require 'active_support/core_ext/module/attribute_accessors'
# This is the parent Association class which defines the variables
# used by all associations.
#
# The hierarchy is defined as follows:
# Association
# - SingularAssociation
# - BelongsToAssociation
# - HasOneAssociation
# - CollectionAssociation
# - HasManyAssociation
module ActiveRecord::Associations::Builder
class Association #:nodoc:
class << self
attr_accessor :extensions
# TODO: This class accessor is needed to make activerecord-deprecated_finders work.
# We can move it to a constant in 5.0.
attr_accessor :valid_options
end
self.extensions = []
self.valid_options = [:class_name, :class, :foreign_key, :validate]
attr_reader :name, :scope, :options
def self.build(model, name, scope, options, &block)
if model.dangerous_attribute_method?(name)
raise ArgumentError, "You tried to define an association named #{name} on the model #{model.name}, but " \
"this will conflict with a method #{name} already defined by Active Record. " \
"Please choose a different association name."
end
builder = create_builder model, name, scope, options, &block
reflection = builder.build(model)
define_accessors model, reflection
define_callbacks model, reflection
builder.define_extensions model
reflection
end
def self.create_builder(model, name, scope, options, &block)
raise ArgumentError, "association names must be a Symbol" unless name.kind_of?(Symbol)
new(model, name, scope, options, &block)
end
def initialize(model, name, scope, options)
# TODO: Move this to create_builder as soon we drop support to activerecord-deprecated_finders.
if scope.is_a?(Hash)
options = scope
scope = nil
end
# TODO: Remove this model argument as soon we drop support to activerecord-deprecated_finders.
@name = name
@scope = scope
@options = options
validate_options
if scope && scope.arity == 0
@scope = proc { instance_exec(&scope) }
end
end
def build(model)
ActiveRecord::Reflection.create(macro, name, scope, options, model)
end
def macro
raise NotImplementedError
end
def valid_options
Association.valid_options + Association.extensions.flat_map(&:valid_options)
end
def validate_options
options.assert_valid_keys(valid_options)
end
def define_extensions(model)
end
def self.define_callbacks(model, reflection)
if dependent = reflection.options[:dependent]
check_dependent_options(dependent)
add_destroy_callbacks(model, reflection)
end
Association.extensions.each do |extension|
extension.build model, reflection
end
end
# Defines the setter and getter methods for the association
# class Post < ActiveRecord::Base
# has_many :comments
# end
#
# Post.first.comments and Post.first.comments= methods are defined by this method...
def self.define_accessors(model, reflection)
mixin = model.generated_association_methods
name = reflection.name
define_readers(mixin, name)
define_writers(mixin, name)
end
def self.define_readers(mixin, name)
mixin.class_eval <<-CODE, __FILE__, __LINE__ + 1
def #{name}(*args)
association(:#{name}).reader(*args)
end
CODE
end
def self.define_writers(mixin, name)
mixin.class_eval <<-CODE, __FILE__, __LINE__ + 1
def #{name}=(value)
association(:#{name}).writer(value)
end
CODE
end
def self.valid_dependent_options
raise NotImplementedError
end
private
def self.check_dependent_options(dependent)
unless valid_dependent_options.include? dependent
raise ArgumentError, "The :dependent option must be one of #{valid_dependent_options}, but is :#{dependent}"
end
end
def self.add_destroy_callbacks(model, reflection)
name = reflection.name
model.before_destroy lambda { |o| o.association(name).handle_dependency }
end
end
end