+++ /dev/null
-------------------------------------------------------------------------------
--- --
--- 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 . --
--- S I N G L E _ E N T R Y --
--- --
--- B o d y --
--- --
--- $Revision: 1.2 $
--- --
--- Copyright (C) 1998-2001 Ada Core Technologies --
--- --
--- 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). --
--- --
-------------------------------------------------------------------------------
-
-pragma Style_Checks (All_Checks);
--- 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)
---
--- 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).
-
-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
-
-with Ada.Exceptions;
--- used for Exception_Id;
-
-with Unchecked_Conversion;
-
-package body System.Tasking.Protected_Objects.Single_Entry is
-
- package STPO renames System.Task_Primitives.Operations;
-
- function To_Address is new
- Unchecked_Conversion (Protection_Entry_Access, System.Address);
-
- -----------------------
- -- Local Subprograms --
- -----------------------
-
- procedure Send_Program_Error
- (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
-
- --------------------------
- -- Entry Calls Handling --
- --------------------------
-
- procedure Wakeup_Entry_Caller
- (Self_ID : Task_ID;
- Entry_Call : Entry_Call_Link;
- New_State : Entry_Call_State);
- pragma Inline (Wakeup_Entry_Caller);
- -- This is called at the end of service of an entry call,
- -- to abort the caller if he is in an abortable part, and
- -- to wake up the caller if he is on Entry_Caller_Sleep.
- -- Call it holding the lock of Entry_Call.Self.
- --
- -- Timed_Call or Simple_Call:
- -- The caller is waiting on Entry_Caller_Sleep, in
- -- Wait_For_Completion, or Wait_For_Completion_With_Timeout.
-
- procedure Wait_For_Completion
- (Self_ID : Task_ID;
- Entry_Call : Entry_Call_Link);
- pragma Inline (Wait_For_Completion);
- -- This procedure suspends the calling task until the specified entry call
- -- has either been completed or cancelled. On exit, the call will not be
- -- queued. This waits for calls on protected entries.
- -- Call this only when holding Self_ID locked.
-
- procedure Wait_For_Completion_With_Timeout
- (Self_ID : Task_ID;
- Entry_Call : Entry_Call_Link;
- Wakeup_Time : Duration;
- Mode : Delay_Modes);
- -- Same as Wait_For_Completion but it waits for a timeout with the value
- -- specified in Wakeup_Time as well.
- -- Self_ID will be locked by this procedure.
-
- procedure Check_Exception
- (Self_ID : Task_ID;
- Entry_Call : Entry_Call_Link);
- pragma Inline (Check_Exception);
- -- Raise any pending exception from the Entry_Call.
- -- This should be called at the end of every compiler interface procedure
- -- that implements an entry call.
- -- The caller should not be holding any locks, or there will be deadlock.
-
- procedure PO_Do_Or_Queue
- (Self_Id : Task_ID;
- Object : Protection_Entry_Access;
- Entry_Call : Entry_Call_Link);
- -- This procedure executes or queues an entry call, depending
- -- on the status of the corresponding barrier. It assumes that the
- -- specified object is locked.
-
- ---------------------
- -- Check_Exception --
- ---------------------
-
- procedure Check_Exception
- (Self_ID : Task_ID;
- Entry_Call : Entry_Call_Link)
- is
- procedure Internal_Raise (X : Ada.Exceptions.Exception_Id);
- pragma Import (C, Internal_Raise, "__gnat_raise_with_msg");
-
- use type Ada.Exceptions.Exception_Id;
-
- E : constant Ada.Exceptions.Exception_Id :=
- Entry_Call.Exception_To_Raise;
-
- begin
- if E /= Ada.Exceptions.Null_Id then
- Internal_Raise (E);
- end if;
- end Check_Exception;
-
- ------------------------
- -- Send_Program_Error --
- ------------------------
-
- procedure Send_Program_Error
- (Self_Id : Task_ID;
- Entry_Call : Entry_Call_Link)
- is
- Caller : constant Task_ID := Entry_Call.Self;
- begin
- Entry_Call.Exception_To_Raise := Program_Error'Identity;
- STPO.Write_Lock (Caller);
- Wakeup_Entry_Caller (Self_Id, Entry_Call, Done);
- STPO.Unlock (Caller);
- end Send_Program_Error;
-
- -------------------------
- -- Wait_For_Completion --
- -------------------------
-
- -- Call this only when holding Self_ID locked
-
- procedure Wait_For_Completion
- (Self_ID : Task_ID;
- Entry_Call : Entry_Call_Link) is
- begin
- pragma Assert (Self_ID = Entry_Call.Self);
- Self_ID.Common.State := Entry_Caller_Sleep;
-
- STPO.Sleep (Self_ID, Entry_Caller_Sleep);
-
- Self_ID.Common.State := Runnable;
- end Wait_For_Completion;
-
- --------------------------------------
- -- Wait_For_Completion_With_Timeout --
- --------------------------------------
-
- -- This routine will lock Self_ID.
