diff options
Diffstat (limited to 'activerecord/lib/active_record/reflection.rb')
| -rw-r--r-- | activerecord/lib/active_record/reflection.rb | 253 |
1 files changed, 196 insertions, 57 deletions
diff --git a/activerecord/lib/active_record/reflection.rb b/activerecord/lib/active_record/reflection.rb index 7f47a812eb..e801bc4afa 100644 --- a/activerecord/lib/active_record/reflection.rb +++ b/activerecord/lib/active_record/reflection.rb @@ -1,10 +1,18 @@ +require 'active_support/core_ext/class/attribute' +require 'active_support/core_ext/module/deprecation' + module ActiveRecord # = Active Record Reflection module Reflection # :nodoc: extend ActiveSupport::Concern + included do + class_attribute :reflections + self.reflections = {} + end + # Reflection enables to interrogate Active Record classes and objects - # about their associations and aggregations. This information can, + # 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 # and displays the associations to other objects. @@ -20,36 +28,27 @@ module ActiveRecord when :composed_of reflection = AggregateReflection.new(macro, name, options, active_record) end - write_inheritable_hash :reflections, name => reflection - reflection - end - # Returns a hash containing all AssociationReflection objects for the current class. - # Example: - # - # Invoice.reflections - # Account.reflections - # - def reflections - read_inheritable_attribute(:reflections) || write_inheritable_attribute(:reflections, {}) + 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.select { |reflection| reflection.is_a?(AggregateReflection) } + reflections.values.grep(AggregateReflection) end - # Returns the AggregateReflection object for the named +aggregation+ (use the symbol). + # Returns the AggregateReflection object for the named +aggregation+ (use the symbol). # - # Account.reflect_on_aggregation(:balance) #=> the balance AggregateReflection + # Account.reflect_on_aggregation(:balance) # => the balance AggregateReflection # def reflect_on_aggregation(aggregation) reflections[aggregation].is_a?(AggregateReflection) ? reflections[aggregation] : nil end - # Returns an array of AssociationReflection objects for all the - # associations in the class. If you only want to reflect on a certain - # association type, pass in the symbol (<tt>:has_many</tt>, <tt>:has_one</tt>, + # Returns an array of AssociationReflection objects for all the + # associations in the class. If you only want to reflect on a certain + # association type, pass in the symbol (<tt>:has_many</tt>, <tt>:has_one</tt>, # <tt>:belongs_to</tt>) as the first parameter. # # Example: @@ -58,7 +57,7 @@ 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.select { |reflection| reflection.is_a?(AssociationReflection) } + association_reflections = reflections.values.grep(AssociationReflection) macro ? association_reflections.select { |reflection| reflection.macro == macro } : association_reflections end @@ -78,7 +77,7 @@ module ActiveRecord end - # Abstract base class for AggregateReflection and AssociationReflection. Objects of + # Abstract base class for AggregateReflection and AssociationReflection. Objects of # AggregateReflection and AssociationReflection are returned by the Reflection::ClassMethods. class MacroReflection attr_reader :active_record @@ -89,23 +88,23 @@ module ActiveRecord # Returns the name of the macro. # - # <tt>composed_of :balance, :class_name => 'Money'</tt> returns <tt>:balance</tt> + # <tt>composed_of :balance, :class_name => 'Money'</tt> returns <tt>:balance</tt> # <tt>has_many :clients</tt> returns <tt>:clients</tt> attr_reader :name - # Returns the macro type. + # Returns the macro type. # # <tt>composed_of :balance, :class_name => 'Money'</tt> returns <tt>:composed_of</tt> # <tt>has_many :clients</tt> returns <tt>:has_many</tt> attr_reader :macro - # Returns the hash of options used for the macro. + # 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 +{}+ attr_reader :options - # Returns the class for the macro. + # Returns the class for the macro. # # <tt>composed_of :balance, :class_name => 'Money'</tt> returns the Money class # <tt>has_many :clients</tt> returns the Client class @@ -113,7 +112,7 @@ module ActiveRecord @klass ||= class_name.constantize end - # Returns the class name for the macro. + # Returns the class name for the macro. # # <tt>composed_of :balance, :class_name => 'Money'</tt> returns <tt>'Money'</tt> # <tt>has_many :clients</tt> returns <tt>'Client'</tt> @@ -138,12 +137,12 @@ module ActiveRecord