Module: Mongoid::Acts::NestedSet::Rebuild

Included in:
Document::ClassMethods
Defined in:
lib/mongoid_nested_set/rebuild.rb

Instance Method Summary collapse

Instance Method Details

#rebuild!(options = {}) ⇒ Object

Rebuilds the left & rights if unset or invalid. Also very useful for converting from acts_as_tree. Warning: Very expensive!



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# File 'lib/mongoid_nested_set/rebuild.rb', line 7

def rebuild!(options = {})
  # Don't rebuild a valid tree.
  return true if valid?

  scope = lambda{ |node| {} }
  if acts_as_nested_set_options[:scope]
    scope = lambda { |node| node.nested_set_scope.options.merge(node.nested_set_scope.selector) }
  end
  indices = {}

  set_left_and_rights = lambda do |node|
    # set left
    left = (indices[scope.call(node)] += 1)
    # find
    node.nested_set_scope.where(parent_field_name => node.id).asc(left_field_name).asc(right_field_name).each { |n| set_left_and_rights.call(n) }
    # set right
    right = (indices[scope.call(node)] += 1)

    node.class.collection.find(:_id => node.id).update(
      {"$set" => {left_field_name => left, right_field_name => right}},
      {:safe => true}
    )
  end

  # Find root node(s)
  root_nodes = self.where(parent_field_name => nil).asc(left_field_name).asc(right_field_name).asc(:_id).each do |root_node|
    # setup index for this scope
    indices[scope.call(root_node)] ||= 0
    set_left_and_rights.call(root_node)
  end
end