Module: Mover::ClassMethods

Defined in:
lib/mover.rb

Instance Method Summary collapse

Instance Method Details

#after_copy(*to_class, &block) ⇒ Object 



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# File 'lib/mover.rb', line 24

def after_copy(*to_class, &block)
  @after_copy ||= []
  @after_copy << [ to_class, block ]
end

#after_move(*to_class, &block) ⇒ Object 



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# File 'lib/mover.rb', line 14

def after_move(*to_class, &block)
  @after_move ||= []
  @after_move << [ to_class, block ]
end

#before_copy(*to_class, &block) ⇒ Object 



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# File 'lib/mover.rb', line 29

def before_copy(*to_class, &block)
  @before_copy ||= []
  @before_copy << [ to_class, block ]
end

#before_move(*to_class, &block) ⇒ Object 



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# File 'lib/mover.rb', line 19

def before_move(*to_class, &block)
  @before_move ||= []
  @before_move << [ to_class, block ]
end

#copy_to(to_class, conditions, instance = nil) ⇒ Object 



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# File 'lib/mover.rb', line 130

def copy_to(to_class, conditions, instance=nil)
  move_to(to_class, conditions, instance, true)
end

#move_to(to_class, conditions, instance = nil, copy = false) ⇒ Object 



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# File 'lib/mover.rb', line 34

def move_to(to_class, conditions, instance=nil, copy = false)
  from_class = self
  # Conditions
  add_conditions! where = '', conditions
  # Columns
  insert = from_class.column_names & to_class.column_names
  insert -= [ 'moved_at' ]
  insert.collect! { |col| connection.quote_column_name(col) }
  select = insert.clone
  # Magic columns
  if to_class.column_names.include?('moved_at')
    insert << connection.quote_column_name('moved_at')
    select << connection.quote(Time.now.utc)
  end
  # Callbacks
  collector = lambda do |(classes, block)|
    classes.collect! { |c| eval(c.to_s) }
    block if classes.include?(to_class) || classes.empty?
  end
  if copy
    before = (@before_copy || []).collect(&collector).compact
    after = (@after_copy || []).collect(&collector).compact
  else # move
    before = (@before_move || []).collect(&collector).compact
    after = (@after_move || []).collect(&collector).compact
  end
  # Instances
  instances =
    if instance
      [ instance ]
    elsif before.empty? && after.empty?
      []
    else
      self.find(:all, :conditions => where[5..-1])
    end
  # Callback executor
  exec_callbacks = lambda do |callbacks|
    callbacks.each do |block|
      instances.each { |instance| instance.instance_eval(&block) }
    end
  end
  # Execute
  transaction do
    exec_callbacks.call before
    if copy
      # for copy existing rows require an UPDATE statment, new rows require an INSERT statement
      from_ids   = from_class.find(:all, :select => "id", :conditions => where[5..-1]).collect(&:id)
      to_ids     = to_class.find(:all, :select => "id", :conditions => where[5..-1]).collect(&:id)
      trash_ids  = to_ids - from_ids
      # rid of the 'extra' to_ids to ensure to_ids is always be a subset of from_ids
      insert_ids = from_ids - to_ids - trash_ids
      update_ids = to_ids - insert_ids - trash_ids
      
      unless update_ids.empty?
        # add table scope to columns for the UPDATE statement
        update = []
        insert.each_with_index{|col, i|
          to   = insert[i].include?('`') ? "#{to_class.table_name}.#{insert[i]}"   : insert[i]
          from = select[i].include?('`') ? "#{from_class.table_name}.#{select[i]}" : select[i]
          update << "#{to} = #{from}"
        }
        where_ids = update_ids.collect{|x| "#{from_class.table_name}.id = #{x}"}
        connection.execute(<<-SQL)
          UPDATE #{to_class.table_name}
          INNER JOIN #{from_class.table_name}
          ON #{to_class.table_name}.id = #{from_class.table_name}.id
          AND (#{where_ids.join(' AND ')})
          SET #{update.join(', ')}
        SQL
      end

      unless insert_ids.empty?
        # insert ids, same as move except using a different where clause
        where_ids = insert_ids.collect{|x| "#{from_class.table_name}.id = #{x}"}
        sql =<<-SQL
          INSERT INTO #{to_class.table_name} (#{insert.join(', ')})
          SELECT #{select.join(', ')}
          FROM #{from_class.table_name}
          WHERE (#{where_ids.join(' OR ')})
        SQL
        connection.execute(sql)
      end
    else
      # moves
      connection.execute(<<-SQL)
        INSERT INTO #{to_class.table_name} (#{insert.join(', ')})
        SELECT #{select.join(', ')}
        FROM #{from_class.table_name}
        #{where}
      SQL
      connection.execute("DELETE FROM #{from_class.table_name} #{where}")
    end
    exec_callbacks.call after
  end
end

#reserve_id ⇒ Object 



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# File 'lib/mover.rb', line 134

def reserve_id
  id = nil
  transaction do
    id = connection.insert("INSERT INTO #{self.table_name} () VALUES ()")
    connection.execute("DELETE FROM #{self.table_name} WHERE id = #{id}") if id
  end
  id
end