Class: SimpleNestedSet::Rebuild::FromParents

Inherits:
Object
  • Object
show all
Includes:
SqlAbstraction
Defined in:
lib/simple_nested_set/rebuild/from_parents.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from SqlAbstraction

#group_concat, #order_by

Constructor Details

#initialize ⇒ FromParents

Returns a new instance of FromParents.



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# File 'lib/simple_nested_set/rebuild/from_parents.rb', line 8

def initialize
  @num = 0
end

Instance Attribute Details

#num ⇒ Object

Returns the value of attribute num.



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# File 'lib/simple_nested_set/rebuild/from_parents.rb', line 6

def num
  @num
end

Instance Method Details

#child?(node, child) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/simple_nested_set/rebuild/from_parents.rb', line 47

def child?(node, child)
  if child.root?
    false
  elsif direct_child?(node, child)
    true
  else
    # recurse to find indirect children,
    # i.e. the child is one of the grandchildren of the node
    child?(node, child.parent)
  end
end

#direct_child?(node, child) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/simple_nested_set/rebuild/from_parents.rb', line 59

def direct_child? node, child
  child.parent_id == node.id
end

#extract_children(node, nodes) ⇒ Object 



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# File 'lib/simple_nested_set/rebuild/from_parents.rb', line 41

def extract_children(node, nodes)
  children = nodes.select { |child| child?(node, child) }
  nodes.replace(nodes - children)
  children
end

#renumber(nodes) ⇒ Object 



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# File 'lib/simple_nested_set/rebuild/from_parents.rb', line 31

def renumber(nodes)
  until nodes.empty?
    node = nodes.shift
    node.lft = self.num += 1
    num = renumber(extract_children(node, nodes))
    node.rgt = self.num += 1
  end
  num
end

#run(nested_set, sort_order = :id) ⇒ Object 



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# File 'lib/simple_nested_set/rebuild/from_parents.rb', line 12

def run(nested_set, sort_order = :id)
  order_columns = ([:parent_id] + Array[sort_order]).uniq.compact

  db_adapter = nested_set.first.class.connection.instance_variable_get('@config')[:adapter].to_sym

  order_clause = order_columns.map do |col|
    order_by(db_adapter, col)
  end

  nodes = if nested_set.respond_to?(:except)
            nested_set.except(:order).order(order_clause)
          else
            nested_set.reorder(order_clause)
          end.to_a

  renumber(nodes.dup)
  nodes.each(&:save)
end