Use class_of in Immutable

[gitmo/Class-MOP.git] / lib / Class / MOP / Class.pm

diff --git a/lib/Class/MOP/Class.pm b/lib/Class/MOP/Class.pm
index 24c4677..482797e 100644 (file)
--- a/lib/Class/MOP/Class.pm
+++ b/lib/Class/MOP/Class.pm
@@ -11,7 +11,7 @@ use Class::MOP::Method::Wrapped;
 use Carp         'confess';
 use Scalar::Util 'blessed', 'weaken';
 
-our $VERSION   = '0.78';
+our $VERSION   = '0.79';
 $VERSION = eval $VERSION;
 our $AUTHORITY = 'cpan:STEVAN';
 
@@ -169,16 +169,17 @@ sub check_metaclass_compatibility {
             : ref($super_meta);
 
         ($self->isa($super_meta_type))
-            || confess $self->name . "->meta => (" . (ref($self)) . ")" .
-                       " is not compatible with the " .
-                       $superclass_name . "->meta => (" . ($super_meta_type)     . ")";
+            || confess "Class::MOP::class_of(" . $self->name . ") => ("
+                       . (ref($self)) . ")" .  " is not compatible with the " .
+                       "Class::MOP::class_of(".$superclass_name . ") => ("
+                       . ($super_meta_type) . ")";
         # NOTE:
         # we also need to check that instance metaclasses
         # are compatibile in the same the class.
         ($self->instance_metaclass->isa($super_meta->instance_metaclass))
-            || confess $self->name . "->meta->instance_metaclass => (" . ($self->instance_metaclass) . ")" .
+            || confess "Class::MOP::class_of(" . $self->name . ")->instance_metaclass => (" . ($self->instance_metaclass) . ")" .
                        " is not compatible with the " .
-                       $superclass_name . "->meta->instance_metaclass => (" . ($super_meta->instance_metaclass) . ")";
+                       "Class::MOP::class_of(" . $superclass_name . ")->instance_metaclass => (" . ($super_meta->instance_metaclass) . ")";
     }
 }
 
@@ -404,20 +405,16 @@ sub clone_instance {
 sub rebless_instance {
     my ($self, $instance, %params) = @_;
 
-    my $old_metaclass;
-    if ($instance->can('meta')) {
-        ($instance->meta->isa('Class::MOP::Class'))
-            || confess 'Cannot rebless instance if ->meta is not an instance of Class::MOP::Class';
-        $old_metaclass = $instance->meta;
-    }
-    else {
-        $old_metaclass = $self->initialize(ref($instance));
-    }
+    my $old_metaclass = Class::MOP::class_of($instance);
 
-    my $meta_instance = $self->get_meta_instance();
+    my $old_class = $old_metaclass ? $old_metaclass->name : blessed($instance);
+    $self->name->isa($old_class)
+        || confess "You may rebless only into a subclass of ($old_class), of which (". $self->name .") isn't.";
+
+    $old_metaclass->rebless_instance_away($instance, $self, %params)
+        if $old_metaclass;
 
-    $self->name->isa($old_metaclass->name)
-        || confess "You may rebless only into a subclass of (". $old_metaclass->name ."), of which (". $self->name .") isn't.";
+    my $meta_instance = $self->get_meta_instance();
 
     # rebless!
     # we use $_[1] here because of t/306_rebless_overload.t regressions on 5.8.8
@@ -442,6 +439,10 @@ sub rebless_instance {
     $instance;
 }
 
+sub rebless_instance_away {
+    # this intentionally does nothing, it is just a hook
+}
+
 # Inheritance
 
 sub superclasses {
@@ -975,18 +976,31 @@ sub is_immutable { 0 }
 sub immutable_transformer { $_[0]->{immutable_transformer} }
 sub _set_immutable_transformer { $_[0]->{immutable_transformer} = $_[1] }
 
+sub make_immutable {
+    my $self = shift;
+
+    return if $self->is_immutable;
+
+    my $transformer = $self->immutable_transformer
+        || $self->_make_immutable_transformer(@_);
+
+    $self->_set_immutable_transformer($transformer);
+
+    $transformer->make_metaclass_immutable;
+}
+
 {
     my %Default_Immutable_Options = (
         read_only   => [qw/superclasses/],
         cannot_call => [
-            qw/
+            qw(
                 add_method
                 alias_method
                 remove_method
                 add_attribute
                 remove_attribute
                 remove_package_symbol
-                /
+                )
         ],
         memoize => {
             class_precedence_list => 'ARRAY',
@@ -1019,22 +1033,19 @@ sub _set_immutable_transformer { $_[0]->{immutable_transformer} = $_[1] }
         },
     );
 
-    sub make_immutable {
-        my $self = shift;
-
-        return if $self->is_immutable;
-
-        my $transformer = $self->immutable_transformer
-            || Class::MOP::Immutable->new(
-            $self,
-            %Default_Immutable_Options,
-            @_
-            );
+    sub _default_immutable_transformer_options {
+        return %Default_Immutable_Options;
+    }
+}
 
-        $self->_set_immutable_transformer($transformer);
+sub _make_immutable_transformer {
+    my $self = shift;
 
-        $transformer->make_metaclass_immutable;
-    }
+    Class::MOP::Immutable->new(
+        $self,
+        $self->_default_immutable_transformer_options,
+        @_
+    );
 }
 
 sub make_mutable {
@@ -1223,6 +1234,12 @@ like constructor parameters and used to initialize the object's
 attributes. Any existing attributes that are already set will be
 overwritten.
 
+Before reblessing the instance, this method will call
+C<rebless_instance_away> on the instance's current metaclass. This method
+will be passed the instance, the new metaclass, and any parameters
+specified to C<rebless_instance>. By default, C<rebless_instance_away>
+does nothing; it is merely a hook.
+
 =item B<< $metaclass->new_object(%params) >>
 
 This method is used to create a new object of the metaclass's