diff options
Diffstat (limited to 'activerecord/lib/active_record/scoping/default.rb')
| -rw-r--r-- | activerecord/lib/active_record/scoping/default.rb | 159 |
1 files changed, 159 insertions, 0 deletions
diff --git a/activerecord/lib/active_record/scoping/default.rb b/activerecord/lib/active_record/scoping/default.rb new file mode 100644 index 0000000000..6caf9b3251 --- /dev/null +++ b/activerecord/lib/active_record/scoping/default.rb @@ -0,0 +1,159 @@ +# frozen_string_literal: true + +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, default: [] + class_attribute :default_scope_override, instance_writer: false, instance_predicate: false, default: 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? ? _scoping(relation) { yield } : relation + end + + def _scoping(relation) # :nodoc: + previous, self.current_scope = current_scope(true), relation + yield + ensure + self.current_scope = previous + 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 + + private + + # 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) # :doc: + 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) + 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 do + if scope = default_scope + (base_rel ||= relation).merge!(scope) + end + end + 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? + ScopeRegistry.value_for(:ignore_default_scope, base_class) + end + + def ignore_default_scope=(ignore) + 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 + return if ignore_default_scope? + + begin + self.ignore_default_scope = true + yield + ensure + self.ignore_default_scope = false + end + end + end + end + end +end |