package Mouse::Meta::Attribute; use Mouse::Util qw(:meta); # enables strict and warnings use Carp (); use Mouse::Meta::TypeConstraint; my %valid_options = map { $_ => undef } ( 'accessor', 'auto_deref', 'builder', 'clearer', 'coerce', 'default', 'documentation', 'does', 'handles', 'init_arg', 'is', 'isa', 'lazy', 'lazy_build', 'name', 'predicate', 'reader', 'required', 'traits', 'trigger', 'type_constraint', 'weak_ref', 'writer', # internally used 'associated_class', 'associated_methods', # Moose defines, but Mouse doesn't #'definition_context', #'initializer', #'insertion_order', # special case for AttributeHelpers 'provides', 'curries', ); sub new { my $class = shift; my $name = shift; my $args = $class->Mouse::Object::BUILDARGS(@_); # XXX: for backward compatibility (with method modifiers) if($class->can('canonicalize_args') != \&canonicalize_args){ %{$args} = $class->canonicalize_args($name, %{$args}); } $class->_process_options($name, $args); $args->{name} = $name; # check options # (1) known by core my @bad = grep{ !exists $valid_options{$_} } keys %{$args}; # (2) known by subclasses if(@bad && $class ne __PACKAGE__){ my %valid_attrs = ( map { $_ => undef } grep { defined } map { $_->init_arg() } $class->meta->get_all_attributes() ); @bad = grep{ !exists $valid_attrs{$_} } @bad; } # (3) bad options found if(@bad){ @bad = sort @bad; Carp::cluck("Found unknown argument(s) passed to '$name' attribute constructor in '$class': @bad"); } my $self = bless $args, $class; # extra attributes if($class ne __PACKAGE__){ $class->meta->_initialize_object($self, $args); } return $self; } sub has_read_method { $_[0]->has_reader || $_[0]->has_accessor } sub has_write_method { $_[0]->has_writer || $_[0]->has_accessor } sub _create_args { # DEPRECATED $_[0]->{_create_args} = $_[1] if @_ > 1; $_[0]->{_create_args} } sub interpolate_class{ my($class, $args) = @_; if(my $metaclass = delete $args->{metaclass}){ $class = Mouse::Util::resolve_metaclass_alias( Attribute => $metaclass ); } my @traits; if(my $traits_ref = delete $args->{traits}){ for (my $i = 0; $i < @{$traits_ref}; $i++) { my $trait = Mouse::Util::resolve_metaclass_alias(Attribute => $traits_ref->[$i], trait => 1); next if $class->does($trait); push @traits, $trait; # are there options? push @traits, $traits_ref->[++$i] if ref($traits_ref->[$i+1]); } if (@traits) { $class = Mouse::Meta::Class->create_anon_class( superclasses => [ $class ], roles => \@traits, cache => 1, )->name; } } return( $class, @traits ); } sub canonicalize_args{ # DEPRECATED my ($self, $name, %args) = @_; Carp::cluck("$self->canonicalize_args has been deprecated." . "Use \$self->_process_options instead."); return %args; } sub create { # DEPRECATED my ($self, $class, $name, %args) = @_; Carp::cluck("$self->create has been deprecated." . "Use \$meta->add_attribute and \$attr->install_accessors instead."); # noop return $self; } sub _coerce_and_verify { my($self, $value, $instance) = @_; my $type_constraint = $self->{type_constraint}; return $value if !defined $type_constraint; if ($self->should_coerce && $type_constraint->has_coercion) { $value = $type_constraint->coerce($value); } $self->verify_against_type_constraint($value); return $value; } sub verify_against_type_constraint { my ($self, $value) = @_; my $type_constraint = $self->{type_constraint}; return 1 if !$type_constraint; return 1 if $type_constraint->check($value); $self->_throw_type_constraint_error($value, $type_constraint); } sub _throw_type_constraint_error { my($self, $value, $type) = @_; $self->throw_error( sprintf q{Attribute (%s) does not pass the type constraint because: %s}, $self->name, $type->get_message($value), ); } sub clone_and_inherit_options{ my $self = shift; my $args = $self->Mouse::Object::BUILDARGS(@_); my($attribute_class, @traits) = ref($self)->interpolate_class($args); $args->{traits} = \@traits if @traits; # do not inherit the 'handles' attribute foreach my $name(keys %{$self}){ if(!exists $args->{$name} && $name ne 'handles'){ $args->{$name} = $self->{$name}; } } # remove temporary caches foreach my $attr(keys %{$args}){ if($attr =~ /\A _/xms){ delete $args->{$attr}; } } return $attribute_class->new($self->name, $args); } sub