Redmine 3.4.4

lib/redmine/acts/positioned.rb

@@ -0,0 +1,118 @@
+# Redmine - project management software
+# Copyright (C) 2006-2017  Jean-Philippe Lang
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License
+# as published by the Free Software Foundation; either version 2
+# of the License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+
+module Redmine
+  module Acts
+    module Positioned
+      def self.included(base)
+        base.extend ClassMethods
+      end
+
+      # This extension provides the capabilities for reordering objects in a list.
+      # The class needs to have a +position+ column defined as an integer on the
+      # mapped database table.
+      module ClassMethods
+        # Configuration options are:
+        #
+        # * +scope+ - restricts what is to be considered a list. Must be a symbol
+        # or an array of symbols
+        def acts_as_positioned(options = {})
+          class_attribute :positioned_options
+          self.positioned_options = {:scope => Array(options[:scope])}
+
+          send :include, Redmine::Acts::Positioned::InstanceMethods
+
+          before_save :set_default_position
+          after_save :update_position
+          after_destroy :remove_position
+        end
+      end
+
+      module InstanceMethods
+        def self.included(base)
+          base.extend ClassMethods
+        end
+
+        private
+
+        def position_scope
+          build_position_scope {|c| send(c)}
+        end
+
+        def position_scope_was
+          build_position_scope {|c| send("#{c}_was")}
+        end
+
+        def build_position_scope
+          condition_hash = self.class.positioned_options[:scope].inject({}) do |h, column|
+            h[column] = yield(column)
+            h
+          end
+          self.class.where(condition_hash)
+        end
+
+        def set_default_position
+          if position.nil?
+            self.position = position_scope.maximum(:position).to_i + (new_record? ? 1 : 0)
+          end
+        end
+
+        def update_position
+          if !new_record? && position_scope_changed?
+            remove_position
+            insert_position
+          elsif position_changed?
+            if position_was.nil?
+              insert_position
+            else
+              shift_positions
+            end
+          end
+        end
+
+        def insert_position
+          position_scope.where("position >= ? AND id <> ?", position, id).update_all("position = position + 1")
+        end
+
+        def remove_position
+          position_scope_was.where("position >= ? AND id <> ?", position_was, id).update_all("position = position - 1")
+        end
+
+        def position_scope_changed?
+          (changed & self.class.positioned_options[:scope].map(&:to_s)).any?
+        end
+
+        def shift_positions
+          offset = position_was <=> position
+          min, max = [position, position_was].sort
+          r = position_scope.where("id <> ? AND position BETWEEN ? AND ?", id, min, max).update_all("position = position + #{offset}")
+          if r != max - min
+            reset_positions_in_list
+          end
+        end
+
+        def reset_positions_in_list
+          position_scope.reorder(:position, :id).pluck(:id).each_with_index do |record_id, p|
+            self.class.where(:id => record_id).update_all(:position => p+1)
+          end
+        end
+      end
+    end
+  end
+end
+
+ActiveRecord::Base.send :include, Redmine::Acts::Positioned