module ActiveRecord::Transactions

def self.included(base)
  base.extend(ClassMethods)
  base.class_eval do
    [:destroy, :save, :save!].each do |method|
      alias_method_chain method, :transactions
    end
  end
end

def destroy_with_transactions #:nodoc:
  transaction { destroy_without_transactions }
end

def rollback_active_record_state!
  id_present = has_attribute?(self.class.primary_key)
  previous_id = id
  previous_new_record = new_record?
  yield
rescue Exception
  @new_record = previous_new_record
  if id_present
    self.id = previous_id
  else
    @attributes.delete(self.class.primary_key)
    @attributes_cache.delete(self.class.primary_key)
  end
  raise
end

def save_with_transactions(perform_validation = true) #:nodoc:
  rollback_active_record_state! { transaction { save_without_transactions(perform_validation) } }
end

def save_with_transactions! #:nodoc:
  rollback_active_record_state! { transaction { save_without_transactions! } }
end

def transaction(&block)
  self.class.transaction(&block)
end