X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FClass%2FMOP%2FClass.pm;h=ff6516e4042b1a388a1f04d04ced1d1ff0508a76;hb=448af783a9e0cb39b939c86157f3e1cedd897c34;hp=f98b44bdfc460e4dc8f9ed03df95b52a6fe03e5e;hpb=5f3c057adabc76dca64d77e3a62484138f790930;p=gitmo%2FClass-MOP.git

diff --git a/lib/Class/MOP/Class.pm b/lib/Class/MOP/Class.pm
index f98b44b..ff6516e 100644
--- a/lib/Class/MOP/Class.pm
+++ b/lib/Class/MOP/Class.pm
@@ -8,6 +8,7 @@ use Carp         'confess';
 use Scalar::Util 'blessed', 'reftype';
 use Sub::Name    'subname';
 use B            'svref_2object';
+use Clone         ();
 
 our $VERSION = '0.03';
 
@@ -22,7 +23,8 @@ sub meta { Class::MOP::Class->initialize($_[0]) }
     # there is no need to worry about destruction though
     # because they should die only when the program dies.
     # After all, do package definitions even get reaped?
-    my %METAS;
+    my %METAS;    
+    
     sub initialize {
         my $class        = shift;
         my $package_name = shift;
@@ -30,8 +32,7 @@ sub meta { Class::MOP::Class->initialize($_[0]) }
             || confess "You must pass a package name";    
         # make sure the package name is not blessed
         $package_name = blessed($package_name) || $package_name;
-        return $METAS{$package_name} if exists $METAS{$package_name};
-        $METAS{$package_name} = $class->construct_class_instance($package_name, @_);
+        $class->construct_class_instance(':package' => $package_name, @_);
     }
     
     # NOTE: (meta-circularity) 
@@ -42,16 +43,20 @@ sub meta { Class::MOP::Class->initialize($_[0]) }
     # normal &construct_instance.
     sub construct_class_instance {
         my $class        = shift;
-        my $package_name = shift;
+        my %options      = @_;
+        my $package_name = $options{':package'};
         (defined $package_name && $package_name)
-            || confess "You must pass a package name";    
+            || confess "You must pass a package name";  
+        return $METAS{$package_name} if exists $METAS{$package_name};              
         $class = blessed($class) || $class;
+        # now create the metaclass
+        my $meta;
         if ($class =~ /^Class::MOP::/) {    
-            bless { 
+            $meta = bless { 
                 '$:package'             => $package_name, 
                 '%:attributes'          => {},
-                '$:attribute_metaclass' => 'Class::MOP::Attribute',
-                '$:method_metaclass'    => 'Class::MOP::Method',                
+                '$:attribute_metaclass' => $options{':attribute_metaclass'} || 'Class::MOP::Attribute',
+                '$:method_metaclass'    => $options{':method_metaclass'}    || 'Class::MOP::Method',                
             } => $class;
         }
         else {
@@ -59,8 +64,30 @@ sub meta { Class::MOP::Class->initialize($_[0]) }
             # it is safe to use meta here because
             # class will always be a subclass of 
             # Class::MOP::Class, which defines meta
-            bless $class->meta->construct_instance(':package' => $package_name, @_) => $class
+            $meta = bless $class->meta->construct_instance(%options) => $class
         }
+        # and check the metaclass compatibility
+        $meta->check_metaclass_compatability();
+        $METAS{$package_name} = $meta;
+    }
+    
+    sub check_metaclass_compatability {
+        my $self = shift;
+
+        # this is always okay ...
+        return if blessed($self) eq 'Class::MOP::Class';
+
+        my @class_list = $self->class_precedence_list;
+        shift @class_list; # shift off $self->name
+
+        foreach my $class_name (@class_list) { 
+            next unless $METAS{$class_name};
+            my $meta = $METAS{$class_name};
+            ($self->isa(blessed($meta)))
+                || confess $self->name . "->meta => (" . (blessed($self)) . ")" . 
+                           " is not compatible with the " . 
+                           $class_name . "->meta => (" . (blessed($meta)) . ")";
+        }        
     }
 }
 
@@ -94,10 +121,28 @@ sub create {
     return $meta;
 }
 
+## Attribute readers
+
+# NOTE:
+# all these attribute readers will be bootstrapped 
+# away in the Class::MOP bootstrap section
+
+sub name                { $_[0]->{'$:package'}             }
+sub get_attribute_map   { $_[0]->{'%:attributes'}          }
+sub attribute_metaclass { $_[0]->{'$:attribute_metaclass'} }
+sub method_metaclass    { $_[0]->{'$:method_metaclass'}    }
+
 # Instance Construction & Cloning
 
 sub new_object {
     my $class = shift;
+    # NOTE:
+    # we need to protect the integrity of the 
+    # Class::MOP::Class singletons here, so we
+    # delegate this to &construct_class_instance
+    # which will deal with the singletons
+    return $class->construct_class_instance(@_)
+        if $class->name->isa('Class::MOP::Class');
     bless $class->construct_instance(@_) => $class->name;
 }
 
