Turned ActiveRecord::Acts::Tree into a plugin #9514 [lifolifo]

README

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+acts_as_tree
+============
+
+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 < ActiveRecord::Base
+    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
+
+Copyright (c) 2007 David Heinemeier Hansson, released under the MIT license  

Rakefile

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+require 'rake'
+require 'rake/testtask'
+require 'rake/rdoctask'
+
+desc 'Default: run unit tests.'
+task :default => :test
+
+desc 'Test acts_as_tree plugin.'
+Rake::TestTask.new(:test) do |t|
+  t.libs << 'lib'
+  t.pattern = 'test/**/*_test.rb'
+  t.verbose = true
+end
+
+desc 'Generate documentation for in_place_editing plugin.'
+Rake::RDocTask.new(:rdoc) do |rdoc|
+  rdoc.rdoc_dir = 'rdoc'
+  rdoc.title    = 'InPlaceEditing'
+  rdoc.options << '--line-numbers' << '--inline-source'
+  rdoc.rdoc_files.include('README')
+  rdoc.rdoc_files.include('lib/**/*.rb')
+end

init.rb

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+require 'acts_as_tree'

lib/acts_as_tree.rb

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+module ActsAsTree
+  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 < ActiveRecord::Base
+  #     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", :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, :class_name => name, :foreign_key => configuration[:foreign_key], :order => configuration[:order], :dependent => :destroy
+
+      class_eval <<-EOV
+        include ActsAsTree::InstanceMethods
+
+        def self.roots
+          find(:all, :conditions => "#{configuration[:foreign_key]} IS NULL", :order => #{configuration[:order].nil? ? "nil" : %Q{"#{configuration[:order]}"}})
+        end
+
+        def self.root
+          find(:first, :conditions => "#{configuration[:foreign_key]} IS NULL", :order => #{configuration[:order].nil? ? "nil" : %Q{"#{configuration[:order]}"}})
+        end
+      EOV
+    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 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
+
+ActiveRecord::Base.send(:include, ActsAsTree)

test/abstract_unit.rb

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+$:.unshift(File.dirname(__FILE__) + '/../../../rails/activesupport/lib')
+$:.unshift(File.dirname(__FILE__) + '/../../../rails/activerecord/lib')
+$:.unshift(File.dirname(__FILE__) + '/../lib')
+
+require 'test/unit'
+require 'active_support'
+require 'active_record'
+require 'active_record/fixtures'
+require 'acts_as_tree'
+
+config = YAML::load(IO.read(File.dirname(__FILE__) + '/database.yml'))
+ActiveRecord::Base.logger = Logger.new(File.dirname(__FILE__) + "/debug.log")
+ActiveRecord::Base.configurations = {'test' => config[ENV['DB'] || 'sqlite3']}
+ActiveRecord::Base.establish_connection(ActiveRecord::Base.configurations['test'])
+
+load(File.dirname(__FILE__) + "/schema.rb") if File.exist?(File.dirname(__FILE__) + "/schema.rb")
+
+class Test::Unit::TestCase #:nodoc:
+  self.fixture_path = File.dirname(__FILE__) + "/fixtures/" 
+  self.use_transactional_fixtures = true
+  self.use_instantiated_fixtures  = false
+
+  def create_fixtures(*table_names, &block)
+    Fixtures.create_fixtures(File.dirname(__FILE__) + "/fixtures/", table_names, {}, &block)
+  end
+
+  def assert_queries(num = 1)
+    $query_count = 0
+    yield
+  ensure
+    assert_equal num, $query_count, "#{$query_count} instead of #{num} queries were executed."
+  end
+
+  def assert_no_queries(&block)
+    assert_queries(0, &block)
+  end
+
+end

