diff options
Diffstat (limited to 'activerecord/lib/active_record/associations/association_proxy.rb')
| -rw-r--r-- | activerecord/lib/active_record/associations/association_proxy.rb | 206 |
1 files changed, 119 insertions, 87 deletions
diff --git a/activerecord/lib/active_record/associations/association_proxy.rb b/activerecord/lib/active_record/associations/association_proxy.rb index 6720d83199..addc64cb42 100644 --- a/activerecord/lib/active_record/associations/association_proxy.rb +++ b/activerecord/lib/active_record/associations/association_proxy.rb @@ -7,14 +7,15 @@ module ActiveRecord # This is the root class of all association proxies ('+ Foo' signifies an included module Foo): # # AssociationProxy - # BelongsToAssociation - # BelongsToPolymorphicAssociation - # AssociationCollection + HasAssociation + # SingularAssociaton + # HasOneAssociation + # HasOneThroughAssociation + ThroughAssociation + # BelongsToAssociation + # BelongsToPolymorphicAssociation + # AssociationCollection # HasAndBelongsToManyAssociation # HasManyAssociation # HasManyThroughAssociation + ThroughAssociation - # HasOneAssociation + HasAssociation - # HasOneThroughAssociation + ThroughAssociation # # Association proxies in Active Record are middlemen between the object that # holds the association, known as the <tt>@owner</tt>, and the actual associated @@ -50,10 +51,9 @@ module ActiveRecord # is computed directly through SQL and does not trigger by itself the # instantiation of the actual post records. class AssociationProxy #:nodoc: - alias_method :proxy_respond_to?, :respond_to? alias_method :proxy_extend, :extend - delegate :to_param, :to => :proxy_target - instance_methods.each { |m| undef_method m unless m.to_s =~ /^(?:nil\?|send|object_id|to_a)$|^__|^respond_to_missing|proxy_/ } + + instance_methods.each { |m| undef_method m unless m.to_s =~ /^(?:nil\?|send|object_id|to_a)$|^__|^respond_to|proxy_/ } def initialize(owner, reflection) @owner, @reflection = owner, reflection @@ -64,6 +64,10 @@ module ActiveRecord construct_scope end + def to_param + proxy_target.to_param + end + # Returns the owner of the proxy. def proxy_owner @owner @@ -75,21 +79,15 @@ module ActiveRecord @reflection end - # Returns the \target of the proxy, same as +target+. - def proxy_target - @target - end - # Does the proxy or its \target respond to +symbol+? def respond_to?(*args) - proxy_respond_to?(*args) || (load_target && @target.respond_to?(*args)) + super || (load_target && @target.respond_to?(*args)) end # Forwards <tt>===</tt> explicitly to the \target because the instance method # removal above doesn't catch it. Loads the \target if needed. def ===(other) - load_target - other === @target + other === load_target end # Returns the name of the table of the related class: @@ -116,6 +114,7 @@ module ActiveRecord # Reloads the \target and returns +self+ on success. def reload reset + construct_scope load_target self unless @target.nil? end @@ -127,23 +126,25 @@ module ActiveRecord # Asserts the \target has been loaded setting the \loaded flag to +true+. def loaded - @loaded = true + @loaded = true + @stale_state = stale_state end # The target is stale if the target no longer points to the record(s) that the # relevant foreign_key(s) refers to. If stale, the association accessor method - # on the owner will reload the target. It's up to subclasses to implement this - # method if relevant. + # on the owner will reload the target. It's up to subclasses to implement the + # state_state method if relevant. # # Note that if the target has not been loaded, it is not considered stale. def stale_target? - false + loaded? && @stale_state != stale_state end # Returns the target of this proxy, same as +proxy_target+. - def target - @target - end + attr_reader :target + + # Returns the \target of the proxy, same as +target+. + alias :proxy_target :target # Sets the target of this proxy to <tt>\target</tt>, and the \loaded flag to +true+. def target=(target) @@ -153,17 +154,16 @@ module ActiveRecord # Forwards the call to the target. Loads the \target if needed. def inspect - load_target - @target.inspect + load_target.inspect end def send(method, *args) - if proxy_respond_to?(method) - super - else - load_target - @target.send(method, *args) - end + return super if respond_to?(method) + load_target.send(method, *args) + end + + def scoped + target_scope & @association_scope end protected @@ -176,69 +176,85 @@ module ActiveRecord @reflection.klass.send(:sanitize_sql, sql, table_name) end - # Merges into +options+ the ones coming from the reflection. - def merge_options_from_reflection!(options) - options.reverse_merge!