------------------------------------------------------------------------------
-- --
--- GNU ADA RUN-TIME LIBRARY (GNARL) COMPONENTS --
+-- GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS --
-- --
--- SYSTEM.TASKING.PROTECTED_OBJECTS.SINGLE_ENTRY --
+-- SYSTEM.TASKING.PROTECTED_OBJECTS.SINGLE_ENTRY --
-- --
--- B o d y --
+-- B o d y --
-- --
--- --
--- Copyright (C) 1998-2002, Free Software Foundation, Inc. --
+-- Copyright (C) 1998-2009, Free Software Foundation, Inc. --
-- --
-- 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- --
+-- 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 GNARL; 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/>. --
-- --
--- GNARL was developed by the GNARL team at Florida State University. It is --
--- now maintained by Ada Core Technologies, Inc. (http://www.gnat.com). --
+-- GNARL was developed by the GNARL team at Florida State University. --
+-- Extensive contributions were provided by Ada Core Technologies, Inc. --
-- --
------------------------------------------------------------------------------
pragma Style_Checks (All_Checks);
--- Turn off subprogram ordering check, since restricted GNARLI
--- subprograms are gathered together at end.
+-- Turn off subprogram ordering check, since restricted GNARLI subprograms are
+-- gathered together at end.
-- This package provides an optimized version of Protected_Objects.Operations
-- and Protected_Objects.Entries making the following assumptions:
---
--- PO have only one entry
--- There is only one caller at a time (No_Entry_Queue)
--- There is no dynamic priority support (No_Dynamic_Priorities)
--- No Abort Statements
--- (No_Abort_Statements, Max_Asynchronous_Select_Nesting => 0)
--- PO are at library level
--- No Requeue
--- None of the tasks will terminate (no need for finalization)
---
+
+-- PO has only one entry
+-- There is only one caller at a time (No_Entry_Queue)
+-- There is no dynamic priority support (No_Dynamic_Priorities)
+-- No Abort Statements
+-- (No_Abort_Statements, Max_Asynchronous_Select_Nesting => 0)
+-- PO are at library level
+-- No Requeue
+-- None of the tasks will terminate (no need for finalization)
+
-- This interface is intended to be used in the ravenscar and restricted
-- profiles, the compiler is responsible for ensuring that the conditions
-- mentioned above are respected, except for the No_Entry_Queue restriction
-- that is checked dynamically in this package, since the check cannot be
-- performed at compile time, and is relatively cheap (see PO_Do_Or_Queue,
--- PO_Service_Entry).
+-- Service_Entry).
pragma Polling (Off);
-- Turn off polling, we do not want polling to take place during tasking
-- operations. It can cause infinite loops and other problems.
pragma Suppress (All_Checks);
-
-with System.Task_Primitives.Operations;
--- used for Self
--- Finalize_Lock
--- Write_Lock
--- Unlock
+-- Why is this required ???
with Ada.Exceptions;
--- used for Exception_Id;
+with System.Task_Primitives.Operations;
with System.Parameters;
--- used for Single_Lock
package body System.Tasking.Protected_Objects.Single_Entry is
-----------------------
procedure Send_Program_Error
- (Self_Id : Task_ID;
+ (Self_Id : Task_Id;
Entry_Call : Entry_Call_Link);
pragma Inline (Send_Program_Error);
-- Raise Program_Error in the caller of the specified entry call
--------------------------
procedure Wakeup_Entry_Caller
- (Self_ID : Task_ID;
+ (Self_ID : Task_Id;
Entry_Call : Entry_Call_Link;
New_State : Entry_Call_State);
pragma Inline (Wakeup_Entry_Caller);
-- specified in Wakeup_Time as well.
procedure Check_Exception
- (Self_ID : Task_ID;
+ (Self_ID : Task_Id;
Entry_Call : Entry_Call_Link);
pragma Inline (Check_Exception);
-- Raise any pending exception from the Entry_Call.
-- The caller should not be holding any locks, or there will be deadlock.
