зеркало из https://github.com/github/ruby.git
67 строки
1.5 KiB
Ruby
67 строки
1.5 KiB
Ruby
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
|
|
# foo = Object.new
|
|
# p foo.to_s # original's class
|
|
# foo = WeakRef.new(foo)
|
|
# p foo.to_s # should be same class
|
|
# ObjectSpace.garbage_collect
|
|
# 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+
|
|
|
|
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[self] or defined?(@delegate_sd_obj))
|
|
end
|
|
end
|
|
|
|
if __FILE__ == $0
|
|
# require 'thread'
|
|
foo = Object.new
|
|
p foo.to_s # original's class
|
|
foo = WeakRef.new(foo)
|
|
p foo.to_s # should be same class
|
|
ObjectSpace.garbage_collect
|
|
ObjectSpace.garbage_collect
|
|
p foo.to_s # should raise exception (recycled)
|
|
end
|