path: root/lib/weakref.rb

# frozen_string_literal: true require "delegate" # Weak Reference class that allows a referenced object to be # garbage-collected. # # A WeakRef may be used exactly like the object it references. # # Usage: # # foo = Object.new # create a new object instance # p foo.to_s # original's class # foo = WeakRef.new(foo) # reassign foo with WeakRef instance # p foo.to_s # should be same class # GC.start # start the garbage collector # p foo.to_s # should raise exception (recycled) # class WeakRef < Delegator VERSION = "0.1.3" ## # RefError is raised when a referenced object has been recycled by the # garbage collector class RefError < StandardError end @@__map = ::ObjectSpace::WeakMap.new ## # Creates a weak reference to +orig+ def initialize(orig) case orig when true, false, nil @delegate_sd_obj = orig else @@__map[self] = orig end super end def __getobj__(&_block) # :nodoc: @@__map[self] or defined?(@delegate_sd_obj) ? @delegate_sd_obj : Kernel::raise(RefError, "Invalid Reference - probably recycled", Kernel::caller(2)) end def __setobj__(obj) # :nodoc: end ## # Returns true if the referenced object is still alive. def weakref_alive? @@__map.key?(self) or defined?(@delegate_sd_obj) end end