Add AdvisoryLock module

acts_as_list.gemspec

@@ -25,5 +25,6 @@ Gem::Specification.new do |s|
 
   # Dependencies (installed via "bundle install")
   s.add_dependency "activerecord", ">= 4.2"
+  s.add_dependency "with_advisory_lock", "~> 4.0"
   s.add_development_dependency "bundler", ">= 1.0.0"
 end

lib/acts_as_list.rb

@@ -10,3 +10,4 @@
 require "acts_as_list/active_record/acts/no_update"
 require "acts_as_list/active_record/acts/sequential_updates_method_definer"
 require "acts_as_list/active_record/acts/active_record"
+require "acts_as_list/active_record/acts/advisory_lock"

lib/acts_as_list/active_record/acts/advisory_lock.rb

@@ -0,0 +1,43 @@
+# frozen_string_literal: true
+
+require 'with_advisory_lock'
+
+module ActiveRecord
+  module Acts #:nodoc:
+    module List #:nodoc:
+      module AdvisoryLock  #:nodoc:
+        def self.included(base)
+          base.prepend(InstanceMethods)
+        end
+
+        def self.acts_as_list_methods
+          ActiveRecord::Acts::List::InstanceMethods.public_instance_methods
+        end
+
+        def self.acts_as_list_lockable_methods
+          acts_as_list_methods.grep(/^(insert_|move_|remove_|set_|(dec|inc)rement_)/)
+        end
+
+        module InstanceMethods
+          AdvisoryLock.acts_as_list_lockable_methods.each do |m|
+            define_method(m) do |*args|
+              with_table_lock do
+                super(*args)
+              end
+            end
+          end
+
+          def advisory_lock_name
+            format('lock-%s', acts_as_list_class.to_s.downcase)
+          end
+
+          def with_table_lock
+            acts_as_list_class.with_advisory_lock(advisory_lock_name) do
+              yield
+            end
+          end
+        end
+      end
+    end
+  end
+end

lib/acts_as_list/active_record/acts/list.rb

@@ -37,6 +37,7 @@ def acts_as_list(options = {})
 
           include ActiveRecord::Acts::List::InstanceMethods
           include ActiveRecord::Acts::List::NoUpdate
+          include ActiveRecord::Acts::List::AdvisoryLock if configuration[:advisory_lock]
         end
 
         # This +acts_as+ extension provides the capabilities for sorting and reordering a number of objects in a list.