use strict;
use warnings;
-use Scalar::Util 'weaken', 'reftype';
+use Scalar::Util 'blessed', 'weaken', 'reftype';
use Carp 'confess';
-use Moose::Util::TypeConstraints ':no_export';
+our $VERSION = '0.08';
-our $VERSION = '0.01';
+use Moose::Meta::Method::Accessor;
+use Moose::Util::TypeConstraints ();
use base 'Class::MOP::Attribute';
-Moose::Meta::Attribute->meta->add_attribute(
- Class::MOP::Attribute->new('weak_ref' => (
- reader => 'weak_ref',
- predicate => {
- 'has_weak_ref' => sub { $_[0]->weak_ref() ? 1 : 0 }
- }
- ))
-);
-
-Moose::Meta::Attribute->meta->add_attribute(
- Class::MOP::Attribute->new('type_constraint' => (
- reader => 'type_constraint',
- predicate => 'has_type_constraint',
- ))
-);
-
-Moose::Meta::Attribute->meta->add_before_method_modifier('new' => sub {
- my (undef, undef, %options) = @_;
- (reftype($options{type_constraint}) && reftype($options{type_constraint}) eq 'CODE')
- || confess "Type cosntraint parameter must be a code-ref, not " . $options{type_constraint}
- if exists $options{type_constraint};
-});
+# options which are not directly used
+# but we store them for metadata purposes
+__PACKAGE__->meta->add_attribute('isa' => (reader => '_isa_metadata'));
+__PACKAGE__->meta->add_attribute('does' => (reader => '_does_metadata'));
+__PACKAGE__->meta->add_attribute('is' => (reader => '_is_metadata'));
+
+# these are actual options for the attrs
+__PACKAGE__->meta->add_attribute('required' => (reader => 'is_required' ));
+__PACKAGE__->meta->add_attribute('lazy' => (reader => 'is_lazy' ));
+__PACKAGE__->meta->add_attribute('coerce' => (reader => 'should_coerce' ));
+__PACKAGE__->meta->add_attribute('weak_ref' => (reader => 'is_weak_ref' ));
+__PACKAGE__->meta->add_attribute('auto_deref' => (reader => 'should_auto_deref'));
+__PACKAGE__->meta->add_attribute('type_constraint' => (
+ reader => 'type_constraint',
+ predicate => 'has_type_constraint',
+));
+__PACKAGE__->meta->add_attribute('trigger' => (
+ reader => 'trigger',
+ predicate => 'has_trigger',
+));
+__PACKAGE__->meta->add_attribute('handles' => (
+ reader => 'handles',
+ predicate => 'has_handles',
+));
+
+sub new {
+ my ($class, $name, %options) = @_;
+ $class->_process_options($name, \%options);
+ return $class->SUPER::new($name, %options);
+}
-sub generate_accessor_method {
- my ($self, $attr_name) = @_;
- if ($self->has_type_constraint) {
- if ($self->has_weak_ref) {
- return sub {
- if (scalar(@_) == 2) {
- (defined $self->type_constraint->($_[1]))
- || confess "Attribute ($attr_name) does not pass the type contraint"
- if defined $_[1];
- $_[0]->{$attr_name} = $_[1];
- weaken($_[0]->{$attr_name});
- }
- $_[0]->{$attr_name};
- };
- }
+sub clone_and_inherit_options {
+ my ($self, %options) = @_;
+ # you can change default, required and coerce
+ my %actual_options;
+ foreach my $legal_option (qw(default coerce required)) {
+ if (exists $options{$legal_option}) {
+ $actual_options{$legal_option} = $options{$legal_option};
+ delete $options{$legal_option};
+ }
+ }
+ # 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 {
- return sub {
- if (scalar(@_) == 2) {
- (defined $self->type_constraint->($_[1]))
- || confess "Attribute ($attr_name) does not pass the type contraint"
- if defined $_[1];
- $_[0]->{$attr_name} = $_[1];
- }
- $_[0]->{$attr_name};
- };
- }
- }
- else {
- if ($self->has_weak_ref) {
- return sub {
- if (scalar(@_) == 2) {
- $_[0]->{$attr_name} = $_[1];
- weaken($_[0]->{$attr_name});
- }
- $_[0]->{$attr_name};
- };
+ $type_constraint = Moose::Util::TypeConstraints::find_type_constraint($options{isa});
+ (defined $type_constraint)
+ || confess "Could not find the type constraint '" . $options{isa} . "'";
}
- else {
- sub {
- $_[0]->{$attr_name} = $_[1] if scalar(@_) == 2;
- $_[0]->{$attr_name};
- };
- }
- }
+ # 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) . ")";
+ $self->clone(%actual_options);
}
-sub generate_writer_method {
- my ($self, $attr_name) = @_;
- if ($self->has_type_constraint) {
- if ($self->has_weak_ref) {
- return sub {
- (defined $self->type_constraint->($_[1]))
