/usr/lib/perl5/Mouse/Meta/Attribute.pm is in libmouse-perl 0.97-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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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',
'insertion_order',
'is',
'isa',
'lazy',
'lazy_build',
'name',
'predicate',
'reader',
'required',
'traits',
'trigger',
'type_constraint',
'weak_ref',
'writer',
# internally used
'associated_class',
'associated_methods',
'__METACLASS__',
# Moose defines, but Mouse doesn't
#'definition_context',
#'initializer',
# special case for AttributeHelpers
'provides',
'curries',
);
our @CARP_NOT = qw(Mouse::Meta::Class);
sub new {
my $class = shift;
my $name = shift;
my $args = $class->Mouse::Object::BUILDARGS(@_);
$class->_process_options($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){
Carp::carp(
"Found unknown argument(s) passed to '$name' attribute constructor in '$class': "
. Mouse::Util::english_list(@bad));
}
my $self = bless $args, $class;
if($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 get_read_method { $_[0]->reader || $_[0]->accessor }
sub get_write_method { $_[0]->writer || $_[0]->accessor }
sub get_read_method_ref{
my($self) = @_;
return $self->{_mouse_cache_read_method_ref}
||= $self->_get_accessor_method_ref('get_read_method', '_generate_reader');
}
sub get_write_method_ref{
my($self) = @_;
return $self->{_mouse_cache_write_method_ref}
||= $self->_get_accessor_method_ref('get_write_method', '_generate_writer');
}
sub interpolate_class{
my($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( $class, @traits );
}
sub verify_against_type_constraint {
my ($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 illegal_options_for_inheritance {
return qw(reader writer accessor clearer predicate);
}
sub clone_and_inherit_options{
my $self = shift;
my $args = $self->Mouse::Object::BUILDARGS(@_);
foreach my $illegal($self->illegal_options_for_inheritance) {
if(exists $args->{$illegal} and exists $self->{$illegal}) {
$self->throw_error("Illegal inherited option: $illegal");
}
}
foreach my $name(keys %{$self}){
if(!exists $args->{$name}){
$args->{$name} = $self->{$name}; # inherit from self
}
}
my($attribute_class, @traits) = ref($self)->interpolate_class($args);
$args->{traits} = \@traits if @traits;
# remove temporary caches
foreach my $attr(keys %{$args}){
if($attr =~ /\A _mouse_cache_/xms){
delete $args->{$attr};
}
}
# remove default if lazy_build => 1
if($args->{lazy_build}) {
delete $args->{default};
}
return $attribute_class->new($self->name, $args);
}
sub _get_accessor_method_ref {
my($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, $metaclass);
}
}
sub set_value {
my($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->{_mouse_cache_predicate_ref}
||= $self->_get_accessor_method_ref('predicate', '_generate_predicate');
return $accessor_ref->($object);
}
sub clear_value {
my($self, $object) = @_;
my $accessor_ref = $self->{_mouse_cache_crealer_ref}
||= $self->_get_accessor_method_ref('clearer', '_generate_clearer');
return $accessor_ref->($object);
}
sub associate_method{
#my($attribute, $method_name) = @_;
my($attribute) = @_;
$attribute->{associated_methods}++;
return;
}
sub install_accessors{
my($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);
my $name = $attribute->{$type};
# TODO: do something for compatibility
# if( $metaclass->name->can($name) ) {
# my $t = $metaclass->has_method($name) ? 'method' : 'function';
# Carp::cluck("You are overwriting a locally defined $t"
# . " ($name) with an accessor");
# }
$metaclass->add_method($name => $code);
$attribute->associate_method($name);
}
}
# install delegation
if(exists $attribute->{handles}){
my %handles = $attribute->_canonicalize_handles();
while(my($handle, $method_to_call) = each %handles){
next if Mouse::Object->can($handle);
if($metaclass->has_method($handle)) {
$attribute->throw_error("You cannot overwrite a locally defined method ($handle) with a delegation");
}
$metaclass->add_method($handle =>
$attribute->_make_delegation_method(
$handle, $method_to_call));
$attribute->associate_method($handle);
}
}
return;
}
sub delegation_metaclass() { ## no critic
'Mouse::Meta::Method::Delegation'
}
sub _canonicalize_handles {
my($self) = @_;
my $handles = $self->{handles};
my $handle_type = ref $handles;
if ($handle_type eq 'HASH') {
return %$handles;
}
elsif ($handle_type eq 'ARRAY') {
return map { $_ => $_ } @$handles;
}
elsif ($handle_type eq 'Regexp') {
my $meta = $self->_find_delegate_metaclass();
return map { $_ => $_ }
grep { /$handles/ }
Mouse::Util::is_a_metarole($meta)
? $meta->get_method_list
: $meta->get_all_method_names;
}
elsif ($handle_type eq 'CODE') {
return $handles->( $self, $self->_find_delegate_metaclass() );
}
else {
$self->throw_error("Unable to canonicalize the 'handles' option with $handles");
}
}
sub _find_delegate_metaclass {
my($self) = @_;
my $meta;
if($self->{isa}) {
$meta = Mouse::Meta::Class->initialize("$self->{isa}");
}
elsif($self->{does}) {
$meta = Mouse::Util::get_metaclass_by_name("$self->{does}");
}
defined($meta) or $self->throw_error(
"Cannot find delegate metaclass for attribute " . $self->name);
return $meta;
}
sub _make_delegation_method {
my($self, $handle, $method_to_call) = @_;
return Mouse::Util::load_class($self->delegation_metaclass)
->_generate_delegation($self, $handle, $method_to_call);
}
1;
__END__
=head1 NAME
Mouse::Meta::Attribute - The Mouse attribute metaclass
=head1 VERSION
This document describes Mouse version 0.97
=head1 DESCRIPTION
This is a meta object protocol for Mouse attributes,
which is a subset of Moose::Meta::Attribute.
=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<reader>, C<writer>, or
C<accessor> names. If the attribute is read-only ('ro') then it will
have a C<reader> method with the same attribute as the name.
If it is read-write ('rw') then it will have an C<accessor> method
with the same name. If you provide an explicit C<writer> for a
read-write attribute, then you will have a C<reader> with the same
name as the attribute, and a C<writer> 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<Moose::Meta::TypeConstraint> object.
If you I<also> provide a C<does> option, then your C<isa> option must
be a class name, and that class must do the role specified with
C<does>.
=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<This option is not yet supported.>
=item C<< coerce => Bool >>
This option is only valid for objects with a type constraint
(C<isa>). If this is true, then coercions will be applied whenever
this attribute is set.
You can make both this and the C<weak_ref> 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<default> or C<builder>,
which will satisfy its required-ness.
A required attribute must have a C<default>, C<builder> or a
non-C<undef> C<init_arg>
=item C<< lazy => Bool >>
A lazy attribute must have a C<default> or C<builder>. 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<MethodName> 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<true>
on success, otherwise C<confess>es.
=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<Moose::Meta::Attribute>
L<Class::MOP::Attribute>
=cut
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