lighttroupe/luz

#
# DeepClone makes a whole independent new Object, with new copies of internal data structures.
#
# Optionally filter what is cloned vs linked in new object with passed proc.
#
# new_object = object.deep_clone
#
module DeepClone
    def deep_clone(cloned_objects = {}, &is_cloneable_callback)
        return cloned_objects[self] if cloned_objects[self]
        case self
        when Hash
            klone = self.clone.clear
            self.each { |k,v| klone[k.deep_clone(cloned_objects, &is_cloneable_callback)] = v.deep_clone(cloned_objects, &is_cloneable_callback) }
        when Array
            klone = self.clone.map { |obj| obj.deep_clone(cloned_objects, &is_cloneable_callback) }
        else
            begin
                # Determine if we should clone or reuse this object
                is_root_object = cloned_objects.empty?        # (just started clone process)
                if is_root_object || (is_cloneable_callback && is_cloneable_callback.call(self))
                    # klone this object (if possible)
                    begin
                        klone = self.clone
                    rescue NotImplementedError
                        klone = self
                    end
                else
                    # refer to this object
                    klone = self
                end
            rescue
                klone = self
            end
        end
        cloned_objects[self] = klone if klone

        # clone instance variables
        klone.instance_variables.each { |v|
            klone.instance_variable_set(v, klone.instance_variable_get(v).deep_clone(cloned_objects, &is_cloneable_callback))
        }
        klone
    end
end

if $0 == __FILE__
    require 'test/unit'

    class Object
        include DeepClone
    end

    class TestDeepClone < Test::Unit::TestCase
        def test_sometime
            string = "test"
            array = [1,2,3,string]
            assert_equal [1,2,3,string], array.deep_clone
            assert_equal string.object_id, array.deep_clone.last.object_id
            assert_not_equal string.object_id, array.deep_clone { |obj| obj.is_a?(String) }.last.object_id
        end
    end
end