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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 _ I M P L E M E N T A T I O N --
-- --
-- S p e c --
-- --
-- Copyright (C) 1992-2009, 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 3, 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. --
-- --
-- As a special exception under Section 7 of GPL version 3, you are granted --
-- additional permissions described in the GCC Runtime Library Exception, --
-- version 3.1, as published by the Free Software Foundation. --
-- --
-- You should have received a copy of the GNU General Public License and --
-- a copy of the GCC Runtime Library Exception along with this program; --
-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
-- <http://www.gnu.org/licenses/>. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc. --
-- --
------------------------------------------------------------------------------
with Ada.Unchecked_Conversion;
with System.Storage_Elements;
with System.Finalization_Root;
package System.Finalization_Implementation is
pragma Elaborate_Body;
package SSE renames System.Storage_Elements;
package SFR renames System.Finalization_Root;
------------------------------------------------
-- Finalization Management Abstract Interface --
------------------------------------------------
function To_Finalizable_Ptr is new Ada.Unchecked_Conversion
(Source => System.Address, Target => SFR.Finalizable_Ptr);
Collection_Finalization_Started : constant SFR.Finalizable_Ptr :=
To_Finalizable_Ptr (SSE.To_Address (1));
-- This is used to implement the rule in RM 4.8(10.2/2) that requires an
-- allocator to raise Program_Error if the collection finalization has
-- already started. See also Ada.Finalization.List_Controller. Finalize on
-- List_Controller first sets the list to Collection_Finalization_Started,
-- to indicate that finalization has started. An allocator will call
-- Attach_To_Final_List, which checks for the special value and raises
-- Program_Error if appropriate. The Collection_Finalization_Started value
-- must be different from 'Access of any finalizable object, and different
-- from null. See AI-280.
Global_Final_List : SFR.Finalizable_Ptr;
-- This list stores the controlled objects defined in library-level
-- packages. They will be finalized after the main program completion.
procedure Finalize_Global_List;
-- The procedure to be called in order to finalize the global list
procedure Attach_To_Final_List
(L : in out SFR.Finalizable_Ptr;
Obj : in out SFR.Finalizable;
Nb_Link : Short_Short_Integer);
-- Attach finalizable object Obj to the linked list L. Nb_Link controls the
-- number of link of the linked_list, and is one of: 0 for no attachment, 1
-- for simple linked lists or 2 for doubly linked lists or even 3 for a
-- simple attachment of a whole array of elements. Attachment to a simply
-- linked list is not protected against concurrent access and should only
-- be used in contexts where it doesn't matter, such as for objects
-- allocated on the stack. In the case of an attachment on a doubly linked
-- list, L must not be null and Obj will be inserted AFTER the first
-- element and the attachment is protected against concurrent call.
-- Typically used to attach to a dynamically allocated object to a
-- List_Controller (whose first element is always a dummy element)
type Finalizable_Ptr_Ptr is access all SFR.Finalizable_Ptr;
-- A pointer to a finalization list. This is used as the type of the extra
-- implicit formal which are passed to build-in-place functions that return
-- controlled types (see Sem_Ch6). That extra formal is then passed on to
-- Move_Final_List (below).
procedure Move_Final_List
(From : in out SFR.Finalizable_Ptr;
To : Finalizable_Ptr_Ptr);
-- Move all objects on From list to To list. This is used to implement
-- build-in-place function returns. The return object is initially placed
-- on a finalization list local to the return statement, in case the
-- return statement is left prematurely (due to raising an exception,
-- being aborted, or a goto or exit statement). Once the return statement
-- has completed successfully, Move_Final_List is called to move the
-- return object to the caller's finalization list.
procedure Finalize_List (L : SFR.Finalizable_Ptr);
-- Call Finalize on each element of the list L
procedure Finalize_One (Obj : in out SFR.Finalizable);
-- Call Finalize on Obj and remove its final list
---------------------
-- Deep Procedures --
---------------------
procedure Deep_Tag_Attach
(L : in out SFR.Finalizable_Ptr;
A : System.Address;
B : Short_Short_Integer);
-- Generic attachment for tagged objects with controlled components.
-- A is the address of the object, L the finalization list when it needs
-- to be attached and B the attachment level (see Attach_To_Final_List).
-----------------------------
-- Record Controller Types --
-----------------------------
-- Definition of the types of the controller component that is included
-- in records containing controlled components. This controller is
-- attached to the finalization chain of the upper-level and carries
-- the pointer of the finalization chain for the lower level.
type Limited_Record_Controller is new SFR.Root_Controlled with record
F : SFR.Finalizable_Ptr;
end record;
procedure Initialize (Object : in out Limited_Record_Controller);
-- Does nothing currently
procedure Finalize (Object : in out Limited_Record_Controller);
-- Finalize the controlled components of the enclosing record by following
-- the list starting at Object.F.
type Record_Controller is
new Limited_Record_Controller with record
My_Address : System.Address;
end record;
procedure Initialize (Object : in out Record_Controller);
-- Initialize the field My_Address to the Object'Address
procedure Adjust (Object : in out Record_Controller);
-- Adjust the components and their finalization pointers by subtracting by
-- the offset of the target and the source addresses of the assignment.
-- Inherit Finalize from Limited_Record_Controller
procedure Detach_From_Final_List (Obj : in out SFR.Finalizable);
-- Remove the specified object from its Final list, which must be a doubly
-- linked list.
end System.Finalization_Implementation;
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