Checking in changes prior to tagging of version 0.40_09. Changelog diff is:
[gitmo/Mouse.git] / lib / Mouse / Meta / Attribute.pm
CommitLineData
306290e8 1package Mouse::Meta::Attribute;
bc69ee88 2use Mouse::Util qw(:meta); # enables strict and warnings
c3398f5b 3
2efc0af1 4use Carp ();
2efc0af1 5
684db121 6use Mouse::Meta::TypeConstraint;
d7d8d49b 7
8#use Mouse::Meta::Method::Accessor;
9use Mouse::Meta::Method::Delegation;
c3398f5b 10
4ab51fb0 11
87ca293b 12sub _process_options{
13 my($class, $name, $args) = @_;
c3398f5b 14
04493075 15
16 # XXX: for backward compatibility (with method modifiers)
17 if($class->can('canonicalize_args') != \&canonicalize_args){
18 %{$args} = $class->canonicalize_args($name, %{$args});
19 }
20
2efc0af1 21 # taken from Class::MOP::Attribute::new
22
23 defined($name)
24 or $class->throw_error('You must provide a name for the attribute');
2e7e86c6 25
1b9e472d 26 if(!exists $args->{init_arg}){
27 $args->{init_arg} = $name;
2efc0af1 28 }
29
30 # 'required' requires eigher 'init_arg', 'builder', or 'default'
1b9e472d 31 my $can_be_required = defined( $args->{init_arg} );
2efc0af1 32
1b9e472d 33 if(exists $args->{builder}){
c6d8f5ca 34 # XXX:
35 # Moose refuses a CODE ref builder, but Mouse doesn't for backward compatibility
36 # This feature will be changed in a future. (gfx)
121acb8a 37 $class->throw_error('builder must be a defined scalar value which is a method name')
c6d8f5ca 38 #if ref $args->{builder} || !defined $args->{builder};
39 if !defined $args->{builder};
2efc0af1 40
41 $can_be_required++;
42 }
1b9e472d 43 elsif(exists $args->{default}){
44 if(ref $args->{default} && ref($args->{default}) ne 'CODE'){
2efc0af1 45 $class->throw_error("References are not allowed as default values, you must "
46 . "wrap the default of '$name' in a CODE reference (ex: sub { [] } and not [])");
47 }
48 $can_be_required++;
49 }
50
1b9e472d 51 if( $args->{required} && !$can_be_required ) {
121acb8a 52 $class->throw_error("You cannot have a required attribute ($name) without a default, builder, or an init_arg");
2efc0af1 53 }
54
1b9e472d 55 # taken from Mouse::Meta::Attribute->new and _process_args->
2efc0af1 56
1b9e472d 57 if(exists $args->{is}){
58 my $is = $args->{is};
2efc0af1 59
60 if($is eq 'ro'){
1b9e472d 61 $args->{reader} ||= $name;
2efc0af1 62 }
63 elsif($is eq 'rw'){
1b9e472d 64 if(exists $args->{writer}){
65 $args->{reader} ||= $name;
2efc0af1 66 }
67 else{
1b9e472d 68 $args->{accessor} ||= $name;
2efc0af1 69 }
70 }
71 elsif($is eq 'bare'){
72 # do nothing, but don't complain (later) about missing methods
73 }
74 else{
75 $is = 'undef' if !defined $is;
76 $class->throw_error("I do not understand this option (is => $is) on attribute ($name)");
77 }
78 }
79
80 my $tc;
1b9e472d 81 if(exists $args->{isa}){
82 $args->{type_constraint} = Mouse::Util::TypeConstraints::find_or_create_isa_type_constraint($args->{isa});
2efc0af1 83 }
1b9e472d 84 elsif(exists $args->{does}){
9f74c401 85 $args->{type_constraint} = Mouse::Util::TypeConstraints::find_or_create_does_type_constraint($args->{does});
2efc0af1 86 }
1b9e472d 87 $tc = $args->{type_constraint};
2efc0af1 88
1b9e472d 89 if($args->{coerce}){
2efc0af1 90 defined($tc)
91 || $class->throw_error("You cannot have coercion without specifying a type constraint on attribute ($name)");
