Class: WeakRef

Inherits:
Delegator
  • Object
show all
Defined in:
lib/weakref.rb

Overview

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)

Defined Under Namespace

Classes: RefError

Constant Summary collapse

@@__map = 
::ObjectSpace::WeakMap.new

Instance Method Summary collapse

Constructor Details

#initialize(orig) ⇒ WeakRef

Creates a weak reference to orig

Raises an ArgumentError if the given orig is immutable, such as Symbol, Integer, or Float.



36
37
38
39
40
41
42
43
44
 
# File 'lib/weakref.rb', line 36

def initialize(orig)
  case orig
  when true, false, nil
    @delegate_sd_obj = orig
  else
    @@__map[self] = orig
  end
  super
end

Instance Method Details

#__getobj__ ⇒ Object

:nodoc:



46
47
48
49
 
# File 'lib/weakref.rb', line 46

def __getobj__ # :nodoc:
  @@__map[self] or defined?(@delegate_sd_obj) ? @delegate_sd_obj :
    Kernel::raise(RefError, "Invalid Reference - probably recycled", Kernel::caller(2))
end

#__setobj__(obj) ⇒ Object

:nodoc:



51
52
 
# File 'lib/weakref.rb', line 51

def __setobj__(obj) # :nodoc:
end

#weakref_alive? ⇒ Boolean

Returns true if the referenced object is still alive.

Returns:

  • (Boolean) 


57
58
59
 
# File 'lib/weakref.rb', line 57

def weakref_alive?
  @@__map.key?(self) or defined?(@delegate_sd_obj)
end