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   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --     A D A . F I N A L I Z A T I O N . L I S T _ C O N T R O L L E R      --
   6 --                                                                          --
   7 --                                B o d y                                   --
   8 --                                                                          --
   9 --                                                                          --
  10 --          Copyright (C) 1992-1997 Free Software Foundation, Inc.          --
  11 --                                                                          --
  12 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
  13 -- terms of the  GNU General Public License as published  by the Free Soft- --
  14 -- ware  Foundation;  either version 2,  or (at your option) any later ver- --
  15 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  16 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  17 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  18 -- for  more details.  You should have  received  a copy of the GNU General --
  19 -- Public License  distributed with GNAT;  see file COPYING.  If not, write --
  20 -- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
  21 -- MA 02111-1307, USA.                                                      --
  22 --                                                                          --
  23 -- As a special exception,  if other files  instantiate  generics from this --
  24 -- unit, or you link  this unit with other files  to produce an executable, --
  25 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  26 -- covered  by the  GNU  General  Public  License.  This exception does not --
  27 -- however invalidate  any other reasons why  the executable file  might be --
  28 -- covered by the  GNU Public License.                                      --
  29 --                                                                          --
  30 -- GNAT was originally developed  by the GNAT team at  New York University. --
  31 -- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). --
  32 --                                                                          --
  33 ------------------------------------------------------------------------------
  34
  35 with System.Finalization_Root;
  36 package Ada.Finalization.List_Controller is
  37 pragma Elaborate_Body (List_Controller);
  38
  39    package SFR renames System.Finalization_Root;
  40
  41    ----------------------------
  42    -- Simple_List_Controller --
  43    ----------------------------
  44
  45    type Simple_List_Controller is new Ada.Finalization.Limited_Controlled
  46      with record
  47         F : SFR.Finalizable_Ptr;
  48      end record;
  49       --  Used by the compiler to carry a list of temporary objects that
  50       --  needs to be finalized after having being used. This list is
  51       --  embedded in a controlled type so that if an exception is raised
  52       --  while those temporaries are still in use, they will be reclaimed
  53       --  by the normal finalization mechanism.
  54
  55    procedure Finalize (Object : in out Simple_List_Controller);
  56
  57    ---------------------
  58    -- List_Controller --
  59    ---------------------
  60
  61    --  Management of a bidirectional linked heterogenous list of
  62    --  dynamically Allocated objects. To simplify the management of the
  63    --  linked list, the First and Last elements are statically part of the
  64    --  original List controller:
  65    --
  66    --        +------------+
  67    --        |          --|-->--
  68    --        +------------+
  69    --        |--<--       |                      record with ctrl components
  70    --        |------------|                         +----------+
  71    --     +--|--   L      |                         |          |
  72    --     |  |------------|                         |          |
  73    --     |  |+--------+  |       +--------+        |+--------+|
  74    --     +->||  prev  | F|---<---|--      |----<---||--      ||--<--+
  75    --        ||--------| i|       |--------|        ||--------||     |
  76    --        || next   | r|--->---|      --|---->---||      --||--------+
  77    --        |+--------+ s|       |--------|        ||--------||     |  |
  78    --        |           t|       | ctrl   |        ||        ||     |  |
  79    --        |            |       :        :        |+--------+|     |  |
  80    --        |            |       : object :        |rec       |     |  |
  81    --        |            |       :        :        |controller|     |  |
  82    --        |            |       |        |        |          |     |  v
  83    --        |+--------+  |       +--------+        +----------+     |  |
  84    --        ||  prev -|-L|--------------------->--------------------+  |
  85    --        ||--------| a|                                             |
  86    --        || next   | s|-------------------<-------------------------+
  87    --        |+--------+ t|
  88    --        |            |
  89    --        +------------+
  90
  91    type List_Controller is new Ada.Finalization.Limited_Controlled
  92      with record
  93         F    :  SFR.Finalizable_Ptr;
  94         First,
  95         Last : aliased SFR.Root_Controlled;
  96      end record;
  97    --  Controls the chains of dynamically allocated controlled
  98    --  objects makes sure that they get finalized upon exit from
  99    --  the access type that defined them
 100
 101    procedure Initialize (Object : in out List_Controller);
 102    procedure Finalize   (Object : in out List_Controller);
 103
 104 end Ada.Finalization.List_Controller;