92
1b9e472d 93 $args->{weak_ref}
121acb8a 94 && $class->throw_error("You cannot have a weak reference to a coerced value on attribute ($name)");
2efc0af1 95 }
96
1b9e472d 97 if ($args->{lazy_build}) {
98 exists($args->{default})
121acb8a 99 && $class->throw_error("You can not use lazy_build and default for the same attribute ($name)");
100
1b9e472d 101 $args->{lazy} = 1;
102 $args->{builder} ||= "_build_${name}";
121acb8a 103 if ($name =~ /^_/) {
1b9e472d 104 $args->{clearer} ||= "_clear${name}";
105 $args->{predicate} ||= "_has${name}";
121acb8a 106 }
107 else {
1b9e472d 108 $args->{clearer} ||= "clear_${name}";
109 $args->{predicate} ||= "has_${name}";
121acb8a 110 }
2efc0af1 111 }
112
1b9e472d 113 if ($args->{auto_deref}) {
121acb8a 114 defined($tc)
115 || $class->throw_error("You cannot auto-dereference without specifying a type constraint on attribute ($name)");
2efc0af1 116
121acb8a 117 ( $tc->is_a_type_of('ArrayRef') || $tc->is_a_type_of('HashRef') )
118 || $class->throw_error("You cannot auto-dereference anything other than a ArrayRef or HashRef on attribute ($name)");
2efc0af1 119 }
120
1b9e472d 121 if (exists $args->{trigger}) {
122 ('CODE' eq ref $args->{trigger})
121acb8a 123 || $class->throw_error("Trigger must be a CODE ref on attribute ($name)");
2efc0af1 124 }
45959ffa 125
1b9e472d 126 if ($args->{lazy}) {
127 (exists $args->{default} || defined $args->{builder})
121acb8a 128 || $class->throw_error("You cannot have lazy attribute ($name) without specifying a default value for it");
2efc0af1 129 }
90fe520e 130
87ca293b 131 return;
132}
133
134sub new {
135 my $class = shift;
136 my $name = shift;
137
138 my %args = (@_ == 1) ? %{ $_[0] } : @_;
139
140 $class->_process_options($name, \%args);
141
142 $args{name} = $name;
143
926290ac 144 my $self = bless \%args, $class;
2efc0af1 145
1b9e472d 146 # extra attributes
147 if($class ne __PACKAGE__){
926290ac 148 $class->meta->_initialize_object($self, \%args);
90fe520e 149 }
c3398f5b 150
2efc0af1 151# XXX: there is no fast way to check attribute validity
1b9e472d 152# my @bad = ...;
2efc0af1 153# if(@bad){
154# @bad = sort @bad;
155# Carp::cluck("Found unknown argument(s) passed to '$name' attribute constructor in '$class': @bad");
156# }
157
926290ac 158 return $self;
c3398f5b 159}
160
43165725 161sub has_read_method { $_[0]->has_reader || $_[0]->has_accessor }
162sub has_write_method { $_[0]->has_writer || $_[0]->has_accessor }
1b9e472d 163
df77fd72 164sub _create_args { # DEPRECATED
1bfebf5f 165 $_[0]->{_create_args} = $_[1] if @_ > 1;
166 $_[0]->{_create_args}
167}
168
87ca293b 169sub interpolate_class{
8cf51b82 170 my($class, $args) = @_;
c3398f5b 171
1b9e472d 172 if(my $metaclass = delete $args->{metaclass}){
173 $class = Mouse::Util::resolve_metaclass_alias( Attribute => $metaclass );
174 }
1bfebf5f 175
87ca293b 176 my @traits;
1b9e472d 177 if(my $traits_ref = delete $args->{traits}){
87ca293b 178
f3f04eed 179 for (my $i = 0; $i < @{$traits_ref}; $i++) {
180 my $trait = Mouse::Util::resolve_metaclass_alias(Attribute => $traits_ref->[$i], trait => 1);
b2500191 181
f3f04eed 182 next if $class->does($trait);
74be9f76 183
f3f04eed 184 push @traits, $trait;
1b9e472d 185
f3f04eed 186 # are there options?
