Module: ActiveSupport::DescendantsTracker

Relationships & Source Files
Namespace Children
Modules: `ReloadedClassesFiltering`
Classes: `WeakSet`
Extension / Inclusion / Inheritance Descendants
Extended In: `::AbstractController::Base`, `::ActionCable::Engine`, `::ActionController::API`, `::ActionController::Base`, `::ActionController::Metal`, `::ActionController::Railtie`, `::ActionDispatch::Railtie`, `::ActionMailbox::Engine`, `::ActionMailer::Base`, `::ActionMailer::Preview`, `::ActionMailer::Railtie`, `::ActionText::Engine`, `::ActionView::Railtie`, `::ActionView::TestCase::TestController`, `::ActiveJob::Railtie`, `::ActiveModel::Railtie`, `::ActiveRecord::Base`, `::ActiveRecord::Railtie`, `::ActiveStorage::Engine`, `Railtie`, `::I18n::Railtie`, `::Rails::Application`, `::Rails::ApplicationController`, `::Rails::Engine`, `::Rails::HealthController`, `::Rails::InfoController`, `::Rails::MailersController`, `::Rails::PwaController`, `::Rails::Railtie`, `::Rails::TestUnitRailtie`, `::Rails::WelcomeController`
Defined in:	activesupport/lib/active_support/descendants_tracker.rb

Overview

This module provides an internal implementation to track descendants which is faster than iterating through ObjectSpace.

However Ruby 3.1 provide a fast native Class#subclasses method, so if you know your code won’t be executed on older rubies, including DescendantsTracker does not provide any benefit.

Class Method Summary

.descendants(klass)
.subclasses(klass)
.clear(classes) Internal use only
.disable_clear! Internal use only
.reject!(classes) Internal use only

Instance Method Summary

#descendants

Class Method Details

.clear(classes)

This method is for internal use only.

[ GitHub ]

# File 'activesupport/lib/active_support/descendants_tracker.rb', line 78


def clear(classes) # :nodoc:
  raise "DescendantsTracker.clear was disabled because config.enable_reloading is false" if @clear_disabled

  classes.each do |klass|
    @excluded_descendants << klass
    klass.descendants.each do |descendant|
      @excluded_descendants << descendant
    end
  end
end

.descendants(klass)

[ GitHub ]

# File 'activesupport/lib/active_support/descendants_tracker.rb', line 102


def descendants(klass)
  klass.descendants
end

.disable_clear!

This method is for internal use only.

[ GitHub ]

# File 'activesupport/lib/active_support/descendants_tracker.rb', line 69


def disable_clear! # :nodoc:
  unless @clear_disabled
    @clear_disabled = true
    ReloadedClassesFiltering.remove_method(:subclasses)
    ReloadedClassesFiltering.remove_method(:descendants)
    @excluded_descendants = nil
  end
end

.reject!(classes)

This method is for internal use only.

[ GitHub ]

# File 'activesupport/lib/active_support/descendants_tracker.rb', line 89


def reject!(classes) # :nodoc:
  if @excluded_descendants
    classes.reject! { |d| @excluded_descendants.include?(d) }
  end
  classes
end

.subclasses(klass)

[ GitHub ]

# File 'activesupport/lib/active_support/descendants_tracker.rb', line 98


def subclasses(klass)
  klass.subclasses
end

Instance Method Details

#descendants

[ GitHub ]

# File 'activesupport/lib/active_support/descendants_tracker.rb', line 107


def descendants
  subclasses = DescendantsTracker.reject!(self.subclasses)
  subclasses.concat(subclasses.flat_map(&:descendants))
end