diff options
Diffstat (limited to 'activerecord/lib/active_record/associations/preloader/through_association.rb')
-rw-r--r-- | activerecord/lib/active_record/associations/preloader/through_association.rb | 108 |
1 files changed, 47 insertions, 61 deletions
diff --git a/activerecord/lib/active_record/associations/preloader/through_association.rb b/activerecord/lib/active_record/associations/preloader/through_association.rb index fa32cc5553..a6b7ab80a2 100644 --- a/activerecord/lib/active_record/associations/preloader/through_association.rb +++ b/activerecord/lib/active_record/associations/preloader/through_association.rb @@ -3,78 +3,54 @@ module ActiveRecord module Associations class Preloader - module ThroughAssociation #:nodoc: - def through_reflection - reflection.through_reflection - end - - def source_reflection - reflection.source_reflection - end - - def associated_records_by_owner(preloader) - through_scope = through_scope() - - preloader.preload(owners, - through_reflection.name, - through_scope) - - through_records = owners.map do |owner| - center = owner.association(through_reflection.name).target - [owner, Array(center)] - end - - reset_association(owners, through_reflection.name, through_scope) - - middle_records = through_records.flat_map(&:last) - - reflection_scope = reflection_scope() if reflection.scope - - preloaders = preloader.preload(middle_records, - source_reflection.name, - reflection_scope) - + class ThroughAssociation < Association # :nodoc: + def run(preloader) + already_loaded = owners.first.association(through_reflection.name).loaded? + through_scope = through_scope() + reflection_scope = target_reflection_scope + through_preloaders = preloader.preload(owners, through_reflection.name, through_scope) + middle_records = through_preloaders.flat_map(&:preloaded_records) + preloaders = preloader.preload(middle_records, source_reflection.name, reflection_scope) @preloaded_records = preloaders.flat_map(&:preloaded_records) - middle_to_pl = preloaders.each_with_object({}) do |pl, h| - pl.owners.each { |middle| - h[middle] = pl - } - end - - through_records.each_with_object({}) do |(lhs, center), records_by_owner| - pl_to_middle = center.group_by { |record| middle_to_pl[record] } - - records_by_owner[lhs] = pl_to_middle.flat_map do |pl, middles| - rhs_records = middles.flat_map { |r| - r.association(source_reflection.name).target - }.compact - - # Respect the order on `reflection_scope` if it exists, else use the natural order. - if reflection_scope && !reflection_scope.order_values.empty? - @id_map ||= id_to_index_map @preloaded_records - rhs_records.sort_by { |rhs| @id_map[rhs] } - else - rhs_records + owners.each do |owner| + through_records = Array(owner.association(through_reflection.name).target) + if already_loaded + if source_type = reflection.options[:source_type] + through_records = through_records.select do |record| + record[reflection.foreign_type] == source_type + end end + else + owner.association(through_reflection.name).reset if through_scope + end + result = through_records.flat_map do |record| + association = record.association(source_reflection.name) + target = association.target + association.reset if preload_scope + target end + result.compact! + if reflection_scope + result.sort_by! { |rhs| preload_index[rhs] } if reflection_scope.order_values.any? + result.uniq! if reflection_scope.distinct_value + end + associate_records_to_owner(owner, result) end end private + def through_reflection + reflection.through_reflection + end - def id_to_index_map(ids) - id_map = {} - ids.each_with_index { |id, index| id_map[id] = index } - id_map + def source_reflection + reflection.source_reflection end - def reset_association(owners, association_name, should_reset) - # Don't cache the association - we would only be caching a subset - if should_reset - owners.each { |owner| - owner.association(association_name).reset - } + def preload_index + @preload_index ||= @preloaded_records.each_with_object({}).with_index do |(id, result), index| + result[id] = index end end @@ -115,6 +91,16 @@ module ActiveRecord scope unless scope.empty_scope? end + + def target_reflection_scope + if preload_scope + reflection_scope.merge(preload_scope) + elsif reflection.scope + reflection_scope + else + nil + end + end end end end |