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Class: ActiveRecord::Associations::Preloader::ThroughAssociation

Do not use. This class is for internal use only.
Relationships & Source Files
Super Chains via Extension / Inclusion / Inheritance
Class Chain:
self, Association
Instance Chain:
self, Association
Inherits: ActiveRecord::Associations::Preloader::Association
Defined in: activerecord/lib/active_record/associations/preloader/through_association.rb

Constant Summary

Class Method Summary

Association - Inherited

.association_route_for, .new

Instance Attribute Summary

Association - Inherited

#klass, #run?, #model, #owners, #preload_scope, #reflection

Instance Method Summary

Association - Inherited

#associate_records_from_unscoped,
#destination_key_name

The name of the key on the associated records.
#future_classes,
#ignore_loaded_target!

Owners' already loaded targets don't reflect the preload scope, so they must not be reused when the scope filters the records.
#load_records, #loaded?, #loader_query, #owners_by_key, #preloaded_records, #records_by_owner, #run, #runnable_loaders, #scope, #set_inverse, #table_name, #target_for, #associate_records_to_owner, #association_route, #build_scope, #cascade_strict_loading, #destination_fixed_values,
#destination_key_value

Loaded records can be subclasses of klass with their own aliases.
#match_normalizers,
#origin_key_value

Owners are grouped so that each loader's owners share its route.
#reflection_scope

Constructor Details

This class inherits a constructor from ActiveRecord::Associations::Preloader::Association

Class Method Details

.association_route_for

[ GitHub ] 

  


# File 'activerecord/lib/active_record/associations/preloader/through_association.rb', line 10



def self.association_route_for(*)
end


  







Instance Attribute Details



  

    #data_available?  ⇒ Boolean  (readonly, private)
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/associations/preloader/through_association.rb', line 70



def data_available?
  owners.all? { |owner| loaded?(owner) } ||
    through_preloaders.all?(&:run?) && source_preloaders.all?(&:run?)
end


  








  

    #source_order_applies?  ⇒ Boolean  (readonly, private)
  



  

    
As in SQL, an explicit order on the through association beats the
default order of the source.

  





  


  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/associations/preloader/through_association.rb', line 140



def source_order_applies?
  return @source_order_applies if defined?(@source_order_applies)

  @source_order_applies = scope.order_values.any? ||
    (!scope.effective_order_values.empty? &&
      through_preloaders.none? { |loader| loader.scope.order_values.any? })
end


  








  

    #source_scope_filters_source?  ⇒ Boolean  (readonly, private)
  



  

    
When the through scope doesn't eager load the source records with the
conditions or the order, the source scope filters or sorts them instead.

  





  


  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/associations/preloader/through_association.rb', line 133



def source_scope_filters_source?
  !through_scope_filters_source? &&
    (!reflection_scope.where_clause.empty? || !reflection_scope.effective_order_values.empty?)
end


  








  

    #through_scope_filters_source?  ⇒ Boolean  (readonly, private)
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/associations/preloader/through_association.rb', line 125



def through_scope_filters_source?
  !reflection.options[:disable_joins] &&
    through_reflection.klass.table_name != klass.table_name &&
    !reflection_scope.where_clause.empty?
end


  







Instance Method Details



  

    #associate_records_from_unscoped  
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/associations/preloader/through_association.rb', line 13



def associate_records_from_unscoped(*)
end


  








  

    #destination_fixed_values   (private)
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/associations/preloader/through_association.rb', line 66



def destination_fixed_values
  EMPTY_FIXED_VALUES
end


  








  

    #filter_by_source_type(through_records)   (private)
  



  

    
Already loaded through records aren't filtered by source_type.

  



  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/associations/preloader/through_association.rb', line 86



def filter_by_source_type(through_records)
  if source_type = reflection.options[:source_type]
    source_type = source_type.to_s
    through_records.select do |record|
      record.read_attr(reflection.foreign_type) == source_type
    end
  else
    through_records
  end
end


  








  

    #future_classes  
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/associations/preloader/through_association.rb', line 50



def future_classes
  if run?
    []
  elsif through_preloaders.all?(&:run?)
    source_preloaders.flat_map(&:future_classes).uniq
  else
    through_classes = through_preloaders.flat_map(&:future_classes)
    source_classes = source_reflection.
      chain.
      reject { |reflection| reflection.respond_to?(:polymorphic?) && reflection.polymorphic? }.
      map(&:klass)
    (through_classes + source_classes).uniq
  end
end


  








  

