From: Shawn M Moore <sartak@gmail.com>
Date: Sun, 25 May 2008 00:57:35 +0000 (+0000)
Subject: MooseX::AttributeHelpers::Trait::Base
X-Git-Tag: 0.18_01~30
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=3b5070d198dd35cbbeb6a932719e5ce86dd49ceb;p=gitmo%2FMooseX-AttributeHelpers.git

MooseX::AttributeHelpers::Trait::Base
---

diff --git a/lib/MooseX/AttributeHelpers/Trait/Base.pm b/lib/MooseX/AttributeHelpers/Trait/Base.pm
new file mode 100644
index 0000000..9ab3f6e
--- /dev/null
+++ b/lib/MooseX/AttributeHelpers/Trait/Base.pm
@@ -0,0 +1,153 @@
+
+package MooseX::AttributeHelpers::Trait::Base;
+use Moose::Role;
+use Moose::Util::TypeConstraints;
+
+our $VERSION   = '0.04';
+our $AUTHORITY = 'cpan:STEVAN';
+
+requires 'helper_type';
+
+# this is the method map you define ...
+has 'provides' => (
+    is      => 'ro',
+    isa     => 'HashRef',
+    default => sub {{}}
+);
+
+
+# these next two are the possible methods
+# you can use in the 'provides' map.
+
+# provide a Class or Role which we can
+# collect the method providers from
+has 'method_provider' => (
+    is        => 'ro',
+    isa       => 'ClassName',
+    predicate => 'has_method_provider',
+);
+
+# or you can provide a HASH ref of anon subs
+# yourself. This will also collect and store
+# the methods from a method_provider as well
+has 'method_constructors' => (
+    is      => 'ro',
+    isa     => 'HashRef',
+    lazy    => 1,
+    default => sub {
+        my $self = shift;
+        return +{} unless $self->has_method_provider;
+        # or grab them from the role/class
+        my $method_provider = $self->method_provider->meta;
+        return +{
+            map {
+                $_ => $method_provider->get_method($_)
+            } $method_provider->get_method_list
+        };
+    },
+);
+
+# extend the parents stuff to make sure
+# certain bits are now required ...
+has '+$!default'       => (required => 1);
+has '+type_constraint' => (required => 1);
+
+## Methods called prior to instantiation
+
+sub process_options_for_provides {
+    my ($self, $options) = @_;
+
+    if (my $type = $self->helper_type) {
+        (exists $options->{isa})
+            || confess "You must define a type with the $type metaclass";
+
+        my $isa = $options->{isa};
+
+        unless (blessed($isa) && $isa->isa('Moose::Meta::TypeConstraint')) {
+            $isa = Moose::Util::TypeConstraints::find_or_create_type_constraint($isa);
+        }
+
+        ($isa->is_a_type_of($type))
+            || confess "The type constraint for a $type ($options->{isa}) must be a subtype of $type";
+    }
+}
+
+before '_process_options' => sub {
+    my ($self, $name, $options) = @_;
+    $self->process_options_for_provides($options, $name);
+};
+
+## methods called after instantiation
+
+# this confirms that provides has
+# all valid possibilities in it
+sub check_provides_values {
+    my $self = shift;
+
+    my $method_constructors = $self->method_constructors;
+
+    foreach my $key (keys %{$self->provides}) {
+        (exists $method_constructors->{$key})
+            || confess "$key is an unsupported method type";
+    }
+}
+
+after 'install_accessors' => sub {
+    my $attr  = shift;
+    my $class = $attr->associated_class;
+
+    # grab the reader and writer methods
+    # as well, this will be useful for
+    # our method provider constructors
+    my $attr_reader = $attr->get_read_method_ref;
+    my $attr_writer = $attr->get_write_method_ref;
+
+
+    # before we install them, lets
+    # make sure they are valid
+    $attr->check_provides_values;
+
+    my $method_constructors = $attr->method_constructors;
+
+    my $class_name = $class->name;
+
+    foreach my $key (keys %{$attr->provides}) {
+
+        my $method_name = $attr->provides->{$key};
+
+        if ($class->has_method($method_name)) {
+            confess "The method ($method_name) already exists in class (" . $class->name . ")";
+        }
+
+        my $method = MooseX::AttributeHelpers::Meta::Method::Provided->wrap(
+            $method_constructors->{$key}->(
+                $attr,
+                $attr_reader,
+                $attr_writer,
+            ),
+            package_name => $class_name,
+            name => $method_name,
+        );
+        
+        $attr->associate_method($method);
+        $class->add_method($method_name => $method);
+    }
+};
+
+after 'remove_accessors' => sub {
+    my $attr  = shift;
+    my $class = $attr->associated_class;
+    foreach my $key (keys %{$attr->provides}) {
+        my $method_name = $attr->provides->{$key};
+        my $method = $class->get_method($method_name);
+        $class->remove_method($method_name)
+            if blessed($method) &&
+               $method->isa('MooseX::AttributeHelpers::Meta::Method::Provided');
+    }
+};
+
+no Moose::Role;
+no Moose::Util::TypeConstraints;
+
+1;
+