end - # Holds all the meta-data about an aggregation as it was specified in the + # Holds all the meta-data about an aggregation as it was specified in the # Active Record class. class AggregateReflection < MacroReflection #:nodoc: end - # Holds all the meta-data about an association as it was specified in the + # Holds all the meta-data about an association as it was specified in the # Active Record class. class AssociationReflection < MacroReflection #:nodoc: # Returns the target association's class. @@ -198,8 +197,21 @@ module ActiveRecord @quoted_table_name ||= klass.quoted_table_name end + def foreign_key + @foreign_key ||= options[:foreign_key] || derive_foreign_key + end + def primary_key_name - @primary_key_name ||= options[:foreign_key] || derive_primary_key_name + foreign_key + end + deprecate :primary_key_name => :foreign_key + + def foreign_type + @foreign_type ||= options[:foreign_type] || "#{name}_type" + end + + def type + @type ||= "#{options[:as]}_type" end def primary_key_column @@ -207,7 +219,18 @@ module ActiveRecord end def association_foreign_key - @association_foreign_key ||= @options[:association_foreign_key] || class_name.foreign_key + @association_foreign_key ||= options[:association_foreign_key] || class_name.foreign_key + end + + def association_primary_key + @association_primary_key ||= + options[:primary_key] || + !options[:polymorphic] && klass.primary_key || + 'id' + end + + def active_record_primary_key + @active_record_primary_key ||= options[:primary_key] || active_record.primary_key end def counter_cache_column @@ -239,18 +262,32 @@ module ActiveRecord end def through_reflection - false - end - - def through_reflection_primary_key_name + nil end def source_reflection nil end + # A chain of reflections from this one back to the owner. For more see the explanation in + # ThroughReflection. + def chain + [self] + end + + # An array of arrays of conditions. Each item in the outside array corresponds to a reflection + # in the #chain. The inside arrays are simply conditions (and each condition may itself be + # a hash, array, arel predicate, etc...) + def conditions + conditions = [options[:conditions]].compact + conditions << { type => active_record.base_class.name } if options[:as] + [conditions] + end + + alias :source_macro :macro + def has_inverse? - !@options[:inverse_of].nil? + @options[:inverse_of] end def inverse_of @@ -289,22 +326,36 @@ module ActiveRecord !options[:validate].nil? ? options[:validate] : (options[:autosave] == true || macro == :has_many) end - def dependent_conditions(record, base_class, extra_conditions) - dependent_conditions = [] - dependent_conditions << "#{primary_key_name} = #{record.send(name).send(:owner_quoted_id)}" - dependent_conditions << "#{options[:as]}_type = '#{base_class.name}'" if options[:as] - dependent_conditions << klass.send(:sanitize_sql, options[:conditions]) if options[:conditions] - dependent_conditions << extra_conditions if extra_conditions - dependent_conditions = dependent_conditions.collect {|where| "(#{where})" }.join(" AND ") - dependent_conditions = dependent_conditions.gsub('@', '\@') - dependent_conditions - end - # Returns +true+ if +self+ is a +belongs_to+ reflection. def belongs_to? macro == :belongs_to end + def association_class + case macro + when :belongs_to + if options[:polymorphic] + Associations::BelongsToPolymorphicAssociation + else + Associations::BelongsToAssociation + end + when :has_and_belongs_to_many + Associations::HasAndBelongsToManyAssociation + when :has_many + if options[:through] + Associations::HasManyThroughAssociation + else + Associations::HasManyAssociation + end + when :has_one + if options[:through] + Associations::HasOneThroughAssociation + else + Associations::HasOneAssociation + end + end + end + private def derive_class_name class_name = name.to_s.camelize @@ -312,7 +363,7 @@ module ActiveRecord class_name end - def derive_primary_key_name + def derive_foreign_key if belongs_to? "#{name}_id" elsif options[:as] @@ -326,6 +377,8 @@ module ActiveRecord # Holds all the meta-data about a :through association as it was specified # in the Active Record class. class ThroughReflection < AssociationReflection #:nodoc: + delegate :foreign_key, :foreign_type, :association_foreign_key, :active_record_primary_key, :to => :source_reflection + # Gets the source of the through reflection. It checks both a singularized # and pluralized form for <tt>:belongs_to</tt> or <tt>:has_many</tt>. # @@ -353,6 +406,88 @@ module