187 push @traits, $traits_ref->[++$i]
188 if ref($traits_ref->[$i+1]);
189 }
c3398f5b 190
1b9e472d 191 if (@traits) {
192 $class = Mouse::Meta::Class->create_anon_class(
193 superclasses => [ $class ],
194 roles => \@traits,
195 cache => 1,
196 )->name;
1b9e472d 197 }
74be9f76 198 }
199
87ca293b 200 return( $class, @traits );
1b9e472d 201}
202
df77fd72 203sub canonicalize_args{ # DEPRECATED
1b9e472d 204 my ($self, $name, %args) = @_;
205
206 Carp::cluck("$self->canonicalize_args has been deprecated."
04493075 207 . "Use \$self->_process_options instead.")
8aba926d 208 if Mouse::Util::_MOUSE_VERBOSE;
1b9e472d 209
210 return %args;
211}
212
ce5920b7 213sub create { # DEPRECATED
1b9e472d 214 my ($self, $class, $name, %args) = @_;
215
216 Carp::cluck("$self->create has been deprecated."
04493075 217 . "Use \$meta->add_attribute and \$attr->install_accessors instead.")
8aba926d 218 if Mouse::Util::_MOUSE_VERBOSE;
1b9e472d 219
220 # noop
221 return $self;
c3398f5b 222}
223
ffbbf459 224sub _coerce_and_verify {
225 my($self, $value, $instance) = @_;
226
227 my $type_constraint = $self->{type_constraint};
4331a3f9 228 return $value if !defined $type_constraint;
ffbbf459 229
230 if ($self->should_coerce && $type_constraint->has_coercion) {
231 $value = $type_constraint->coerce($value);
232 }
233
ffbbf459 234 $self->verify_against_type_constraint($value);
235
236 return $value;
237}
238
20e25eb9 239sub verify_against_type_constraint {
f55f60dd 240 my ($self, $value) = @_;
5aa30ced 241
ffbbf459 242 my $type_constraint = $self->{type_constraint};
4331a3f9 243 return 1 if !$type_constraint;
ffbbf459 244 return 1 if $type_constraint->check($value);
5aa30ced 245
ffbbf459 246 $self->verify_type_constraint_error($self->name, $value, $type_constraint);
b3b74cc6 247}
5aa30ced 248
b3b74cc6 249sub verify_type_constraint_error {
250 my($self, $name, $value, $type) = @_;
4331a3f9 251 $self->throw_error("Attribute ($name) does not pass the type constraint because: "
252 . $type->get_message($value));
5aa30ced 253}
254
df77fd72 255sub coerce_constraint { # DEPRECATED
8a7f2a8a 256 my $type = $_[0]->{type_constraint}
257 or return $_[1];
e763d56e 258
259 Carp::cluck("coerce_constraint() has been deprecated, which was an internal utility anyway");
260
7ca5c5fb 261 return Mouse::Util::TypeConstraints->typecast_constraints($_[0]->associated_class->name, $type, $_[1]);
4188b837 262}
263
1b9e472d 264sub clone_and_inherit_options{
8cf51b82 265 my($self, %args) = @_;
266
267 my($attribute_class, @traits) = ref($self)->interpolate_class(\%args);
1b9e472d 268
8cf51b82 269 $args{traits} = \@traits if @traits;
4f41d79b 270 # do not inherit the 'handles' attribute
271 foreach my $name(keys %{$self}){
272 if(!exists $args{$name} && $name ne 'handles'){
273 $args{$name} = $self->{$name};
274 }
275 }
276 return $attribute_class->new($self->name, %args);
1b9e472d 277}
278
df77fd72 279sub clone_parent { # DEPRECATED
1bfebf5f 280 my $self = shift;
281 my $class = shift;
282 my $name = shift;
283 my %args = ($self->get_parent_args($class, $name), @_);
284
1b9e472d 285 Carp::cluck("$self->clone_parent has been deprecated."
