Current File : //proc/thread-self/root/opt/alt/ruby27/share/ruby/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
##
# 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+
#
# Raises an ArgumentError if the given +orig+ is immutable, such as Symbol,
# Integer, or Float.
def initialize(orig)
case orig
when true, false, nil
@delegate_sd_obj = orig
else
@@__map[self] = orig
end
super
end
def __getobj__ # :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
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