ActiveRecord @through_reflection ||= active_record.reflect_on_association(options[:through]) end + # Returns an array of reflections which are involved in this association. Each item in the + # array corresponds to a table which will be part of the query for this association. + # + # The chain is built by recursively calling #chain on the source reflection and the through + # reflection. The base case for the recursion is a normal association, which just returns + # [self] as its #chain. + def chain + @chain ||= begin + chain = source_reflection.chain + through_reflection.chain + chain[0] = self # Use self so we don't lose the information from :source_type + chain + end + end + + # Consider the following example: + # + # class Person + # has_many :articles + # has_many :comment_tags, :through => :articles + # end + # + # class Article + # has_many :comments + # has_many :comment_tags, :through => :comments, :source => :tags + # end + # + # class Comment + # has_many :tags + # end + # + # There may be conditions on Person.comment_tags, Article.comment_tags and/or Comment.tags, + # but only Comment.tags will be represented in the #chain. So this method creates an array + # of conditions corresponding to the chain. Each item in the #conditions array corresponds + # to an item in the #chain, and is itself an array of conditions from an arbitrary number + # of relevant reflections, plus any :source_type or polymorphic :as constraints. + def conditions + @conditions ||= begin + conditions = source_reflection.conditions + + # Add to it the conditions from this reflection if necessary. + conditions.first << options[:conditions] if options[:conditions] + + through_conditions = through_reflection.conditions + + if options[:source_type] + through_conditions.first << { foreign_type => options[:source_type] } + end + + # Recursively fill out the rest of the array from the through reflection + conditions += through_conditions + + # And return + conditions + end + end + + # The macro used by the source association + def source_macro + source_reflection.source_macro + end + + # A through association is nested iff there would be more than one join table + def nested? + chain.length > 2 || through_reflection.macro == :has_and_belongs_to_many + end + + # We want to use the klass from this reflection, rather than just delegate straight to + # the source_reflection, because the source_reflection may be polymorphic. We still + # need to respect the source_reflection's :primary_key option, though. + def association_primary_key + @association_primary_key ||= begin + # 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] || klass.primary_key + end + end + # Gets an array of possible <tt>:through</tt> source reflection names: # # [:singularized, :pluralized] @@ -361,11 +496,23 @@ module ActiveRecord @source_reflection_names ||= (options[:source] ? [options[:source]] : [name.to_s.singularize, name]).collect { |n| n.to_sym } end + def source_options + source_reflection.options + end + + def through_options + through_reflection.options + end + def check_validity! if through_reflection.nil? raise HasManyThroughAssociationNotFoundError.new(active_record.name, self) end + if through_reflection.options[:polymorphic] + raise HasManyThroughAssociationPolymorphicThroughError.new(active_record.name, self) + end + if source_reflection.nil? raise HasManyThroughSourceAssociationNotFoundError.new(self) end @@ -375,24 +522,16 @@ module ActiveRecord end if source_reflection.options[:polymorphic] && options[:source_type].nil? - raise HasManyThroughAssociationPolymorphicError.new(active_record.name, self, source_reflection) + raise HasManyThroughAssociationPolymorphicSourceError.new(active_record.name, self, source_reflection) end - unless [:belongs_to, :has_many, :has_one].include?(source_reflection.macro) && source_reflection.options[:through].nil? - raise HasManyThroughSourceAssociationMacroError.new(self) + if macro == :has_one && through_reflection.collection? + raise HasOneThroughCantAssociateThroughCollection.new(active_record.name, self, through_reflection) end check_validity_of_inverse! end - def through_reflection_primary_key - through_reflection.belongs_to? ? through_reflection.klass.primary_key : through_reflection.primary_key_name - end - - def through_reflection_primary_key_name - through_reflection.primary_key_name if through_reflection.belongs_to? - end - private def derive_class_name # get the class_name of the belongs_to association of the through reflection |