Added insert_at(position) to acts_as_list #1083 [DeLynnB]

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@1179 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

activerecord/CHANGELOG

 *SVN*
 
+* Added insert_at(position) to acts_as_list #1083 [DeLynnB]
+
 * Removed the default order by id on has_and_belongs_to_many queries as it could kill performance on large sets (you can still specify by hand with :order)
 
 * Fixed that Base.silence should restore the old logger level when done, not just set it to DEBUG #1084 [yon@milliped.com]

activerecord/lib/active_record/acts/list.rb

@@ -71,6 +71,10 @@ def position_column
       # lower in the list of all chapters. Likewise, <tt>chapter.first?</tt> would return true if that chapter is
       # the first in the list of all chapters.
       module InstanceMethods
+        def insert_at(position = 1)
+          position == 1 ? add_to_list_top : insert_at_position(position)
+        end
+
         def move_lower
           return unless lower_item
 
@@ -107,7 +111,6 @@ def remove_from_list
           decrement_positions_on_lower_items
         end
 
-
         def increment_position
           update_attribute position_column, self.send(position_column).to_i + 1
         end
@@ -168,24 +171,45 @@ def assume_top_position
             update_attribute(position_column, 1)
           end
 
+          # This has the effect of moving all the higher items up one.
+          def decrement_positions_on_higher_items(position)
+            self.class.update_all(
+              "#{position_column} = (#{position_column} - 1)", "#{scope_condition} AND #{position_column} <= #{position}"
+            )
+	       end
+
           # This has the effect of moving all the lower items up one.
           def decrement_positions_on_lower_items
             self.class.update_all(
-              "#{position_column} = (#{position_column} - 1)",  "#{scope_condition} AND #{position_column} > #{send(position_column).to_i}"
+              "#{position_column} = (#{position_column} - 1)", "#{scope_condition} AND #{position_column} > #{send(position_column).to_i}"
             )
           end
-  
+
+          # This has the effect of moving all the higher items down one.
           def increment_positions_on_higher_items
             self.class.update_all(
-              "#{position_column} = (#{position_column} + 1)",  "#{scope_condition} AND #{position_column} < #{send(position_column).to_i}"
+              "#{position_column} = (#{position_column} + 1)", "#{scope_condition} AND #{position_column} < #{send(position_column).to_i}"
             )
           end
 
+          # This has the effect of moving all the lower items down one.
+          def increment_positions_on_lower_items(position)
+	         self.class.update_all(
+	           "#{position_column} = (#{position_column} + 1)", "#{scope_condition} AND #{position_column} >= #{position}"
+	         )
+	       end
+
           def increment_positions_on_all_items
             self.class.update_all(
               "#{position_column} = (#{position_column} + 1)",  "#{scope_condition}"
             )
           end
+
+          def insert_at_position(position)
+            remove_from_list
+	         increment_positions_on_lower_items(position)
+            self.update_attribute(position_column, position)
+          end
       end     
     end
   end

activerecord/test/mixin_test.rb

@@ -5,7 +5,7 @@
 
 class ListTest < Test::Unit::TestCase
   fixtures :mixins
-  
+ 
   def test_reordering
     
     assert_equal [@mixins['list_1'].find, 
@@ -100,6 +100,32 @@ def test_insert
     assert new.first?
     assert new.last?
   end    
+
+  def test_insert_at
+    new = ListMixin.create("parent_id" => 20)
+    assert_equal 1, new.pos
+
+	 new = ListMixin.create("parent_id" => 20)
+	 assert_equal 2, new.pos
+	
+	 new = ListMixin.create("parent_id" => 20)
+	 assert_equal 3, new.pos
+
+	 new4 = ListMixin.create("parent_id" => 20)
+	 assert_equal 4, new4.pos
+
+	 new4.insert_at(3)
+	 assert_equal 3, new4.pos
+
+	 new.reload
+	 assert_equal 4, new.pos
+    
+    new.insert_at(2)
+    assert_equal 2, new.pos
+
+    new4.reload
+    assert_equal 4, new4.pos
+  end
   
   def test_delete_middle
     
@@ -186,7 +212,6 @@ def test_insert
     assert @tree_1.children.include?(@tree_2)
     assert @tree_1.children.include?(@tree_4)
   end
-  
 
 end
 
@@ -229,7 +254,6 @@ def test_many_updates
 
   end
 
-  
   def test_create_turned_off
     Mixin.record_timestamps = false