X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FClass%2FMOP%2FInstance.pm;h=e3163edd662528f742bf082666933687b256f7f3;hb=e45f0a07c741bb8b8eedbbab139d245fc4cf7c4a;hp=13010c2764161555b00cd253e43050b8d3fb2157;hpb=eb49acde749ac77e0d8d5218914507a8db2afb05;p=gitmo%2FClass-MOP.git

diff --git a/lib/Class/MOP/Instance.pm b/lib/Class/MOP/Instance.pm
index 13010c2..e3163ed 100644
--- a/lib/Class/MOP/Instance.pm
+++ b/lib/Class/MOP/Instance.pm
@@ -4,149 +4,209 @@ 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 $VERSION   = '0.68';
+$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, $meta ) = @_;
+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, %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, $slot_name);
+    }
+}
+
+sub deinitialize_all_slots {
+    my ($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 slot_initialized {
+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) = @_;
+    bless $instance, $metaclass->name;
+}
+
+sub is_dependent_on_superclasses {
+    return; # for meta instances that require updates on inherited slot changes
+}
 
 # inlinable operation snippets
 
-sub inline_get_slot_value {
+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_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;
@@ -155,78 +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>
 
-=item B<add_slot>
+Creates a new instance meta-object and gathers all the slots from
+the list of C<@attrs> given.
 
-=item B<bless_instance_structure>
+=item B<BUILDARGS>
+
+Processes arguments for compatibility.
+
+=item B<meta>
+
+Returns the metaclass of L<Class::MOP::Instance>.
+
+=back
+
+=head2 Creation of Instances
+
+=over 4
 
 =item B<create_instance>
 
-=item B<get_all_parents>
+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.
 
-=item B<get_slot_value>
+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<has_slot>
+=item B<clone_instance ($instance_structure)>
 
-=item B<has_slot_recursively>
+Creates a shallow clone of $instance_structure.
 
-=item B<initialize_slot>
+=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>
 
-=item B<inline_get_slot_value>
+This returns the metaclass associated with this instance.
 
-=item B<inline_initialize_slot>
+=item B<get_all_slots>
 
-=item B<inline_set_slot_value>
+This will return the current list of slots based on what was
+given to this object in C<new>.
 
-=item B<inline_set_slot_value_with_init>
+=item B<is_valid_slot ($slot_name)>
 
-=item B<inline_slot_initialized>
+This will return true if C<$slot_name> is a valid slot name.
 
-=item B<remove_slot>
+=item B<is_dependent_on_superclasses>
 
-=item B<set_slot_value>
+This method returns true when the meta instance must be recreated on any
+superclass changes.
 
-=item B<set_slot_value_with_init>
+Defaults to false.
 
-=item B<slot_initialized>
+=item B<get_all_attributes>
+
+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)>
 
-This will return a B<Class::MOP::Class> instance which is related 
-to this class.
+=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
 
-=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
 
-=cut
\ No newline at end of file