- || confess "Attribute ($attr_name) does not pass the type contraint"
- if defined $_[1];
- $_[0]->{$attr_name} = $_[1];
- weaken($_[0]->{$attr_name});
- };
+sub _process_options {
+ my ($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";
}
- else {
- return sub {
- (defined $self->type_constraint->($_[1]))
- || confess "Attribute ($attr_name) does not pass the type contraint"
- if defined $_[1];
- $_[0]->{$attr_name} = $_[1];
- };
+ elsif ($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 => " . $options->{is} . ")"
+ }
}
- else {
- if ($self->has_weak_ref) {
- return sub {
- $_[0]->{$attr_name} = $_[1];
- weaken($_[0]->{$attr_name});
- };
+
+ 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 {
- return sub { $_[0]->{$attr_name} = $_[1] };
+
+ if ($options->{isa} =~ /\|/) {
+ my @type_constraints = split /\s*\|\s*/ => $options->{isa};
+ $options->{type_constraint} = Moose::Util::TypeConstraints::create_type_constraint_union(
+ @type_constraints
+ );
+ }
+ else {
+ # otherwise assume it is a constraint
+ my $constraint = Moose::Util::TypeConstraints::find_type_constraint($options->{isa});
+ # if the constraing it not found ....
+ unless (defined $constraint) {
+ # assume it is a foreign class, and make
+ # an anon constraint for it
+ $constraint = Moose::Util::TypeConstraints::subtype(
+ 'Object',
+ Moose::Util::TypeConstraints::where { $_->isa($options->{isa}) }
+ );
+ }
+ $options->{type_constraint} = $constraint;
+ }
}
+ }
+ 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 {
+ # otherwise assume it is a constraint
+ my $constraint = Moose::Util::TypeConstraints::find_type_constraint($options->{does});
+ # if the constraing it not found ....
+ unless (defined $constraint) {
+ # assume it is a foreign class, and make
+ # an anon constraint for it
+ $constraint = Moose::Util::TypeConstraints::subtype(
+ 'Role',
+ Moose::Util::TypeConstraints::where { $_->does($options->{does}) }
+ );
+ }
+ $options->{type_constraint} = $constraint;
+ }
+ }
+
+ 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} && $options->{lazy}) {
+ (exists $options->{default})
+ || confess "You cannot have lazy attribute without specifying a default value for it";
+ }
+}
+
+sub initialize_instance_slot {
+ my ($self, $meta_instance, $instance, $params) = @_;
+ my $init_arg = $self->init_arg();
+ # try to fetch the init arg from the %params ...
+
+ my $val;
+ if (exists $params->{$init_arg}) {
+ $val = $params->{$init_arg};
+ }
+ 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;
+ }
+
+ # if nothing was in the %params, we can use the
+ # attribute's default value (if it has one)
+ if (!defined $val && $self->has_default) {
+ $val = $self->default($instance);
+ }
+ if (defined $val) {
+ if ($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 (" .
+ $type_constraint->name .
+ ") with '$val'";
+ }
}
+
+ $meta_instance->set_slot_value($instance, $self->name, $val);
+ $meta_instance->weaken_slot_value($instance, $self->name)
+ if ref $val && $self->is_weak_ref;
+}
+
+## Accessor inline subroutines
+
+sub _inline_check_constraint {
+ my ($self, $value) = @_;
+ return '' unless $self->has_type_constraint;
+
+ # FIXME - remove 'unless defined($value) - constraint Undef
+ return sprintf <<'EOF', $value, $value, $value, $value
+defined($type_constraint->(%s))
+ || confess "Attribute (" . $attr->name . ") does not pass the type constraint ("
+ . $attr->type_constraint->name . ") with " . (defined(%s) ? "'%s'" : "undef")
+ if defined(%s);
+EOF
+}
+
+sub _inline_check_coercion {
+ my $self = shift;
+ return '' unless $self->should_coerce;
+ return 'my $val = $attr->type_constraint->coerce($_[1]);'
+}
+
+sub _inline_check_required {
+ my $self = shift;
+ return '' unless $self->is_required;
+ return 'defined($_[1]) || confess "Attribute ($attr_name) is required, so cannot be set to undef";'
+}
+
+sub _inline_check_lazy {
+ my $self = shift;
+ return '' unless $self->is_lazy;
+ if ($self->has_type_constraint) {
+ # NOTE:
+ # this could probably be cleaned
+ # up and streamlined a little more
+ return 'unless (exists $_[0]->{$attr_name}) {' .
