use strict;
use warnings;
-use Carp 'confess';
-use Scalar::Util 'blessed', 'reftype', 'weaken';
+use Scalar::Util 'weaken', 'blessed';
-our $VERSION = '0.01';
+our $VERSION = '0.78_02';
+$VERSION = eval $VERSION;
+our $AUTHORITY = 'cpan:STEVAN';
-sub meta {
- require Class::MOP::Class;
- Class::MOP::Class->initialize(blessed($_[0]) || $_[0]);
+use base 'Class::MOP::Object';
+
+sub BUILDARGS {
+ my ($class, @args) = @_;
+
+ if ( @args == 1 ) {
+ unshift @args, "associated_metaclass";
+ } elsif ( @args >= 2 && blessed($args[0]) && $args[0]->isa("Class::MOP::Class") ) {
+ # compat mode
+ my ( $meta, @attrs ) = @args;
+ @args = ( associated_metaclass => $meta, attributes => \@attrs );
+ }
+
+ my %options = @args;
+ # FIXME lazy_build
+ $options{slots} ||= [ map { $_->slots } @{ $options{attributes} || [] } ];
+ $options{slot_hash} = { map { $_ => undef } @{ $options{slots} } }; # FIXME lazy_build
+
+ return \%options;
+}
+
+sub new {
+ my $class = shift;
+ my $options = $class->BUILDARGS(@_);
+
+ # FIXME replace with a proper constructor
+ my $instance = $class->_new(%$options);
+
+ # FIXME weak_ref => 1,
+ weaken($instance->{'associated_metaclass'});
+
+ return $instance;
}
-sub new {
- my ( $class, $meta ) = @_;
+sub _new {
+ my ( $class, %options ) = @_;
bless {
- meta => $meta,
- instance_layout => {}
- } => $class;
+ # NOTE:
+ # I am not sure that it makes
+ # sense to pass in the meta
+ # The ideal would be to just
+ # pass in the class name, but
+ # that is placing too much of
+ # an assumption on bless(),
+ # which is *probably* a safe
+ # assumption,.. but you can
+ # never tell <:)
+ 'associated_metaclass' => $options{associated_metaclass},
+ 'attributes' => $options{attributes},
+ 'slots' => $options{slots},
+ 'slot_hash' => $options{slot_hash},
+ } => $class;
}
+sub _class_name { $_[0]->{_class_name} ||= $_[0]->associated_metaclass->name }
+
+sub associated_metaclass { $_[0]{'associated_metaclass'} }
+
sub create_instance {
- my ( $self, $class ) = @_;
-
- # rely on autovivification
- $self->bless_instance_structure( {}, $class );
+ my $self = shift;
+ bless {}, $self->_class_name;
}
+# for compatibility
sub bless_instance_structure {
- my ( $self, $instance_structure, $class ) = @_;
- $class ||= $self->{meta}->name;
- bless $instance_structure, $class;
+ my ($self, $instance_structure) = @_;
+ bless $instance_structure, $self->_class_name;
}
-sub get_all_parents {
- my $self = shift;
- my @parents = $self->{meta}->class_precedence_list;
- shift @parents; # shift off ourselves
- return map { $_->get_meta_instance } map { $_->meta || () } @parents;
+sub clone_instance {
+ my ($self, $instance) = @_;
+ bless { %$instance }, $self->_class_name;
}
# operations on meta instance
-sub add_slot {
- my ($self, $slot_name ) = @_;
- confess "The slot '$slot_name' already exists"
- if 0 && $self->has_slot_recursively( $slot_name ); # FIXME
- $self->{instance_layout}->{$slot_name} = undef;
-}
-
sub get_all_slots {
my $self = shift;
- keys %{ $self->{instance_layout} };
+ return @{$self->{'slots'}};
}
-sub get_all_slots_recursively {
+sub get_all_attributes {
my $self = shift;
- return (
- $self->get_all_slots,
- map { $_->get_all_slots } $self->get_all_parents,
- ),
+ return @{$self->{attributes}};
}
-sub has_slot {
+sub is_valid_slot {
my ($self, $slot_name) = @_;
- exists $self->{instance_layout}->{$slot_name} ? 1 : 0;
-}
-
-sub has_slot_recursively {
- my ( $self, $slot_name ) = @_;
- return 1 if $self->has_slot($slot_name);
- $_->has_slot_recursively($slot_name) && return 1 for $self->get_all_parents;
- return 0;
+ exists $self->{'slot_hash'}->{$slot_name};
}
-sub remove_slot {
- my ( $self, $slot_name ) = @_;
- # NOTE:
- # this does not search recursively cause
- # that is not the domain of this meta-instance
- # it is specific to this class ...
