diff options
Diffstat (limited to 'activerecord/lib/active_record/associations/preloader.rb')
| -rw-r--r-- | activerecord/lib/active_record/associations/preloader.rb | 15 |
1 files changed, 12 insertions, 3 deletions
diff --git a/activerecord/lib/active_record/associations/preloader.rb b/activerecord/lib/active_record/associations/preloader.rb index 3992a240b9..ecf6fb8643 100644 --- a/activerecord/lib/active_record/associations/preloader.rb +++ b/activerecord/lib/active_record/associations/preloader.rb @@ -54,6 +54,8 @@ module ActiveRecord autoload :BelongsTo, 'active_record/associations/preloader/belongs_to' 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 @@ -88,9 +90,6 @@ module ActiveRecord # [ :books, :author ] # { author: :avatar } # [ :books, { author: :avatar } ] - - NULL_RELATION = Struct.new(:values, :where_clause, :joins_values).new({}, Relation::WhereClause.empty, []) - def preload(records, associations, preload_scope = nil) records = Array.wrap(records).compact.uniq associations = Array.wrap(associations) @@ -107,6 +106,7 @@ module ActiveRecord private + # Loads all the given data into +records+ for the +association+. def preloaders_on(association, records, scope) case association when Hash @@ -132,6 +132,11 @@ module ActiveRecord } end + # Loads all the given data into +records+ for a singular +association+. + # + # Functions by instantiating a preloader class such as Preloader::HasManyThrough and + # call the +run+ method for each passed in class in the +records+ argument. + # # Not all records have the same class, so group then preload group on the reflection # itself so that if various subclass share the same association then we do not split # them unnecessarily @@ -181,6 +186,10 @@ module ActiveRecord def self.preloaded_records; []; end 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 + # that accepts a preloader. def preloader_for(reflection, owners, rhs_klass) return NullPreloader unless rhs_klass |