+ ' if ($attr->has_default) {' .
+ ' my $default = $attr->default($_[0]);' .
+ ' (defined($type_constraint->($default)))' .
+ ' || confess "Attribute (" . $attr->name . ") does not pass the type constraint ("' .
+ ' . $attr->type_constraint->name . ") with " . (defined($default) ? "\'$default\'" : "undef")' .
+ ' if defined($default);' .
+ ' $_[0]->{$attr_name} = $default; ' .
+ ' }' .
+ ' else {' .
+ ' $_[0]->{$attr_name} = undef;' .
+ ' }' .
+ '}';
+ }
+ return '$_[0]->{$attr_name} = ($attr->has_default ? $attr->default($_[0]) : undef)'
+ . 'unless exists $_[0]->{$attr_name};';
+}
+
+
+sub _inline_store {
+ my ($self, $instance, $value) = @_;
+
+ my $mi = $self->associated_class->get_meta_instance;
+ my $slot_name = sprintf "'%s'", $self->slots;
+
+ my $code = $mi->inline_set_slot_value($instance, $slot_name, $value) . ";";
+ $code .= $mi->inline_weaken_slot_value($instance, $slot_name, $value) . ";"
+ if $self->is_weak_ref;
+ return $code;
+}
+
+sub _inline_trigger {
+ my ($self, $instance, $value) = @_;
+ return '' unless $self->has_trigger;
+ return sprintf('$attr->trigger->(%s, %s, $attr);', $instance, $value);
+}
+
+sub _inline_get {
+ my ($self, $instance) = @_;
+
+ my $mi = $self->associated_class->get_meta_instance;
+ my $slot_name = sprintf "'%s'", $self->slots;
+
+ return $mi->inline_get_slot_value($instance, $slot_name);
+}
+
+sub _inline_auto_deref {
+ my ( $self, $ref_value ) = @_;
+
+ return $ref_value unless $self->should_auto_deref;
+
+ my $type_constraint = $self->type_constraint;
+
+ my $sigil;
+ if ($type_constraint->is_a_type_of('ArrayRef')) {
+ $sigil = '@';
+ }
+ elsif ($type_constraint->is_a_type_of('HashRef')) {
+ $sigil = '%';
+ }
+ else {
+ confess "Can not auto de-reference the type constraint '" . $type_constraint->name . "'";
+ }
+
+ "(wantarray() ? $sigil\{ ( $ref_value ) || return } : ( $ref_value ) )";
+}
+
+sub generate_accessor_method {
+ my ($attr, $attr_name) = @_;
+ my $value_name = $attr->should_coerce ? '$val' : '$_[1]';
+ my $mi = $attr->associated_class->get_meta_instance;
+ my $slot_name = sprintf "'%s'", $attr->slots;
+ my $inv = '$_[0]';
+ my $code = 'sub { '
+ . 'if (scalar(@_) == 2) {'
+ . $attr->_inline_check_required
+ . $attr->_inline_check_coercion
+ . $attr->_inline_check_constraint($value_name)
+ . $attr->_inline_store($inv, $value_name)
+ . $attr->_inline_trigger($inv, $value_name)
+ . ' }'
+ . $attr->_inline_check_lazy
+ . 'return ' . $attr->_inline_auto_deref($attr->_inline_get($inv))
+ . ' }';
+
+ # NOTE:
+ # set up the environment
+ my $type_constraint = $attr->type_constraint
+ ? $attr->type_constraint->_compiled_type_constraint
+ : undef;
+
+ my $sub = eval $code;
+ confess "Could not create accessor for '$attr_name' because $@ \n code: $code" if $@;
+ return $sub;
+}
+
+sub generate_writer_method {
+ my ($attr, $attr_name) = @_;
+ my $value_name = $attr->should_coerce ? '$val' : '$_[1]';
+ my $inv = '$_[0]';
+ my $code = 'sub { '
+ . $attr->_inline_check_required
+ . $attr->_inline_check_coercion
+ . $attr->_inline_check_constraint($value_name)
+ . $attr->_inline_store($inv, $value_name)
+ . $attr->_inline_trigger($inv, $value_name)
+ . ' }';
+
+ # NOTE:
+ # set up the environment
+ my $type_constraint = $attr->type_constraint
+ ? $attr->type_constraint->_compiled_type_constraint
+ : undef;
+
+ my $sub = eval $code;
+ confess "Could not create writer for '$attr_name' because $@ \n code: $code" if $@;
+ return $sub;
+}
+
+sub generate_reader_method {
+ my $attr = shift;
+ my $attr_name = $attr->slots;
+ my $code = 'sub {'
+ . 'confess "Cannot assign a value to a read-only accessor" if @_ > 1;'
+ . $attr->_inline_check_lazy
+ . 'return ' . $attr->_inline_auto_deref( '$_[0]->{$attr_name}' ) . ';'
+ . '}';
+ my $sub = eval $code;
+ confess "Could not create reader for '$attr_name' because $@ \n code: $code" if $@;
+ return $sub;
+}
+
+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 name of the accessor for this attribute
+ my $accessor_name = $self->reader || $self->accessor;
+ (defined $accessor_name)
+ || confess "You cannot install delegation without a reader or accessor for the attribute";
+
+ # make sure we handle HASH accessors correctly
+ ($accessor_name) = keys %{$accessor_name}
+ if ref($accessor_name) eq 'HASH';
+
+ # 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 ($handle) with a delegation";
+
+ if ((reftype($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
+ ((shift)->$accessor_name())->$method_to_call(@_);
+ });
+ }
+ }
+ }
+
+ return;
+}
+
+# private methods to help delegation ...
