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module ActiveRecord
# = Active Record Has Many Association
module Associations
# This is the proxy that handles a has many association.
#
# If the association has a <tt>:through</tt> option further specialization
# is provided by its child HasManyThroughAssociation.
class HasManyAssociation < CollectionAssociation #:nodoc:
include ForeignAssociation
def handle_dependency
case options[:dependent]
when :restrict_with_exception
raise ActiveRecord::DeleteRestrictionError.new(reflection.name) unless empty?
when :restrict_with_error
unless empty?
record = klass.human_attribute_name(reflection.name).downcase
message = owner.errors.generate_message(:base, :'restrict_dependent_destroy.many', record: record, raise: true) rescue nil
if message
ActiveSupport::Deprecation.warn(<<-MESSAGE.squish)
The error key `:'restrict_dependent_destroy.many'` has been deprecated and will be removed in Rails 5.1.
Please use `:'restrict_dependent_destroy.has_many'` instead.
MESSAGE
end
owner.errors.add(:base, message || :'restrict_dependent_destroy.has_many', record: record)
throw(:abort)
end
else
if options[:dependent] == :destroy
# No point in executing the counter update since we're going to destroy the parent anyway
load_target.each { |t| t.destroyed_by_association = reflection }
destroy_all
else
delete_all
end
end
end
def insert_record(record, validate = true, raise = false)
set_owner_attributes(record)
set_inverse_instance(record)
if raise
record.save!(:validate => validate)
else
record.save(:validate => validate)
end
end
def empty?
if has_cached_counter?
size.zero?
else
super
end
end
private
# Returns the number of records in this collection.
#
# If the association has a counter cache it gets that value. Otherwise
# it will attempt to do a count via SQL, bounded to <tt>:limit</tt> if
# there's one. Some configuration options like :group make it impossible
# to do an SQL count, in those cases the array count will be used.
#
# That does not depend on whether the collection has already been loaded
# or not. The +size+ method is the one that takes the loaded flag into
# account and delegates to +count_records+ if needed.
#
# If the collection is empty the target is set to an empty array and
# the loaded flag is set to true as well.
def count_records
count = if has_cached_counter?
owner._read_attribute cached_counter_attribute_name
else
scope.count
end
# If there's nothing in the database and @target has no new records
# we are certain the current target is an empty array. This is a
# documented side-effect of the method that may avoid an extra SELECT.
@target ||= [] and loaded! if count == 0
[association_scope.limit_value, count].compact.min
end
def has_cached_counter?(reflection = reflection())
owner.attribute_present?(cached_counter_attribute_name(reflection))
end
def cached_counter_attribute_name(reflection = reflection())
if reflection.options[:counter_cache]
reflection.options[:counter_cache].to_s
else
"#{reflection.name}_count"
end
end
def update_counter(difference, reflection = reflection())
update_counter_in_database(difference, reflection)
update_counter_in_memory(difference, reflection)
end
def update_counter_in_database(difference, reflection = reflection())
if has_cached_counter?(reflection)
counter = cached_counter_attribute_name(reflection)
owner.class.update_counters(owner.id, counter => difference)
end
end
def update_counter_in_memory(difference, reflection = reflection())
if counter_must_be_updated_by_has_many?(reflection)
counter = cached_counter_attribute_name(reflection)
owner[counter] += difference
owner.send(:clear_attribute_changes, counter) # eww
end
end
# This shit is nasty. We need to avoid the following situation:
#
# * An associated record is deleted via record.destroy
# * Hence the callbacks run, and they find a belongs_to on the record with a
# :counter_cache options which points back at our owner. So they update the
# counter cache.
# * In which case, we must make sure to *not* update the counter cache, or else
# it will be decremented twice.
#
# Hence this method.
def inverse_which_updates_counter_cache(reflection = reflection())
counter_name = cached_counter_attribute_name(reflection)
inverse_which_updates_counter_named(counter_name, reflection)
end
alias inverse_updates_counter_cache? inverse_which_updates_counter_cache
def inverse_which_updates_counter_named(counter_name, reflection)
reflection.klass._reflections.values.find { |inverse_reflection|
inverse_reflection.belongs_to? &&
inverse_reflection.counter_cache_column == counter_name
}
end
def inverse_updates_counter_in_memory?(reflection)
inverse = inverse_which_updates_counter_cache(reflection)
inverse && inverse == reflection.inverse_of
end
def counter_must_be_updated_by_has_many?(reflection)
!inverse_updates_counter_in_memory?(reflection) && has_cached_counter?(reflection)
end
def delete_count(method, scope)
if method == :delete_all
scope.delete_all
else
scope.update_all(reflection.foreign_key => nil)
end
end
def delete_or_nullify_all_records(method)
count = delete_count(method, self.scope)
update_counter(-count)
end
# Deletes the records according to the <tt>:dependent</tt> option.
def delete_records(records, method)
if method == :destroy
records.each(&:destroy!)
update_counter(-records.length) unless inverse_updates_counter_cache?
else
scope = self.scope.where(reflection.klass.primary_key => records)
update_counter(-delete_count(method, scope))
end
end
def concat_records(records, *)
update_counter_if_success(super, records.length)
end
def _create_record(attributes, *)
if attributes.is_a?(Array)
super
else
update_counter_if_success(super, 1)
end
end
def update_counter_if_success(saved_successfully, difference)
if saved_successfully
update_counter_in_memory(difference)
end
saved_successfully
end
end
end
end
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