X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FMoose%2FMeta%2FAttribute.pm;h=c83c9cb8c5c3f949c45630c22c27f96c6117d725;hb=66e08a8a24af859f9b44dde64398400cb52a5f87;hp=f3c9c636c718268f28c4c91b0df0aedb45eaa41a;hpb=c0e30cf5d3bbad2b5622975e47c08d8d009e1e97;p=gitmo%2FMoose.git diff --git a/lib/Moose/Meta/Attribute.pm b/lib/Moose/Meta/Attribute.pm index f3c9c63..c83c9cb 100644 --- a/lib/Moose/Meta/Attribute.pm +++ b/lib/Moose/Meta/Attribute.pm @@ -4,18 +4,496 @@ package Moose::Meta::Attribute; use strict; use warnings; +use Scalar::Util 'blessed', 'weaken', 'reftype'; +use Carp 'confess'; +use overload (); + +our $VERSION = '0.15'; +our $AUTHORITY = 'cpan:STEVAN'; + +use Moose::Meta::Method::Accessor; +use Moose::Util::TypeConstraints (); + use base 'Class::MOP::Attribute'; -Moose::Meta::Attribute->meta->add_around_method_modifier('new' => sub { - my $cont = shift; - my ($class, $attribute_name, %options) = @_; - - # extract the sigil and accessor name - my ($init_arg) = ($attribute_name =~ /^[\$\@\%][\.\:](.*)$/); - - $cont->($class, $attribute_name, (init_arg => $init_arg, %options)); -}); +# options which are not directly used +# but we store them for metadata purposes +__PACKAGE__->meta->add_attribute('isa' => (reader => '_isa_metadata')); +__PACKAGE__->meta->add_attribute('does' => (reader => '_does_metadata')); +__PACKAGE__->meta->add_attribute('is' => (reader => '_is_metadata')); + +# these are actual options for the attrs +__PACKAGE__->meta->add_attribute('required' => (reader => 'is_required' )); +__PACKAGE__->meta->add_attribute('lazy' => (reader => 'is_lazy' )); +__PACKAGE__->meta->add_attribute('lazy_build' => (reader => 'is_lazy_build' )); +__PACKAGE__->meta->add_attribute('coerce' => (reader => 'should_coerce' )); +__PACKAGE__->meta->add_attribute('weak_ref' => (reader => 'is_weak_ref' )); +__PACKAGE__->meta->add_attribute('auto_deref' => (reader => 'should_auto_deref')); +__PACKAGE__->meta->add_attribute('type_constraint' => ( + reader => 'type_constraint', + predicate => 'has_type_constraint', +)); +__PACKAGE__->meta->add_attribute('trigger' => ( + reader => 'trigger', + predicate => 'has_trigger', +)); +__PACKAGE__->meta->add_attribute('handles' => ( + reader => 'handles', + predicate => 'has_handles', +)); +__PACKAGE__->meta->add_attribute('documentation' => ( + reader => 'documentation', + predicate => 'has_documentation', +)); + +sub new { + my ($class, $name, %options) = @_; + $class->_process_options($name, \%options); + return $class->SUPER::new($name, %options); +} + +sub clone_and_inherit_options { + my ($self, %options) = @_; + # you can change default, required, coerce, documentation and lazy + my %actual_options; + foreach my $legal_option (qw(default coerce required documentation lazy)) { + if (exists $options{$legal_option}) { + $actual_options{$legal_option} = $options{$legal_option}; + delete $options{$legal_option}; + } + } + + # handles can only be added, not changed + if ($options{handles}) { + confess "You can only add the 'handles' option, you cannot change it" + if $self->has_handles; + $actual_options{handles} = $options{handles}; + delete $options{handles}; + } + + # isa can be changed, but only if the + # new type is a subtype + if ($options{isa}) { + my $type_constraint; + if (blessed($options{isa}) && $options{isa}->isa('Moose::Meta::TypeConstraint')) { + $type_constraint = $options{isa}; + } + else { + $type_constraint = Moose::Util::TypeConstraints::find_or_create_type_constraint( + $options{isa} + ); + (defined $type_constraint) + || confess "Could not find the type constraint '" . $options{isa} . "'"; + } + # NOTE: + # check here to see if the new type + # is a subtype of the old one + ($type_constraint->is_subtype_of($self->type_constraint->name)) + || confess "New type constraint setting must be a subtype of inherited one" + # iff we have a type constraint that is ... + if $self->has_type_constraint; + # then we use it :) + $actual_options{type_constraint} = $type_constraint; + delete $options{isa}; + } + (scalar keys %options == 0) + || confess "Illegal inherited options => (" . (join ', ' => keys %options) . ")"; + $self->clone(%actual_options); +} + +sub _process_options { + my ($class, $name, $options) = @_; + + if (exists $options->{is}) { + if ($options->{is} eq 'ro') { + $options->{reader} ||= $name; + (!exists $options->{trigger}) + || confess "Cannot have a trigger on a read-only attribute"; + } + elsif ($options->{is} eq 'rw') { + $options->{accessor} = $name; + ((reftype($options->{trigger}) || '') eq 'CODE') + || confess "Trigger must be a CODE ref" + if exists $options->{trigger}; + } + else { + confess "I do not understand this option (is => " . $options->{is} . ")" + } + } + + if (exists $options->{isa}) { + if (exists $options->{does}) { + if (eval { $options->{isa}->can('does') }) { + ($options->{isa}->does($options->{does})) + || confess "Cannot have an isa option and a does option if the isa does not do the does"; + } + else { + confess "Cannot have an isa option which cannot ->does()"; + } + } + + # allow for anon-subtypes here ... + if (blessed($options->{isa}) && $options->{isa}->isa('Moose::Meta::TypeConstraint')) { + $options->{type_constraint} = $options->{isa}; + } + else { + $options->{type_constraint} = Moose::Util::TypeConstraints::find_or_create_type_constraint( + $options->{isa} => { + parent => Moose::Util::TypeConstraints::find_type_constraint('Object'), + constraint => sub { $_[0]->isa($options->{isa}) } + } + ); + } + } + elsif (exists $options->{does}) { + # allow for anon-subtypes here ... + if (blessed($options->{does}) && $options->{does}->isa('Moose::Meta::TypeConstraint')) { + $options->{type_constraint} = $options->{isa}; + } + else { + $options->{type_constraint} = Moose::Util::TypeConstraints::find_or_create_type_constraint( + $options->{does} => { + parent => Moose::Util::TypeConstraints::find_type_constraint('Role'), + constraint => sub { $_[0]->does($options->{does}) } + } + ); + } + } + + if (exists $options->{coerce} && $options->{coerce}) { + (exists $options->{type_constraint}) + || confess "You cannot have coercion without specifying a type constraint"; + confess "You cannot have a weak reference to a coerced value" + if $options->{weak_ref}; + } + + if (exists $options->{auto_deref} && $options->{auto_deref}) { + (exists $options->{type_constraint}) + || confess "You cannot auto-dereference without specifying a type constraint"; + ($options->{type_constraint}->is_a_type_of('ArrayRef') || + $options->{type_constraint}->is_a_type_of('HashRef')) + || confess "You cannot auto-dereference anything other than a ArrayRef or HashRef"; + } + + if (exists $options->{lazy_build} && $options->{lazy_build} == 1) { + confess("You can not use lazy_build and default for the same attribute") + if exists $options->{default}; + $options->{lazy} = 1; + $options->{required} = 1; + $options->{builder} ||= "_build_${name}"; + if ($name =~ /^_/) { + $options->{clearer} ||= "_clear${name}"; + $options->{predicate} ||= "_has${name}"; + } + else { + $options->{clearer} ||= "clear_${name}"; + $options->{predicate} ||= "has_${name}"; + } + } + + if (exists $options->{lazy} && $options->{lazy}) { + (exists $options->{default} || exists $options->{builder} ) + || confess "You cannot have lazy attribute without specifying a default value for it"; + } + +} + +sub initialize_instance_slot { + my ($self, $meta_instance, $instance, $params) = @_; + my $init_arg = $self->init_arg(); + # try to fetch the init arg from the %params ... + + my $val; + my $value_is_set; + if (exists $params->{$init_arg}) { + $val = $params->{$init_arg}; + $value_is_set = 1; + } + else { + # skip it if it's lazy + return if $self->is_lazy; + # and die if it's required and doesn't have a default value + confess "Attribute (" . $self->name . ") is required" + if $self->is_required && !$self->has_default && !$self->has_builder; + + # if nothing was in the %params, we can use the + # attribute's default value (if it has one) + if ($self->has_default) { + $val = $self->default($instance); + $value_is_set = 1; + } + elsif ($self->has_builder) { + if (my $builder = $instance->can($self->builder)){ + $val = $instance->$builder; + $value_is_set = 1; + } + else { + confess(blessed($instance)." does not support builder method '".