procedure PO_Do_Or_Queue
- (Self_Id : Task_ID;
+ (Self_Id : Task_Id;
Object : Protection_Entry_Access;
Entry_Call : Entry_Call_Link);
-- This procedure executes or queues an entry call, depending
---------------------
procedure Check_Exception
- (Self_ID : Task_ID;
+ (Self_ID : Task_Id;
Entry_Call : Entry_Call_Link)
is
pragma Warnings (Off, Self_ID);
use type Ada.Exceptions.Exception_Id;
E : constant Ada.Exceptions.Exception_Id :=
- Entry_Call.Exception_To_Raise;
+ Entry_Call.Exception_To_Raise;
begin
if E /= Ada.Exceptions.Null_Id then
------------------------
procedure Send_Program_Error
- (Self_Id : Task_ID;
+ (Self_Id : Task_Id;
Entry_Call : Entry_Call_Link)
is
- Caller : constant Task_ID := Entry_Call.Self;
+ Caller : constant Task_Id := Entry_Call.Self;
begin
Entry_Call.Exception_To_Raise := Program_Error'Identity;
-------------------------
procedure Wait_For_Completion (Entry_Call : Entry_Call_Link) is
- Self_Id : constant Task_ID := Entry_Call.Self;
+ Self_Id : constant Task_Id := Entry_Call.Self;
begin
Self_Id.Common.State := Entry_Caller_Sleep;
STPO.Sleep (Self_Id, Entry_Caller_Sleep);
Wakeup_Time : Duration;
Mode : Delay_Modes)
is
- Self_Id : constant Task_ID := Entry_Call.Self;
+ Self_Id : constant Task_Id := Entry_Call.Self;
Timedout : Boolean;
+
Yielded : Boolean;
+ pragma Unreferenced (Yielded);
use type Ada.Exceptions.Exception_Id;
STPO.Timed_Sleep
(Self_Id, Wakeup_Time, Mode, Entry_Caller_Sleep, Timedout, Yielded);
- if Timedout then
- Entry_Call.State := Cancelled;
- else
- Entry_Call.State := Done;
- end if;
-
+ Entry_Call.State := (if Timedout then Cancelled else Done);
Self_Id.Common.State := Runnable;
end Wait_For_Completion_With_Timeout;
-- to complete.
procedure Wakeup_Entry_Caller
- (Self_ID : Task_ID;
+ (Self_ID : Task_Id;
Entry_Call : Entry_Call_Link;
New_State : Entry_Call_State)
is
pragma Warnings (Off, Self_ID);
- Caller : constant Task_ID := Entry_Call.Self;
+ Caller : constant Task_Id := Entry_Call.Self;
begin
pragma Assert (New_State = Done or else New_State = Cancelled);
Compiler_Info : System.Address;
Entry_Body : Entry_Body_Access)
is
- Init_Priority : Integer := Ceiling_Priority;
begin
- if Init_Priority = Unspecified_Priority then
- Init_Priority := System.Priority'Last;
- end if;
+ Initialize_Protection (Object.Common'Access, Ceiling_Priority);
- STPO.Initialize_Lock (Init_Priority, Object.L'Access);
- Object.Ceiling := System.Any_Priority (Init_Priority);
Object.Compiler_Info := Compiler_Info;
Object.Call_In_Progress := null;
Object.Entry_Body := Entry_Body;
-- Do not call this procedure from within the run-time system.
procedure Lock_Entry (Object : Protection_Entry_Access) is
- Ceiling_Violation : Boolean;
begin
- STPO.Write_Lock (Object.L'Access, Ceiling_Violation);
-
- if Ceiling_Violation then
- raise Program_Error;
- end if;
+ Lock (Object.Common'Access);
end Lock_Entry;
--------------------------
-- Lock_Read_Only_Entry --
--------------------------
- -- Compiler interface only.
- -- Do not call this procedure from within the runtime system.
+ -- Compiler interface only
+
+ -- Do not call this procedure from within the runtime system
procedure Lock_Read_Only_Entry (Object : Protection_Entry_Access) is
- Ceiling_Violation : Boolean;
begin
- STPO.Read_Lock (Object.L'Access, Ceiling_Violation);
-
- if Ceiling_Violation then
- raise Program_Error;
- end if;
+ Lock_Read_Only (Object.Common'Access);
end Lock_Read_Only_Entry;
--------------------
--------------------
procedure PO_Do_Or_Queue
- (Self_Id : Task_ID;
+ (Self_Id : Task_Id;
Object : Protection_Entry_Access;
Entry_Call : Entry_Call_Link)
is
Barrier_Value : Boolean;
+
begin
-- When the Action procedure for an entry body returns, it must be
-- completed (having called [Exceptional_]Complete_Entry_Body).
if Barrier_Value then
if Object.Call_In_Progress /= null then
+
-- This violates the No_Entry_Queue restriction, send
-- Program_Error to the caller.
end if;
elsif Entry_Call.Mode /= Conditional_Call then
- Object.Entry_Queue := Entry_Call;
+ if Object.Entry_Queue /= null then
+
+ -- This violates the No_Entry_Queue restriction, send
+ -- Program_Error to the caller.
+
+ Send_Program_Error (Self_Id, Entry_Call);
+ return;
+ else
+ Object.Entry_Queue := Entry_Call;
+ end if;
+
else
-- Conditional_Call
function Protected_Count_Entry (Object : Protection_Entry) return Natural is
begin
- if Object.Call_In_Progress /= null then
+ if Object.Entry_Queue /= null then
return 1;
else
return 0;
Uninterpreted_Data : System.Address;
Mode : Call_Modes)
is
- Self_Id : constant Task_ID := STPO.Self;
- Entry_Call : Entry_Call_Record renames Self_Id.Entry_Calls (1);
- Ceiling_Violation : Boolean;
-
+ Self_Id : constant Task_Id := STPO.Self;
+ Entry_Call : Entry_Call_Record renames Self_Id.Entry_Calls (1);
begin
- STPO.Write_Lock (Object.L'Access, Ceiling_Violation);
-
- if Ceiling_Violation then
- raise Program_Error;
+ -- If pragma Detect_Blocking is active then Program_Error must be
+ -- raised if this potentially blocking operation is called from a
+ -- protected action.