04493075 286 . "Use \$meta->add_attribute and \$attr->install_accessors instead.")
8aba926d 287 if Mouse::Util::_MOUSE_VERBOSE;
1b9e472d 288
7ca5c5fb 289 $self->clone_and_inherited_args($class, $name, %args);
1bfebf5f 290}
291
df77fd72 292sub get_parent_args { # DEPRECATED
1bfebf5f 293 my $self = shift;
294 my $class = shift;
295 my $name = shift;
296
724c77c0 297 for my $super ($class->linearized_isa) {
bb733405 298 my $super_attr = $super->can("meta") && $super->meta->get_attribute($name)
1bfebf5f 299 or next;
300 return %{ $super_attr->_create_args };
301 }
302
fce211ae 303 $self->throw_error("Could not find an attribute by the name of '$name' to inherit from");
304}
305
2a464664 306
0126c27c 307sub get_read_method {
43165725 308 $_[0]->reader || $_[0]->accessor
df77fd72 309}
0126c27c 310sub get_write_method {
43165725 311 $_[0]->writer || $_[0]->accessor
df77fd72 312}
2a464664 313
314sub get_read_method_ref{
315 my($self) = @_;
316
317 $self->{_read_method_ref} ||= do{
318 my $metaclass = $self->associated_class
319 or $self->throw_error('No asocciated class for ' . $self->name);
320
321 my $reader = $self->{reader} || $self->{accessor};
322 if($reader){
323 $metaclass->name->can($reader);
324 }
325 else{
4ab51fb0 326 $self->accessor_metaclass->_generate_reader($self, $metaclass);
2a464664 327 }
328 };
329}
330
331sub get_write_method_ref{
332 my($self) = @_;
333
334 $self->{_write_method_ref} ||= do{
335 my $metaclass = $self->associated_class
336 or $self->throw_error('No asocciated class for ' . $self->name);
337
338 my $reader = $self->{writer} || $self->{accessor};
339 if($reader){
340 $metaclass->name->can($reader);
341 }
342 else{
4ab51fb0 343 $self->accessor_metaclass->_generate_writer($self, $metaclass);
2a464664 344 }
345 };
346}
347
4ab51fb0 348sub _canonicalize_handles {
349 my($self, $handles) = @_;
350
351 if (ref($handles) eq 'HASH') {
352 return %$handles;
353 }
354 elsif (ref($handles) eq 'ARRAY') {
355 return map { $_ => $_ } @$handles;
356 }
9ae9702e 357 elsif (ref($handles) eq 'Regexp') {
358 my $class_or_role = ($self->{isa} || $self->{does})
359 || $self->throw_error("Cannot delegate methods based on a Regexp without a type constraint (isa)");
360
361 my $meta = Mouse::Meta::Class->initialize("$class_or_role"); # "" for stringify
362 return map { $_ => $_ }
007481ba 363 grep { !Mouse::Object->can($_) && $_ =~ $handles }
f48920c1 364 Mouse::Util::is_a_metarole($meta)
745220df 365 ? $meta->get_method_list
366 : $meta->get_all_method_names;
9ae9702e 367 }
4ab51fb0 368 else {
369 $self->throw_error("Unable to canonicalize the 'handles' option with $handles");
370 }
371}
372
04493075 373sub associate_method{
e5e22afd 374 my ($attribute, $method_name) = @_;
04493075 375 $attribute->{associated_methods}++;
376 return;
377}
378
d7d8d49b 379
380sub delegation_metaclass() { 'Mouse::Meta::Method::Delegation' }
381
1b9e472d 382sub install_accessors{
383 my($attribute) = @_;
384
93540011 385 my $metaclass = $attribute->associated_class;
4ab51fb0 386 my $accessor_class = $attribute->accessor_metaclass;
1b9e472d 387
4ab51fb0 388 foreach my $type(qw(accessor reader writer predicate clearer)){
1b9e472d 389 if(exists $attribute->{$type}){