-
- -- This procedure waits for the entry call to
- -- be served, with a timeout. It tries to cancel the
- -- call if the timeout expires before the call is served.
-
- -- If we wake up from the timed sleep operation here,
- -- it may be for the following possible reasons:
-
- -- 1) The entry call is done being served.
- -- 2) The timeout has expired (Timedout = True)
-
- -- Once the timeout has expired we may need to continue to wait if
- -- the call is already being serviced. In that case, we want to go
- -- back to sleep, but without any timeout. The variable Timedout is
- -- used to control this. If the Timedout flag is set, we do not need
- -- to Sleep with a timeout. We just sleep until we get a wakeup for
- -- some status change.
-
- procedure Wait_For_Completion_With_Timeout
- (Self_ID : Task_ID;
- Entry_Call : Entry_Call_Link;
- Wakeup_Time : Duration;
- Mode : Delay_Modes)
- is
- Timedout : Boolean;
- Yielded : Boolean;
-
- use type Ada.Exceptions.Exception_Id;
-
- begin
- STPO.Write_Lock (Self_ID);
-
- pragma Assert (Entry_Call.Self = Self_ID);
- pragma Assert (Entry_Call.Mode = Timed_Call);
- Self_ID.Common.State := Entry_Caller_Sleep;
-
- 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;
-
- Self_ID.Common.State := Runnable;
- STPO.Unlock (Self_ID);
- end Wait_For_Completion_With_Timeout;
-
- -------------------------
- -- Wakeup_Entry_Caller --
- -------------------------
-
- -- This is called at the end of service of an entry call, to abort the
- -- caller if he is in an abortable part, and to wake up the caller if it
- -- is on Entry_Caller_Sleep. It assumes that the call is already off-queue.
-
- -- (This enforces the rule that a task must be off-queue if its state is
- -- Done or Cancelled.) Call it holding the lock of Entry_Call.Self.
-
- -- Timed_Call or Simple_Call:
- -- The caller is waiting on Entry_Caller_Sleep, in
- -- Wait_For_Completion, or Wait_For_Completion_With_Timeout.
-
- -- Conditional_Call:
- -- The caller might be in Wait_For_Completion,
- -- waiting for a rendezvous (possibly requeued without abort)
- -- to complete.
-
- procedure Wakeup_Entry_Caller
- (Self_ID : Task_ID;
- Entry_Call : Entry_Call_Link;
- New_State : Entry_Call_State)
- is
- Caller : constant Task_ID := Entry_Call.Self;
- begin
- pragma Assert (New_State = Done or else New_State = Cancelled);
- pragma Assert
- (Caller.Common.State /= Terminated and then
- Caller.Common.State /= Unactivated);
-
- Entry_Call.State := New_State;
- STPO.Wakeup (Caller, Entry_Caller_Sleep);
- end Wakeup_Entry_Caller;
-
- -----------------------
- -- Restricted GNARLI --
- -----------------------
-
- --------------------------------
- -- Complete_Single_Entry_Body --
- --------------------------------
-
- procedure Complete_Single_Entry_Body (Object : Protection_Entry_Access) is
- begin
- -- Nothing needs to be done since
- -- Object.Call_In_Progress.Exception_To_Raise has already been set to
- -- Null_Id
- null;
- end Complete_Single_Entry_Body;
-
- --------------------------------------------
- -- Exceptional_Complete_Single_Entry_Body --
- --------------------------------------------
-
- procedure Exceptional_Complete_Single_Entry_Body
- (Object : Protection_Entry_Access;
- Ex : Ada.Exceptions.Exception_Id) is
- begin
- Object.Call_In_Progress.Exception_To_Raise := Ex;
- end Exceptional_Complete_Single_Entry_Body;
-
- ---------------------------------
- -- Initialize_Protection_Entry --
- ---------------------------------
-
- procedure Initialize_Protection_Entry
- (Object : Protection_Entry_Access;
- Ceiling_Priority : Integer;
- 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;
-
- 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;
- Object.Entry_Queue := null;
- end Initialize_Protection_Entry;
-
- ----------------
- -- Lock_Entry --
- ----------------
-
- -- Compiler interface only.
- -- 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;
- end Lock_Entry;
-
- --------------------------
- -- Lock_Read_Only_Entry --
- --------------------------
-
- -- 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;
- end Lock_Read_Only_Entry;
-
- --------------------
- -- PO_Do_Or_Queue --
- --------------------
-
- procedure PO_Do_Or_Queue
- (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).
