278 lines
13 KiB
Ruby
278 lines
13 KiB
Ruby
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module ActiveRecord
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module AssociationPreload #:nodoc:
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def self.included(base)
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base.extend(ClassMethods)
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end
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module ClassMethods
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# Loads the named associations for the activerecord record (or records) given
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# preload_options is passed only one level deep: don't pass to the child associations when associations is a Hash
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protected
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def preload_associations(records, associations, preload_options={})
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records = [records].flatten.compact.uniq
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return if records.empty?
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case associations
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when Array then associations.each {|association| preload_associations(records, association, preload_options)}
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when Symbol, String then preload_one_association(records, associations.to_sym, preload_options)
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when Hash then
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associations.each do |parent, child|
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raise "parent must be an association name" unless parent.is_a?(String) || parent.is_a?(Symbol)
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preload_associations(records, parent, preload_options)
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reflection = reflections[parent]
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parents = records.map {|record| record.send(reflection.name)}.flatten
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unless parents.empty? || parents.first.nil?
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parents.first.class.preload_associations(parents, child)
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end
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end
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end
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end
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private
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def preload_one_association(records, association, preload_options={})
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class_to_reflection = {}
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# Not all records have the same class, so group then preload
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# group on the reflection itself so that if various subclass share the same association then we do not split them
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# unncessarily
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records.group_by {|record| class_to_reflection[record.class] ||= record.class.reflections[association]}.each do |reflection, records|
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raise ConfigurationError, "Association named '#{ association }' was not found; perhaps you misspelled it?" unless reflection
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send("preload_#{reflection.macro}_association", records, reflection, preload_options)
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end
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end
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def add_preloaded_records_to_collection(parent_records, reflection_name, associated_record)
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parent_records.each do |parent_record|
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association_proxy = parent_record.send(reflection_name)
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association_proxy.loaded
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association_proxy.target.push(*[associated_record].flatten)
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end
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end
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def add_preloaded_record_to_collection(parent_records, reflection_name, associated_record)
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parent_records.each do |parent_record|
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association_proxy = parent_record.send(reflection_name)
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association_proxy.loaded
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association_proxy.target = associated_record
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end
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end
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def set_association_collection_records(id_to_record_map, reflection_name, associated_records, key)
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associated_records.each do |associated_record|
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mapped_records = id_to_record_map[associated_record[key].to_s]
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add_preloaded_records_to_collection(mapped_records, reflection_name, associated_record)
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end
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end
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def set_association_single_records(id_to_record_map, reflection_name, associated_records, key)
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seen_keys = {}
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associated_records.each do |associated_record|
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#this is a has_one or belongs_to: there should only be one record.
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#Unfortunately we can't (in portable way) ask the database for 'all records where foo_id in (x,y,z), but please
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# only one row per distinct foo_id' so this where we enforce that
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next if seen_keys[associated_record[key].to_s]
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seen_keys[associated_record[key].to_s] = true
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mapped_records = id_to_record_map[associated_record[key].to_s]
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mapped_records.each do |mapped_record|
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mapped_record.send("set_#{reflection_name}_target", associated_record)
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end
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end
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end
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def construct_id_map(records)
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id_to_record_map = {}
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ids = []
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records.each do |record|
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ids << record.id
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mapped_records = (id_to_record_map[record.id.to_s] ||= [])
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mapped_records << record
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end
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ids.uniq!
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return id_to_record_map, ids
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end
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def preload_has_and_belongs_to_many_association(records, reflection, preload_options={})
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table_name = reflection.klass.quoted_table_name
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id_to_record_map, ids = construct_id_map(records)
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records.each {|record| record.send(reflection.name).loaded}
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options = reflection.options
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conditions = "t0.#{reflection.primary_key_name} IN (?)"
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conditions << append_conditions(options, preload_options)
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associated_records = reflection.klass.find(:all, :conditions => [conditions, ids],
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:include => options[:include],
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:joins => "INNER JOIN #{connection.quote_table_name options[:join_table]} as t0 ON #{reflection.klass.quoted_table_name}.#{reflection.klass.primary_key} = t0.#{reflection.association_foreign_key}",
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:select => "#{options[:select] || table_name+'.*'}, t0.#{reflection.primary_key_name} as _parent_record_id",
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:order => options[:order])
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set_association_collection_records(id_to_record_map, reflection.name, associated_records, '_parent_record_id')
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end
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def preload_has_one_association(records, reflection, preload_options={})
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id_to_record_map, ids = construct_id_map(records)
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options = reflection.options
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if options[:through]
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records.each {|record| record.send(reflection.name) && record.send(reflection.name).loaded}
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through_records = preload_through_records(records, reflection, options[:through])
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through_reflection = reflections[options[:through]]
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through_primary_key = through_reflection.primary_key_name
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unless through_records.empty?
