1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
5 -- S Y S T E M . F I N A L I Z A T I O N _ R O O T --
9 -- Copyright (C) 1992-2009, Free Software Foundation, Inc. --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 3, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. --
18 -- As a special exception under Section 7 of GPL version 3, you are granted --
19 -- additional permissions described in the GCC Runtime Library Exception, --
20 -- version 3.1, as published by the Free Software Foundation. --
22 -- You should have received a copy of the GNU General Public License and --
23 -- a copy of the GCC Runtime Library Exception along with this program; --
24 -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
25 -- <http://www.gnu.org/licenses/>. --
27 -- GNAT was originally developed by the GNAT team at New York University. --
28 -- Extensive contributions were provided by Ada Core Technologies Inc. --
30 ------------------------------------------------------------------------------
32 -- This unit provides the basic support for controlled (finalizable) types
35 with Ada.Unchecked_Conversion;
37 package System.Finalization_Root is
40 type Root_Controlled is tagged;
42 type Finalizable_Ptr is access all Root_Controlled'Class;
44 function To_Finalizable_Ptr is
45 new Ada.Unchecked_Conversion (Address, Finalizable_Ptr);
48 new Ada.Unchecked_Conversion (Finalizable_Ptr, Address);
50 type Empty_Root_Controlled is abstract tagged null record;
51 -- Just for the sake of Controlled equality (see Ada.Finalization)
53 type Root_Controlled is new Empty_Root_Controlled with record
54 Prev, Next : Finalizable_Ptr;
56 subtype Finalizable is Root_Controlled'Class;
58 procedure Initialize (Object : in out Root_Controlled);
59 procedure Finalize (Object : in out Root_Controlled);
60 procedure Adjust (Object : in out Root_Controlled);
62 -- Stream-oriented attributes for Root_Controlled. These must be empty so
63 -- as to not copy the finalization chain pointers. They are declared in
64 -- a nested package so that they do not create primitive operations of
65 -- Root_Controlled. Otherwise this would add unwanted primitives to (the
66 -- full view of) Ada.Finalization.Limited_Controlled, which would cause
67 -- trouble in cases where a limited controlled type is used as the
68 -- designated type of a remote access-to-classwide type.
70 package Stream_Attributes is
73 (Stream : not null access Ada.Streams.Root_Stream_Type'Class;
74 Item : Root_Controlled) is null;
77 (Stream : not null access Ada.Streams.Root_Stream_Type'Class;
78 Item : out Root_Controlled) is null;
80 end Stream_Attributes;
82 for Root_Controlled'Read use Stream_Attributes.Read;
83 for Root_Controlled'Write use Stream_Attributes.Write;
85 end System.Finalization_Root;