require "active_support/execution_wrapper" module ActiveSupport #-- # This class defines several callbacks: # # to_prepare -- Run once at application startup, and also from # +to_run+. # # to_run -- Run before a work run that is reloading. If # +reload_classes_only_on_change+ is true (the default), the class # unload will have already occurred. # # to_complete -- Run after a work run that has reloaded. If # +reload_classes_only_on_change+ is false, the class unload will # have occurred after the work run, but before this callback. # # before_class_unload -- Run immediately before the classes are # unloaded. # # after_class_unload -- Run immediately after the classes are # unloaded. # class Reloader < ExecutionWrapper define_callbacks :prepare define_callbacks :class_unload def self.to_prepare(*args, &block) set_callback(:prepare, *args, &block) end def self.before_class_unload(*args, &block) set_callback(:class_unload, *args, &block) end def self.after_class_unload(*args, &block) set_callback(:class_unload, :after, *args, &block) end to_run(:after) { self.class.prepare! } # Initiate a manual reload def self.reload! executor.wrap do new.tap do |instance| begin instance.run! ensure instance.complete! end end end prepare! end def self.run! # :nodoc: if check! super else Null end end # Run the supplied block as a work unit, reloading code as needed def self.wrap executor.wrap do super end end class_attribute :executor, default: Executor class_attribute :check, default: lambda { false } def self.check! # :nodoc: @should_reload ||= check.call end def self.reloaded! # :nodoc: @should_reload = false end def self.prepare! # :nodoc: new.run_callbacks(:prepare) end def initialize super @locked = false end # Acquire the ActiveSupport::Dependencies::Interlock unload lock, # ensuring it will be released automatically def require_unload_lock! unless @locked ActiveSupport::Dependencies.interlock.start_unloading @locked = true end end # Release the unload lock if it has been previously obtained def release_unload_lock! if @locked @locked = false ActiveSupport::Dependencies.interlock.done_unloading end end def run! # :nodoc: super release_unload_lock! end def class_unload!(&block) # :nodoc: require_unload_lock! run_callbacks(:class_unload, &block) end def complete! # :nodoc: super self.class.reloaded! ensure release_unload_lock! end end end