require 'active_support/callbacks' module ActiveSupport class ExecutionWrapper include ActiveSupport::Callbacks Null = Object.new # :nodoc: def Null.complete! # :nodoc: end define_callbacks :run define_callbacks :complete def self.to_run(*args, &block) set_callback(:run, *args, &block) end def self.to_complete(*args, &block) set_callback(:complete, *args, &block) end # Register an object to be invoked during both the +run+ and # +complete+ steps. # # +hook.complete+ will be passed the value returned from +hook.run+, # and will only be invoked if +run+ has previously been called. # (Mostly, this means it won't be invoked if an exception occurs in # a preceding +to_run+ block; all ordinary +to_complete+ blocks are # invoked in that situation.) def self.register_hook(hook, outer: false) if outer run_args = [prepend: true] complete_args = [:after] else run_args = complete_args = [] end to_run(*run_args) do hook_state[hook] = hook.run end to_complete(*complete_args) do if hook_state.key?(hook) hook.complete hook_state[hook] end end end # Run this execution. # # Returns an instance, whose +complete!+ method *must* be invoked # after the work has been performed. # # Where possible, prefer +wrap+. def self.run! if active? Null else new.tap do |instance| success = nil begin instance.run! success = true ensure instance.complete! unless success end end end end # Perform the work in the supplied block as an execution. def self.wrap return yield if active? instance = run! begin yield ensure instance.complete! end end class << self # :nodoc: attr_accessor :active end def self.inherited(other) # :nodoc: super other.active = Concurrent::Hash.new end self.active = Concurrent::Hash.new def self.active? # :nodoc: @active[Thread.current] end def run! # :nodoc: self.class.active[Thread.current] = true run_callbacks(:run) end # Complete this in-flight execution. This method *must* be called # exactly once on the result of any call to +run!+. # # Where possible, prefer +wrap+. def complete! run_callbacks(:complete) ensure self.class.active.delete Thread.current end private def hook_state @_hook_state ||= {} end end end