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require 'set'
require 'active_support/concern'
module ActiveRecord
module Delegation # :nodoc:
module DelegateCache
def relation_delegate_class(klass) # :nodoc:
@relation_delegate_cache[klass]
end
def initialize_relation_delegate_cache # :nodoc:
@relation_delegate_cache = cache = {}
[
ActiveRecord::Relation,
ActiveRecord::Associations::CollectionProxy,
ActiveRecord::AssociationRelation
].each do |klass|
delegate = Class.new(klass) {
include ClassSpecificRelation
}
const_set klass.name.gsub('::', '_'), delegate
cache[klass] = delegate
end
end
def inherited(child_class)
child_class.initialize_relation_delegate_cache
super
end
end
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.
BLACKLISTED_ARRAY_METHODS = [
:compact!, :flatten!, :reject!, :reverse!, :rotate!, :map!,
:shuffle!, :slice!, :sort!, :sort_by!, :delete_if,
:keep_if, :pop, :shift, :delete_at, :select!
].to_set # :nodoc:
delegate :to_xml, :to_yaml, :length, :collect, :map, :each, :all?, :include?, :to_ary, :join, to: :to_a
delegate :table_name, :quoted_table_name, :primary_key, :quoted_primary_key,
:connection, :columns_hash, :to => :klass
module ClassSpecificRelation # :nodoc:
extend ActiveSupport::Concern
included do
@delegation_mutex = Mutex.new
end
module ClassMethods # :nodoc:
def name
superclass.name
end
def delegate_to_scoped_klass(method)
@delegation_mutex.synchronize do
return if method_defined?(method)
if method.to_s =~ /\A[a-zA-Z_]\w*[!?]?\z/
module_eval <<-RUBY, __FILE__, __LINE__ + 1
def #{method}(*args, &block)
scoping { @klass.#{method}(*args, &block) }
end
RUBY
else
define_method method do |*args, &block|
scoping { @klass.public_send(method, *args, &block) }
end
end
end
end
def delegate(method, opts = {})
@delegation_mutex.synchronize do
return if method_defined?(method)
super
end
end
end
protected
def method_missing(method, *args, &block)
if @klass.respond_to?(method)
self.class.delegate_to_scoped_klass(method)
scoping { @klass.public_send(method, *args, &block) }
elsif arel.respond_to?(method)
self.class.delegate method, :to => :arel
arel.public_send(method, *args, &block)
else
super
end
end
end
module ClassMethods # :nodoc:
def create(klass, *args)
relation_class_for(klass).new(klass, *args)
end
private
def relation_class_for(klass)
klass.relation_delegate_class(self)
end
end
def respond_to?(method, include_private = false)
super || @klass.respond_to?(method, include_private) ||
array_delegable?(method) ||
arel.respond_to?(method, include_private)
end
protected
def array_delegable?(method)
Array.method_defined?(method) && BLACKLISTED_ARRAY_METHODS.exclude?(method)
end
def method_missing(method, *args, &block)
if @klass.respond_to?(method)
scoping { @klass.public_send(method, *args, &block) }
elsif array_delegable?(method)
to_a.public_send(method, *args, &block)
elsif arel.respond_to?(method)
arel.public_send(method, *args, &block)
else
super
end
end
end
end
|