test/acts_as_tree_test.rb

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+require File.join(File.dirname(__FILE__), 'abstract_unit')
+require File.join(File.dirname(__FILE__), 'fixtures/mixin')
+
+class TreeTest < Test::Unit::TestCase
+  fixtures :mixins
+
+  def test_children
+    assert_equal mixins(:tree_1).children, mixins(:tree_2, :tree_4)
+    assert_equal mixins(:tree_2).children, [mixins(:tree_3)]
+    assert_equal mixins(:tree_3).children, []
+    assert_equal mixins(:tree_4).children, []
+  end
+
+  def test_parent
+    assert_equal mixins(:tree_2).parent, mixins(:tree_1)
+    assert_equal mixins(:tree_2).parent, mixins(:tree_4).parent
+    assert_nil mixins(:tree_1).parent
+  end
+
+  def test_delete
+    assert_equal 6, TreeMixin.count
+    mixins(:tree_1).destroy
+    assert_equal 2, TreeMixin.count
+    mixins(:tree2_1).destroy
+    mixins(:tree3_1).destroy
+    assert_equal 0, TreeMixin.count
+  end
+
+  def test_insert
+    @extra = mixins(:tree_1).children.create
+
+    assert @extra
+
+    assert_equal @extra.parent, mixins(:tree_1)
+
+    assert_equal 3, mixins(:tree_1).children.size
+    assert mixins(:tree_1).children.include?(@extra)
+    assert mixins(:tree_1).children.include?(mixins(:tree_2))
+    assert mixins(:tree_1).children.include?(mixins(:tree_4))
+  end
+
+  def test_ancestors
+    assert_equal [], mixins(:tree_1).ancestors
+    assert_equal [mixins(:tree_1)], mixins(:tree_2).ancestors
+    assert_equal mixins(:tree_2, :tree_1), mixins(:tree_3).ancestors
+    assert_equal [mixins(:tree_1)], mixins(:tree_4).ancestors
+    assert_equal [], mixins(:tree2_1).ancestors
+    assert_equal [], mixins(:tree3_1).ancestors
+  end
+
+  def test_root
+    assert_equal mixins(:tree_1), TreeMixin.root
+    assert_equal mixins(:tree_1), mixins(:tree_1).root
+    assert_equal mixins(:tree_1), mixins(:tree_2).root
+    assert_equal mixins(:tree_1), mixins(:tree_3).root
+    assert_equal mixins(:tree_1), mixins(:tree_4).root
+    assert_equal mixins(:tree2_1), mixins(:tree2_1).root
+    assert_equal mixins(:tree3_1), mixins(:tree3_1).root
+  end
+
+  def test_roots
+    assert_equal mixins(:tree_1, :tree2_1, :tree3_1), TreeMixin.roots
+  end
+
+  def test_siblings
+    assert_equal mixins(:tree2_1, :tree3_1), mixins(:tree_1).siblings
+    assert_equal [mixins(:tree_4)], mixins(:tree_2).siblings
+    assert_equal [], mixins(:tree_3).siblings
+    assert_equal [mixins(:tree_2)], mixins(:tree_4).siblings
+    assert_equal mixins(:tree_1, :tree3_1), mixins(:tree2_1).siblings
+    assert_equal mixins(:tree_1, :tree2_1), mixins(:tree3_1).siblings
+  end
+
+  def test_self_and_siblings
+    assert_equal mixins(:tree_1, :tree2_1, :tree3_1), mixins(:tree_1).self_and_siblings
+    assert_equal mixins(:tree_2, :tree_4), mixins(:tree_2).self_and_siblings
+    assert_equal [mixins(:tree_3)], mixins(:tree_3).self_and_siblings
+    assert_equal mixins(:tree_2, :tree_4), mixins(:tree_4).self_and_siblings
+    assert_equal mixins(:tree_1, :tree2_1, :tree3_1), mixins(:tree2_1).self_and_siblings
+    assert_equal mixins(:tree_1, :tree2_1, :tree3_1), mixins(:tree3_1).self_and_siblings
+  end           
+end
+
+class TreeTestWithEagerLoading < Test::Unit::TestCase
+  fixtures :mixins
+
+  def test_eager_association_loading
+    roots = TreeMixin.find(:all, :include=>"children", :conditions=>"mixins.parent_id IS NULL", :order=>"mixins.id")
+    assert_equal mixins(:tree_1, :tree2_1, :tree3_1), roots
+    assert_no_queries do
+      assert_equal 2, roots[0].children.size
+      assert_equal 0, roots[1].children.size
+      assert_equal 0, roots[2].children.size
+    end
+  end
+
+  def test_eager_association_loading_with_recursive_cascading_three_levels_has_many
+    root_node = RecursivelyCascadedTreeMixin.find(:first, :include=>{:children=>{:children=>:children}}, :order => 'mixins.id')
+    assert_equal mixins(:recursively_cascaded_tree_4), assert_no_queries { root_node.children.first.children.first.children.first }
+  end
+
+  def test_eager_association_loading_with_recursive_cascading_three_levels_has_one
+    root_node = RecursivelyCascadedTreeMixin.find(:first, :include=>{:first_child=>{:first_child=>:first_child}}, :order => 'mixins.id')
+    assert_equal mixins(:recursively_cascaded_tree_4), assert_no_queries { root_node.first_child.first_child.first_child }
+  end
+
+  def test_eager_association_loading_with_recursive_cascading_three_levels_belongs_to
+    leaf_node = RecursivelyCascadedTreeMixin.find(:first, :include=>{:parent=>{:parent=>:parent}}, :order => 'mixins.id DESC')
+    assert_equal mixins(:recursively_cascaded_tree_1), assert_no_queries { leaf_node.parent.parent.parent }
+  end
+end
+
+class TreeTestWithoutOrder < Test::Unit::TestCase
+  fixtures :mixins
+
+  def test_root
+    assert mixins(:tree_without_order_1, :tree_without_order_2).include?(TreeMixinWithoutOrder.root)
+  end
+
+  def test_roots
+    assert_equal [], mixins(:tree_without_order_1, :tree_without_order_2) - TreeMixinWithoutOrder.roots
+  end
+end

test/database.yml

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+sqlite:
+  :adapter: sqlite
+  :dbfile: acts_as_tree_plugin.sqlite.db
+sqlite3:
+  :adapter: sqlite3
+  :dbfile: acts_as_tree_plugin.sqlite3.db
+postgresql:
+  :adapter: postgresql
+  :username: postgres
+  :password: postgres
+  :database: acts_as_tree_plugin_test
+  :min_messages: ERROR
+mysql:
+  :adapter: mysql
+  :host: localhost
+  :username: rails
+  :password:
+  :database: acts_as_tree_plugin_test

test/fixtures/mixin.rb

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+class Mixin < ActiveRecord::Base
+end
+
+class TreeMixin < Mixin 
+  acts_as_tree :foreign_key => "parent_id", :order => "id"
+end
+
+class TreeMixinWithoutOrder < Mixin
+  acts_as_tree :foreign_key => "parent_id"
+end
+
+class RecursivelyCascadedTreeMixin < Mixin
+  acts_as_tree :foreign_key => "parent_id"
+  has_one :first_child, :class_name => 'RecursivelyCascadedTreeMixin', :foreign_key => :parent_id
+end