diff options
Diffstat (limited to 'activerecord/lib/active_record/reflection.rb')
| -rw-r--r-- | activerecord/lib/active_record/reflection.rb | 231 |
1 files changed, 170 insertions, 61 deletions
diff --git a/activerecord/lib/active_record/reflection.rb b/activerecord/lib/active_record/reflection.rb index 60eda96f08..f47282b7fd 100644 --- a/activerecord/lib/active_record/reflection.rb +++ b/activerecord/lib/active_record/reflection.rb @@ -5,10 +5,33 @@ module ActiveRecord included do class_attribute :reflections + class_attribute :aggregate_reflections self.reflections = {} + self.aggregate_reflections = {} end - # Reflection enables to interrogate Active Record classes and objects + def self.create(macro, name, scope, options, ar) + case macro + when :has_and_belongs_to_many + klass = AssociationReflection + when :has_many, :belongs_to, :has_one + klass = options[:through] ? ThroughReflection : AssociationReflection + when :composed_of + klass = AggregateReflection + end + + klass.new(macro, name, scope, options, ar) + end + + def self.add_reflection(ar, name, reflection) + ar.reflections = ar.reflections.merge(name => reflection) + end + + def self.add_aggregate_reflection(ar, name, reflection) + ar.aggregate_reflections = ar.aggregate_reflections.merge(name => reflection) + end + + # \Reflection enables to interrogate Active Record classes and objects # about their associations and aggregations. This information can, # for example, be used in a form builder that takes an Active Record object # and creates input fields for all of the attributes depending on their type @@ -17,22 +40,9 @@ module ActiveRecord # MacroReflection class has info for AggregateReflection and AssociationReflection # classes. module ClassMethods - def create_reflection(macro, name, scope, options, active_record) - case macro - when :has_many, :belongs_to, :has_one, :has_and_belongs_to_many - klass = options[:through] ? ThroughReflection : AssociationReflection - reflection = klass.new(macro, name, scope, options, active_record) - when :composed_of - reflection = AggregateReflection.new(macro, name, scope, options, active_record) - end - - self.reflections = self.reflections.merge(name => reflection) - reflection - end - # Returns an array of AggregateReflection objects for all the aggregations in the class. def reflect_on_all_aggregations - reflections.values.grep(AggregateReflection) + aggregate_reflections.values end # Returns the AggregateReflection object for the named +aggregation+ (use the symbol). @@ -40,8 +50,7 @@ module ActiveRecord # Account.reflect_on_aggregation(:balance) # => the balance AggregateReflection # def reflect_on_aggregation(aggregation) - reflection = reflections[aggregation] - reflection if reflection.is_a?(AggregateReflection) + aggregate_reflections[aggregation] end # Returns an array of AssociationReflection objects for all the @@ -55,7 +64,7 @@ module ActiveRecord # Account.reflect_on_all_associations(:has_many) # returns an array of all has_many associations # def reflect_on_all_associations(macro = nil) - association_reflections = reflections.values.grep(AssociationReflection) + association_reflections = reflections.values macro ? association_reflections.select { |reflection| reflection.macro == macro } : association_reflections end @@ -65,8 +74,7 @@ module ActiveRecord # Invoice.reflect_on_association(:line_items).macro # returns :has_many # def reflect_on_association(association) - reflection = reflections[association] - reflection if reflection.is_a?(AssociationReflection) + reflections[association] end # Returns an array of AssociationReflection objects for all associations which have <tt>:autosave</tt> enabled. @@ -100,7 +108,7 @@ module ActiveRecord # Returns the hash of options used for the macro. # # <tt>composed_of :balance, class_name: 'Money'</tt> returns <tt>{ class_name: "Money" }</tt> - # <tt>has_many :clients</tt> returns +{}+ + # <tt>has_many :clients</tt> returns <tt>{}</tt> attr_reader :options attr_reader :active_record @@ -113,10 +121,16 @@ module ActiveRecord @scope = scope @options = options @active_record = active_record + @klass = options[:class] @plural_name = active_record.pluralize_table_names ? name.to_s.pluralize : name.to_s end + def autosave=(autosave) + @automatic_inverse_of = false + @options[:autosave] = autosave + end + # Returns the class for the macro. # # <tt>composed_of :balance, class_name: 'Money'</tt> returns the Money class @@ -178,9 +192,14 @@ module ActiveRecord @klass ||= active_record.send(:compute_type, class_name) end - def initialize(*args) + attr_reader :type, :foreign_type + + def initialize(macro, name, scope, options, active_record) super @collection = [:has_many, :has_and_belongs_to_many].include?