------------------------------------------------------------------------------ -- -- -- GNAT COMPILER COMPONENTS -- -- -- -- S Y S T E M . F I N A L I Z A T I O N _ M A S T E R S -- -- -- -- S p e c -- -- -- -- Copyright (C) 2011, 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 -- -- . -- -- -- -- GNAT was originally developed by the GNAT team at New York University. -- -- Extensive contributions were provided by Ada Core Technologies Inc. -- -- -- ------------------------------------------------------------------------------ with Ada.Finalization; with Ada.Unchecked_Conversion; with System.Storage_Elements; with System.Storage_Pools; pragma Compiler_Unit; package System.Finalization_Masters is pragma Preelaborate (System.Finalization_Masters); -- A reference to primitive Finalize_Address. The expander generates an -- implementation of this procedure for each controlled and class-wide -- type. Since controlled objects are simply viewed as addresses once -- allocated through a master, Finalize_Address provides a backward -- indirection from an address to a type-specific context. type Finalize_Address_Ptr is access procedure (Obj : System.Address); -- Heterogeneous collection type structure. The implementation allows for -- finalizable objects of different base types to be serviced by the same -- master. type FM_Node; type FM_Node_Ptr is access all FM_Node; type FM_Node is record Prev : FM_Node_Ptr := null; Next : FM_Node_Ptr := null; end record; -- A reference to any derivation from Root_Storage_Pool. Since this type -- may not be used to allocate objects, its storage size is zero. type Any_Storage_Pool_Ptr is access System.Storage_Pools.Root_Storage_Pool'Class; for Any_Storage_Pool_Ptr'Storage_Size use 0; -- Finalization master type structure. A unique master is associated with -- each access-to-controlled or access-to-class-wide type. Masters also act -- as components of subpools. type Finalization_Master is new Ada.Finalization.Limited_Controlled with record Base_Pool : Any_Storage_Pool_Ptr := null; -- A reference to the pool which this finalization master services. This -- field is used in conjunction with the build-in-place machinery. Objects : aliased FM_Node; -- A doubly linked list which contains the headers of all controlled -- objects allocated in a [sub]pool. Finalize_Address : Finalize_Address_Ptr := null; -- A reference to the routine reponsible for object finalization Finalization_Started : Boolean := False; pragma Atomic (Finalization_Started); -- A flag used to detect allocations which occur during the finalization -- of a master. The allocations must raise Program_Error. This scenario -- may arise in a multitask environment. The flag is atomic because it -- is accessed without Lock_Task / Unlock_Task. end record; type Finalization_Master_Ptr is access all Finalization_Master; for Finalization_Master_Ptr'Storage_Size use 0; -- Since RTSfind cannot contain names of the form RE_"+", the following -- routine serves as a wrapper around System.Storage_Elements."+". function Add_Offset_To_Address (Addr : System.Address; Offset : System.Storage_Elements.Storage_Offset) return System.Address; function Address_To_FM_Node_Ptr is new Ada.Unchecked_Conversion (Address, FM_Node_Ptr); procedure Attach (N : not null FM_Node_Ptr; L : not null FM_Node_Ptr); -- Prepend a node to a specific finalization master function Base_Pool (Master : Finalization_Master) return Any_Storage_Pool_Ptr; -- Return a reference to the underlying storage pool on which the master -- operates. procedure Detach (N : not null FM_Node_Ptr); -- Remove a node from an arbitrary finalization master overriding procedure Finalize (Master : in out Finalization_Master); -- Lock the master to prevent allocations during finalization. Iterate over -- the list of allocated controlled objects, finalizing each one by calling -- its specific Finalize_Address. In the end, deallocate the dummy head. function Header_Offset return System.Storage_Elements.Storage_Offset; -- Return the size of type FM_Node as Storage_Offset function Header_Size return System.Storage_Elements.Storage_Count; -- Return the size of type FM_Node as Storage_Count overriding procedure Initialize (Master : in out Finalization_Master); -- Initialize the dummy head of a finalization master procedure pm (Master : Finalization_Master); -- Debug routine, outputs the contents of a master procedure Set_Base_Pool (Master : in out Finalization_Master; Pool_Ptr : Any_Storage_Pool_Ptr); -- Set the underlying pool of a finalization master procedure Set_Finalize_Address (Master : in out Finalization_Master; Fin_Addr_Ptr : Finalize_Address_Ptr); -- Set the clean up routine of a finalization master end System.Finalization_Masters;