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require 'active_support/core_ext/object/blank'
module ActiveRecord
# = Active Record Has Many Through Association
module Associations
class HasManyThroughAssociation < HasManyAssociation #:nodoc:
include ThroughAssociation
alias_method :new, :build
# Returns the size of the collection by executing a SELECT COUNT(*) query if the collection hasn't been
# loaded and calling collection.size if it has. If it's more likely than not that the collection does
# have a size larger than zero, and you need to fetch that collection afterwards, it'll take one fewer
# SELECT query if you use #length.
def size
if has_cached_counter?
owner.send(:read_attribute, cached_counter_attribute_name)
elsif loaded?
target.size
else
count
end
end
def concat(*records)
unless owner.new_record?
records.flatten.each do |record|
raise_on_type_mismatch(record)
record.save! if record.new_record?
end
end
super
end
def insert_record(record, validate = true)
ensure_not_nested
return if record.new_record? && !record.save(:validate => validate)
through_record(record).save!
update_counter(1)
record
end
private
def through_record(record)
through_association = owner.association(through_reflection.name)
attributes = construct_join_attributes(record)
through_record = Array.wrap(through_association.target).find { |candidate|
candidate.attributes.slice(*attributes.keys) == attributes
}
unless through_record
through_record = through_association.build(attributes)
through_record.send("#{source_reflection.name}=", record)
end
through_record
end
def build_record(attributes, options = {})
ensure_not_nested
record = super(attributes, options)
inverse = source_reflection.inverse_of
if inverse
if inverse.macro == :has_many
record.send(inverse.name) << through_record(record)
elsif inverse.macro == :has_one
record.send("#{inverse.name}=", through_record(record))
end
end
record
end
def target_reflection_has_associated_record?
if through_reflection.macro == :belongs_to && owner[through_reflection.foreign_key].blank?
false
else
true
end
end
def update_through_counter?(method)
case method
when :destroy
!inverse_updates_counter_cache?(through_reflection)
when :nullify
false
else
true
end
end
def delete_records(records, method)
ensure_not_nested
through = owner.association(through_reflection.name)
scope = through.scoped.where(construct_join_attributes(*records))
case method
when :destroy
count = scope.destroy_all.length
when :nullify
count = scope.update_all(source_reflection.foreign_key => nil)
else
count = scope.delete_all
end
delete_through_records(through, records)
if through_reflection.macro == :has_many && update_through_counter?(method)
update_counter(-count, through_reflection)
end
update_counter(-count)
end
def delete_through_records(through, records)
if through_reflection.macro == :has_many
records.each do |record|
through.target.delete(through_record(record))
end
else
records.each do |record|
through.target = nil if through.target == through_record(record)
end
end
end
def find_target
return [] unless target_reflection_has_associated_record?
scoped.all
end
# NOTE - not sure that we can actually cope with inverses here
def invertible_for?(record)
false
end
end
end
end
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