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- # frozen_string_literal: true
-
- module ActiveRecord
- module Acts
- module Tree
- def self.included(base)
- base.extend(ClassMethods)
- end
-
- # Specify this +acts_as+ extension if you want to model a tree structure by providing a parent association and a children
- # association. This requires that you have a foreign key column, which by default is called +parent_id+.
- #
- # class Category < ApplicationRecord
- # acts_as_tree :order => "name"
- # end
- #
- # Example:
- # root
- # \_ child1
- # \_ subchild1
- # \_ subchild2
- #
- # root = Category.create("name" => "root")
- # child1 = root.children.create("name" => "child1")
- # subchild1 = child1.children.create("name" => "subchild1")
- #
- # root.parent # => nil
- # child1.parent # => root
- # root.children # => [child1]
- # root.children.first.children.first # => subchild1
- #
- # In addition to the parent and children associations, the following instance methods are added to the class
- # after calling <tt>acts_as_tree</tt>:
- # * <tt>siblings</tt> - Returns all the children of the parent, excluding the current node (<tt>[subchild2]</tt> when called on <tt>subchild1</tt>)
- # * <tt>self_and_siblings</tt> - Returns all the children of the parent, including the current node (<tt>[subchild1, subchild2]</tt> when called on <tt>subchild1</tt>)
- # * <tt>ancestors</tt> - Returns all the ancestors of the current node (<tt>[child1, root]</tt> when called on <tt>subchild2</tt>)
- # * <tt>root</tt> - Returns the root of the current node (<tt>root</tt> when called on <tt>subchild2</tt>)
- module ClassMethods
- # Configuration options are:
- #
- # * <tt>foreign_key</tt> - specifies the column name to use for tracking of the tree (default: +parent_id+)
- # * <tt>order</tt> - makes it possible to sort the children according to this SQL snippet.
- # * <tt>counter_cache</tt> - keeps a count in a +children_count+ column if set to +true+ (default: +false+).
- def acts_as_tree(options = {})
- configuration = { :foreign_key => "parent_id", :dependent => :destroy, :order => nil, :counter_cache => nil }
- configuration.update(options) if options.is_a?(Hash)
-
- belongs_to :parent, :class_name => name, :foreign_key => configuration[:foreign_key], :counter_cache => configuration[:counter_cache]
- has_many :children, lambda {order(configuration[:order])}, :class_name => name, :foreign_key => configuration[:foreign_key], :dependent => configuration[:dependent]
-
- scope :roots, lambda {
- where("#{configuration[:foreign_key]} IS NULL").
- order(configuration[:order])
- }
- send :include, ActiveRecord::Acts::Tree::InstanceMethods
- end
- end
-
- module InstanceMethods
- # Returns list of ancestors, starting from parent until root.
- #
- # subchild1.ancestors # => [child1, root]
- def ancestors
- node, nodes = self, []
- nodes << node = node.parent while node.parent
- nodes
- end
-
- # Returns list of descendants.
- #
- # root.descendants # => [child1, subchild1, subchild2]
- def descendants(depth=nil)
- depth ||= 0
- result = children.dup
- unless depth == 1
- result += children.collect {|child| child.descendants(depth-1)}.flatten
- end
- result
- end
-
- # Returns list of descendants and a reference to the current node.
- #
- # root.self_and_descendants # => [root, child1, subchild1, subchild2]
- def self_and_descendants(depth=nil)
- [self] + descendants(depth)
- end
-
- # Returns the root node of the tree.
- def root
- node = self
- node = node.parent while node.parent
- node
- end
-
- # Returns all siblings of the current node.
- #
- # subchild1.siblings # => [subchild2]
- def siblings
- self_and_siblings - [self]
- end
-
- # Returns all siblings and a reference to the current node.
- #
- # subchild1.self_and_siblings # => [subchild1, subchild2]
- def self_and_siblings
- parent ? parent.children : self.class.roots
- end
- end
- end
- end
- end
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