use Scalar::Util 'weaken', 'blessed';
-our $VERSION = '0.02';
+our $VERSION = '0.82_01';
+$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, @attrs) = @_;
- my @slots = map { $_->slots } @attrs;
+sub _new {
+ my ( $class, %options ) = @_;
bless {
# 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(),
+ # 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
+ # assumption,.. but you can
# never tell <:)
- meta => $meta,
- slots => { map { $_ => undef } @slots },
- } => $class;
+ '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 = shift;
- $self->bless_instance_structure({});
+ bless {}, $self->_class_name;
}
+# for compatibility
sub bless_instance_structure {
+ Carp::cluck('The bless_instance_structure method is deprecated.'
+ . " It will be removed in a future release.\n");
+
my ($self, $instance_structure) = @_;
- bless $instance_structure, $self->{meta}->name;
+ bless $instance_structure, $self->_class_name;
}
sub clone_instance {
my ($self, $instance) = @_;
- $self->bless_instance_structure({ %$instance });
+ bless { %$instance }, $self->_class_name;
}
# operations on meta instance
sub get_all_slots {
my $self = shift;
- return keys %{$self->{slots}};
+ return @{$self->{'slots'}};
+}
+
+sub get_all_attributes {
+ my $self = shift;
+ return @{$self->{attributes}};
}
sub is_valid_slot {
my ($self, $slot_name) = @_;
- exists $self->{slots}->{$slot_name} ? 1 : 0;
+ exists $self->{'slot_hash'}->{$slot_name};
}
# operations on created instances
sub get_slot_value {
my ($self, $instance, $slot_name) = @_;
- return $instance->{$slot_name};
+ $instance->{$slot_name};
}
sub set_slot_value {
sub initialize_slot {
my ($self, $instance, $slot_name) = @_;
- $self->set_slot_value($instance, $slot_name, undef);
+ return;
}
sub deinitialize_slot {
sub is_slot_initialized {
my ($self, $instance, $slot_name, $value) = @_;
- exists $instance->{$slot_name} ? 1 : 0;
+ exists $instance->{$slot_name};
}
sub weaken_slot_value {
- my ($self, $instance, $slot_name) = @_;
- weaken $instance->{$slot_name};
+ my ($self, $instance, $slot_name) = @_;
+ 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, $slot_name));
+ my ($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], $metaclass->name;
+}
+
+sub is_dependent_on_superclasses {
+ return; # for meta instances that require updates on inherited slot changes
}
# inlinable operation snippets
sub inline_slot_access {
my ($self, $instance, $slot_name) = @_;
- sprintf "%s->{%s}", $instance, $slot_name;
+ sprintf q[%s->{"%s"}], $instance, quotemeta($slot_name);
}
sub inline_get_slot_value {
sub inline_set_slot_value {
my ($self, $instance, $slot_name, $value) = @_;
- $self->inline_slot_access($instance, $slot_name) . " = $value",
+ $self->inline_slot_access($instance, $slot_name) . " = $value",
}
sub inline_initialize_slot {
my ($self, $instance, $slot_name) = @_;
- $self->inline_set_slot_value($instance, $slot_name, 'undef'),
+ return '';
}
sub inline_deinitialize_slot {
}
sub inline_is_slot_initialized {
my ($self, $instance, $slot_name) = @_;
- "exists " . $self->inline_slot_access($instance, $slot_name) . " ? 1 : 0";
+ "exists " . $self->inline_slot_access($instance, $slot_name);
}
sub inline_weaken_slot_value {
=pod
-=head1 NAME
+=head1 NAME
Class::MOP::Instance - Instance Meta Object
-=head1 SYNOPSIS
-
- # for the most part, this protocol is internal
- # and not for public usage, but this how one
- # might use it
-
- package Foo;
-
- use strict;
- use warnings;
- use metaclass (
- ':instance_metaclass' => 'ArrayBasedStorage::Instance',
- );
-
- # now Foo->new produces blessed ARRAY ref based objects
-
=head1 DESCRIPTION
-This is a sub-protocol which governs instance creation
-and access to the slots of the instance structure.
+The Instance Protocol controls the creation of object instances, and
+the storage of attribute values in those instances.
-This may seem like over-abstraction, but by abstracting
-this process into a sub-protocol we make it possible to
-easily switch the details of how an object's instance is
-stored with minimal impact. In most cases just subclassing
-this class will be all you need to do (see the examples;
-F<examples/ArrayBasedStorage.pod> and
-F<examples/InsideOutClass.pod> for details).
+Using this API directly in your own code violates encapsulation, and
+we recommend that you use the appropriate APIs in L<Class::MOP::Class>
+and L<Class::MOP::Attribute> instead. Those APIs in turn call the
+methods in this class as appropriate.
+
+This class also participates in generating inlined code by providing
+snippets of code to access an object instance.
=head1 METHODS
+=head2 Object construction
+
=over 4
-=item B<new ($meta, @attrs)>
+=item B<< Class::MOP::Instance->new(%options) >>
+
+This method creates a new meta-instance object.
-Creates a new instance meta-object and gathers all the slots from
-the list of C<@attrs> given.
+It accepts the following keys in C<%options>:
-=item B<meta>
+=over 8
-This will return a B<Class::MOP::Class> instance which is related
-to this class.
+=item * associated_metaclass
+
+The L<Class::MOP::Class> object for which instances will be created.
