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------------------------------------------------------------------------------
-- --
-- GNU ADA RUN-TIME LIBRARY (GNARL) COMPONENTS --
-- --
-- S Y S T E M . T A S K I N G . P R O T E C T E D _ O B J E C T S . --
-- E N T R I E S --
-- --
-- B o d y --
-- --
-- $Revision: 1.11 $
-- --
-- Copyright (C) 1991-2001, Florida State University --
-- --
-- GNARL 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. GNARL 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 GNARL; see file COPYING. If not, write --
-- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
-- MA 02111-1307, 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. --
-- --
-- GNARL was developed by the GNARL team at Florida State University. It is --
-- now maintained by Ada Core Technologies Inc. in cooperation with Florida --
-- State University (http://www.gnat.com). --
-- --
------------------------------------------------------------------------------
-- This package contains all the simple primitives related to
-- Protected_Objects with entries (i.e init, lock, unlock).
-- The handling of protected objects with no entries is done in
-- System.Tasking.Protected_Objects, the complex routines for protected
-- objects with entries in System.Tasking.Protected_Objects.Operations.
-- The split between Entries and Operations is needed to break circular
-- dependencies inside the run time.
-- Note: the compiler generates direct calls to this interface, via Rtsfind.
with Ada.Exceptions;
-- used for Exception_Occurrence_Access
with System.Task_Primitives.Operations;
-- used for Initialize_Lock
-- Write_Lock
-- Unlock
-- Get_Priority
-- Wakeup
with System.Tasking.Initialization;
-- used for Defer_Abort,
-- Undefer_Abort,
-- Change_Base_Priority
pragma Elaborate_All (System.Tasking.Initialization);
-- this insures that tasking is initialized if any protected objects are
-- created.
package body System.Tasking.Protected_Objects.Entries is
package STPO renames System.Task_Primitives.Operations;
use Ada.Exceptions;
use STPO;
Locking_Policy : Character;
pragma Import (C, Locking_Policy, "__gl_locking_policy");
--------------
-- Finalize --
--------------
procedure Finalize (Object : in out Protection_Entries) is
Entry_Call : Entry_Call_Link;
Caller : Task_ID;
Ceiling_Violation : Boolean;
Self_ID : constant Task_ID := STPO.Self;
Old_Base_Priority : System.Any_Priority;
begin
if Object.Finalized then
return;
end if;
STPO.Write_Lock (Object.L'Unrestricted_Access, Ceiling_Violation);
if Ceiling_Violation then
-- Dip our own priority down to ceiling of lock.
-- See similar code in Tasking.Entry_Calls.Lock_Server.
STPO.Write_Lock (Self_ID);
Old_Base_Priority := Self_ID.Common.Base_Priority;
Self_ID.New_Base_Priority := Object.Ceiling;
Initialization.Change_Base_Priority (Self_ID);
STPO.Unlock (Self_ID);
STPO.Write_Lock (Object.L'Unrestricted_Access, Ceiling_Violation);
if Ceiling_Violation then
Raise_Exception (Program_Error'Identity, "Ceiling Violation");
end if;
Object.Old_Base_Priority := Old_Base_Priority;
Object.Pending_Action := True;
end if;
-- Send program_error to all tasks still queued on this object.
for E in Object.Entry_Queues'Range loop
Entry_Call := Object.Entry_Queues (E).Head;
while Entry_Call /= null loop
Caller := Entry_Call.Self;
Entry_Call.Exception_To_Raise := Program_Error'Identity;
STPO.Write_Lock (Caller);
Initialization.Wakeup_Entry_Caller (Self_ID, Entry_Call, Done);
STPO.Unlock (Caller);
exit when Entry_Call = Object.Entry_Queues (E).Tail;
Entry_Call := Entry_Call.Next;
end loop;
end loop;
Object.Finalized := True;
STPO.Unlock (Object.L'Unrestricted_Access);
STPO.Finalize_Lock (Object.L'Unrestricted_Access);
end Finalize;
-------------------------------------
-- Has_Interrupt_Or_Attach_Handler --
-------------------------------------
function Has_Interrupt_Or_Attach_Handler
(Object : Protection_Entries_Access)
return Boolean
is
begin
return False;
end Has_Interrupt_Or_Attach_Handler;
-----------------------------------
-- Initialize_Protection_Entries --
-----------------------------------
procedure Initialize_Protection_Entries
(Object : Protection_Entries_Access;
Ceiling_Priority : Integer;
Compiler_Info : System.Address;
Entry_Bodies : Protected_Entry_Body_Access;
Find_Body_Index : Find_Body_Index_Access)
is
Init_Priority : Integer := Ceiling_Priority;
Self_ID : constant Task_ID := STPO.Self;
begin
if Init_Priority = Unspecified_Priority then
Init_Priority := System.Priority'Last;
end if;
if Locking_Policy = 'C'
and then Has_Interrupt_Or_Attach_Handler (Object)
and then Init_Priority not in System.Interrupt_Priority
then
-- Required by C.3.1(11)
raise Program_Error;
end if;
Initialization.Defer_Abort (Self_ID);
Initialize_Lock (Init_Priority, Object.L'Access);
Initialization.Undefer_Abort (Self_ID);
Object.Ceiling := System.Any_Priority (Init_Priority);
Object.Compiler_Info := Compiler_Info;
Object.Pending_Action := False;
Object.Call_In_Progress := null;
Object.Entry_Bodies := Entry_Bodies;
Object.Find_Body_Index := Find_Body_Index;
for E in Object.Entry_Queues'Range loop
Object.Entry_Queues (E).Head := null;
Object.Entry_Queues (E).Tail := null;
end loop;
end Initialize_Protection_Entries;
------------------
-- Lock_Entries --
------------------
procedure Lock_Entries
(Object : Protection_Entries_Access; Ceiling_Violation : out Boolean) is
begin
-- The lock is made without defering abortion.
-- Therefore the abortion has to be deferred before calling this
-- routine. This means that the compiler has to generate a Defer_Abort
-- call before the call to Lock.
-- The caller is responsible for undeferring abortion, and compiler
-- generated calls must be protected with cleanup handlers to ensure
-- that abortion is undeferred in all cases.
pragma Assert (STPO.Self.Deferral_Level > 0);
Write_Lock (Object.L'Access, Ceiling_Violation);
end Lock_Entries;
procedure Lock_Entries (Object : Protection_Entries_Access) is
Ceiling_Violation : Boolean;
begin
pragma Assert (STPO.Self.Deferral_Level > 0);
Write_Lock (Object.L'Access, Ceiling_Violation);
if Ceiling_Violation then
Raise_Exception (Program_Error'Identity, "Ceiling Violation");
end if;
end Lock_Entries;
----------------------------
-- Lock_Read_Only_Entries --
----------------------------
procedure Lock_Read_Only_Entries (Object : Protection_Entries_Access) is
Ceiling_Violation : Boolean;
begin
Read_Lock (Object.L'Access, Ceiling_Violation);
if Ceiling_Violation then
Raise_Exception (Program_Error'Identity, "Ceiling Violation");
end if;
end Lock_Read_Only_Entries;
--------------------
-- Unlock_Entries --
--------------------
procedure Unlock_Entries (Object : Protection_Entries_Access) is
begin
Unlock (Object.L'Access);
end Unlock_Entries;
end System.Tasking.Protected_Objects.Entries;
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