X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FClass%2FMOP%2FInstance.pm;h=e90ba69d5b29ad017039d6c0d1d10c2b5ec356e6;hb=c16a3087fabac823b511ab1fcfa10d0f64f53bf6;hp=b8e24509b65739ddbfc848b4e8e13a2467ef5dbf;hpb=fc3ddd1d180b39fdcde1f7169e14cfbc7fdf55de;p=gitmo%2FClass-MOP.git

diff --git a/lib/Class/MOP/Instance.pm b/lib/Class/MOP/Instance.pm
index b8e2450..e90ba69 100644
--- a/lib/Class/MOP/Instance.pm
+++ b/lib/Class/MOP/Instance.pm
@@ -4,57 +4,108 @@ package Class::MOP::Instance;
 use strict;
 use warnings;
 
-use Carp         'confess';
-use Scalar::Util 'blessed', 'reftype', 'weaken';
+use Scalar::Util 'weaken', 'blessed';
 
-our $VERSION = '0.01';
+our $VERSION   = '0.74';
+$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 { $_->name } @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 => \@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 {
     my ($self, $instance_structure) = @_;
-    bless $instance_structure, $self->{meta}->name;
+    bless $instance_structure, $self->_class_name;
+}
+
+sub clone_instance {
+    my ($self, $instance) = @_;
+    bless { %$instance }, $self->_class_name;
 }
 
 # operations on meta instance
 
 sub get_all_slots {
     my $self = shift;
-    return @{$self->{slots}};
+    return @{$self->{'slots'}};
+}
+
+sub get_all_attributes {
+    my $self = shift;
+    return @{$self->{attributes}};
+}
+
+sub is_valid_slot {
+    my ($self, $slot_name) = @_;
+    exists $self->{'slot_hash'}->{$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 {
@@ -64,34 +115,98 @@ sub set_slot_value {
 
 sub initialize_slot {
     my ($self, $instance, $slot_name) = @_;
-    $instance->{$slot_name} = undef;
+    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} ? 1 : 0;
+    exists $instance->{$slot_name};
+}
+
+sub weaken_slot_value {
+    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, $slot_name));
+}
+
+sub rebless_instance_structure {
+    my ($self, $instance, $metaclass) = @_;
+    bless $instance, $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 "%s->{%s}", $instance, $slot_name;
+}
+
 sub inline_get_slot_value {
-    my ($self, $instance_var_name, $slot_name) = @_;
-    return ($instance_var_name . '->{\'' . $slot_name . '\'}');
+    my ($self, $instance, $slot_name) = @_;
+    $self->inline_slot_access($instance, $slot_name);
 }
 
 sub inline_set_slot_value {
-    my ($self, $instance_var_name, $slot_name, $value_name) = @_;
-    return ($self->inline_get_slot_value($instance_var_name, $slot_name) . ' = ' . $value_name); 
+    my ($self, $instance, $slot_name, $value) = @_;
+    $self->inline_slot_access($instance, $slot_name) . " = $value",
 }
 
 sub inline_initialize_slot {
-    my ($self, $instance_var_name, $slot_name) = @_;
-    $self->inline_set_slot_value($instance_var_name, $slot_name, 'undef');
+    my ($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_var_name, $slot_name) = @_;
-    return ('exists ' . $self->inline_get_slot_value($instance_var_name, $slot_name) . ' ? 1 : 0'); 
+    my ($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;
@@ -100,68 +215,183 @@ __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 %args>
+
+Creates a new instance meta-object and gathers all the slots from
+the list of C<@attrs> given.
+
+=item B<BUILDARGS>
+
+Processes arguments for compatibility.
+
+=item B<meta>
+
+Returns the metaclass of L<Class::MOP::Instance>.
 
-=item B<bless_instance_structure>
+=back
+
+=head2 Creation of Instances
 
-=item B<compute_layout_from_class>
+=over 4
 
 =item B<create_instance>
 
+This creates the appropriate structure needed for the instance and blesses it.
+
+=item B<bless_instance_structure ($instance_structure)>
+
+This does just exactly what it says it does.
+
+This method has been deprecated but remains for compatibility reasons. None of
+the subclasses of L<Class::MOP::Instance> ever bothered to actually make use of
+it, so it was deemed unnecessary fluff.
+
+=item B<clone_instance ($instance_structure)>
+
+Creates a shallow clone of $instance_structure.
+
+=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<associated_metaclass>
+
+This returns the metaclass associated with this instance.
+
 =item B<get_all_slots>
 
-=item B<get_slot_value>
+This will return the current list of slots based on what was
+given to this object in C<new>.
 
-=item B<set_slot_value>
+=item B<is_valid_slot ($slot_name)>
 
-=item B<initialize_slot>
+This will return true if C<$slot_name> is a valid slot name.
 
-=item B<is_slot_initialized>
+=item B<is_dependent_on_superclasses>
 
-=item B<inline_get_slot_value>
+This method returns true when the meta instance must be recreated on any
+superclass changes.
 
-=item B<inline_set_slot_value>
+Defaults to false.
 
-=item B<inline_initialize_slot>
+=item B<get_all_attributes>
 
-=item B<inline_is_slot_initialized>
+This will return the current list of attributes (as
+Class::MOP::Attribute objects) based on what was given to this object
+in C<new>.
 
 =back
 
-=head2 Introspection
+=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<meta>
+=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)>
 
-This will return a B<Class::MOP::Class> instance which is related 
-to this class.
+=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
 
-=head1 AUTHOR
+=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 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
+