- confess "The slot '$slot_name' does not exist (maybe it's inherited?)"
- if 0 && $self->has_slot( $slot_name ); # FIXME
- delete $self->{instance_layout}->{$slot_name};
-}
-
-
# operations on created instances
sub get_slot_value {
my ($self, $instance, $slot_name) = @_;
- return $instance->{$slot_name};
+ $instance->{$slot_name};
}
-# can be called only after initialize_slot_value
sub set_slot_value {
my ($self, $instance, $slot_name, $value) = @_;
$instance->{$slot_name} = $value;
}
-# convenience method
-# non autovivifying stores will have this as { initialize_slot unless slot_initlized; set_slot_value }
-sub set_slot_value_with_init {
- my ( $self, $instance, $slot_name, $value ) = @_;
- $self->set_slot_value( $instance, $slot_name, $value );
+sub initialize_slot {
+ my ($self, $instance, $slot_name) = @_;
+ return;
}
-sub initialize_slot {
+sub deinitialize_slot {
my ( $self, $instance, $slot_name ) = @_;
+ delete $instance->{$slot_name};
+}
+
+sub initialize_all_slots {
+ my ($self, $instance) = @_;
+ foreach my $slot_name ($self->get_all_slots) {
+ $self->initialize_slot($instance, $slot_name);
+ }
}
-sub slot_initialized {
+sub deinitialize_all_slots {
+ my ($self, $instance) = @_;
+ foreach my $slot_name ($self->get_all_slots) {
+ $self->deinitialize_slot($instance, $slot_name);
+ }
+}
+
+sub is_slot_initialized {
+ my ($self, $instance, $slot_name, $value) = @_;
+ exists $instance->{$slot_name};
+}
+
+sub weaken_slot_value {
my ($self, $instance, $slot_name) = @_;
- exists $instance->{$slot_name} ? 1 : 0;
+ weaken $instance->{$slot_name};
+}
+
+sub strengthen_slot_value {
+ my ($self, $instance, $slot_name) = @_;
+ $self->set_slot_value($instance, $slot_name, $self->get_slot_value($instance, $slot_name));
+}
+
+sub rebless_instance_structure {
+ my ($self, $instance, $metaclass) = @_;
+
+ # we use $_[1] here because of t/306_rebless_overload.t regressions on 5.8.8
+ bless $_[1], $metaclass->name;
}
+sub is_dependent_on_superclasses {
+ return; # for meta instances that require updates on inherited slot changes
+}
# inlinable operation snippets
+sub is_inlinable { 1 }
+
+sub inline_create_instance {
+ my ($self, $class_variable) = @_;
+ 'bless {} => ' . $class_variable;
+}
+
+sub inline_slot_access {
+ my ($self, $instance, $slot_name) = @_;
+ sprintf q[%s->{"%s"}], $instance, quotemeta($slot_name);
+}
+
sub inline_get_slot_value {
my ($self, $instance, $slot_name) = @_;
- sprintf "%s->{%s}", $instance, $slot_name;
+ $self->inline_slot_access($instance, $slot_name);
}
sub inline_set_slot_value {
my ($self, $instance, $slot_name, $value) = @_;
- $self->_inline_slot_lvalue . " = $value",
+ $self->inline_slot_access($instance, $slot_name) . " = $value",
}
-sub inline_set_slot_value_with_init {
- my ( $self, $instance, $slot_name, $value) = @_;
- $self->inline_set_slot_value( $instance, $slot_name, $value ) . ";";
+sub inline_initialize_slot {
+ my ($self, $instance, $slot_name) = @_;
+ return '';
}
-sub inline_initialize_slot {
- return "";
+sub inline_deinitialize_slot {
+ my ($self, $instance, $slot_name) = @_;
+ "delete " . $self->inline_slot_access($instance, $slot_name);
+}
+sub inline_is_slot_initialized {
+ my ($self, $instance, $slot_name) = @_;
