X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FClass%2FMOP%2FInstance.pm;h=77c5d536b5373cb9d579e1fefc08e2aa3d00096e;hb=7202116b012d65b1c71d42819a0d2aa2ec5d3bd1;hp=7d1e573814d12e96b60e969d638365de77d6f4bb;hpb=24869f62f2c588b527cdb80aee59a9867e51f0ba;p=gitmo%2FClass-MOP.git

diff --git a/lib/Class/MOP/Instance.pm b/lib/Class/MOP/Instance.pm
index 7d1e573..77c5d53 100644
--- a/lib/Class/MOP/Instance.pm
+++ b/lib/Class/MOP/Instance.pm
@@ -4,30 +4,168 @@ package Class::MOP::Instance;
 use strict;
 use warnings;
 
-use Carp         'confess';
-use Scalar::Util 'blessed', 'reftype', 'weaken';
+use Scalar::Util 'weaken', 'blessed';
+
+our $VERSION   = '0.64';
+our $AUTHORITY = 'cpan:STEVAN';
+
+use base 'Class::MOP::Object';
+
+sub new {
+    my ($class, $meta, @attrs) = @_;
+    my @slots = map { $_->slots } @attrs;
+    my $instance = bless {
+        # NOTE:
+        # I am not sure that it makes
+        # sense to pass in the meta
+        # The ideal would be to just
+        # pass in the class name, but
+        # that is placing too much of
+        # an assumption on bless(),
+        # which is *probably* a safe
+        # assumption,.. but you can
+        # never tell <:)
+        '$!meta'  => $meta,
+        '@!slots' => { map { $_ => undef } @slots },
+    } => $class;
+
+    weaken($instance->{'$!meta'});
+
+    return $instance;
+}
+
+sub associated_metaclass { (shift)->{'$!meta'} }
+
+sub create_instance {
+    my $self = shift;
+    $self->bless_instance_structure({});
+}
+
+sub bless_instance_structure {
+    my ($self, $instance_structure) = @_;
+    bless $instance_structure, $self->associated_metaclass->name;
+}
+
+sub clone_instance {
+    my ($self, $instance) = @_;
+    $self->bless_instance_structure({ %$instance });
+}
+
+# operations on meta instance
+
+sub get_all_slots {
+    my $self = shift;
+    return keys %{$self->{'@!slots'}};
+}
+
+sub is_valid_slot {
+    my ($self, $slot_name) = @_;
+    exists $self->{'@!slots'}->{$slot_name};
+}
+
+# operations on created instances
 
-our $VERSION = '0.01';
+sub get_slot_value {
+    my ($self, $instance, $slot_name) = @_;
+    $instance->{$slot_name};
+}
+
+sub set_slot_value {
+    my ($self, $instance, $slot_name, $value) = @_;
+    $instance->{$slot_name} = $value;
+}
+
+sub initialize_slot {
+    my ($self, $instance, $slot_name) = @_;
+    return;
+}
+
+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, $slot_name);
+    }
+}
+
+sub deinitialize_all_slots {
+    my ($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 meta { 
-    require Class::MOP::Class;
-    Class::MOP::Class->initialize(blessed($_[0]) || $_[0]);
+sub weaken_slot_value {
+    my ($self, $instance, $slot_name) = @_;
+    weaken $instance->{$slot_name};
 }
 
-sub new { 
-    my $class = shift;
-    my $meta  = shift;
-    bless {
-        instance => bless {} => $meta->name
-    } => $class; 
+sub strengthen_slot_value {
+    my ($self, $instance, $slot_name) = @_;
+    $self->set_slot_value($instance, $slot_name, $self->get_slot_value($instance, $slot_name));
 }
 
-sub add_slot {
-    my ($self, $slot_name, $value) = @_;
-    return $self->{instance}->{$slot_name} = $value;
+sub rebless_instance_structure {
+    my ($self, $instance, $metaclass) = @_;
+    bless $instance, $metaclass->name;
 }
 
-sub get_instance { (shift)->{instance} }
+# 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 "%s->{%s}", $instance, $slot_name;
+}
+
+sub inline_get_slot_value {
+    my ($self, $instance, $slot_name) = @_;
+    $self->inline_slot_access($instance, $slot_name);
+}
+
+sub inline_set_slot_value {
+    my ($self, $instance, $slot_name, $value) = @_;
+    $self->inline_slot_access($instance, $slot_name) . " = $value",
+}
+
+sub inline_initialize_slot {
+    my ($self, $instance, $slot_name) = @_;
+    return '';
+}
+
+sub inline_deinitialize_slot {
+    my ($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, $slot_name);
+}
+
+sub inline_weaken_slot_value {
+    my ($self, $instance, $slot_name) = @_;
+    sprintf "Scalar::Util::weaken( %s )", $self->inline_slot_access($instance, $slot_name);
+}
+
+sub inline_strengthen_slot_value {
+    my ($self, $instance, $slot_name) = @_;
+    $self->inline_set_slot_value($instance, $slot_name, $self->inline_slot_access($instance, $slot_name));
+}
 
