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require 'active_support/core_ext/array'
require 'active_support/core_ext/hash/except'
require 'active_support/core_ext/object/metaclass'
module ActiveRecord
module NamedScope
extend ActiveSupport::Concern
module ClassMethods
# Returns a relation if invoked without any arguments.
#
# posts = Post.scoped
# posts.size # Fires "select count(*) from posts" and returns the count
# posts.each {|p| puts p.name } # Fires "select * from posts" and loads post objects
#
# Returns an anonymous named scope if any options are supplied.
#
# shirts = Shirt.scoped(:conditions => {:color => 'red'})
# shirts = shirts.scoped(:include => :washing_instructions)
#
# Anonymous \scopes tend to be useful when procedurally generating complex queries, where passing
# intermediate values (scopes) around as first-class objects is convenient.
#
# You can define a scope that applies to all finders using ActiveRecord::Base.default_scope.
def scoped(options = {}, &block)
if options.present?
Scope.init(self, options, &block)
else
current_scoped_methods ? unscoped.merge(current_scoped_methods) : unscoped.spawn
end
end
def scopes
read_inheritable_attribute(:scopes) || write_inheritable_attribute(:scopes, {})
end
# Adds a class method for retrieving and querying objects. A scope represents a narrowing of a database query,
# such as <tt>:conditions => {:color => :red}, :select => 'shirts.*', :include => :washing_instructions</tt>.
#
# class Shirt < ActiveRecord::Base
# scope :red, :conditions => {:color => 'red'}
# scope :dry_clean_only, :joins => :washing_instructions, :conditions => ['washing_instructions.dry_clean_only = ?', true]
# end
#
# The above calls to <tt>scope</tt> define class methods Shirt.red and Shirt.dry_clean_only. Shirt.red,
# in effect, represents the query <tt>Shirt.find(:all, :conditions => {:color => 'red'})</tt>.
#
# Unlike <tt>Shirt.find(...)</tt>, however, the object returned by Shirt.red is not an Array; it resembles the association object
# constructed by a <tt>has_many</tt> declaration. For instance, you can invoke <tt>Shirt.red.find(:first)</tt>, <tt>Shirt.red.count</tt>,
# <tt>Shirt.red.find(:all, :conditions => {:size => 'small'})</tt>. Also, just
# as with the association objects, named \scopes act like an Array, implementing Enumerable; <tt>Shirt.red.each(&block)</tt>,
# <tt>Shirt.red.first</tt>, and <tt>Shirt.red.inject(memo, &block)</tt> all behave as if Shirt.red really was an Array.
#
# These named \scopes are composable. For instance, <tt>Shirt.red.dry_clean_only</tt> will produce all shirts that are both red and dry clean only.
# Nested finds and calculations also work with these compositions: <tt>Shirt.red.dry_clean_only.count</tt> returns the number of garments
# for which these criteria obtain. Similarly with <tt>Shirt.red.dry_clean_only.average(:thread_count)</tt>.
#
# All \scopes are available as class methods on the ActiveRecord::Base descendant upon which the \scopes were defined. But they are also available to
# <tt>has_many</tt> associations. If,
#
# class Person < ActiveRecord::Base
# has_many :shirts
# end
#
# then <tt>elton.shirts.red.dry_clean_only</tt> will return all of Elton's red, dry clean
# only shirts.
#
# Named \scopes can also be procedural:
#
# class Shirt < ActiveRecord::Base
# scope :colored, lambda { |color|
# { :conditions => { :color => color } }
# }
# end
#
# In this example, <tt>Shirt.colored('puce')</tt> finds all puce shirts.
#
# Named \scopes can also have extensions, just as with <tt>has_many</tt> declarations:
#
# class Shirt < ActiveRecord::Base
# scope :red, :conditions => {:color => 'red'} do
# def dom_id
# 'red_shirts'
# end
# end
# end
#
#
# For testing complex named \scopes, you can examine the scoping options using the
# <tt>proxy_options</tt> method on the proxy itself.
#
# class Shirt < ActiveRecord::Base
# scope :colored, lambda { |color|
# { :conditions => { :color => color } }
# }
# end
#
# expected_options = { :conditions => { :colored => 'red' } }
# assert_equal expected_options, Shirt.colored('red').proxy_options
def scope(name, options = {}, &block)
name = name.to_sym
if !scopes[name] && respond_to?(name, true)
raise ArgumentError, "Cannot define named_scope :#{name} because #{self.name}.#{name} method already exists."
end
scopes[name] = lambda do |parent_scope, *args|
Scope.init(parent_scope, case options
when Hash, Relation
options
when Proc
options.call(*args)
end, &block)
end
metaclass.instance_eval do
define_method name do |*args|
scopes[name].call(self, *args)
end
end
end
def named_scope(*args, &block)
ActiveSupport::Deprecation.warn("Base#named_scope has been deprecated, please use Base.scope instead.", caller)
scope(*args, &block)
end
end
class Scope < Relation
attr_accessor :current_scoped_methods_when_defined
delegate :scopes, :with_scope, :with_exclusive_scope, :scoped_methods, :scoped, :to => :klass
def self.init(klass, options, &block)
relation = new(klass, klass.arel_table)
scope = if options.is_a?(Hash)
klass.scoped.apply_finder_options(options.except(:extend))
else
options ? klass.scoped.merge(options) : klass.scoped
end
relation = relation.merge(scope)
Array.wrap(options[:extend]).each {|extension| relation.send(:extend, extension) } if options.is_a?(Hash)
relation.send(:extend, Module.new(&block)) if block_given?
relation.current_scoped_methods_when_defined = klass.send(:current_scoped_methods)
relation
end
def find(*args)
options = args.extract_options!
relation = options.present? ? apply_finder_options(options) : self
case args.first
when :first, :last, :all
relation.send(args.first)
else
options.present? ? relation.find(*args) : super
end
end
def first(*args)
if args.first.kind_of?(Integer) || (loaded? && !args.first.kind_of?(Hash))
to_a.first(*args)
else
args.first.present? ? apply_finder_options(args.first).first : super
end
end
def last(*args)
if args.first.kind_of?(Integer) || (loaded? && !args.first.kind_of?(Hash))
to_a.last(*args)
else
args.first.present? ? apply_finder_options(args.first).last : super
end
end
def count(*args)
options = args.extract_options!
options.present? ? apply_finder_options(options).count(*args) : super
end
def ==(other)
to_a == other.to_a
end
private
def method_missing(method, *args, &block)
if klass.respond_to?(method)
with_scope(self) do
if current_scoped_methods_when_defined && !scoped_methods.include?(current_scoped_methods_when_defined) && !scopes.include?(method)
with_scope(current_scoped_methods_when_defined) { klass.send(method, *args, &block) }
else
klass.send(method, *args, &block)
end
end
else
super
end
end
end
end
end
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