lib/standard/gc.nit

   1 # This file is part of NIT ( http://www.nitlanguage.org ).
   2 #
   3 # This file is free software, which comes along with NIT.  This software is
   4 # distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
   5 # without  even  the implied warranty of  MERCHANTABILITY or  FITNESS FOR A
   6 # PARTICULAR PURPOSE.  You can modify it is you want,  provided this header
   7 # is kept unaltered, and a notification of the changes is added.
   8 # You  are  allowed  to  redistribute it and sell it, alone or is a part of
   9 # another product.
  10
  11 # Access to the Nit internal garbage collection mechanism
  12 module gc
  13
  14 import kernel
  15
  16 redef class Sys
  17         # Initiate a garbage collection
  18         fun force_garbage_collection is intern
  19 end
  20
  21 # An object needing finalization
  22 #
  23 # Sub-classes of `Finalizable` must no have cycles, or else they will not be
  24 # liberated. For this reason, it is recommended to sub-class `Finalizable`
  25 # only on simple objects directly managing a limited resource. This use case
  26 # is common when wrapping an extern instance with a standard object.
  27 class Finalizable
  28
  29         # Liberate any resources held by `self` before the memory holding `self` is freed
  30         #
  31         # This method is invoked by the GC during a garbage collection when `self`
  32         # is no longer referenced. It can also be called by the user. Its implementation
  33         # must be planned accordingly and ensure that it may be invoked more than once.
  34         #
  35         # The object are finialized in a topological order, it is safe for this method
  36         # to use attributes of this instances.
  37         fun finalize do end
  38 end