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------------------------------------------------------------------------------
-- --
-- GNAT COMPILER COMPONENTS --
-- --
-- S Y S T E M . F I N A L I Z A T I O N _ R O O T --
-- --
-- S p e c --
-- --
-- Copyright (C) 1992-2007, Free Software Foundation, Inc. --
-- --
-- GNAT is free software; you can redistribute it and/or modify it under --
-- terms of the GNU General Public License as published by the Free Soft- --
-- ware Foundation; either version 2, or (at your option) any later ver- --
-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
-- for more details. You should have received a copy of the GNU General --
-- Public License distributed with GNAT; see file COPYING. If not, write --
-- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, --
-- Boston, MA 02110-1301, USA. --
-- --
-- As a special exception, if other files instantiate generics from this --
-- unit, or you link this unit with other files to produce an executable, --
-- this unit does not by itself cause the resulting executable to be --
-- covered by the GNU General Public License. This exception does not --
-- however invalidate any other reasons why the executable file might be --
-- covered by the GNU Public License. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc. --
-- --
------------------------------------------------------------------------------
-- This unit provides the basic support for controlled (finalizable) types
with Ada.Streams;
with Ada.Unchecked_Conversion;
package System.Finalization_Root is
pragma Preelaborate;
type Root_Controlled is tagged;
type Finalizable_Ptr is access all Root_Controlled'Class;
function To_Finalizable_Ptr is
new Ada.Unchecked_Conversion (Address, Finalizable_Ptr);
function To_Addr is
new Ada.Unchecked_Conversion (Finalizable_Ptr, Address);
type Empty_Root_Controlled is abstract tagged null record;
-- Just for the sake of Controlled equality (see Ada.Finalization)
type Root_Controlled is new Empty_Root_Controlled with record
Prev, Next : Finalizable_Ptr;
end record;
subtype Finalizable is Root_Controlled'Class;
procedure Initialize (Object : in out Root_Controlled);
procedure Finalize (Object : in out Root_Controlled);
procedure Adjust (Object : in out Root_Controlled);
-- Stream-oriented attibutes for Root_Controlled. These must be empty so
-- as to not copy the finalization chain pointers. They are declared in
-- a nested package so that they do not create primitive operations of
-- Root_Controlled. Otherwise this would add unwanted primitives to (the
-- full view of) Ada.Finalization.Limited_Controlled, which would cause
-- trouble in cases where a limited controlled type is used as the
-- designated type of a remote access-to-classwide type.
package Stream_Attributes is
procedure Write
(Stream : not null access Ada.Streams.Root_Stream_Type'Class;
Item : Root_Controlled) is null;
procedure Read
(Stream : not null access Ada.Streams.Root_Stream_Type'Class;
Item : out Root_Controlled) is null;
end Stream_Attributes;
for Root_Controlled'Read use Stream_Attributes.Read;
for Root_Controlled'Write use Stream_Attributes.Write;
end System.Finalization_Root;
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