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) 1992-2007, 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 2, 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. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING. If not, write --
19 -- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, --
20 -- Boston, MA 02110-1301, USA. --
22 -- As a special exception, if other files instantiate generics from this --
23 -- unit, or you link this unit with other files to produce an executable, --
24 -- this unit does not by itself cause the resulting executable to be --
25 -- covered by the GNU General Public License. This exception does not --
26 -- however invalidate any other reasons why the executable file might be --
27 -- covered by the GNU Public License. --
29 -- GNAT was originally developed by the GNAT team at New York University. --
30 -- Extensive contributions were provided by Ada Core Technologies Inc. --
32 ------------------------------------------------------------------------------
34 -- This unit provides the basic support for controlled (finalizable) types
37 with Ada
.Unchecked_Conversion
;
39 package System
.Finalization_Root
is
42 type Root_Controlled
is tagged;
44 type Finalizable_Ptr
is access all Root_Controlled
'Class;
46 function To_Finalizable_Ptr
is
47 new Ada
.Unchecked_Conversion
(Address
, Finalizable_Ptr
);
50 new Ada
.Unchecked_Conversion
(Finalizable_Ptr
, Address
);
52 type Empty_Root_Controlled
is abstract tagged null record;
53 -- Just for the sake of Controlled equality (see Ada.Finalization)
55 type Root_Controlled
is new Empty_Root_Controlled
with record
56 Prev
, Next
: Finalizable_Ptr
;
58 subtype Finalizable
is Root_Controlled
'Class;
60 procedure Initialize
(Object
: in out Root_Controlled
);
61 procedure Finalize
(Object
: in out Root_Controlled
);
62 procedure Adjust
(Object
: in out Root_Controlled
);
64 -- Stream-oriented attributes for Root_Controlled. These must be empty so
65 -- as to not copy the finalization chain pointers. They are declared in
66 -- a nested package so that they do not create primitive operations of
67 -- Root_Controlled. Otherwise this would add unwanted primitives to (the
68 -- full view of) Ada.Finalization.Limited_Controlled, which would cause
69 -- trouble in cases where a limited controlled type is used as the
70 -- designated type of a remote access-to-classwide type.
72 package Stream_Attributes
is
75 (Stream
: not null access Ada
.Streams
.Root_Stream_Type
'Class;
76 Item
: Root_Controlled
) is null;
79 (Stream
: not null access Ada
.Streams
.Root_Stream_Type
'Class;
80 Item
: out Root_Controlled
) is null;
82 end Stream_Attributes
;
84 for Root_Controlled
'Read use Stream_Attributes
.Read
;
85 for Root_Controlled
'Write use Stream_Attributes
.Write
;
87 end System
.Finalization_Root
;