discourse/app/models/concerns/positionable.rb

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2014-04-19 00:00:40 -04:00
module Positionable
extend ActiveSupport::Concern
included do
before_save do
self.position ||= self.class.count
end
end
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def move_to(position_arg)
position = [[position_arg, 0].max, self.class.count - 1].min
if self.position.nil? or position > self.position
self.exec_sql "
UPDATE #{self.class.table_name}
SET position = position - 1
WHERE position > :current_position and position <= :new_position",
{current_position: self.position, new_position: position}
elsif position < self.position
self.exec_sql "
UPDATE #{self.class.table_name}
SET position = position + 1
WHERE position >= :new_position and position < :current_position",
{current_position: self.position, new_position: position}
else
# Not moving to a new position
return
end
self.exec_sql "
UPDATE #{self.class.table_name}
SET position = :position
WHERE id = :id", {id: id, position: position}
end
end