+
+sub _canonicalize_handles {
+ my $self = shift;
+ my $handles = $self->handles;
+ if (ref($handles) eq 'HASH') {
+ return %{$handles};
+ }
+ elsif (ref($handles) eq 'ARRAY') {
+ return map { $_ => $_ } @{$handles};
+ }
+ elsif (ref($handles) eq 'Regexp') {
+ ($self->has_type_constraint)
+ || confess "Cannot delegate methods based on a RegExpr without a type constraint (isa)";
+ return map { ($_ => $_) }
+ grep { $handles } $self->_get_delegate_method_list;
+ }
+ elsif (ref($handles) eq 'CODE') {
+ return $handles->($self, $self->_find_delegate_metaclass);
+ }
+ else {
+ confess "Unable to canonicalize the 'handles' option with $handles";
+ }
+}
+
+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;
=head1 NAME
-Moose::Meta::Attribute - The Moose attribute metaobject
-
-=head1 SYNOPSIS
+Moose::Meta::Attribute - The Moose attribute metaclass
=head1 DESCRIPTION
This is a subclass of L<Class::MOP::Attribute> with Moose specific
-extensions.
+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<Class::MOP::Attribute> documentation.
=head1 METHODS
+=head2 Overridden methods
+
+These methods override methods in L<Class::MOP::Attribute> and add
+Moose specific features. You can safely assume though that they
+will behave just as L<Class::MOP::Attribute> does.
+
=over 4
=item B<new>
+=item B<initialize_instance_slot>
+
=item B<generate_accessor_method>
=item B<generate_writer_method>
+=item B<generate_reader_method>
+
+=item B<install_accessors>
+
=back
+=head2 Additional Moose features
+
+Moose attributes support type-constraint checking, weak reference
+creation and type coercion.
+
=over 4
+=item B<clone_and_inherit_options>
+
+This is to support the C<has '+foo'> feature, it clones an attribute
+from a superclass and allows a very specific set of changes to be made
+to the attribute.
+
=item B<has_type_constraint>
+Returns true if this meta-attribute has a type constraint.
+
=item B<type_constraint>
-=item B<has_weak_ref>
+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<Moose::Meta::TypeConstraint>.
+
+=item B<has_handles>
+
+Returns true if this meta-attribute performs delegation.
+
+=item B<handles>
+
+This returns the value which was passed into the handles option.
+
+=item B<is_weak_ref>
+
+Returns true if this meta-attribute produces a weak reference.
+
+=item B<is_required>
+
+Returns true if this meta-attribute is required to have a value.
+
+=item B<is_lazy>
-=item B<weak_ref>
+Returns true if this meta-attribute should be initialized lazily.
+
+NOTE: lazy attributes, B<must> have a C<default> field set.
+
+=item B<should_coerce>
+
+Returns true if this meta-attribute should perform type coercion.
+
+=item B<should_auto_deref>
+
+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<ArrayRef> or I<HashRef>.
+
+=item B<has_trigger>
+
+Returns true if this meta-attribute has a trigger set.
+
+=item B<trigger>
+
+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<basic>
+bi-directional relations.
=back
Stevan Little E<lt>stevan@iinteractive.comE<gt>
+Yuval Kogman E<lt>nothingmuch@woobling.comE<gt>
+
=head1 COPYRIGHT AND LICENSE
Copyright 2006 by Infinity Interactive, Inc.
This library is free software; you can redistribute it and/or modify
it under the same terms as Perl itself.
-=cut
\ No newline at end of file
+=cut
projects / gitmo/Moose.git / blobdiff