diff options
Diffstat (limited to 'activerecord/lib/active_record/locking')
-rw-r--r-- | activerecord/lib/active_record/locking/optimistic.rb | 62 |
1 files changed, 42 insertions, 20 deletions
diff --git a/activerecord/lib/active_record/locking/optimistic.rb b/activerecord/lib/active_record/locking/optimistic.rb index 4528d8783c..9f053453bd 100644 --- a/activerecord/lib/active_record/locking/optimistic.rb +++ b/activerecord/lib/active_record/locking/optimistic.rb @@ -11,7 +11,7 @@ module ActiveRecord # # == Usage # - # Active Records support optimistic locking if the field +lock_version+ is present. Each update to the + # Active Record supports optimistic locking if the +lock_version+ field is present. Each update to the # record increments the +lock_version+ column and the locking facilities ensure that records instantiated twice # will let the last one saved raise a +StaleObjectError+ if the first was also updated. Example: # @@ -80,17 +80,15 @@ module ActiveRecord begin relation = self.class.unscoped - stmt = relation.where( - relation.table[self.class.primary_key].eq(id).and( - relation.table[lock_col].eq(self.class.quote_value(previous_lock_value, column_for_attribute(lock_col))) - ) - ).arel.compile_update( - arel_attributes_with_values_for_update(attribute_names), - self.class.primary_key + affected_rows = relation.where( + self.class.primary_key => id, + lock_col => previous_lock_value, + ).update_all( + attribute_names.map do |name| + [name, _read_attribute(name)] + end.to_h ) - affected_rows = self.class.connection.update stmt - unless affected_rows == 1 raise ActiveRecord::StaleObjectError.new(self, "update") end @@ -120,7 +118,7 @@ module ActiveRecord if locking_enabled? column_name = self.class.locking_column column = self.class.columns_hash[column_name] - substitute = self.class.connection.substitute_at(column, relation.bind_values.length) + substitute = self.class.connection.substitute_at(column) relation = relation.where(self.class.arel_table[column_name].eq(substitute)) relation.bind_values << [column, self[column_name].to_i] @@ -141,7 +139,7 @@ module ActiveRecord # Set the column to use for optimistic locking. Defaults to +lock_version+. def locking_column=(value) - @column_defaults = nil + clear_caches_calculated_from_columns @locking_column = value.to_s end @@ -163,18 +161,42 @@ module ActiveRecord super end - def column_defaults - @column_defaults ||= begin - defaults = super - - if defaults.key?(locking_column) && lock_optimistically - defaults[locking_column] ||= 0 + private + + # We need to apply this decorator here, rather than on module inclusion. The closure + # created by the matcher would otherwise evaluate for `ActiveRecord::Base`, not the + # sub class being decorated. As such, changes to `lock_optimistically`, or + # `locking_column` would not be picked up. + def inherited(subclass) + subclass.class_eval do + is_lock_column = ->(name, _) { lock_optimistically && name == locking_column } + decorate_matching_attribute_types(is_lock_column, :_optimistic_locking) do |type| + LockingType.new(type) end - - defaults end + super end end end + + class LockingType < SimpleDelegator # :nodoc: + def type_cast_from_database(value) + # `nil` *should* be changed to 0 + super.to_i + end + + def changed?(old_value, *) + # Ensure we save if the default was `nil` + super || old_value == 0 + end + + def init_with(coder) + __setobj__(coder['subtype']) + end + + def encode_with(coder) + coder['subtype'] = __getobj__ + end + end end end |