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require 'enumerator'
module ActiveRecord
# = Active Record Through Association Scope
module Associations
module ThroughAssociationScope
protected
def construct_scope
{ :create => construct_owner_attributes(@reflection),
:find => { :conditions => construct_conditions,
:joins => construct_joins,
:include => @reflection.options[:include] || @reflection.source_reflection.options[:include],
:select => construct_select,
:order => @reflection.options[:order],
:limit => @reflection.options[:limit],
:readonly => @reflection.options[:readonly],
} }
end
# Build SQL conditions from attributes, qualified by table name.
def construct_conditions
reflection = @reflection.through_reflection_chain.last
conditions = construct_quoted_owner_attributes(reflection).map do |attr, value|
"#{table_aliases[reflection]}.#{attr} = #{value}"
end
conditions << sql_conditions if sql_conditions
"(" + conditions.join(') AND (') + ")"
end
# Associate attributes pointing to owner, quoted.
def construct_quoted_owner_attributes(reflection)
if as = reflection.options[:as]
{ "#{as}_id" => owner_quoted_id,
"#{as}_type" => reflection.klass.quote_value(
@owner.class.base_class.name.to_s,
reflection.klass.columns_hash["#{as}_type"]) }
elsif reflection.macro == :belongs_to
{ reflection.klass.primary_key => @owner.class.quote_value(@owner[reflection.primary_key_name]) }
else
{ reflection.primary_key_name => owner_quoted_id }
end
end
def construct_from
@reflection.table_name
end
def construct_select(custom_select = nil)
distinct = "DISTINCT " if @reflection.options[:uniq]
selected = custom_select || @reflection.options[:select] || "#{distinct}#{@reflection.quoted_table_name}.*"
end
def construct_joins(custom_joins = nil)
# puts @reflection.through_reflection_chain.map(&:inspect)
"#{construct_through_joins} #{@reflection.options[:joins]} #{custom_joins}"
end
def construct_through_joins
joins = []
# Iterate over each pair in the through reflection chain, joining them together
@reflection.through_reflection_chain.each_cons(2) do |left, right|
polymorphic_join = nil
case
when left.source_reflection.nil?
left_primary_key = left.primary_key_name
right_primary_key = right.klass.primary_key
if left.options[:as]
polymorphic_join = "AND %s.%s = %s" % [
table_aliases[left], "#{left.options[:as]}_type",
# TODO: Why right.klass.name? Rather than left.active_record.name?
# TODO: Also should maybe use the base_class (see related code in JoinAssociation)
@owner.class.quote_value(right.klass.name)
]
end
when left.source_reflection.macro == :belongs_to
left_primary_key = left.klass.primary_key
right_primary_key = left.source_reflection.primary_key_name
if left.options[:source_type]
polymorphic_join = "AND %s.%s = %s" % [
table_aliases[right],
left.source_reflection.options[:foreign_type].to_s,
@owner.class.quote_value(left.options[:source_type])
]
end
else
left_primary_key = left.source_reflection.primary_key_name
right_primary_key = right.klass.primary_key
if left.source_reflection.options[:as]
polymorphic_join = "AND %s.%s = %s" % [
table_aliases[left],
"#{left.source_reflection.options[:as]}_type",
@owner.class.quote_value(right.klass.name)
]
end
end
if right.quoted_table_name == table_aliases[right]
table = right.quoted_table_name
else
table = "#{right.quoted_table_name} #{table_aliases[right]}"
end
joins << "INNER JOIN %s ON %s.%s = %s.%s %s" % [
table,
table_aliases[left], left_primary_key,
table_aliases[right], right_primary_key,
polymorphic_join
]
end
joins.join(" ")
end
# TODO: Use the same aliasing strategy (and code?) as JoinAssociation (as this is the
# documented behaviour)
def table_aliases
@table_aliases ||= begin
tally = {}
@reflection.through_reflection_chain.inject({}) do |aliases, reflection|
if tally[reflection.table_name].nil?
tally[reflection.table_name] = 1
aliases[reflection] = reflection.quoted_table_name
else
tally[reflection.table_name] += 1
aliased_table_name = reflection.table_name + "_#{tally[reflection.table_name]}"
aliases[reflection] = reflection.klass.connection.quote_table_name(aliased_table_name)
end
aliases
end
end
end
# Construct attributes for associate pointing to owner.
def construct_owner_attributes(reflection)
if as = reflection.options[:as]
{ "#{as}_id" => @owner.id,
"#{as}_type" => @owner.class.base_class.name.to_s }
else
{ reflection.primary_key_name => @owner.id }
end
end
# Construct attributes for :through pointing to owner and associate.
def construct_join_attributes(associate)
# TODO: revisit this to allow it for deletion, supposing dependent option is supported
raise ActiveRecord::HasManyThroughCantAssociateThroughHasOneOrManyReflection.new(@owner, @reflection) if [:has_one, :has_many].include?(@reflection.source_reflection.macro)
join_attributes = construct_owner_attributes(@reflection.through_reflection).merge(@reflection.source_reflection.primary_key_name => associate.id)
if @reflection.options[:source_type]
join_attributes.merge!(@reflection.source_reflection.options[:foreign_type] => associate.class.base_class.name.to_s)
end
if @reflection.through_reflection.options[:conditions].is_a?(Hash)
join_attributes.merge!(@reflection.through_reflection.options[:conditions])
end
join_attributes
end
def conditions
@conditions = build_conditions unless defined?(@conditions)
@conditions
end
def build_conditions
association_conditions = @reflection.options[:conditions]
through_conditions = build_through_conditions
source_conditions = @reflection.source_reflection.options[:conditions]
uses_sti = !@reflection.through_reflection.klass.descends_from_active_record?
if association_conditions || through_conditions || source_conditions || uses_sti
all = []
[association_conditions, source_conditions].each do |conditions|
all << interpolate_sql(sanitize_sql(conditions)) if conditions
end
all << through_conditions if through_conditions
all << build_sti_condition if uses_sti
all.map { |sql| "(#{sql})" } * ' AND '
end
end
def build_through_conditions
conditions = @reflection.through_reflection.options[:conditions]
if conditions.is_a?(Hash)
interpolate_sql(@reflection.through_reflection.klass.send(:sanitize_sql, conditions)).gsub(
@reflection.quoted_table_name,
@reflection.through_reflection.quoted_table_name)
elsif conditions
interpolate_sql(sanitize_sql(conditions))
end
end
def build_sti_condition
@reflection.through_reflection.klass.send(:type_condition).to_sql
end
alias_method :sql_conditions, :conditions
end
end
end
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