diff options
Diffstat (limited to 'activerecord/lib/active_record/associations/has_many_through_association.rb')
-rw-r--r-- | activerecord/lib/active_record/associations/has_many_through_association.rb | 80 |
1 files changed, 56 insertions, 24 deletions
diff --git a/activerecord/lib/active_record/associations/has_many_through_association.rb b/activerecord/lib/active_record/associations/has_many_through_association.rb index 2e818dca5d..2683aaf5da 100644 --- a/activerecord/lib/active_record/associations/has_many_through_association.rb +++ b/activerecord/lib/active_record/associations/has_many_through_association.rb @@ -6,6 +6,13 @@ module ActiveRecord class HasManyThroughAssociation < HasManyAssociation #:nodoc: include ThroughAssociation + def initialize(owner, reflection) + super + + @through_records = {} + @through_association = nil + end + # Returns the size of the collection by executing a SELECT COUNT(*) query if the collection hasn't been # loaded and calling collection.size if it has. If it's more likely than not that the collection does # have a size larger than zero, and you need to fetch that collection afterwards, it'll take one fewer @@ -42,27 +49,38 @@ module ActiveRecord end end - through_record(record).save! + save_through_record(record) update_counter(1) record end private - def through_record(record) - through_association = owner.association(through_reflection.name) - attributes = construct_join_attributes(record) - - through_record = Array.wrap(through_association.target).find { |candidate| - candidate.attributes.slice(*attributes.keys) == attributes - } + def through_association + @through_association ||= owner.association(through_reflection.name) + end - unless through_record - through_record = through_association.build(attributes) + # We temporarily cache through record that has been build, because if we build a + # through record in build_record and then subsequently call insert_record, then we + # want to use the exact same object. + # + # However, after insert_record has been called, we clear the cache entry because + # we want it to be possible to have multiple instances of the same record in an + # association + def build_through_record(record) + @through_records[record.object_id] ||= begin + ensure_mutable + + through_record = through_association.build through_record.send("#{source_reflection.name}=", record) + through_record end + end - through_record + def save_through_record(record) + build_through_record(record).save! + ensure + @through_records.delete(record.object_id) end def build_record(attributes, options = {}) @@ -73,9 +91,9 @@ module ActiveRecord inverse = source_reflection.inverse_of if inverse if inverse.macro == :has_many - record.send(inverse.name) << through_record(record) + record.send(inverse.name) << build_through_record(record) elsif inverse.macro == :has_one - record.send("#{inverse.name}=", through_record(record)) + record.send("#{inverse.name}=", build_through_record(record)) end end @@ -104,8 +122,12 @@ module ActiveRecord def delete_records(records, method) ensure_not_nested - through = owner.association(through_reflection.name) - scope = through.scoped.where(construct_join_attributes(*records)) + # This is unoptimised; it will load all the target records + # even when we just want to delete everything. + records = load_target if records == :all + + scope = through_association.scoped + scope.where! construct_join_attributes(*records) case method when :destroy @@ -116,7 +138,7 @@ module ActiveRecord count = scope.delete_all end - delete_through_records(through, records) + delete_through_records(records) if through_reflection.macro == :has_many && update_through_counter?(method) update_counter(-count, through_reflection) @@ -125,15 +147,25 @@ module ActiveRecord update_counter(-count) end - def delete_through_records(through, records) - if through_reflection.macro == :has_many - records.each do |record| - through.target.delete(through_record(record)) - end - else - records.each do |record| - through.target = nil if through.target == through_record(record) + def through_records_for(record) + attributes = construct_join_attributes(record) + candidates = Array.wrap(through_association.target) + candidates.find_all { |c| c.attributes.slice(*attributes.keys) == attributes } + end + + def delete_through_records(records) + records.each do |record| + through_records = through_records_for(record) + + if through_reflection.macro == :has_many + through_records.each { |r| through_association.target.delete(r) } + else + if through_records.include?(through_association.target) + through_association.target = nil + end end + + @through_records.delete(record.object_id) end end |