+
+=item * attributes
+
+An array reference of L<Class::MOP::Attribute> objects. These are the
+attributes which can be stored in each instance.
=back
-=head2 Creation of Instances
+=back
+
+=head2 Creating and altering instances
=over 4
-=item B<create_instance>
+=item B<< $metainstance->create_instance >>
-This creates the appropriate structure needed for the instance and
-then calls C<bless_instance_structure> to bless it into the class.
+This method returns a reference blessed into the associated
+metaclass's class.
-=item B<bless_instance_structure ($instance_structure)>
+The default is to use a hash reference. Subclasses can override this.
-This does just exactly what it says it does.
+=item B<< $metainstance->clone_instance($instance) >>
-=item B<clone_instance ($instance_structure)>
+Given an instance, this method creates a new object by making
+I<shallow> clone of the original.
=back
-=head2 Instrospection
-
-NOTE: There might be more methods added to this part of the API,
-we will add then when we need them basically.
+=head2 Introspection
=over 4
-=item B<get_all_slots>
+=item B<< $metainstance->associated_metaclass >>
+
+This returns the L<Class::MOP::Class> object associated with the
+meta-instance object.
-This will return the current list of slots based on what was
-given to this object in C<new>.
+=item B<< $metainstance->get_all_slots >>
-=item B<is_valid_slot ($slot_name)>
+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<< $metainstance->get_all_attributes >>
+
+This returns a list of attributes corresponding to the attributes
+passed to the constructor.
=back
=head2 Operations on Instance Structures
-An important distinction of this sub-protocol is that the
-instance meta-object is a different entity from the actual
-instance it creates. For this reason, any actions on slots
-require that the C<$instance_structure> is passed into them.
+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<$instance_structure> always require
+that the object instance be passed to the method.
=over 4
-=item B<get_slot_value ($instance_structure, $slot_name)>
+=item B<< $metainstance->get_slot_value($instance_structure, $slot_name) >>
-=item B<set_slot_value ($instance_structure, $slot_name, $value)>
+=item B<< $metainstance->set_slot_value($instance_structure, $slot_name, $value) >>
-=item B<initialize_slot ($instance_structure, $slot_name)>
+=item B<< $metainstance->initialize_slot($instance_structure, $slot_name) >>
-=item B<deinitialize_slot ($instance_structure, $slot_name)>
+=item B<< $metainstance->deinitialize_slot($instance_structure, $slot_name) >>
-=item B<initialize_all_slots ($instance_structure)>
+=item B<< $metainstance->initialize_all_slots($instance_structure) >>
-=item B<deinitialize_all_slots ($instance_structure)>
+=item B<< $metainstance->deinitialize_all_slots($instance_structure) >>
-=item B<is_slot_initialized ($instance_structure, $slot_name)>
+=item B<< $metainstance->is_slot_initialized($instance_structure, $slot_name) >>
-=item B<weaken_slot_value ($instance_structure, $slot_name)>
+=item B<< $metainstance->weaken_slot_value($instance_structure, $slot_name) >>
-=item B<strengthen_slot_value ($instance_structure, $slot_name)>
+=item B<< $metainstance->strengthen_slot_value($instance_structure, $slot_name) >>
-=back
+=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.
-=head2 Inlineable Instance Operations
+=back
-This part of the API is currently un-used. It is there for use
-in future experiments in class finailization mostly. Best to
-ignore this for now.
+=head2 Inlinable Instance Operations
=over 4
-=item B<is_inlinable>
+=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) >>
-Each meta-instance should override this method to tell Class::MOP if it's
-possible to inline the slot access.
+=item B<< $metainstance->inline_set_slot_value($instance_variable, $slot_name, $value) >>
-This is currently only used by Class::MOP::Class::Immutable when performing
-optimizations.
+=item B<< $metainstance->inline_initialize_slot($instance_variable, $slot_name) >>
-=item B<inline_create_instance>
+=item B<< $metainstance->inline_deinitialize_slot($instance_variable, $slot_name) >>
-=item B<inline_slot_access ($instance_structure, $slot_name)>
+=item B<< $metainstance->inline_is_slot_initialized($instance_variable, $slot_name) >>
-=item B<inline_get_slot_value ($instance_structure, $slot_name)>
+=item B<< $metainstance->inline_weaken_slot_value($instance_variable, $slot_name) >>
-=item B<inline_set_slot_value ($instance_structure, $slot_name, $value)>
+=item B<< $metainstance->inline_strengthen_slot_value($instance_variable, $slot_name) >>
-=item B<inline_initialize_slot ($instance_structure, $slot_name)>
+These methods all expect two arguments. The first is the name of a
+variable, than when inlined, will represent the object
+instance. Typically this will be a literal string like C<'$_[0]'>.
-=item B<inline_deinitialize_slot ($instance_structure, $slot_name)>
+The second argument is a slot name.
+
+The method returns a snippet of code that, when inlined, performs some
+operation on the instance.
+
+=back
+
+=head2 Introspection
+
+=over 4
-=item B<inline_is_slot_initialized ($instance_structure, $slot_name)>
+=item B<< Class::MOP::Instance->meta >>
-=item B<inline_weaken_slot_value ($instance_structure, $slot_name)>
+This will return a L<Class::MOP::Class> instance for this class.
-=item B<inline_strengthen_slot_value ($instance_structure, $slot_name)>
+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 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
projects / gitmo/Class-MOP.git / blobdiff