+
+ if Detect_Blocking
+ and then Self_Id.Common.Protected_Action_Nesting > 0
+ then
+ raise Program_Error with "potentially blocking operation";
end if;
+ Lock_Entry (Object);
+
Entry_Call.Mode := Mode;
Entry_Call.State := Now_Abortable;
Entry_Call.Uninterpreted_Data := Uninterpreted_Data;
-----------------------------------
function Protected_Single_Entry_Caller
- (Object : Protection_Entry) return Task_ID is
+ (Object : Protection_Entry) return Task_Id is
begin
return Object.Call_In_Progress.Self;
end Protected_Single_Entry_Caller;
-------------------
procedure Service_Entry (Object : Protection_Entry_Access) is
- Self_Id : constant Task_ID := STPO.Self;
- Entry_Call : constant Entry_Call_Link := Object.Entry_Queue;
- Caller : Task_ID;
- Barrier_Value : Boolean;
+ Self_Id : constant Task_Id := STPO.Self;
+ Entry_Call : constant Entry_Call_Link := Object.Entry_Queue;
+ Caller : Task_Id;
begin
- if Entry_Call /= null then
- Barrier_Value := Object.Entry_Body.Barrier (Object.Compiler_Info, 1);
-
- if Barrier_Value then
- if Object.Call_In_Progress /= null then
- -- This violates the No_Entry_Queue restriction, send
- -- Program_Error to the caller.
-
- Send_Program_Error (Self_Id, Entry_Call);
- return;
- end if;
-
- Object.Call_In_Progress := Entry_Call;
- Object.Entry_Body.Action
- (Object.Compiler_Info, Entry_Call.Uninterpreted_Data, 1);
- Object.Call_In_Progress := null;
- Caller := Entry_Call.Self;
-
- if Single_Lock then
- STPO.Lock_RTS;
- end if;
-
- STPO.Write_Lock (Caller);
- Wakeup_Entry_Caller (Self_Id, Entry_Call, Done);
- STPO.Unlock (Caller);
-
- if Single_Lock then
- STPO.Unlock_RTS;
- end if;
+ if Entry_Call /= null
+ and then Object.Entry_Body.Barrier (Object.Compiler_Info, 1)
+ then
+ Object.Entry_Queue := null;
+
+ if Object.Call_In_Progress /= null then
+
+ -- Violation of No_Entry_Queue restriction, raise exception
+
+ Send_Program_Error (Self_Id, Entry_Call);
+ Unlock_Entry (Object);
+ return;
end if;
+
+ Object.Call_In_Progress := Entry_Call;
+ Object.Entry_Body.Action
+ (Object.Compiler_Info, Entry_Call.Uninterpreted_Data, 1);
+ Object.Call_In_Progress := null;
+ Caller := Entry_Call.Self;
+ Unlock_Entry (Object);
+
+ if Single_Lock then
+ STPO.Lock_RTS;
+ end if;
+
+ STPO.Write_Lock (Caller);
+ Wakeup_Entry_Caller (Self_Id, Entry_Call, Done);
+ STPO.Unlock (Caller);
+
+ if Single_Lock then
+ STPO.Unlock_RTS;
+ end if;
+
+ else
+ -- Just unlock the entry
+
+ Unlock_Entry (Object);
end if;
exception
when others =>
Send_Program_Error (Self_Id, Entry_Call);
+ Unlock_Entry (Object);
end Service_Entry;
---------------------------------------
-- Timed_Protected_Single_Entry_Call --
---------------------------------------
- -- Compiler interface only. Do not call from within the RTS.
+ -- Compiler interface only (do not call from within the RTS)
procedure Timed_Protected_Single_Entry_Call
(Object : Protection_Entry_Access;
Mode : Delay_Modes;
Entry_Call_Successful : out Boolean)
is
- Self_Id : constant Task_ID := STPO.Self;
+ Self_Id : constant Task_Id := STPO.Self;
Entry_Call : Entry_Call_Record renames Self_Id.Entry_Calls (1);
- Ceiling_Violation : Boolean;
begin
- STPO.Write_Lock (Object.L'Access, Ceiling_Violation);
-
- if Ceiling_Violation then
- raise Program_Error;
+ -- If pragma Detect_Blocking is active then Program_Error must be
+ -- raised if this potentially blocking operation is called from a
+ -- protected action.
+
+ if Detect_Blocking
+ and then Self_Id.Common.Protected_Action_Nesting > 0
+ then
+ raise Program_Error with "potentially blocking operation";
end if;
+ Lock (Object.Common'Access);
+
Entry_Call.Mode := Timed_Call;
Entry_Call.State := Now_Abortable;
Entry_Call.Uninterpreted_Data := Uninterpreted_Data;
procedure Unlock_Entry (Object : Protection_Entry_Access) is
begin
- STPO.Unlock (Object.L'Access);
+ Unlock (Object.Common'Access);
end Unlock_Entry;
end System.Tasking.Protected_Objects.Single_Entry;
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