clone_parent { # DEPRECATED my $self = shift; my $class = shift; my $name = shift; my %args = ($self->get_parent_args($class, $name), @_); Carp::cluck("$self->clone_parent has been deprecated." . "Use \$meta->add_attribute and \$attr->install_accessors instead."); $self->clone_and_inherited_args($class, $name, %args); } sub get_parent_args { # DEPRECATED my $self = shift; my $class = shift; my $name = shift; for my $super ($class->linearized_isa) { my $super_attr = $super->can("meta") && $super->meta->get_attribute($name) or next; return %{ $super_attr->_create_args }; } $self->throw_error("Could not find an attribute by the name of '$name' to inherit from"); } sub get_read_method { return $_[0]->reader || $_[0]->accessor } sub get_write_method { return $_[0]->writer || $_[0]->accessor } sub _get_accessor_method_ref { my($self, $type, $generator) = @_; my $metaclass = $self->associated_class || $self->throw_error('No asocciated class for ' . $self->name); my $accessor = $self->$type(); if($accessor){ return $metaclass->get_method_body($accessor); } else{ return $self->accessor_metaclass->$generator($self, $metaclass); } } sub get_read_method_ref{ my($self) = @_; return $self->{_read_method_ref} ||= $self->_get_accessor_method_ref('get_read_method', '_generate_reader'); } sub get_write_method_ref{ my($self) = @_; return $self->{_write_method_ref} ||= $self->_get_accessor_method_ref('get_write_method', '_generate_writer'); } sub set_value { my($self, $object, $value) = @_; return $self->get_write_method_ref()->($object, $value); } sub get_value { my($self, $object) = @_; return $self->get_read_method_ref()->($object); } sub has_value { my($self, $object) = @_; my $accessor_ref = $self->{_predicate_ref} ||= $self->_get_accessor_method_ref('predicate', '_generate_predicate'); return $accessor_ref->($object); } sub clear_value { my($self, $object) = @_; my $accessor_ref = $self->{_crealer_ref} ||= $self->_get_accessor_method_ref('clearer', '_generate_clearer'); return $accessor_ref->($object); } sub associate_method{ my ($attribute, $method_name) = @_; $attribute->{associated_methods}++; return; } sub install_accessors{ my($attribute) = @_; my $metaclass = $attribute->associated_class; my $accessor_class = $attribute->accessor_metaclass; foreach my $type(qw(accessor reader writer predicate clearer)){ if(exists $attribute->{$type}){ my $generator = '_generate_' . $type; my $code = $accessor_class->$generator($attribute, $metaclass); $metaclass->add_method($attribute->{$type} => $code); $attribute->associate_method($attribute->{$type}); } } # install delegation if(exists $attribute->{handles}){ my %handles = $attribute->_canonicalize_handles($attribute->{handles}); while(my($handle, $method_to_call) = each %handles){ $metaclass->add_method($handle => $attribute->_make_delegation_method( $handle, $method_to_call)); $attribute->associate_method($handle); } } if($attribute->can('create') != \&create){ # backword compatibility $attribute->create($metaclass, $attribute->name, %{$attribute}); } if(!$attribute->{associated_methods} && ($attribute->{is} || '') ne 'bare'){ Carp::cluck( 'Attribute (' . $attribute->name . ') of class ' . $metaclass->name . ' has no associated methods (did you mean to provide an "is" argument?)'); } return; } sub delegation_metaclass() { 'Mouse::Meta::Method::Delegation' } sub _canonicalize_handles { my($self, $handles) = @_; if (ref($handles) eq 'HASH') { return %$handles; } elsif (ref($handles) eq 'ARRAY') { return map { $_ => $_ } @$handles; } elsif ( ref($handles) eq 'CODE' ) { my $class_or_role = ( $self->{isa} || $self->{does} ) || $self->throw_error( "Cannot find delegate metaclass for attribute " . $self->name ); return $handles->( $self, Mouse::Meta::Class->initialize("$class_or_role")); } elsif (ref($handles) eq 'Regexp') { my $class_or_role = ($self->{isa} || $self->{does}) || $self->throw_error("Cannot delegate methods based on a Regexp without a type constraint (isa)"); my $meta = Mouse::Meta::Class->initialize("$class_or_role"); # "" for stringify return map { $_ => $_ } grep { !Mouse::Object->can($_) && $_ =~ $handles } Mouse::Util::is_a_metarole($meta) ? $meta->get_method_list : $meta->get_all_method_names; } else { $self->throw_error("Unable to canonicalize the 'handles' option with $handles"); } } sub _make_delegation_method { my($self, $handle, $method_to_call) = @_; return Mouse::Util::load_class($self->delegation_metaclass) ->_generate_delegation($self, $handle, $method_to_call); } sub throw_error{ my $self = shift; my $metaclass = (ref $self && $self->associated_class) || 'Mouse::Meta::Class'; $metaclass->throw_error(@_, depth => 1); } 1; __END__ =head1 NAME Mouse::Meta::Attribute - The Mouse attribute metaclass =head1 VERSION This document describes Mouse version 0.50_03 =head1 METHODS =head2 C<< new(%options) -> Mouse::Meta::Attribute >> Instantiates a new Mouse::Meta::Attribute. Does nothing else. It adds the following options to the constructor: =over 4 =item C<< is => 'ro', 'rw', 'bare' >> This provides a shorthand for specifying the C, C, or C names. If the attribute is read-only ('ro') then it will have a C method with the same attribute as the name. If it is read-write ('rw') then it will have an C method with the same name. If you provide an explicit C for a read-write attribute, then you will have a C with the same name as the attribute, and a C with the name you provided. Use 'bare' when you are deliberately not installing any methods (accessor, reader, etc.) associated with this attribute; otherwise, Moose will issue a deprecation warning when this attribute is added to a metaclass. =item C<< isa => Type >> This option accepts a type. The type can be a string, which should be a type name. If the type name is unknown, it is assumed to be a class name. This option can also accept a L object. If you I provide a C option, then your C option must be a class name, and that class must do the role specified with C. =item C<< does => Role >> This is short-hand for saying that the attribute's type must be an object which does the named role. B =item C<< coerce => Bool >> This option is only valid for objects with a type constraint (C). If this is true, then coercions will be applied whenever this attribute is set. You can make both this and the C option true. =item C<< trigger => CodeRef >> This option accepts a subroutine reference, which will be called after the attribute is set. =item C<< required => Bool >> An attribute which is required must be provided to the constructor. An attribute which is required can also have a C or C, which will satisfy its required-ness. A required attribute must have a C, C or a non-C C =item C<< lazy => Bool >> A lazy attribute must have a C or C. When an attribute is lazy, the default value will not be calculated until the attribute is read. =item C<< weak_ref => Bool >> If this is true, the attribute's value will be stored as a weak reference. =item C<< auto_deref => Bool >> If this is true, then the reader will dereference the value when it is called. The attribute must have a type constraint which defines the attribute as an array or hash reference. =item C<< lazy_build => Bool >> Setting this to true makes the attribute lazy and provides a number of default methods. has 'size' => ( is => 'ro', lazy_build => 1, ); is equivalent to this: has 'size' => ( is => 'ro', lazy => 1, builder => '_build_size', clearer => 'clear_size', predicate => 'has_size', ); =back =head2 C<< associate_method(MethodName) >> Associates a method with the attribute. Typically, this is called internally when an attribute generates its accessors. Currently the argument I is ignored in Mouse. =head2 C<< verify_against_type_constraint(Item) -> TRUE | ERROR >> Checks that the given value passes this attribute's type constraint. Returns C on success, otherwise Ces. =head2 C<< clone_and_inherit_options(options) -> Mouse::Meta::Attribute >> Creates a new attribute in the owner class, inheriting options from parent classes. Accessors and helper methods are installed. Some error checking is done. =head2 C<< get_read_method_ref >> =head2 C<< get_write_method_ref >> Returns the subroutine reference of a method suitable for reading or writing the attribute's value in the associated class. These methods always return a subroutine reference, regardless of whether or not the attribute is read- or write-only. =head1 SEE ALSO L L =cut