Refactor column definer module (#258)

* Refactoring: use a better variable name

Rename column -> position_column to make it clear what kind of column we're
talking about.

* Refactoring: rename ColumnMethodDefiner -> PositionColumnMethodDefiner

* Refactoring: extract PositionColumnMethodDefiner.define_instance_methods

* Refactoring: extract PositionColumnMethodDefiner.define_class_methods

* Refactoring: define_class_methods before define_instance_methods

* Refactoring: remove redundant interpolation

* Refactoring: extract .mass_assignment_protection_was_used_by_user?

* Refactoring: extract .protect_attributes_from_mass_assignment

* Replace gratuitous defined? with #respond_to?

* Replace !o.blank? with o.present?

lib/acts_as_list.rb

@@ -1,5 +1,5 @@
 require 'acts_as_list/active_record/acts/list'
-require "acts_as_list/active_record/acts/column_method_definer"
+require "acts_as_list/active_record/acts/position_column_method_definer"
 require "acts_as_list/active_record/acts/scope_method_definer"
 require "acts_as_list/active_record/acts/top_of_list_method_definer"
 require "acts_as_list/active_record/acts/add_new_at_method_definer"

lib/acts_as_list/active_record/acts/list.rb

@@ -20,7 +20,7 @@ def acts_as_list(options = {})
 
     caller_class = self
 
-    ActiveRecord::Acts::List::ColumnMethodDefiner.call(caller_class, configuration[:column])
+    ActiveRecord::Acts::List::PositionColumnMethodDefiner.call(caller_class, configuration[:column])
     ActiveRecord::Acts::List::ScopeMethodDefiner.call(caller_class, configuration[:scope])
     ActiveRecord::Acts::List::TopOfListMethodDefiner.call(caller_class, configuration[:top_of_list])
     ActiveRecord::Acts::List::AddNewAtMethodDefiner.call(caller_class, configuration[:add_new_at])

lib/acts_as_list/active_record/acts/column_method_definer.rb → lib/acts_as_list/active_record/acts/position_column_method_definer.rb

@@ -1,25 +1,19 @@
-module ActiveRecord::Acts::List::ColumnMethodDefiner #:nodoc:
-  def self.call(caller_class, column)
-    caller_class.class_eval do
-      attr_reader :position_changed
-
-      define_method :position_column do
-        column
-      end
+module ActiveRecord::Acts::List::PositionColumnMethodDefiner #:nodoc:
+  def self.call(caller_class, position_column)
+    define_class_methods(caller_class, position_column)
+    define_instance_methods(caller_class, position_column)
 
-      define_method :"#{column}=" do |position|
-        write_attribute(column, position)
-        @position_changed = true
-      end
+    if mass_assignment_protection_was_used_by_user?(caller_class)
+      protect_attributes_from_mass_assignment(caller_class, position_column)
+    end
+  end
 
-      # only add to attr_accessible
-      # if the class has some mass_assignment_protection
-      if defined?(accessible_attributes) and !accessible_attributes.blank?
-        attr_accessible :"#{column}"
-      end
+  private
 
+  def self.define_class_methods(caller_class, position_column)
+    caller_class.class_eval do
       define_singleton_method :quoted_position_column do
-        @_quoted_position_column ||= connection.quote_column_name(column)
+        @_quoted_position_column ||= connection.quote_column_name(position_column)
       end
 
       define_singleton_method :quoted_position_column_with_table_name do
@@ -47,4 +41,31 @@ def self.call(caller_class, column)
       end
     end
   end
+
+  def self.define_instance_methods(caller_class, position_column)
+    caller_class.class_eval do
+      attr_reader :position_changed
+
+      define_method :position_column do
+        position_column
+      end
+
+      define_method :"#{position_column}=" do |position|
+        write_attribute(position_column, position)
+        @position_changed = true
+      end
+    end
+  end
+
+  def self.mass_assignment_protection_was_used_by_user?(caller_class)
+    caller_class.class_eval do
+      respond_to?(:accessible_attributes) and accessible_attributes.present?
+    end
+  end
+
+  def self.protect_attributes_from_mass_assignment(caller_class, position_column)
+    caller_class.class_eval do
+      attr_accessible position_column.to_sym
+    end
+  end
 end