(macro) + @automatic_inverse_of = nil + @type = options[:as] && "#{options[:as]}_type" + @foreign_type = options[:foreign_type] || "#{name}_type" end # Returns a new, unsaved instance of the associated class. +attributes+ will @@ -190,11 +209,11 @@ module ActiveRecord end def table_name - @table_name ||= klass.table_name + klass.table_name end def quoted_table_name - @quoted_table_name ||= klass.quoted_table_name + klass.quoted_table_name end def join_table @@ -205,16 +224,8 @@ module ActiveRecord @foreign_key ||= options[:foreign_key] || derive_foreign_key end - def foreign_type - @foreign_type ||= options[:foreign_type] || "#{name}_type" - end - - def type - @type ||= options[:as] && "#{options[:as]}_type" - end - def primary_key_column - @primary_key_column ||= klass.columns.find { |c| c.name == klass.primary_key } + klass.columns_hash[klass.primary_key] end def association_foreign_key @@ -238,14 +249,6 @@ module ActiveRecord end end - def columns(tbl_name) - @columns ||= klass.connection.columns(tbl_name) - end - - def reset_column_information - @columns = nil - end - def check_validity! check_validity_of_inverse! @@ -267,7 +270,7 @@ module ActiveRecord end def source_reflection - nil + self end # A chain of reflections from this one back to the owner. For more see the explanation in @@ -289,13 +292,13 @@ module ActiveRecord alias :source_macro :macro def has_inverse? - @options[:inverse_of] + inverse_name end def inverse_of - if has_inverse? - @inverse_of ||= klass.reflect_on_association(options[:inverse_of]) - end + return unless inverse_name + + @inverse_of ||= klass.reflect_on_association inverse_name end def polymorphic_inverse_of(associated_class) @@ -366,7 +369,80 @@ module ActiveRecord options.key? :polymorphic end + VALID_AUTOMATIC_INVERSE_MACROS = [:has_many, :has_one, :belongs_to] + INVALID_AUTOMATIC_INVERSE_OPTIONS = [:conditions, :through, :polymorphic, :foreign_key] + + protected + + def actual_source_reflection # FIXME: this is a horrible name + self + end + private + # Attempts to find the inverse association name automatically. + # If it cannot find a suitable inverse association name, it returns + # nil. + def inverse_name + options.fetch(:inverse_of) do + if @automatic_inverse_of == false + nil + else + @automatic_inverse_of ||= automatic_inverse_of + end + end + end + + # returns either nil or the inverse association name that it finds. + def automatic_inverse_of + if can_find_inverse_of_automatically?(self) + inverse_name = ActiveSupport::Inflector.underscore(active_record.name).to_sym + + begin + reflection = klass.reflect_on_association(inverse_name) + rescue NameError + # Give up: we couldn't compute the klass type so we won't be able + # to find any associations either. + reflection = false + end + + if valid_inverse_reflection?(reflection) + return inverse_name + end + end + + false + end + + # Checks if the inverse reflection that is returned from the + # +automatic_inverse_of+ method is a valid reflection. We must + # make sure that the reflection's active_record name matches up + # with the current reflection's klass name. + # + # Note: klass will always be valid because when there's a NameError + # from calling +klass+, +reflection+ will already be set to false. + def valid_inverse_reflection?(reflection) + reflection && + klass.name == reflection.active_record.name && + can_find_inverse_of_automatically?(reflection) + end + + # Checks to see if the reflection doesn't have any options that prevent + # us from being able to guess the inverse automatically. First, the + # <tt>inverse_of</tt> option cannot be set to false. Second, we must + # have <tt>has_many</tt>, <tt>has_one</tt>, <tt>belongs_to</tt> associations. + # Third, we must not have options such as <tt>:polymorphic</tt> or + # <tt>:foreign_key</tt> which prevent us from correctly guessing the + # inverse association. + # + # Anything with a scope can additionally ruin our attempt at finding an + # inverse, so we exclude reflections with scopes. + def can_find_inverse_of_automatically?(reflection) + reflection.options[:inverse_of] != false && + VALID_AUTOMATIC_INVERSE_MACROS.include?