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module ActiveRecord
module Scoping
module Default
extend ActiveSupport::Concern
included do
# Stores the default scope for the class.
class_attribute :default_scopes, instance_writer: false, instance_predicate: false
class_attribute :default_scope_override, instance_writer: false, instance_predicate: false
self.default_scopes = []
self.default_scope_override = nil
end
module ClassMethods
# Returns a scope for the model without the previously set scopes.
#
# class Post < ActiveRecord::Base
# def self.default_scope
# where(published: true)
# end
# end
#
# Post.all # Fires "SELECT * FROM posts WHERE published = true"
# Post.unscoped.all # Fires "SELECT * FROM posts"
# Post.where(published: false).unscoped.all # Fires "SELECT * FROM posts"
#
# This method also accepts a block. All queries inside the block will
# not use the previously set scopes.
#
# Post.unscoped {
# Post.limit(10) # Fires "SELECT * FROM posts LIMIT 10"
# }
def unscoped
block_given? ? relation.scoping { yield } : relation
end
# Are there attributes associated with this scope?
def scope_attributes? # :nodoc:
super || default_scopes.any? || respond_to?(:default_scope)
end
def before_remove_const #:nodoc:
self.current_scope = nil
end
protected
# Use this macro in your model to set a default scope for all operations on
# the model.
#
# class Article < ActiveRecord::Base
# default_scope { where(published: true) }
# end
#
# Article.all # => SELECT * FROM articles WHERE published = true
#
# The #default_scope is also applied while creating/building a record.
# It is not applied while updating a record.
#
# Article.new.published # => true
# Article.create.published # => true
#
# (You can also pass any object which responds to +call+ to the
# +default_scope+ macro, and it will be called when building the
# default scope.)
#
# If you use multiple #default_scope declarations in your model then
# they will be merged together:
#
# class Article < ActiveRecord::Base
# default_scope { where(published: true) }
# default_scope { where(rating: 'G') }
# end
#
# Article.all # => SELECT * FROM articles WHERE published = true AND rating = 'G'
#
# This is also the case with inheritance and module includes where the
# parent or module defines a #default_scope and the child or including
# class defines a second one.
#
# If you need to do more complex things with a default scope, you can
# alternatively define it as a class method:
#
# class Article < ActiveRecord::Base
# def self.default_scope
# # Should return a scope, you can call 'super' here etc.
# end
# end
def default_scope(scope = nil)
scope = Proc.new if block_given?
if scope.is_a?(Relation) || !scope.respond_to?(:call)
raise ArgumentError,
"Support for calling #default_scope without a block is removed. For example instead " \
"of `default_scope where(color: 'red')`, please use " \
"`default_scope { where(color: 'red') }`. (Alternatively you can just redefine " \
"self.default_scope.)"
end
self.default_scopes += [scope]
end
def build_default_scope(base_rel = nil) # :nodoc:
return if abstract_class?
if default_scope_override.nil?
self.default_scope_override = !Base.is_a?(method(:default_scope).owner)
end
if default_scope_override
# The user has defined their own default scope method, so call that
evaluate_default_scope { default_scope }
elsif default_scopes.any?
base_rel ||= relation
evaluate_default_scope do
default_scopes.inject(base_rel) do |default_scope, scope|
scope = scope.respond_to?(:to_proc) ? scope : scope.method(:call)
default_scope.merge(base_rel.instance_exec(&scope))
end
end
end
end
def ignore_default_scope? # :nodoc:
ScopeRegistry.value_for(:ignore_default_scope, base_class)
end
def ignore_default_scope=(ignore) # :nodoc:
ScopeRegistry.set_value_for(:ignore_default_scope, base_class, ignore)
end
# The ignore_default_scope flag is used to prevent an infinite recursion
# situation where a default scope references a scope which has a default
# scope which references a scope...
def evaluate_default_scope # :nodoc:
return if ignore_default_scope?
begin
self.ignore_default_scope = true
yield
ensure
self.ignore_default_scope = false
end
end
end
end
end
end