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source = reflection.source_reflection.name
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through_records.first.class.preload_associations(through_records, source)
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through_records.each do |through_record|
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add_preloaded_record_to_collection(id_to_record_map[through_record[through_primary_key].to_s],
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reflection.name, through_record.send(source))
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end
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end
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else
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records.each {|record| record.send("set_#{reflection.name}_target", nil)}
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set_association_single_records(id_to_record_map, reflection.name, find_associated_records(ids, reflection, preload_options), reflection.primary_key_name)
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end
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end
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def preload_has_many_association(records, reflection, preload_options={})
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id_to_record_map, ids = construct_id_map(records)
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records.each {|record| record.send(reflection.name).loaded}
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options = reflection.options
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if options[:through]
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through_records = preload_through_records(records, reflection, options[:through])
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through_reflection = reflections[options[:through]]
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through_primary_key = through_reflection.primary_key_name
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unless through_records.empty?
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source = reflection.source_reflection.name
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#add conditions from reflection!
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through_records.first.class.preload_associations(through_records, source, reflection.options)
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through_records.each do |through_record|
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add_preloaded_records_to_collection(id_to_record_map[through_record[through_primary_key].to_s],
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reflection.name, through_record.send(source))
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end
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end
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else
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set_association_collection_records(id_to_record_map, reflection.name, find_associated_records(ids, reflection, preload_options),
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reflection.primary_key_name)
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end
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end
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def preload_through_records(records, reflection, through_association)
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through_reflection = reflections[through_association]
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through_primary_key = through_reflection.primary_key_name
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if reflection.options[:source_type]
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interface = reflection.source_reflection.options[:foreign_type]
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preload_options = {:conditions => ["#{connection.quote_column_name interface} = ?", reflection.options[:source_type]]}
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records.compact!
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records.first.class.preload_associations(records, through_association, preload_options)
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# Dont cache the association - we would only be caching a subset
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through_records = []
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records.each do |record|
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proxy = record.send(through_association)
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if proxy.respond_to?(:target)
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through_records << proxy.target
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proxy.reset
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else # this is a has_one :through reflection
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through_records << proxy if proxy
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end
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end
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through_records.flatten!
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else
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records.first.class.preload_associations(records, through_association)
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through_records = records.map {|record| record.send(through_association)}.flatten
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end
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through_records.compact!
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through_records
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end
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# FIXME: quoting
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def preload_belongs_to_association(records, reflection, preload_options={})
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options = reflection.options
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primary_key_name = reflection.primary_key_name
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if options[:polymorphic]
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polymorph_type = options[:foreign_type]
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klasses_and_ids = {}
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# Construct a mapping from klass to a list of ids to load and a mapping of those ids back to their parent_records
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records.each do |record|
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if klass = record.send(polymorph_type)
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klass_id = record.send(primary_key_name)
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if klass_id
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id_map = klasses_and_ids[klass] ||= {}
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id_list_for_klass_id = (id_map[klass_id.to_s] ||= [])
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id_list_for_klass_id << record
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end
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end
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end
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klasses_and_ids = klasses_and_ids.to_a
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else
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id_map = {}
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records.each do |record|
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key = record.send(primary_key_name)
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if key
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mapped_records = (id_map[key.to_s] ||= [])
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mapped_records << record
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end
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end
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klasses_and_ids = [[reflection.klass.name, id_map]]
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end
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klasses_and_ids.each do |klass_and_id|
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klass_name, id_map = *klass_and_id
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klass = klass_name.constantize
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table_name = klass.quoted_table_name
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primary_key = klass.primary_key
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conditions = "#{table_name}.#{primary_key} IN (?)"
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conditions << append_conditions(options, preload_options)
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associated_records = klass.find(:all, :conditions => [conditions, id_map.keys.uniq],
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:include => options[:include],
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:select => options[:select],
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:joins => options[:joins],
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:order => options[:order])
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set_association_single_records(id_map, reflection.name, associated_records, primary_key)
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end
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end
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def find_associated_records(ids, reflection, preload_options)
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options = reflection.options
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table_name = reflection.klass.quoted_table_name
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if interface = reflection.options[:as]
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conditions = "#{reflection.klass.quoted_table_name}.#{connection.quote_column_name "#{interface}_id"} IN (?) and #{reflection.klass.quoted_table_name}.#{connection.quote_column_name "#{interface}_type"} = '#{self.base_class.name.demodulize}'"
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else
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foreign_key = reflection.primary_key_name
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conditions = "#{reflection.klass.quoted_table_name}.#{foreign_key} IN (?)"
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end
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conditions << append_conditions(options, preload_options)
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reflection.klass.find(:all,
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:select => (preload_options[:select] || options[:select] || "#{table_name}.*"),
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:include => preload_options[:include] || options[:include],
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:conditions => [conditions, ids],
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:joins => options[:joins],
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:group => preload_options[:group] || options[:group],
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:order => preload_options[:order] || options[:order])
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end
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def interpolate_sql_for_preload(sql)
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instance_eval("%@#{sql.gsub('@', '\@')}@")
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end
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def append_conditions(options, preload_options)
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sql = ""
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sql << " AND (#{interpolate_sql_for_preload(sanitize_sql(options[:conditions]))})" if options[:conditions]
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sql << " AND (#{sanitize_sql preload_options[:conditions]})" if preload_options[:conditions]
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sql
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end
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end
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end
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end
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