4ab51fb0 390 my $generator = '_generate_' . $type;
391 my $code = $accessor_class->$generator($attribute, $metaclass);
392 $metaclass->add_method($attribute->{$type} => $code);
e5e22afd 393 $attribute->associate_method($attribute->{$type});
4ab51fb0 394 }
395 }
7ca5c5fb 396
4ab51fb0 397 # install delegation
398 if(exists $attribute->{handles}){
d7d8d49b 399 my $delegation_class = $attribute->delegation_metaclass;
4ab51fb0 400 my %handles = $attribute->_canonicalize_handles($attribute->{handles});
401 my $reader = $attribute->get_read_method_ref;
7ca5c5fb 402
4ab51fb0 403 while(my($handle_name, $method_to_call) = each %handles){
d7d8d49b 404 my $code = $delegation_class->_generate_delegation($attribute, $metaclass,
4ab51fb0 405 $reader, $handle_name, $method_to_call);
406
407 $metaclass->add_method($handle_name => $code);
e5e22afd 408 $attribute->associate_method($handle_name);
1b9e472d 409 }
410 }
411
4ab51fb0 412
1b9e472d 413 if($attribute->can('create') != \&create){
7ca5c5fb 414 # backword compatibility
1b9e472d 415 $attribute->create($metaclass, $attribute->name, %{$attribute});
416 }
417
418 return;
419}
420
fce211ae 421sub throw_error{
422 my $self = shift;
423
424 my $metaclass = (ref $self && $self->associated_class) || 'Mouse::Meta::Class';
425 $metaclass->throw_error(@_, depth => 1);
1bfebf5f 426}
427
c3398f5b 4281;
429
430__END__
431
432=head1 NAME
433
bedd575c 434Mouse::Meta::Attribute - The Mouse attribute metaclass
c3398f5b 435
a25ca8d6 436=head1 VERSION
437
506fb74d 438This document describes Mouse version 0.40_09
a25ca8d6 439
c3398f5b 440=head1 METHODS
441
1820fffe 442=head2 C<< new(%options) -> Mouse::Meta::Attribute >>
c3398f5b 443
306290e8 444Instantiates a new Mouse::Meta::Attribute. Does nothing else.
c3398f5b 445
1820fffe 446It adds the following options to the constructor:
c3398f5b 447
1820fffe 448=over 4
c3398f5b 449
612d3e1a 450=item C<< is => 'ro', 'rw', 'bare' >>
c3398f5b 451
1820fffe 452This provides a shorthand for specifying the C<reader>, C<writer>, or
453C<accessor> names. If the attribute is read-only ('ro') then it will
454have a C<reader> method with the same attribute as the name.
c3398f5b 455
1820fffe 456If it is read-write ('rw') then it will have an C<accessor> method
457with the same name. If you provide an explicit C<writer> for a
458read-write attribute, then you will have a C<reader> with the same
459name as the attribute, and a C<writer> with the name you provided.
c3398f5b 460
1820fffe 461Use 'bare' when you are deliberately not installing any methods
462(accessor, reader, etc.) associated with this attribute; otherwise,
463Moose will issue a deprecation warning when this attribute is added to a
464metaclass.
c3398f5b 465
612d3e1a 466=item C<< isa => Type >>
ab27a55e 467
1820fffe 468This option accepts a type. The type can be a string, which should be
469a type name. If the type name is unknown, it is assumed to be a class
470name.
ab27a55e 471
1820fffe 472This option can also accept a L<Moose::Meta::TypeConstraint> object.
ab27a55e 473
1820fffe 474If you I<also> provide a C<does> option, then your C<isa> option must
475be a class name, and that class must do the role specified with
476C<does>.
