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# 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
end
self.extensions = []
VALID_OPTIONS = [:class_name, :class, :foreign_key, :validate]
def self.build(model, name, scope, options, &block)
extension = define_extensions model, name, &block
reflection = create_reflection model, name, scope, options, extension
define_accessors model, reflection
define_callbacks model, reflection
reflection
end
def self.create_reflection(model, name, scope, options, extension = nil)
raise ArgumentError, "association names must be a Symbol" unless name.kind_of?(Symbol)
if scope.is_a?(Hash)
options = scope
scope = nil
end
validate_options(options)
scope = build_scope(scope, extension)
ActiveRecord::Reflection.create(macro, name, scope, options, model)
end
def self.build_scope(scope, extension)
new_scope = scope
if scope && scope.arity == 0
new_scope = proc { instance_exec(&scope) }
end
if extension
new_scope = wrap_scope new_scope, extension
end
new_scope
end
def self.wrap_scope(scope, extension)
scope
end
def self.macro
raise NotImplementedError
end
def self.valid_options(options)
VALID_OPTIONS + Association.extensions.flat_map(&:valid_options)
end
def self.validate_options(options)
options.assert_valid_keys(valid_options(options))
end
def self.define_extensions(model, name)
end
def self.define_callbacks(model, reflection)
add_before_destroy_callbacks(model, reflection) if reflection.options[:dependent]
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
def self.add_before_destroy_callbacks(model, reflection)
unless valid_dependent_options.include? reflection.options[:dependent]
raise ArgumentError, "The :dependent option must be one of #{valid_dependent_options}, but is :#{reflection.options[:dependent]}"
end
name = reflection.name
model.before_destroy lambda { |o| o.association(name).handle_dependency }
end
end
end
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