WeakRef is a class to represent a reference to an object that is not seen by the tracing phase of the garbage collector. This allows the referenced object to be garbage collected as if nothing is referring to it. Because WeakRef delegates method calls to the referenced object, it may be used in place of that object, i.e. it is of the same duck type.
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)
Create a new WeakRef from orig
.
# File weakref.rb, line 49 def initialize(orig) super __setobj__(orig) end
Return the object this WeakRef references. Raises RefError if the object has been garbage collected. The object returned is the object to which method calls are delegated (see Delegator).
# File weakref.rb, line 57 def __getobj__ unless @@id_rev_map[self.__id__] == @__id raise RefError, "Illegal Reference - probably recycled", caller(2) end begin ObjectSpace._id2ref(@__id) rescue RangeError raise RefError, "Illegal Reference - probably recycled", caller(2) end end
# File weakref.rb, line 68 def __setobj__(obj) @__id = obj.__id__ __old_status = Thread.critical begin Thread.critical = true unless @@id_rev_map.key?(self) ObjectSpace.define_finalizer obj, @@final ObjectSpace.define_finalizer self, @@final end @@id_map[@__id] = [] unless @@id_map[@__id] ensure Thread.critical = __old_status end @@id_map[@__id].push self.__id__ @@id_rev_map[self.__id__] = @__id end