$self->builder."' for attribute '" . $self->name . "'"); + } + } + } + + return unless $value_is_set; + + if ($self->has_type_constraint) { + my $type_constraint = $self->type_constraint; + if ($self->should_coerce && $type_constraint->has_coercion) { + $val = $type_constraint->coerce($val); + } + (defined($type_constraint->check($val))) + || confess "Attribute (" . + $self->name . + ") does not pass the type constraint (" . + $type_constraint->name . + ") with '" . + (defined $val + ? (blessed($val) && overload::Overloaded($val) + ? overload::StrVal($val) + : $val) + : 'undef') . + "'"; + } + + $meta_instance->set_slot_value($instance, $self->name, $val); + $meta_instance->weaken_slot_value($instance, $self->name) + if ref $val && $self->is_weak_ref; +} + +## Slot management + +sub set_value { + my ($self, $instance, $value) = @_; + + my $attr_name = $self->name; + + if ($self->is_required) { + defined($value) + || confess "Attribute ($attr_name) is required, so cannot be set to undef"; + } + + if ($self->has_type_constraint) { + + my $type_constraint = $self->type_constraint; + + if ($self->should_coerce) { + $value = $type_constraint->coerce($value); + } + defined($type_constraint->_compiled_type_constraint->($value)) + || confess "Attribute ($attr_name) does not pass the type constraint (" + . $type_constraint->name + . ") with " + . (defined($value) + ? ("'" . + (blessed($value) && overload::Overloaded($value) + ? overload::StrVal($value) + : $value) + . "'") + : "undef") + if defined($value); + } + my $meta_instance = Class::MOP::Class->initialize(blessed($instance)) + ->get_meta_instance; + + $meta_instance->set_slot_value($instance, $attr_name, $value); + + if (ref $value && $self->is_weak_ref) { + $meta_instance->weaken_slot_value($instance, $attr_name); + } + + if ($self->has_trigger) { + $self->trigger->($instance, $value, $self); + } +} + +sub get_value { + my ($self, $instance) = @_; + + if ($self->is_lazy) { + unless ($self->has_value($instance)) { + if ($self->has_default) { + my $default = $self->default($instance); + $self->set_value($instance, $default); + } + if ( $self->has_builder ){ + if (my $builder = $instance->can($self->builder)){ + $self->set_value($instance, $instance->$builder); + } + else { + confess(blessed($instance) + . " does not support builder method '" + . $self->builder + . "' for attribute '" + . $self->name + . "'"); + } + } + else { + $self->set_value($instance, undef); + } + } + } + + if ($self->should_auto_deref) { + + my $type_constraint = $self->type_constraint; + + if ($type_constraint->is_a_type_of('ArrayRef')) { + my $rv = $self->SUPER::get_value($instance); + return unless defined $rv; + return wantarray ? @{ $rv } : $rv; + } + elsif ($type_constraint->is_a_type_of('HashRef')) { + my $rv = $self->SUPER::get_value($instance); + return unless defined $rv; + return wantarray ? %{ $rv } : $rv; + } + else { + confess "Can not auto de-reference the type constraint '" . $type_constraint->name . "'"; + } + + } + else { + + return $self->SUPER::get_value($instance); + } +} + +## installing accessors + +sub accessor_metaclass { 'Moose::Meta::Method::Accessor' } + +sub install_accessors { + my $self = shift; + $self->SUPER::install_accessors(@_); + + if ($self->has_handles) { + + # NOTE: + # Here we canonicalize the 'handles' option + # this will sort out any details and always + # return an hash of methods which we want + # to delagate to, see that method for details + my %handles = $self->_canonicalize_handles(); + + # find the accessor method for this attribute + my $accessor = $self->get_read_method_ref; + # then unpack it if we need too ... + $accessor = $accessor->body if blessed $accessor; + + # install the delegation ... + my $associated_class = $self->associated_class; + foreach my $handle (keys %handles) { + my $method_to_call = $handles{$handle}; + + (!