@@ -105,7 +150,7 @@ sub construct_instance {
     my ($class, %params) = @_;
     my $instance = {};
     foreach my $attr ($class->compute_all_applicable_attributes()) {
-        my $init_arg = $attr->has_init_arg() ? $attr->init_arg() : $attr->name;
+        my $init_arg = $attr->init_arg();
         # try to fetch the init arg from the %params ...
         my $val;        
         $val = $params{$init_arg} if exists $params{$init_arg};
@@ -119,22 +164,30 @@ sub construct_instance {
 
 sub clone_object {
     my $class    = shift;
-    my $instance = shift;
-    bless $class->clone_instance($instance, @_) => $class->name;
+    my $instance = shift; 
+    (blessed($instance) && $instance->isa($class->name))
+        || confess "You must pass an instance ($instance) of the metaclass (" . $class->name . ")";
+    # NOTE:
+    # we need to protect the integrity of the 
+    # Class::MOP::Class singletons here, they 
+    # should not be cloned.
+    return $instance if $instance->isa('Class::MOP::Class');   
+    bless $class->clone_instance($instance, @_) => blessed($instance);
 }
 
 sub clone_instance {
-    my ($class, $self, %params) = @_;
-    (blessed($self))
+    my ($class, $instance, %params) = @_;
+    (blessed($instance))
         || confess "You can only clone instances, \$self is not a blessed instance";
     # NOTE:
-    # this should actually do a deep clone
-    # instead of this cheap hack. I will 
-    # add that in later. 
-    # (use the Class::Cloneable::Util code)
-    my $clone = { %{$self} }; 
+    # This will deep clone, which might
+    # not be what you always want. So 
+    # the best thing is to write a more
+    # controled &clone method locally 
+    # in the class (see Class::MOP)
+    my $clone = Clone::clone($instance); 
     foreach my $attr ($class->compute_all_applicable_attributes()) {
-        my $init_arg = $attr->has_init_arg() ? $attr->init_arg() : $attr->name;
+        my $init_arg = $attr->init_arg();
         # try to fetch the init arg from the %params ...        
         $clone->{$attr->name} = $params{$init_arg} 
             if exists $params{$init_arg};
@@ -144,7 +197,8 @@ sub clone_instance {
 
 # Informational 
 
-sub name { $_[0]->{'$:package'} }
+# &name should be here too, but it is above
+# because it gets bootstrapped away
 
 sub version {  
     my $self = shift;
@@ -183,9 +237,6 @@ sub class_precedence_list {
 
 ## Methods
 
-# un-used right now ...
-sub method_metaclass { $_[0]->{'$:method_metaclass'} }
-
 sub add_method {
     my ($self, $method_name, $method) = @_;
     (defined $method_name && $method_name)
@@ -306,8 +357,6 @@ sub find_all_methods_by_name {
 
 ## Attributes
 
-sub attribute_metaclass { $_[0]->{'$:attribute_metaclass'} }
-
 sub add_attribute {
     my $self      = shift;
     # either we have an attribute object already
@@ -318,21 +367,21 @@ sub add_attribute {
         || confess "Your attribute must be an instance of Class::MOP::Attribute (or a subclass)";    
     $attribute->attach_to_class($self);
     $attribute->install_accessors();        
-    $self->{'%:attrs'}->{$attribute->name} = $attribute;
+    $self->get_attribute_map->{$attribute->name} = $attribute;
 }
 
 sub has_attribute {
     my ($self, $attribute_name) = @_;
     (defined $attribute_name && $attribute_name)
         || confess "You must define an attribute name";
-    exists $self->{'%:attrs'}->{$attribute_name} ? 1 : 0;    
+    exists $self->get_attribute_map->{$attribute_name} ? 1 : 0;    
 } 
 
 sub get_attribute {
     my ($self, $attribute_name) = @_;
     (defined $attribute_name && $attribute_name)
         || confess "You must define an attribute name";
-    return $self->{'%:attrs'}->{$attribute_name} 
+    return $self->get_attribute_map->{$attribute_name} 
         if $self->has_attribute($attribute_name);    
 } 
 
@@ -340,8 +389,8 @@ sub remove_attribute {
     my ($self, $attribute_name) = @_;
     (defined $attribute_name && $attribute_name)
         || confess "You must define an attribute name";
-    my $removed_attribute = $self->{'%:attrs'}->{$attribute_name};    
-    delete $self->{'%:attrs'}->{$attribute_name} 
+    my $removed_attribute = $self->get_attribute_map->{$attribute_name};    
+    delete $self->get_attribute_map->{$attribute_name} 
         if defined $removed_attribute;        
     $removed_attribute->remove_accessors();        
     $removed_attribute->detach_from_class();    
@@ -350,7 +399,7 @@ sub remove_attribute {
 
 sub get_attribute_list {
     my $self = shift;
-    keys %{$self->{'%:attrs'}};
+    keys %{$self->get_attribute_map};
 } 
 
 sub compute_all_applicable_attributes {
@@ -523,7 +572,7 @@ to it.
 This initializes and returns returns a B<Class::MOP::Class> object 
 for a given a C<$package_name>.
 
-=item B<construct_class_instance ($package_name)>
+=item B<construct_class_instance (%options)>
 
 This will construct an instance of B<Class::MOP::Class>, it is 
 here so that we can actually "tie the knot" for B<Class::MOP::Class> 
@@ -531,6 +580,14 @@ to use C<construct_instance> once all the bootstrapping is done. This
 method is used internally by C<initialize> and should never be called
 from outside of that method really.
 
+=item B<check_metaclass_compatability>
+
+This method is called as the very last thing in the 
+C<construct_class_instance> method. This will check that the 
+metaclass you are creating is compatible with the metaclasses of all 
+your ancestors. For more inforamtion about metaclass compatibility 
+see the C<About Metaclass compatibility> section in L<Class::MOP>.
+
 =back
 
 =head2 Object instance construction and cloning
@@ -730,6 +787,8 @@ their own. See L<Class::MOP::Attribute> for more details.
 
 =item B<attribute_metaclass>
 
+=item B<get_attribute_map>
+
 =item B<add_attribute ($attribute_name, $attribute_meta_object)>
 
 This stores a C<$attribute_meta_object> in the B<Class::MOP::Class>