-
- 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;
- Wakeup_Entry_Caller (Self_Id, Entry_Call, Done);
-
- elsif Entry_Call.Mode /= Conditional_Call then
- Object.Entry_Queue := Entry_Call;
- else
- -- Conditional_Call
-
- STPO.Write_Lock (Entry_Call.Self);
- Wakeup_Entry_Caller (Self_Id, Entry_Call, Cancelled);
- STPO.Unlock (Entry_Call.Self);
- end if;
-
- exception
- when others =>
- Send_Program_Error
- (Self_Id, Entry_Call);
- end PO_Do_Or_Queue;
-
- ----------------------------
- -- Protected_Single_Count --
- ----------------------------
-
- function Protected_Count_Entry (Object : Protection_Entry) return Natural is
- begin
- if Object.Call_In_Progress /= null then
- return 1;
- else
- return 0;
- end if;
- end Protected_Count_Entry;
-
- ---------------------------------
- -- Protected_Single_Entry_Call --
- ---------------------------------
-
- procedure Protected_Single_Entry_Call
- (Object : Protection_Entry_Access;
- 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;
-
- begin
- STPO.Write_Lock (Object.L'Access, Ceiling_Violation);
-
- if Ceiling_Violation then
- raise Program_Error;
- end if;
-
- Entry_Call.Mode := Mode;
- Entry_Call.State := Now_Abortable;
- Entry_Call.Uninterpreted_Data := Uninterpreted_Data;
- Entry_Call.Exception_To_Raise := Ada.Exceptions.Null_Id;
-
- PO_Do_Or_Queue (Self_Id, Object, Entry_Call'Access);
- Unlock_Entry (Object);
-
- -- The call is either `Done' or not. It cannot be cancelled since there
- -- is no ATC construct.
-
- pragma Assert (Entry_Call.State /= Cancelled);
-
- if Entry_Call.State /= Done then
- STPO.Write_Lock (Self_Id);
- Wait_For_Completion (Self_Id, Entry_Call'Access);
- STPO.Unlock (Self_Id);
- end if;
-
- Check_Exception (Self_Id, Entry_Call'Access);
- end Protected_Single_Entry_Call;
-
- -----------------------------------
- -- Protected_Single_Entry_Caller --
- -----------------------------------
-
- function Protected_Single_Entry_Caller
- (Object : Protection_Entry) return Task_ID is
- begin
- return Object.Call_In_Progress.Self;
- end Protected_Single_Entry_Caller;
-
- -------------------
- -- Service_Entry --
- -------------------
-
- 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;
-
- 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;
- STPO.Write_Lock (Caller);
- Wakeup_Entry_Caller (Self_Id, Entry_Call, Done);
- STPO.Unlock (Caller);
- end if;
- end if;
-
- exception
- when others =>
- Send_Program_Error (Self_Id, Entry_Call);
- end Service_Entry;
-
- ---------------------------------------
- -- Timed_Protected_Single_Entry_Call --
- ---------------------------------------
-
- -- Compiler interface only. Do not call from within the RTS.
-
- procedure Timed_Protected_Single_Entry_Call
- (Object : Protection_Entry_Access;
- Uninterpreted_Data : System.Address;
- Timeout : Duration;
- Mode : Delay_Modes;
- Entry_Call_Successful : out Boolean)
- is
- 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;
- end if;
-
- Entry_Call.Mode := Timed_Call;
- Entry_Call.State := Now_Abortable;
- Entry_Call.Uninterpreted_Data := Uninterpreted_Data;
- Entry_Call.Exception_To_Raise := Ada.Exceptions.Null_Id;
-
- PO_Do_Or_Queue (Self_Id, Object, Entry_Call'Access);
- Unlock_Entry (Object);
-
- -- Try to avoid waiting for completed calls.
- -- The call is either `Done' or not. It cannot be cancelled since there
- -- is no ATC construct and the timed wait has not started yet.
-
- pragma Assert (Entry_Call.State /= Cancelled);
-
- if Entry_Call.State = Done then
- Check_Exception (Self_Id, Entry_Call'Access);
- Entry_Call_Successful := True;
- return;
- end if;
-
- Wait_For_Completion_With_Timeout
- (Self_Id, Entry_Call'Access, Timeout, Mode);
-
- pragma Assert (Entry_Call.State >= Done);
-
- Check_Exception (Self_Id, Entry_Call'Access);
- Entry_Call_Successful := Entry_Call.State = Done;
- end Timed_Protected_Single_Entry_Call;
-
- ------------------
- -- Unlock_Entry --
- ------------------
-
- procedure Unlock_Entry (Object : Protection_Entry_Access) is
- begin
- STPO.Unlock (Object.L'Access);
- end Unlock_Entry;
-
-end System.Tasking.Protected_Objects.Single_Entry;
projects / msp430-gcc.git / blobdiff