$associated_class->has_method($handle)) + || confess "You cannot overwrite a locally defined method ($handle) with a delegation"; + + # NOTE: + # handles is not allowed to delegate + # any of these methods, as they will + # override the ones in your class, which + # is almost certainly not what you want. + next if $handle =~ /^BUILD|DEMOLISH$/ || Moose::Object->can($handle); + + if ((reftype($method_to_call) || '') eq 'CODE') { + $associated_class->add_method($handle => $method_to_call); + } + else { + $associated_class->add_method($handle => sub { + # FIXME + # we should check for lack of + # a callable return value from + # the accessor here + my $proxy = (shift)->$accessor(); + @_ = ($proxy, @_); + goto &{ $proxy->can($method_to_call) }; + }); + } + } + } + + return; +} + +# private methods to help delegation ... + +sub _canonicalize_handles { + my $self = shift; + my $handles = $self->handles; + if (my $handle_type = ref($handles)) { + if ($handle_type eq 'HASH') { + return %{$handles}; + } + elsif ($handle_type eq 'ARRAY') { + return map { $_ => $_ } @{$handles}; + } + elsif ($handle_type eq 'Regexp') { + ($self->has_type_constraint) + || confess "Cannot delegate methods based on a RegExpr without a type constraint (isa)"; + return map { ($_ => $_) } + grep { /$handles/ } $self->_get_delegate_method_list; + } + elsif ($handle_type eq 'CODE') { + return $handles->($self, $self->_find_delegate_metaclass); + } + else { + confess "Unable to canonicalize the 'handles' option with $handles"; + } + } + else { + my $role_meta = eval { $handles->meta }; + if ($@) { + confess "Unable to canonicalize the 'handles' option with $handles because : $@"; + } + + (blessed $role_meta && $role_meta->isa('Moose::Meta::Role')) + || confess "Unable to canonicalize the 'handles' option with $handles because ->meta is not a Moose::Meta::Role"; + + return map { $_ => $_ } ( + $role_meta->get_method_list, + $role_meta->get_required_method_list + ); + } +} + +sub _find_delegate_metaclass { + my $self = shift; + if (my $class = $self->_isa_metadata) { + # if the class does have + # a meta method, use it + return $class->meta if $class->can('meta'); + # otherwise we might be + # dealing with a non-Moose + # class, and need to make + # our own metaclass + return Moose::Meta::Class->initialize($class); + } + elsif (my $role = $self->_does_metadata) { + # our role will always have + # a meta method + return $role->meta; + } + else { + confess "Cannot find delegate metaclass for attribute " . $self->name; + } +} + +sub _get_delegate_method_list { + my $self = shift; + my $meta = $self->_find_delegate_metaclass; + if ($meta->isa('Class::MOP::Class')) { + return map { $_->{name} } # NOTE: !never! delegate &meta + grep { $_->{class} ne 'Moose::Object' && $_->{name} ne 'meta' } + $meta->compute_all_applicable_methods; + } + elsif ($meta->isa('Moose::Meta::Role')) { + return $meta->get_method_list; + } + else { + confess "Unable to recognize the delegate metaclass '$meta'"; + } +} 1; @@ -25,44 +503,188 @@ __END__ =head1 NAME -Moose::Meta::Attribute - - -=head1 SYNOPSIS +Moose::Meta::Attribute - The Moose attribute metaclass =head1 DESCRIPTION +This is a subclass of L with Moose specific +extensions. + +For the most part, the only time you will ever encounter an +instance of this class is if you are doing some serious deep +introspection. To really understand this class, you need to refer +to the L documentation. + =head1 METHODS +=head2 Overridden methods + +These methods override methods in L and add +Moose specific features. You can safely assume though that they +will behave just as L does. + =over 4 =item B +=item B + +=item B + +=item B + +=item B + +=item B + + eval { $point->meta->get_attribute('x')->set_value($point, 'fourty-two') }; + if($@) { + print "Oops: $@\n"; + } + +I + +Before setting the value, a check is made on the type constraint of +the attribute, if it has one, to see if the value passes it. If the +value fails to pass, the set operation dies with a L. + +Any coercion to convert values is done before checking the type constraint. + +To check a value against a type constraint before setting it, fetch the +attribute instance using L, +fetch the