lib/ooor/autosave_association.rb
require 'ostruct'
require 'active_support/concern'
module Ooor
# = Ooor Autosave Association, adapted from ActiveRecord 4.1
#
# +AutosaveAssociation+ is a module that takes care of automatically saving
# associated records when their parent is saved. In addition to saving, it
# also destroys any associated records that were marked for destruction.
# (See +mark_for_destruction+ and <tt>marked_for_destruction?</tt>).
#
# Saving of the parent, its associations, and the destruction of marked
# associations, all happen inside a transaction. This should never leave the
# database in an inconsistent state.
#
# If validations for any of the associations fail, their error messages will
# be applied to the parent (TODO)
module AutosaveAssociation
extend ActiveSupport::Concern
module ClassMethods
private
# same as ActiveRecord
def define_non_cyclic_method(name, &block)
define_method(name) do |*args|
result = true; @_already_called ||= {}
# Loop prevention for validation of associations
unless @_already_called[name]
begin
@_already_called[name]=true
result = instance_eval(&block)
ensure
@_already_called[name]=false
end
end
result
end
end
# Adds validation and save callbacks for the association as specified by
# the +reflection+.
#
# For performance reasons, we don't check whether to validate at runtime.
# However the validation and callback methods are lazy and those methods
# get created when they are invoked for the very first time. However,
# this can change, for instance, when using nested attributes, which is
# called _after_ the association has been defined. Since we don't want
# the callbacks to get defined multiple times, there are guards that
# check if the save or validation methods have already been defined
# before actually defining them.
def add_autosave_association_callbacks(reflection) # TODO add support for m2o
save_method = :"autosave_associated_records_for_#{reflection.name}"
validation_method = :"validate_associated_records_for_#{reflection.name}"
collection = true #reflection.collection?
unless method_defined?(save_method)
if collection
before_save :before_save_collection_association
define_non_cyclic_method(save_method) { save_collection_association(reflection) }
before_save save_method
# NOTE Ooor is different from ActiveRecord here: we run the nested callbacks before saving
# the whole hash of values including the nested records
# Doesn't use after_save as that would save associations added in after_create/after_update twice
# after_create save_method
# after_update save_method
else
raise raise ArgumentError, "Not implemented in Ooor; seems OpenERP won't support such nested attribute in the same transaction anyhow"
end
end
if reflection.validate? && !method_defined?(validation_method)
method = (collection ? :validate_collection_association : :validate_single_association)
define_non_cyclic_method(validation_method) { send(method, reflection) }
validate validation_method
end
end
end
# Reloads the attributes of the object as usual and clears <tt>marked_for_destruction</tt> flag.
def reload(options = nil)
@marked_for_destruction = false
@destroyed_by_association = nil
super
end
# Marks this record to be destroyed as part of the parents save transaction.
# This does _not_ actually destroy the record instantly, rather child record will be destroyed
# when <tt>parent.save</tt> is called.
#
# Only useful if the <tt>:autosave</tt> option on the parent is enabled for this associated model.
def mark_for_destruction
@marked_for_destruction = true
end
# Returns whether or not this record will be destroyed as part of the parents save transaction.
#
# Only useful if the <tt>:autosave</tt> option on the parent is enabled for this associated model.
def marked_for_destruction?
@marked_for_destruction
end
# Records the association that is being destroyed and destroying this
# record in the process.
def destroyed_by_association=(reflection)
@destroyed_by_association = reflection
end
# Returns the association for the parent being destroyed.
#
# Used to avoid updating the counter cache unnecessarily.
def destroyed_by_association
@destroyed_by_association
end
# Returns whether or not this record has been changed in any way (including whether
# any of its nested autosave associations are likewise changed)
def changed_for_autosave?
new_record? || changed? || marked_for_destruction? # TODO || nested_records_changed_for_autosave?
end
private
# Returns the record for an association collection that should be validated
# or saved. If +autosave+ is +false+ only new records will be returned,
# unless the parent is/was a new record itself.
def associated_records_to_validate_or_save(association, new_record, autosave)
if new_record
association && association.target
elsif autosave
association.target.find_all { |record| record.changed_for_autosave? }
else
association.target.find_all { |record| record.new_record? }
end
end
# go through nested autosave associations that are loaded in memory (without loading
# any new ones), and return true if is changed for autosave
# def nested_records_changed_for_autosave?
# self.class.reflect_on_all_autosave_associations.any? do |reflection|
# association = association_instance_get(reflection.name)
# association && Array.wrap(association.target).any? { |a| a.changed_for_autosave? }
# end
# end
# Is used as a before_save callback to check while saving a collection
# association whether or not the parent was a new record before saving.
def before_save_collection_association
@new_record_before_save = new_record?
true
end
# Saves any new associated records, or all loaded autosave associations if
# <tt>:autosave</tt> is enabled on the association.
#
# In addition, it destroys all children that were marked for destruction
# with mark_for_destruction.
#
# This all happens inside a transaction, _if_ the Transactions module is included into
# ActiveRecord::Base after the AutosaveAssociation module, which it does by default.
def save_collection_association(reflection)
# if association = association_instance_get(reflection.name)
if target = @loaded_associations[reflection.name] #TODO use a real Association wrapper
association = OpenStruct.new(target: target)
autosave = reflection.options[:autosave]
if records = associated_records_to_validate_or_save(association, @new_record_before_save, autosave)
# NOTE saving the object with its nested associations will properly destroy records in OpenERP
# no need to do it now like in ActiveRecord
records.each do |record|
next if record.destroyed?
saved = true
if autosave != false && (@new_record_before_save || record.new_record?)
if autosave
# saved = association.insert_record(record, false)
record.run_callbacks(:save) { false }
record.run_callbacks(:create) { false }
# else
# association.insert_record(record) unless reflection.nested?
end
elsif autosave
record.run_callbacks(:save) {false}
record.run_callbacks(:update) {false}
# saved = record.save(:validate => false)
end
end
end
# reconstruct the scope now that we know the owner's id
# association.reset_scope if association.respond_to?(:reset_scope)
end
end
end
end