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# frozen_string_literal: true
require "active_support/core_ext/module/delegation"
module ActiveRecord
module Delegation # :nodoc:
class << self
def delegated_classes
[
ActiveRecord::Relation,
ActiveRecord::Associations::CollectionProxy,
ActiveRecord::AssociationRelation,
ActiveRecord::DisableJoinsAssociationRelation,
]
end
def uncacheable_methods
@uncacheable_methods ||= (
delegated_classes.flat_map(&:public_instance_methods) - ActiveRecord::Relation.public_instance_methods
).to_set.freeze
end
end
module DelegateCache # :nodoc:
def relation_delegate_class(klass)
@relation_delegate_cache[klass]
end
def initialize_relation_delegate_cache
@relation_delegate_cache = cache = {}
Delegation.delegated_classes.each do |klass|
delegate = Class.new(klass) {
include ClassSpecificRelation
}
include_relation_methods(delegate)
mangled_name = klass.name.gsub("::", "_")
const_set mangled_name, delegate
private_constant mangled_name
cache[klass] = delegate
end
end
def inherited(child_class)
child_class.initialize_relation_delegate_cache
super
end
def generate_relation_method(method)
generated_relation_methods.generate_method(method)
end
protected
def include_relation_methods(delegate)
superclass.include_relation_methods(delegate) unless base_class?
delegate.include generated_relation_methods
end
private
def generated_relation_methods
@generated_relation_methods ||= GeneratedRelationMethods.new.tap do |mod|
const_set(:GeneratedRelationMethods, mod)
private_constant :GeneratedRelationMethods
end
end
end
class GeneratedRelationMethods < Module # :nodoc:
MUTEX = Mutex.new
def generate_method(method)
MUTEX.synchronize do
return if method_defined?(method)
if /\A[a-zA-Z_]\w*[!?]?\z/.match?(method) && !::ActiveSupport::Delegation::RESERVED_METHOD_NAMES.include?(method.to_s)
module_eval <<-RUBY, __FILE__, __LINE__ + 1
def #{method}(...)
scoping { klass.#{method}(...) }
end
RUBY
else
define_method(method) do |*args, **kwargs, &block|
scoping { klass.public_send(method, *args, **kwargs, &block) }
end
end
end
end
end
private_constant :GeneratedRelationMethods
extend ActiveSupport::Concern
# This module creates compiled delegation methods dynamically at runtime, which makes
# subsequent calls to that method faster by avoiding method_missing. The delegations
# may vary depending on the klass of a relation, so we create a subclass of Relation
# for each different klass, and the delegations are compiled into that subclass only.
delegate :to_xml, :encode_with, :length, :each, :join, :intersect?,
:[], :&, :|, :+, :-, :sample, :reverse, :rotate, :compact, :in_groups, :in_groups_of,
:to_sentence, :to_fs, :to_formatted_s, :as_json,
:shuffle, :split, :slice, :index, :rindex, to: :records
delegate :primary_key, :lease_connection, :connection, :with_connection, :transaction, to: :klass
module ClassSpecificRelation # :nodoc:
extend ActiveSupport::Concern
module ClassMethods # :nodoc:
def name
superclass.name
end
end
private
def method_missing(method, ...)
if @klass.respond_to?(method)
unless Delegation.uncacheable_methods.include?(method)
@klass.generate_relation_method(method)
end
scoping { @klass.public_send(method, ...) }
else
super
end
end
end
module ClassMethods # :nodoc:
def create(klass, *args, **kwargs)
relation_class_for(klass).new(klass, *args, **kwargs)
end
private
def relation_class_for(klass)
klass.relation_delegate_class(self)
end
end
private
def respond_to_missing?(method, _)
super || @klass.respond_to?(method)
end
end
end
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