type_constraint from the attribute using L +and call L. See L +for an example. + =back -=head1 BUGS +=head2 Additional Moose features -All complex software has bugs lurking in it, and this module is no -exception. If you find a bug please either email me, or add the bug -to cpan-RT. +Moose attributes support type-constraint checking, weak reference +creation and type coercion. + +=over 4 + +=item B + +This is to support the C feature, it clones an attribute +from a superclass and allows a very specific set of changes to be made +to the attribute. + +=item B + +Returns true if this meta-attribute has a type constraint. + +=item B + +A read-only accessor for this meta-attribute's type constraint. For +more information on what you can do with this, see the documentation +for L. + +=item B + +Returns true if this meta-attribute performs delegation. + +=item B + +This returns the value which was passed into the handles option. + +=item B + +Returns true if this meta-attribute produces a weak reference. -=head1 CODE COVERAGE +=item B -I use L to test the code coverage of my tests, below is the -L report on this module's test suite. +Returns true if this meta-attribute is required to have a value. -=head1 ACKNOWLEDGEMENTS +=item B + +Returns true if this meta-attribute should be initialized lazily. + +NOTE: lazy attributes, B have a C or C field set. + +=item B + +Returns true if this meta-attribute should be initialized lazily through +the builder generated by lazy_build. Using C 1> will +make your attribute required and lazy. In addition it will set the builder, clearer +and predicate options for you using the following convention. + + #If your attribute name starts with an underscore: + has '_foo' => (lazy_build => 1); + #is the same as + has '_foo' => (lazy => 1, required => 1, predicate => '_has_foo', clearer => '_clear_foo', builder => '_build__foo); + # or + has '_foo' => (lazy => 1, required => 1, predicate => '_has_foo', clearer => '_clear_foo', default => sub{shift->_build__foo}); + + #If your attribute name does not start with an underscore: + has 'foo' => (lazy_build => 1); + #is the same as + has 'foo' => (lazy => 1, required => 1, predicate => 'has_foo', clearer => 'clear_foo', builder => '_build_foo); + # or + has 'foo' => (lazy => 1, required => 1, predicate => 'has_foo', clearer => 'clear_foo', default => sub{shift->_build_foo}); + +The reason for the different naming of the C is that the C +method is a private method while the C and C methods +are public methods. + +NOTE: This means your class should provide a method whose name matches the value +of the builder part, in this case _build__foo or _build_foo. + +=item B + +Returns true if this meta-attribute should perform type coercion. + +=item B + +Returns true if this meta-attribute should perform automatic +auto-dereferencing. + +NOTE: This can only be done for attributes whose type constraint is +either I or I. + +=item B + +Returns true if this meta-attribute has a trigger set. + +=item B + +This is a CODE reference which will be executed every time the +value of an attribute is assigned. The CODE ref will get two values, +the invocant and the new value. This can be used to handle I +bi-directional relations. + +=item B + +This is a string which contains the documentation for this attribute. +It serves no direct purpose right now, but it might in the future +in some kind of automated documentation system perhaps. + +=item B + +Returns true if this meta-attribute has any documentation. + +=back + +=head1 BUGS + +All complex software has bugs lurking in it, and this module is no +exception. If you find a bug please either email me, or add the bug +to cpan-RT. =head1 AUTHOR Stevan Little Estevan@iinteractive.comE +Yuval Kogman Enothingmuch@woobling.comE + =head1 COPYRIGHT AND LICENSE -Copyright 2006 by Infinity Interactive, Inc. +Copyright 2006, 2007 by Infinity Interactive, Inc. L This library is free software; you can redistribute it and/or modify -it under the same terms as Perl itself. +it under the same terms as Perl itself. -=cut \ No newline at end of file +=cut