module ActiveRecord
module Associations
class AssociationScope #:nodoc:
include JoinHelper
attr_reader :association, :alias_tracker
delegate :klass, :owner, :reflection, :interpolate, :to => :association
delegate :chain, :conditions, :options, :source_options, :active_record, :to => :reflection
def initialize(association)
@association = association
@alias_tracker = AliasTracker.new
end
def scope
scope = klass.unscoped
scope = scope.extending(*Array.wrap(options[:extend]))
# It's okay to just apply all these like this. The options will only be present if the
# association supports that option; this is enforced by the association builder.
scope = scope.apply_finder_options(options.slice(
:readonly, :include, :order, :limit, :joins, :group, :having, :offset))
if options[:through] && !options[:include]
scope = scope.includes(source_options[:include])
end
if select = select_value
scope = scope.select(select)
end
add_constraints(scope)
end
private
def select_value
select_value = options[:select]
if reflection.collection?
select_value ||= options[:uniq] && "DISTINCT #{reflection.quoted_table_name}.*"
end
if reflection.macro == :has_and_belongs_to_many
select_value ||= reflection.klass.arel_table[Arel.star]
end
select_value
end
def add_constraints(scope)
tables = construct_tables
chain.each_with_index do |reflection, i|
table, foreign_table = tables.shift, tables.first
if reflection.source_macro == :has_and_belongs_to_many
join_table = tables.shift
scope = scope.joins(join(
join_table,
table[reflection.active_record_primary_key].
eq(join_table[reflection.association_foreign_key])
))
table, foreign_table = join_table, tables.first
end
if reflection.source_macro == :belongs_to
key = reflection.association_primary_key
foreign_key = reflection.foreign_key
else
key = reflection.foreign_key
foreign_key = reflection.active_record_primary_key
end
if reflection == chain.last
scope = scope.where(table[key].eq(owner[foreign_key]))
conditions[i].each do |condition|
if options[:through] && condition.is_a?(Hash)
condition = { table.name => condition }
end
scope = scope.where(interpolate(condition))
end
else
constraint = table[key].eq(foreign_table[foreign_key])
join = join(foreign_table, constraint)
scope = scope.joins(join)
unless conditions[i].empty?
scope = scope.where(sanitize(conditions[i], table))
end
end
end
scope
end
def alias_suffix
reflection.name
end
def table_name_for(reflection)
if reflection == self.reflection
# If this is a polymorphic belongs_to, we want to get the klass from the
# association because it depends on the polymorphic_type attribute of
# the owner
klass.table_name
else
reflection.table_name
end
end
end
end
end