_for_immutable_metaclass {
245 my %methods = %DEFAULT_METHODS;
247 foreach my $read_only_method (@{$self->options->{read_only}}) {
248 my $method = $self->metaclass->meta->find_method_by_name($read_only_method);
251 || confess "Could not find the method '$read_only_method' in " . $self->metaclass->name;
253 $methods{$read_only_method} = sub {
254 confess "This method is read-only" if scalar @_ > 1;
255 goto &{$method->body}
259 foreach my $cannot_call_method (@{$self->options->{cannot_call}}) {
260 $methods{$cannot_call_method} = sub {
261 confess "This method ($cannot_call_method) cannot be called on an immutable instance";
265 my $memoized_methods = $self->options->{memoize};
266 foreach my $method_name (keys %{$memoized_methods}) {
267 my $type = $memoized_methods->{$method_name};
268 if ($type eq 'ARRAY') {
269 $methods{$method_name} = sub { @{$_[0]->{'___' . $method_name}} };
271 elsif ($type eq 'HASH') {
272 $methods{$method_name} = sub { %{$_[0]->{'___' . $method_name}} };
274 elsif ($type eq 'SCALAR') {
275 $methods{$method_name} = sub { $_[0]->{'___' . $method_name} };
279 my $wrapped_methods = $self->options->{wrapped};
281 foreach my $method_name (keys %{ $wrapped_methods }) {
282 my $method = $self->metaclass->meta->find_method_by_name($method_name);
285 || confess "Could not find the method '$method_name' in " . $self->metaclass->name;
287 my $wrapper = $wrapped_methods->{$method_name};
289 $methods{$method_name} = sub { $wrapper->($method, @_) };
292 $methods{get_mutable_metaclass_name} = sub { (shift)->{'___original_class'} };
294 $methods{immutable_transformer} = sub { $self };
307 Class::MOP::Immutable - A class to transform Class::MOP::Class metaclasses
311 use Class::MOP::Immutable;
313 my $immutable_metaclass = Class::MOP::Immutable->new($metaclass, {
314 read_only => [qw/superclasses/],
322 remove_package_symbol
325 class_precedence_list => 'ARRAY',
326 compute_all_applicable_attributes => 'ARRAY',
327 get_meta_instance => 'SCALAR',
328 get_method_map => 'SCALAR',
332 $immutable_metaclass->make_metaclass_immutable(@_)
336 This is basically a module for applying a transformation on a given
337 metaclass. Current features include making methods read-only,
338 making methods un-callable and memoizing methods (in a type specific
341 This module is not for the feint of heart, it does some whacky things
342 to the metaclass in order to make it immutable. If you are just curious,
343 I suggest you turn back now, there is nothing to see here.
349 =item B<new ($metaclass, \%options)>
351 Given a C<$metaclass> and a set of C<%options> this module will
352 prepare an immutable version of the C<$metaclass>, which can then
353 be applied to the C<$metaclass> using the C<make_metaclass_immutable>
358 Returns the options HASH set in C<new>.
362 Returns the metaclass set in C<new>.
364 =item B<immutable_metaclass>
366 Returns the immutable metaclass created within C<new>.
372 =item B<create_immutable_metaclass>
374 This will create the immutable version of the C<$metaclass>, but will
375 not actually change the original metaclass.
377 =item B<create_methods_for_immutable_metaclass>
379 This will create all the methods for the immutable metaclass based
380 on the C<%options> passed into C<new>.
382 =item B<make_metaclass_immutable (%options)>
384 This will actually change the C<$metaclass> into the immutable version.
386 =item B<make_metaclass_mutable (%options)>
388 This will change the C<$metaclass> into the mutable version by reversing
389 the immutable process. C<%options> should be the same options that were
390 given to make_metaclass_immutable.
396 Stevan Little E<lt>stevan@iinteractive.comE<gt>
398 =head1 COPYRIGHT AND LICENSE
400 Copyright 2006-2008 by Infinity Interactive, Inc.
402 L<http://www.iinteractive.com>
404 This library is free software; you can redistribute it and/or modify
405 it under the same terms as Perl itself.