diff options
Diffstat (limited to 'activerecord/lib/active_record/associations/has_many_through_association.rb')
| -rw-r--r-- | activerecord/lib/active_record/associations/has_many_through_association.rb | 227 |
1 files changed, 227 insertions, 0 deletions
diff --git a/activerecord/lib/active_record/associations/has_many_through_association.rb b/activerecord/lib/active_record/associations/has_many_through_association.rb new file mode 100644 index 0000000000..84a9797aa5 --- /dev/null +++ b/activerecord/lib/active_record/associations/has_many_through_association.rb @@ -0,0 +1,227 @@ +# frozen_string_literal: true + +module ActiveRecord + module Associations + # = Active Record Has Many Through Association + class HasManyThroughAssociation < HasManyAssociation #:nodoc: + include ThroughAssociation + + def initialize(owner, reflection) + super + @through_records = {} + end + + def concat(*records) + unless owner.new_record? + records.flatten.each do |record| + raise_on_type_mismatch!(record) + end + end + + super + end + + def insert_record(record, validate = true, raise = false) + ensure_not_nested + + if record.new_record? || record.has_changes_to_save? + return unless super + end + + save_through_record(record) + + record + end + + private + def concat_records(records) + ensure_not_nested + + records = super(records, true) + + if owner.new_record? && records + records.flatten.each do |record| + build_through_record(record) + end + end + + records + end + + # The through record (built with build_record) is temporarily cached + # so that it may be reused if insert_record is subsequently called. + # + # However, after insert_record has been called, the cache is cleared in + # order to allow multiple instances of the same record in an association. + def build_through_record(record) + @through_records[record.object_id] ||= begin + ensure_mutable + + through_record = through_association.build(*options_for_through_record) + through_record.send("#{source_reflection.name}=", record) + + if options[:source_type] + through_record.send("#{source_reflection.foreign_type}=", options[:source_type]) + end + + through_record + end + end + + def options_for_through_record + [through_scope_attributes] + end + + def through_scope_attributes + scope.where_values_hash(through_association.reflection.name.to_s). + except!(through_association.reflection.foreign_key, + through_association.reflection.klass.inheritance_column) + end + + def save_through_record(record) + association = build_through_record(record) + if association.changed? + association.save! + end + ensure + @through_records.delete(record.object_id) + end + + def build_record(attributes) + ensure_not_nested + + record = super + + inverse = source_reflection.inverse_of + if inverse + if inverse.collection? + record.send(inverse.name) << build_through_record(record) + elsif inverse.has_one? + record.send("#{inverse.name}=", build_through_record(record)) + end + end + + record + end + + def remove_records(existing_records, records, method) + super + delete_through_records(records) + end + + def target_reflection_has_associated_record? + !(through_reflection.belongs_to? && owner[through_reflection.foreign_key].blank?) + end + + def update_through_counter?(method) + case method + when :destroy + !through_reflection.inverse_updates_counter_cache? + when :nullify + false + else + true + end + end + + def delete_or_nullify_all_records(method) + delete_records(load_target, method) + end + + def delete_records(records, method) + ensure_not_nested + + scope = through_association.scope + scope.where! construct_join_attributes(*records) + scope = scope.where(through_scope_attributes) + + case method + when :destroy + if scope.klass.primary_key + count = scope.destroy_all.count(&:destroyed?) + else + scope.each(&:_run_destroy_callbacks) + count = scope.delete_all + end + when :nullify + count = scope.update_all(source_reflection.foreign_key => nil) + else + count = scope.delete_all + end + + delete_through_records(records) + + if source_reflection.options[:counter_cache] && method != :destroy + counter = source_reflection.counter_cache_column + klass.decrement_counter counter, records.map(&:id) + end + + if through_reflection.collection? && update_through_counter?(method) + update_counter(-count, through_reflection) + else + update_counter(-count) + end + + count + end + + def difference(a, b) + distribution = distribution(b) + + a.reject { |record| mark_occurrence(distribution, record) } + end + + def intersection(a, b) + distribution = distribution(b) + + a.select { |record| mark_occurrence(distribution, record) } + end + + def mark_occurrence(distribution, record) + distribution[record] > 0 && distribution[record] -= 1 + end + + def distribution(array) + array.each_with_object(Hash.new(0)) do |record, distribution| + distribution[record] += 1 + end + end + + def through_records_for(record) + attributes = construct_join_attributes(record) + candidates = Array.wrap(through_association.target) + candidates.find_all do |c| + attributes.all? do |key, value| + c.public_send(key) == value + end + end + end + + def delete_through_records(records) + records.each do |record| + through_records = through_records_for(record) + + if through_reflection.collection? + through_records.each { |r| through_association.target.delete(r) } + else + if through_records.include?(through_association.target) + through_association.target = nil + end + end + + @through_records.delete(record.object_id) + end + end + + def find_target + return [] unless target_reflection_has_associated_record? + super + end + + # NOTE - not sure that we can actually cope with inverses here + def invertible_for?(record) + false + end + end + end +end |