( - :group => @reflection.options[:group], - :having => @reflection.options[:having], - :limit => @reflection.options[:limit], - :offset => @reflection.options[:offset], - :joins => @reflection.options[:joins], - :include => @reflection.options[:include], - :select => @reflection.options[:select], - :readonly => @reflection.options[:readonly] - ) - end - - # Forwards +with_scope+ to the reflection. - def with_scope(*args, &block) - @reflection.klass.send :with_scope, *args, &block + # Construct the scope for this association. + # + # Note that the association_scope is merged into the targed_scope only when the + # scoped method is called. This is because at that point the call may be surrounded + # by scope.scoping { ... } or with_scope { ... } etc, which affects the scope which + # actually gets built. + def construct_scope + @association_scope = association_scope if target_klass end - # Construct the scope used for find/create queries on the target - def construct_scope - @scope = { - :find => construct_find_scope, - :create => construct_create_scope - } + def association_scope + scope = target_klass.unscoped + scope = scope.create_with(creation_attributes) + scope = scope.apply_finder_options(@reflection.options.slice(:conditions, :readonly, :include)) + scope = scope.select(select_value) if select_value = self.select_value + scope.where(construct_owner_conditions) end - # Implemented by subclasses - def construct_find_scope - raise NotImplementedError + def select_value + @reflection.options[:select] end # Implemented by (some) subclasses - def construct_create_scope - {} + def creation_attributes + { } end def aliased_table - @reflection.klass.arel_table + target_klass.arel_table end # Set the inverse association, if possible def set_inverse_instance(record) if record && invertible_for?(record) - record.send("set_#{inverse_reflection_for(record).name}_target", @owner) + inverse = record.send(:association_proxy, inverse_reflection_for(record).name) + inverse.target = @owner end end - private - # Forwards any missing method call to the \target. - def method_missing(method, *args) - if load_target - unless @target.respond_to?(method) - message = "undefined method `#{method.to_s}' for \"#{@target}\":#{@target.class.to_s}" - raise NoMethodError, message - end + # This class of the target. belongs_to polymorphic overrides this to look at the + # polymorphic_type field on the owner. + def target_klass + @reflection.klass + end + + # Can be overridden (i.e. in ThroughAssociation) to merge in other scopes (i.e. the + # through association's scope) + def target_scope + target_klass.scoped + end - if block_given? - @target.send(method, *args) { |*block_args| yield(*block_args) } - else - @target.send(method, *args) + # Returns a hash linking the owner to the association represented by the reflection + def construct_owner_attributes(reflection = @reflection) + attributes = {} + if reflection.macro == :belongs_to + attributes[reflection.association_primary_key] = @owner[reflection.foreign_key] + else + attributes[reflection.foreign_key] = @owner[reflection.active_record_primary_key] + + if reflection.options[:as] + attributes["#{reflection.options[:as]}_type"] = @owner.class.base_class.name end end + attributes + end + + # Builds an array of arel nodes from the owner attributes hash + def construct_owner_conditions(table = aliased_table, reflection = @reflection) + conditions = construct_owner_attributes(reflection).map do |attr, value| + table[attr].eq(value) + end + table.create_and(conditions) + end + + # Sets the owner attributes on the given record + def set_owner_attributes(record) + if @owner.persisted? + construct_owner_attributes.each { |key, value| record[key] = value } + end end # Loads the \target if needed and returns it. @@ -252,23 +268,36 @@ module ActiveRecord # ActiveRecord::RecordNotFound is rescued within the method, and it is # not reraised. The proxy is \reset and +nil+ is the return value. def load_target - return nil unless defined?(@loaded) - - if !loaded? && (!@owner.new_record? || foreign_key_present) + if !loaded? && (!@owner.new_record? || foreign_key_present?) && target_klass @target = find_target end - @loaded = true + loaded @target rescue ActiveRecord::RecordNotFound reset end - # Can be overwritten by associations that might have the foreign key - # available for an association without having the object itself (and - # still being a new record). Currently, only +belongs_to+ presents - # this scenario (both vanilla and polymorphic). - def foreign_key_present + private + + # Forwards any missing method call to the \target. + def method_missing(method, *args, &block) + if load_target + return super unless @target.respond_to?(method) + @target.send(method, *args, &block) + end + rescue NoMethodError => e + raise e, e.message.sub(/ for #<.*$/, " via proxy for #{@target}") + end + + # Should be true if there is a foreign key present on the @owner which + # references the target. This is used to determine whether we can load + # the target if the @owner is currently a new record (and therefore + # without a key). + # + # Currently implemented by belongs_to (vanilla and polymorphic) and + # has_one/has_many :through associations which go through a belongs_to + def foreign_key_present? false end @@ -282,11 +311,6 @@ module ActiveRecord end end - # Returns the ID of the owner, quoted if needed. - def owner_quoted_id - @owner.quoted_id - end - # Can be redefined by subclasses, notably polymorphic belongs_to # The record parameter is necessary to support polymorphic inverses as we must check for # the association in the specific class of the record. @@ -298,6 +322,14 @@ module ActiveRecord def invertible_for?(record) inverse_reflection_for(record) end + + # This should be implemented to return the values of the relevant key(s) on the owner, + # so that when state_state is different from the value stored on the last find_target, + # the target is stale. + # + # This is only relevant to certain associations, which is why it returns nil by default. + def stale_state + end end end end |