    #middle_records   (private)
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/associations/preloader/through_association.rb', line 81



def middle_records
  filter_by_source_type(through_records_by_owner.values.flatten)
end


  








  

    #preload_index   (private)
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/associations/preloader/through_association.rb', line 119



def preload_index
  @preload_index ||= preloaded_records.each_with_object({}).with_index do |(record, result), index|
    result[record] = index
  end
end


  








  

    #preloaded_records  
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/associations/preloader/through_association.rb', line 16



def preloaded_records
  @preloaded_records ||= source_preloaders.flat_map(&:preloaded_records)
end


  








  

    #records_by_owner  
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/associations/preloader/through_association.rb', line 20



def records_by_owner
  @records_by_owner ||= owners.each_with_object({}) do |owner, result|
    if loaded?(owner)
      result[owner] = target_for(owner)
      next
    end

    through_records = filter_by_source_type(through_records_by_owner[owner] || [])

    records = through_records.flat_map do |record|
      source_records_by_owner[record]
    end

    records.compact!
    records.sort_by! { |rhs| preload_index[rhs] } if source_order_applies?
    records.uniq! if scope.distinct_value
    result[owner] = records
  end
end


  








  

    #runnable_loaders  
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/associations/preloader/through_association.rb', line 40



def runnable_loaders
  if data_available?
    [self]
  elsif through_preloaders.all?(&:run?)
    source_preloaders.flat_map(&:runnable_loaders)
  else
    through_preloaders.flat_map(&:runnable_loaders)
  end
end


  








  

    #source_preloaders   (private)
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/associations/preloader/through_association.rb', line 75



def source_preloaders
  @source_preloaders ||= ActiveRecord::Associations::Preloader.new(records: middle_records, associations: source_reflection.name, scope: scope, associate_by_default: false).loaders.tap do |loaders|
    loaders.each(&:ignore_loaded_target!) if source_scope_filters_source?
  end
end


  








  

    #source_records_by_owner   (private)
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/associations/preloader/through_association.rb', line 111



def source_records_by_owner
  @source_records_by_owner ||= source_preloaders.map(&:records_by_owner).reduce(:merge)
end


  








  

    #source_reflection   (private)
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/associations/preloader/through_association.rb', line 107



def source_reflection
  reflection.source_reflection
end


  








  

    #through_preloaders   (private)
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/associations/preloader/through_association.rb', line 97



def through_preloaders
  @through_preloaders ||= ActiveRecord::Associations::Preloader.new(records: owners, associations: through_reflection.name, scope: through_scope, associate_by_default: false).loaders.tap do |loaders|
    loaders.each(&:ignore_loaded_target!) if through_scope_filters_source?
  end
end


  








  

    #through_records_by_owner   (private)
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/associations/preloader/through_association.rb', line 115



def through_records_by_owner
  @through_records_by_owner ||= through_preloaders.map(&:records_by_owner).reduce(:merge)
end


  








  

    #through_reflection   (private)
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/associations/preloader/through_association.rb', line 103



def through_reflection
  reflection.through_reflection
end


  








  

    #through_scope   (private)
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/associations/preloader/through_association.rb', line 148



def through_scope
  scope = through_reflection.klass.unscoped
  options = reflection.options

  return scope if options[:disable_joins]

  values = reflection_scope.values
  if annotations = values[:annotate]
    scope.annotate!(*annotations)
  end

  if options[:source_type]
    scope.where! reflection.foreign_type => options[:source_type]
  end

  if through_scope_filters_source?
    scope.where_clause += reflection_scope.where_clause

    includes = values[:includes]

    # The class fixed by `source_type` can't be preloaded, only eager loaded.
    if source_type_reflection = reflection.source_type_reflection
      source = source_type_reflection
      scope.eager_load!(includes ? { source => includes } : source)
    else
      source = source_reflection.name
      scope.includes!(includes ? { source => includes } : source)
    end

    if values[:references] && !values[:references].empty?
      scope.references_values |= values[:references]
    else
      scope.references!((source_type_reflection || source_reflection).table_name)
    end

    if joins = values[:joins]
      scope.joins!(source => joins)
    end

    if left_outer_joins = values[:left_outer_joins]
      scope.left_outer_joins!(source => left_outer_joins)
    end

    # Both are kept so that `effective_order_values` picks one as for the source.
    if scope.eager_loading?
      scope.order_values = reflection_scope.order_values
      scope.default_order_values = reflection_scope.default_order_values
    end
  end

  cascade_strict_loading(scope)
end