+ "exists " . $self->inline_slot_access($instance, $slot_name);
}
-sub inline_slot_initialized {
+sub inline_weaken_slot_value {
my ($self, $instance, $slot_name) = @_;
- "exists " . $self->inline_get_slot_value;
+ sprintf "Scalar::Util::weaken( %s )", $self->inline_slot_access($instance, $slot_name);
}
-sub _inline_slot_lvalue {
+sub inline_strengthen_slot_value {
my ($self, $instance, $slot_name) = @_;
- $self->inline_slot_value;
+ $self->inline_set_slot_value($instance, $slot_name, $self->inline_slot_access($instance, $slot_name));
}
1;
=pod
-=head1 NAME
+=head1 NAME
Class::MOP::Instance - Instance Meta Object
-=head1 SYNOPSIS
-
=head1 DESCRIPTION
+The Instance Protocol controls the creation of object instances, and
+the storage of attribute values in those instances.
+
+Using this API directly in your own code violates encapsulation, and
+we recommend that you use the appropriate APIs in L<Class::MOP::Class>
+and L<Class::MOP::Attribute> instead. Those APIs in turn call the
+methods in this class as appropriate.
+
+This class also participates in generating inlined code by providing
+snippets of code to access an object instance.
+
=head1 METHODS
+=head2 Object construction
+
=over 4
-=item B<new>
+=item B<< Class::MOP::Instance->new(%options) >>
-=item B<add_slot>
+This method creates a new meta-instance object.
-=item B<bless_instance_structure>
+It accepts the following keys in C<%options>:
-=item B<create_instance>
+=over 8
-=item B<get_all_parents>
+=item * associated_metaclass
-=item B<get_slot_value>
+The L<Class::MOP::Class> object for which instances will be created.
-=item B<has_slot>
+=item * attributes
-=item B<has_slot_recursively>
+An array reference of L<Class::MOP::Attribute> objects. These are the
+attributes which can be stored in each instance.
-=item B<initialize_slot>
+=back
-=item B<inline_get_slot_value>
+=back
+
+=head2 Creating and altering instances
+
+=over 4
+
+=item B<< $metainstance->create_instance >>
+
+This method returns a reference blessed into the associated
+metaclass's class.
+
+The default is to use a hash reference. Subclasses can override this.
+
+=item B<< $metainstance->clone_instance($instance) >>
+
+Given an instance, this method creates a new object by making
+I<shallow> clone of the original.
+
+=back
+
+=head2 Introspection
+
+=over 4
+
+=item B<< $metainstance->associated_metaclass >>
+
+This returns the L<Class::MOP::Class> object associated with the
+meta-instance object.
+
+=item B<< $metainstance->get_all_slots >>
+
+This returns a list of slot names stored in object instances. In
+almost all cases, slot names correspond directly attribute names.
+
+=item B<< $metainstance->is_valid_slot($slot_name) >>
+
+This will return true if C<$slot_name> is a valid slot name.
+
+=item B<< $metainstance->get_all_attributes >>
+
+This returns a list of attributes corresponding to the attributes
+passed to the constructor.
+
+=back
+
+=head2 Operations on Instance Structures
+
+It's important to understand that the meta-instance object is a
+different entity from the actual instances it creates. For this
+reason, any operations on the C<$instance_structure> always require
+that the object instance be passed to the method.