ab27a55e 477
612d3e1a 478=item C<< does => Role >>
ab27a55e 479
1820fffe 480This is short-hand for saying that the attribute's type must be an
481object which does the named role.
c3398f5b 482
1820fffe 483B<This option is not yet supported.>
c3398f5b 484
612d3e1a 485=item C<< coerce => Bool >>
ab27a55e 486
1820fffe 487This option is only valid for objects with a type constraint
488(C<isa>). If this is true, then coercions will be applied whenever
489this attribute is set.
c3398f5b 490
1820fffe 491You can make both this and the C<weak_ref> option true.
c3398f5b 492
612d3e1a 493=item C<< trigger => CodeRef >>
ab27a55e 494
1820fffe 495This option accepts a subroutine reference, which will be called after
496the attribute is set.
ab27a55e 497
612d3e1a 498=item C<< required => Bool >>
ab27a55e 499
1820fffe 500An attribute which is required must be provided to the constructor. An
501attribute which is required can also have a C<default> or C<builder>,
502which will satisfy its required-ness.
ab27a55e 503
1820fffe 504A required attribute must have a C<default>, C<builder> or a
505non-C<undef> C<init_arg>
ab27a55e 506
612d3e1a 507=item C<< lazy => Bool >>
ab27a55e 508
1820fffe 509A lazy attribute must have a C<default> or C<builder>. When an
510attribute is lazy, the default value will not be calculated until the
511attribute is read.
93f08899 512
612d3e1a 513=item C<< weak_ref => Bool >>
0fff36e6 514
1820fffe 515If this is true, the attribute's value will be stored as a weak
516reference.
c3398f5b 517
612d3e1a 518=item C<< auto_deref => Bool >>
fb706f5c 519
1820fffe 520If this is true, then the reader will dereference the value when it is
521called. The attribute must have a type constraint which defines the
522attribute as an array or hash reference.
523
612d3e1a 524=item C<< lazy_build => Bool >>
1820fffe 525
526Setting this to true makes the attribute lazy and provides a number of
527default methods.
fb706f5c 528
1820fffe 529 has 'size' => (
530 is => 'ro',
531 lazy_build => 1,
532 );
93d190e0 533
1820fffe 534is equivalent to this:
93d190e0 535
1820fffe 536 has 'size' => (
537 is => 'ro',
538 lazy => 1,
539 builder => '_build_size',
540 clearer => 'clear_size',
541 predicate => 'has_size',
542 );
93d190e0 543
1820fffe 544=back
545
e5e22afd 546=head2 C<< associate_method(MethodName) >>
31c5194b 547
548Associates a method with the attribute. Typically, this is called internally
549when an attribute generates its accessors.
550
e5e22afd 551Currently the argument I<MethodName> is ignored in Mouse.
31c5194b 552
1820fffe 553=head2 C<< verify_against_type_constraint(Item) -> TRUE | ERROR >>
554
555Checks that the given value passes this attribute's type constraint. Returns C<true>
556on success, otherwise C<confess>es.
93d190e0 557
1820fffe 558=head2 C<< clone_and_inherit_options(options) -> Mouse::Meta::Attribute >>
f7b11a21 559
612d3e1a 560Creates a new attribute in the owner class, inheriting options from parent classes.
f7b11a21 561Accessors and helper methods are installed. Some error checking is done.
562
9ae9702e 563=head2 C<< get_read_method_ref >>
564
565=head2 C<< get_write_method_ref >>
566
567Returns the subroutine reference of a method suitable for reading or
568writing the attribute's value in the associated class. These methods
569always return a subroutine reference, regardless of whether or not the
df77fd72 570attribute is read- or write-only.
571
1820fffe 572=head1 SEE ALSO
f7b11a21 573
1820fffe 574L<Moose::Meta::Attribute>
f7b11a21 575
31c5194b 576L<Class::MOP::Attribute>
577
c3398f5b 578=cut
579