X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FClass%2FMOP%2FInstance.pm;h=b2e406a8f4f60a1ff482e821d8892f91a47ae93b;hb=f0480c45f215203bc40abc794ac0c03622f02f1d;hp=5c1c3c8115cb29e7070a22fba37b05c660f9549a;hpb=76985bf25a320fe0e48e04bb31ee4699e6f78eeb;p=gitmo%2FClass-MOP.git

diff --git a/lib/Class/MOP/Instance.pm b/lib/Class/MOP/Instance.pm
index 5c1c3c8..b2e406a 100644
--- a/lib/Class/MOP/Instance.pm
+++ b/lib/Class/MOP/Instance.pm
@@ -4,10 +4,10 @@ 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   = '0.03';
+our $AUTHORITY = 'cpan:STEVAN';
 
 sub meta { 
     require Class::MOP::Class;
@@ -15,79 +15,51 @@ sub meta {
 }
 
 sub new { 
-    my ( $class, $meta ) = @_;
+    my ($class, $meta, @attrs) = @_;
+    my @slots = map { $_->slots } @attrs;
     bless {
-        meta            => $meta,
-        instance_layout => {}
+        # 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; 
 }
 
 sub create_instance {
-    my ( $self, $class ) = @_;
-    
-    # rely on autovivification
-    $self->bless_instance_structure( {}, $class );
+    my $self = shift;
+    $self->bless_instance_structure({});
 }
 
 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->{meta}->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) = @_;
+    $self->bless_instance_structure({ %$instance });
 }
 
 # 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} };
-}
-
-sub get_all_slots_recursively {
-    my $self = shift;
-    return (
-        $self->get_all_slots,
-        map { $_->get_all_slots } $self->get_all_parents,
-    ),
+    return keys %{$self->{slots}};
 }
 
-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;
-}
-
-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};
+    exists $self->{slots}->{$slot_name} ? 1 : 0;
 }
 
-
 # operations on created instances
 
 sub get_slot_value {
@@ -95,58 +67,96 @@ sub get_slot_value {
     return $instance->{$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) = @_;
+    $self->set_slot_value($instance, $slot_name, undef);
 }
 
-sub initialize_slot {
+sub deinitialize_slot {
     my ( $self, $instance, $slot_name ) = @_;
+    delete $instance->{$slot_name};
 }
 
-sub slot_initialized {
-    my ($self, $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;
 }
 
+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));
+}
 
 # 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) = @_;
+    $self->inline_set_slot_value($instance, $slot_name, 'undef'),
 }
 
-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) . " ? 1 : 0";
 }
 
-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;
@@ -161,66 +171,150 @@ 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.
+
+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<meta>
+
+This will return a B<Class::MOP::Class> instance which is related 
+to this class.
 
-=item B<add_slot>
+=back
 
-=item B<bless_instance_structure>
+=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 
+then calls C<bless_instance_structure> to bless it into the class.
 
-=item B<get_slot_value>
+=item B<bless_instance_structure ($instance_structure)>
 
-=item B<has_slot>
+This does just exactly what it says it does.
 
-=item B<has_slot_recursively>
+=item B<clone_instance ($instance_structure)>
 
-=item B<initialize_slot>
+=back
 
-=item B<inline_get_slot_value>
+=head2 Instrospection
 
-=item B<inline_initialize_slot>
+NOTE: There might be more methods added to this part of the API, 
+we will add then when we need them basically.
 
-=item B<inline_set_slot_value>
+=over 4
 
-=item B<inline_set_slot_value_with_init>
+=item B<get_all_slots>
 
-=item B<inline_slot_initialized>
+This will return the current list of slots based on what was 
+given to this object in C<new>.
 
-=item B<remove_slot>
+=item B<is_valid_slot ($slot_name)>
 
-=item B<set_slot_value>
+=back
 
-=item B<set_slot_value_with_init>
+=head2 Operations on Instance Structures
 
-=item B<slot_initialized>
+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.
 
-=item B<get_all_slots>
+=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<get_all_slots_recursively>
+=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)>
 
 =back
 
-=head2 Introspection
+=head2 Inlineable Instance Operations
+
+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.
 
 =over 4
 
-=item B<meta>
+=item B<is_inlinable>
 
-This will return a B<Class::MOP::Class> instance which is related 
-to this class.
+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 Class::MOP::Class::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>
 
@@ -233,4 +327,5 @@ 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. 
 
-=cut
\ No newline at end of file
+=cut
+