-- --
-- S p e c --
-- --
--- $Revision: 1.1 $ --
--- --
--- Copyright (C) 1992-1998 Free Software Foundation, Inc. --
+-- 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 2, or (at your option) any later ver- --
+-- 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. 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, 59 Temple Place - Suite 330, Boston, --
--- MA 02111-1307, USA. --
+-- 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. --
-- --
--- 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. --
+-- 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. --
--- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). --
+-- 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 (Finalization_Implementation);
+ pragma Elaborate_Body;
- package SFR renames System.Finalization_Root;
+ 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;
+ -- 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 can be either 0 for no
- -- attachement, 1 for simple linked lists or 2 for doubly linked lists
- -- or even 3 for a simple attachement of a whole array of elements.
- -- Attachement to a simply linked list is not protected against
- -- concurrent access and should only be used in context 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)
+ -- 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;
+ -- 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.
+ -- Call Finalize on Obj and remove its final list
---------------------
-- Deep Procedures --
---------------------
- procedure Deep_Tag_Initialize
- (L : in out SFR.Finalizable_Ptr;
- A : System.Address;
- B : Short_Short_Integer);
- -- Generic initialize 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 attachement level (see Attach_To_Final_List)
-
- procedure Deep_Tag_Adjust
- (L : in out SFR.Finalizable_Ptr;
- A : System.Address;
- B : Short_Short_Integer);
- -- Generic adjust 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 attachement level (see Attach_To_Final_List)
-
- procedure Deep_Tag_Finalize
- (L : in out SFR.Finalizable_Ptr;
- A : System.Address;
- B : Boolean);
- -- Generic finalize 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 attachement level (see Attach_To_Final_List)
-
procedure Deep_Tag_Attach
(L : in out SFR.Finalizable_Ptr;
A : System.Address;
B : Short_Short_Integer);
- -- Generic attachement 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 attachement level (see Attach_To_Final_List)
+ -- 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
+ -- 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
+ overriding 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
+ overriding 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);
+ overriding 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
+ overriding 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.
+ -- Remove the specified object from its Final list, which must be a doubly
+ -- linked list.
end System.Finalization_Implementation;
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