 1;
 
@@ -35,48 +173,164 @@ __END__
 
 =pod
 
-=head1 NAME 
+=head1 NAME
 
 Class::MOP::Instance - Instance Meta Object
 
-=head1 SYNOPSIS
-
 =head1 DESCRIPTION
 
+The meta instance is used by attributes for low level storage.
+
+Using this API generally violates attribute encapsulation and is not
+recommended, instead look at L<Class::MOP::Attribute/get_value>,
+L<Class::MOP::Attribute/set_value> for the recommended way to fiddle with
+attribute values in a generic way, independent of how/whether accessors have
+been defined. Accessors can be found using L<Class::MOP::Class/get_attribute>.
+
+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).
+
 =head1 METHODS
 
 =over 4
 
-=item B<new>
+=item B<new ($meta, @attrs)>
+
+Creates a new instance meta-object and gathers all the slots from
+the list of C<@attrs> given.
 
-=item B<add_slot>
+=item B<meta>
 
-=item B<get_instance>
+This will return a B<Class::MOP::Class> instance which is related
+to this class.
+
+=back
+
+=head2 Creation of Instances
+
+=over 4
+
+=item B<create_instance>
+
+This creates the appropriate structure needed for the instance and
+then calls C<bless_instance_structure> to bless it into the class.
+
+=item B<bless_instance_structure ($instance_structure)>
+
+This does just exactly what it says it does.
+
+=item B<clone_instance ($instance_structure)>
+
+This too does just exactly what it says it does.
 
 =back
 
 =head2 Introspection
 
+NOTE: There might be more methods added to this part of the API,
+we will add then when we need them basically.
+
 =over 4
 
-=item B<meta>
+=item B<associated_metaclass>
 
-This will return a B<Class::MOP::Class> instance which is related 
-to this class.
+This returns the metaclass associated with this instance.
+
+=item B<get_all_slots>
+
+This will return the current list of slots based on what was
+given to this object in C<new>.
+
+=item B<is_valid_slot ($slot_name)>
+
+This will return true if C<$slot_name> is a valid slot name.
+
+=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<$instance_structure> is passed into them.
+
+The names of these methods pretty much explain exactly 
+what they do, if that is not enough then I suggest reading 
+the source, it is very straightfoward.
+
+=over 4
+
+=item B<get_slot_value ($instance_structure, $slot_name)>
+
+=item B<set_slot_value ($instance_structure, $slot_name, $value)>
+
+=item B<initialize_slot ($instance_structure, $slot_name)>
+
+=item B<deinitialize_slot ($instance_structure, $slot_name)>
+
+=item B<initialize_all_slots ($instance_structure)>
+
+=item B<deinitialize_all_slots ($instance_structure)>
+
+=item B<is_slot_initialized ($instance_structure, $slot_name)>
+
+=item B<weaken_slot_value ($instance_structure, $slot_name)>
+
+=item B<strengthen_slot_value ($instance_structure, $slot_name)>
+
+=item B<rebless_instance_structure ($instance_structure, $new_metaclass)>
+
+=back
+
+=head2 Inlineable Instance Operations
+
+=over 4
+
+=item B<is_inlinable>
+
+Each meta-instance should override this method to tell Class::MOP if it's
+possible to inline the slot access. This is currently only used by 
+L<Class::MOP::Immutable> when performing optimizations.
+
+=item B<inline_create_instance>
+
+=item B<inline_slot_access ($instance_structure, $slot_name)>
+
+=item B<inline_get_slot_value ($instance_structure, $slot_name)>
+
+=item B<inline_set_slot_value ($instance_structure, $slot_name, $value)>
+
+=item B<inline_initialize_slot ($instance_structure, $slot_name)>
+
+=item B<inline_deinitialize_slot ($instance_structure, $slot_name)>
+
+=item B<inline_is_slot_initialized ($instance_structure, $slot_name)>
+
+=item B<inline_weaken_slot_value ($instance_structure, $slot_name)>
+
+=item B<inline_strengthen_slot_value ($instance_structure, $slot_name)>
 
 =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 2006-2008 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