diff options
Diffstat (limited to 'activerecord/lib/active_record/associations/preloader.rb')
| -rw-r--r-- | activerecord/lib/active_record/associations/preloader.rb | 54 |
1 files changed, 17 insertions, 37 deletions
diff --git a/activerecord/lib/active_record/associations/preloader.rb b/activerecord/lib/active_record/associations/preloader.rb index 9f77f38b35..e1087be9b3 100644 --- a/activerecord/lib/active_record/associations/preloader.rb +++ b/activerecord/lib/active_record/associations/preloader.rb @@ -1,3 +1,5 @@ +# frozen_string_literal: true + module ActiveRecord module Associations # Implements the details of eager loading of Active Record associations. @@ -42,20 +44,10 @@ module ActiveRecord extend ActiveSupport::Autoload eager_autoload do - autoload :Association, "active_record/associations/preloader/association" - autoload :SingularAssociation, "active_record/associations/preloader/singular_association" - autoload :CollectionAssociation, "active_record/associations/preloader/collection_association" - autoload :ThroughAssociation, "active_record/associations/preloader/through_association" - - autoload :HasMany, "active_record/associations/preloader/has_many" - autoload :HasManyThrough, "active_record/associations/preloader/has_many_through" - autoload :HasOne, "active_record/associations/preloader/has_one" - autoload :HasOneThrough, "active_record/associations/preloader/has_one_through" - autoload :BelongsTo, "active_record/associations/preloader/belongs_to" + autoload :Association, "active_record/associations/preloader/association" + autoload :ThroughAssociation, "active_record/associations/preloader/through_association" end - NULL_RELATION = Struct.new(:values, :where_clause, :joins_values).new({}, Relation::WhereClause.empty, []) - # Eager loads the named associations for the given Active Record record(s). # # In this description, 'association name' shall refer to the name passed @@ -91,14 +83,13 @@ module ActiveRecord # { author: :avatar } # [ :books, { author: :avatar } ] def preload(records, associations, preload_scope = nil) - records = Array.wrap(records).compact.uniq - associations = Array.wrap(associations) - preload_scope = preload_scope || NULL_RELATION + records = records.compact if records.empty? [] else - associations.flat_map { |association| + records.uniq! + Array.wrap(associations).flat_map { |association| preloaders_on association, records, preload_scope } end @@ -147,7 +138,7 @@ module ActiveRecord def preloaders_for_one(association, records, scope) grouped_records(association, records).flat_map do |reflection, klasses| klasses.map do |rhs_klass, rs| - loader = preloader_for(reflection, rs, rhs_klass).new(rhs_klass, rs, reflection, scope) + loader = preloader_for(reflection, rs).new(rhs_klass, rs, reflection, scope) loader.run self loader end @@ -159,6 +150,7 @@ module ActiveRecord records.each do |record| next unless record assoc = record.association(association) + next unless assoc.klass klasses = h[assoc.reflection] ||= {} (klasses[assoc.klass] ||= []) << record end @@ -166,8 +158,6 @@ module ActiveRecord end class AlreadyLoaded # :nodoc: - attr_reader :owners, :reflection - def initialize(klass, owners, reflection, preload_scope) @owners = owners @reflection = reflection @@ -178,34 +168,24 @@ module ActiveRecord def preloaded_records owners.flat_map { |owner| owner.association(reflection.name).target } end - end - class NullPreloader # :nodoc: - def self.new(klass, owners, reflection, preload_scope); self; end - def self.run(preloader); end - def self.preloaded_records; []; end - def self.owners; []; end + protected + attr_reader :owners, :reflection end # Returns a class containing the logic needed to load preload the data - # and attach it to a relation. For example +Preloader::Association+ or - # +Preloader::HasManyThrough+. The class returned implements a `run` method + # and attach it to a relation. The class returned implements a `run` method # that accepts a preloader. - def preloader_for(reflection, owners, rhs_klass) - return NullPreloader unless rhs_klass - + def preloader_for(reflection, owners) if owners.first.association(reflection.name).loaded? return AlreadyLoaded end reflection.check_preloadable! - case reflection.macro - when :has_many - reflection.options[:through] ? HasManyThrough : HasMany - when :has_one - reflection.options[:through] ? HasOneThrough : HasOne - when :belongs_to - BelongsTo + if reflection.options[:through] + ThroughAssociation + else + Association end end end |