-=item B<inline_initialize_slot>
+=over 4
+
+=item B<< $metainstance->get_slot_value($instance_structure, $slot_name) >>
-=item B<inline_set_slot_value>
+=item B<< $metainstance->set_slot_value($instance_structure, $slot_name, $value) >>
-=item B<inline_set_slot_value_with_init>
+=item B<< $metainstance->initialize_slot($instance_structure, $slot_name) >>
-=item B<inline_slot_initialized>
+=item B<< $metainstance->deinitialize_slot($instance_structure, $slot_name) >>
-=item B<remove_slot>
+=item B<< $metainstance->initialize_all_slots($instance_structure) >>
-=item B<set_slot_value>
+=item B<< $metainstance->deinitialize_all_slots($instance_structure) >>
-=item B<set_slot_value_with_init>
+=item B<< $metainstance->is_slot_initialized($instance_structure, $slot_name) >>
-=item B<slot_initialized>
+=item B<< $metainstance->weaken_slot_value($instance_structure, $slot_name) >>
-=item B<get_all_slots>
+=item B<< $metainstance->strengthen_slot_value($instance_structure, $slot_name) >>
-=item B<get_all_slots_recursively>
+=item B<< $metainstance->rebless_instance_structure($instance_structure, $new_metaclass) >>
+
+The exact details of what each method does should be fairly obvious
+from the method name.
+
+=back
+
+=head2 Inlinable Instance Operations
+
+=over 4
+
+=item B<< $metainstance->is_inlinable >>
+
+This is a boolean that indicates whether or not slot access operations
+can be inlined. By default it is true, but subclasses can override
+this.
+
+=item B<< $metainstance->inline_create_instance($class_variable) >>
+
+This method expects a string that, I<when inlined>, will become a
+class name. This would literally be something like C<'$class'>, not an
+actual class name.
+
+It returns a snippet of code that creates a new object for the
+class. This is something like C< bless {}, $class_name >.
+
+=item B<< $metainstance->inline_slot_access($instance_variable, $slot_name) >>
+
+=item B<< $metainstance->inline_get_slot_value($instance_variable, $slot_name) >>
+
+=item B<< $metainstance->inline_set_slot_value($instance_variable, $slot_name, $value) >>
+
+=item B<< $metainstance->inline_initialize_slot($instance_variable, $slot_name) >>
+
+=item B<< $metainstance->inline_deinitialize_slot($instance_variable, $slot_name) >>
+
+=item B<< $metainstance->inline_is_slot_initialized($instance_variable, $slot_name) >>
+
+=item B<< $metainstance->inline_weaken_slot_value($instance_variable, $slot_name) >>
+
+=item B<< $metainstance->inline_strengthen_slot_value($instance_variable, $slot_name) >>
+
+These methods all expect two arguments. The first is the name of a
+variable, than when inlined, will represent the object
+instance. Typically this will be a literal string like C<'$_[0]'>.
+
+The second argument is a slot name.
+
+The method returns a snippet of code that, when inlined, performs some
+operation on the instance.
=back
=over 4
-=item B<meta>
+=item B<< Class::MOP::Instance->meta >>
-This will return a B<Class::MOP::Class> instance which is related
-to this class.
+This will return a L<Class::MOP::Class> instance for this class.
+
+It should also be noted that L<Class::MOP> will actually bootstrap
+this module by installing a number of attribute meta-objects into its
+metaclass.
=back
-=head1 AUTHOR
+=head1 AUTHORS
+
+Yuval Kogman E<lt>nothingmuch@woobling.comE<gt>
Stevan Little E<lt>stevan@iinteractive.comE<gt>
=head1 COPYRIGHT AND LICENSE
-Copyright 2006 by Infinity Interactive, Inc.
+Copyright 2006-2009 by Infinity Interactive, Inc.
L<http://www.iinteractive.com>
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
-=cut
\ No newline at end of file
projects / gitmo/Class-MOP.git / blobdiff