(reflection.macro) && + !INVALID_AUTOMATIC_INVERSE_OPTIONS.any? { |opt| reflection.options[opt] } && + !reflection.scope + end + def derive_class_name class_name = name.to_s.camelize class_name = class_name.singularize if collection? @@ -398,7 +474,12 @@ module ActiveRecord delegate :foreign_key, :foreign_type, :association_foreign_key, :active_record_primary_key, :type, :to => :source_reflection - # Gets the source of the through reflection. It checks both a singularized + def initialize(macro, name, scope, options, active_record) + super + @source_reflection_name = options[:source] + end + + # Returns the source of the through reflection. It checks both a singularized # and pluralized form for <tt>:belongs_to</tt> or <tt>:has_many</tt>. # # class Post < ActiveRecord::Base @@ -412,12 +493,11 @@ module ActiveRecord # end # # tags_reflection = Post.reflect_on_association(:tags) - # - # taggings_reflection = tags_reflection.source_reflection + # tags_reflection.source_reflection # # => <ActiveRecord::Reflection::AssociationReflection: @macro=:belongs_to, @name=:tag, @active_record=Tagging, @plural_name="tags"> # def source_reflection - @source_reflection ||= source_reflection_names.collect { |name| through_reflection.klass.reflect_on_association(name) }.compact.first + through_reflection.klass.reflect_on_association(source_reflection_name) end # Returns the AssociationReflection object specified in the <tt>:through</tt> option @@ -429,10 +509,11 @@ module ActiveRecord # end # # tags_reflection = Post.reflect_on_association(:tags) - # taggings_reflection = tags_reflection.through_reflection + # tags_reflection.through_reflection + # # => <ActiveRecord::Reflection::AssociationReflection: @macro=:has_many, @name=:taggings, @active_record=Post, @plural_name="taggings"> # def through_reflection - @through_reflection ||= active_record.reflect_on_association(options[:through]) + active_record.reflect_on_association(options[:through]) end # Returns an array of reflections which are involved in this association. Each item in the @@ -454,7 +535,9 @@ module ActiveRecord # def chain @chain ||= begin - chain = source_reflection.chain + through_reflection.chain + a = source_reflection.chain + b = through_reflection.chain + chain = a + b chain[0] = self # Use self so we don't lose the information from :source_type chain end @@ -505,7 +588,7 @@ module ActiveRecord # A through association is nested if there would be more than one join table def nested? - chain.length > 2 || through_reflection.macro == :has_and_belongs_to_many + chain.length > 2 || through_reflection.has_and_belongs_to_many? end # We want to use the klass from this reflection, rather than just delegate straight to @@ -514,12 +597,7 @@ module ActiveRecord def association_primary_key(klass = nil) # Get the "actual" source reflection if the immediate source reflection has a # source reflection itself - source_reflection = self.source_reflection - while source_reflection.source_reflection - source_reflection = source_reflection.source_reflection - end - - source_reflection.options[:primary_key] || primary_key(klass || self.klass) + actual_source_reflection.options[:primary_key] || primary_key(klass || self.klass) end # Gets an array of possible <tt>:through</tt> source reflection names in both singular and plural form. @@ -534,7 +612,32 @@ module ActiveRecord # # => [:tag, :tags] # def source_reflection_names - @source_reflection_names ||= (options[:source] ? [options[:source]] : [name.to_s.singularize, name]).collect { |n| n.to_sym } + (options[:source] ? [options[:source]] : [name.to_s.singularize, name]).collect { |n| n.to_sym }.uniq + end + + def source_reflection_name # :nodoc: + return @source_reflection_name if @source_reflection_name + + names = [name.to_s.singularize, name].collect { |n| n.to_sym }.uniq + names = names.find_all { |n| + through_reflection.klass.reflect_on_association(n) + } + + if names.length > 1 + example_options = options.dup + example_options[:source] = source_reflection_names.first + ActiveSupport::Deprecation.warn <<-eowarn +Ambiguous source reflection for through association. Please specify a :source +directive on your declaration like: + + class #{active_record.name} < ActiveRecord::Base + #{macro} :#{name}, #{example_options} + end + + eowarn + end + + @source_reflection_name = names.first end def source_options @@ -573,6 +676,12 @@ module ActiveRecord check_validity_of_inverse! end + protected + + def actual_source_reflection # FIXME: this is a horrible name + source_reflection.actual_source_reflection + end + private def derive_class_name # get the class_name of the belongs_to association of the through reflection |