+++ /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 . --
--- O P E R A T I O N S --
--- --
--- S p e c --
--- --
--- $Revision: 1.1.16.1 $
--- --
--- Copyright (C) 1992-2001, 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- --
--- 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. --
--- Extensive contributions were provided by Ada Core Technologies Inc. --
--- --
-------------------------------------------------------------------------------
-
--- This package contains all the extended primitives related to
--- Protected_Objects with entries.
--- The handling of protected objects with no entries is done in
--- System.Tasking.Protected_Objects, the simple routines for protected
--- objects with entries in System.Tasking.Protected_Objects.Entries.
--- 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.
--- Any changes to this interface may require corresponding compiler changes.
-
-with Ada.Exceptions;
--- used for Exception_Id
-
-with System.Tasking.Protected_Objects.Entries;
-
-package System.Tasking.Protected_Objects.Operations is
- pragma Elaborate_Body;
-
- type Communication_Block is private;
- -- Objects of this type are passed between GNARL calls to allow RTS
- -- information to be preserved.
-
- procedure Protected_Entry_Call
- (Object : Entries.Protection_Entries_Access;
- E : Protected_Entry_Index;
- Uninterpreted_Data : System.Address;
- Mode : Call_Modes;
- Block : out Communication_Block);
- -- Make a protected entry call to the specified object.
- -- Pend a protected entry call on the protected object represented
- -- by Object. A pended call is not queued; it may be executed immediately
- -- or queued, depending on the state of the entry barrier.
- --
- -- E
- -- The index representing the entry to be called.
- --
- -- Uninterpreted_Data
- -- This will be returned by Next_Entry_Call when this call is serviced.
- -- It can be used by the compiler to pass information between the
- -- caller and the server, in particular entry parameters.
- --
- -- Mode
- -- The kind of call to be pended
- --
- -- Block
- -- Information passed between runtime calls by the compiler
-
- procedure Timed_Protected_Entry_Call
- (Object : Entries.Protection_Entries_Access;
- E : Protected_Entry_Index;
- Uninterpreted_Data : System.Address;
- Timeout : Duration;
- Mode : Delay_Modes;
- Entry_Call_Successful : out Boolean);
- -- Same as the Protected_Entry_Call but with time-out specified.
- -- This routines is used when we do not use ATC mechanism to implement
- -- timed entry calls.
-
- procedure Service_Entries (Object : Entries.Protection_Entries_Access);
- pragma Inline (Service_Entries);
-
- procedure PO_Service_Entries
- (Self_ID : Task_ID;
- Object : Entries.Protection_Entries_Access);
- -- Service all entry queues of the specified object, executing the
- -- corresponding bodies of any queued entry calls that are waiting
- -- on True barriers. This is used when the state of a protected
- -- object may have changed, in particular after the execution of
- -- the statement sequence of a protected procedure.
- -- Note that servicing an entry may change the value of one or more
- -- barriers, so this routine keeps checking barriers until all of
- -- them are closed.
- --
- -- This must be called with abortion deferred and with the corresponding
- -- object locked.
-
- procedure Complete_Entry_Body (Object : Entries.Protection_Entries_Access);
- -- Called from within an entry body procedure, indicates that the
- -- corresponding entry call has been serviced.
-
- procedure Exceptional_Complete_Entry_Body
- (Object : Entries.Protection_Entries_Access;
- Ex : Ada.Exceptions.Exception_Id);
- -- Perform all of the functions of Complete_Entry_Body. In addition,
- -- report in Ex the exception whose propagation terminated the entry
- -- body to the runtime system.
-
- procedure Cancel_Protected_Entry_Call (Block : in out Communication_Block);
- -- Attempt to cancel the most recent protected entry call. If the call is
- -- not queued abortably, wait until it is or until it has completed.
- -- If the call is actually cancelled, the called object will be
- -- locked on return from this call. Get_Cancelled (Block) can be
- -- used to determine if the cancellation took place; there
- -- may be entries needing service in this case.
- --
- -- Block passes information between this and other runtime calls.
-
- function Enqueued (Block : Communication_Block) return Boolean;
- -- Returns True if the Protected_Entry_Call which returned the
- -- specified Block object was queued; False otherwise.
-
- function Cancelled (Block : Communication_Block) return Boolean;
- -- Returns True if the Protected_Entry_Call which returned the
- -- specified Block object was cancelled, False otherwise.
-
- procedure Requeue_Protected_Entry
- (Object : Entries.Protection_Entries_Access;
- New_Object : Entries.Protection_Entries_Access;
- E : Protected_Entry_Index;
- With_Abort : Boolean);
- -- If Object = New_Object, queue the protected entry call on Object
- -- currently being serviced on the queue corresponding to the entry
- -- represented by E.
- --
- -- If Object /= New_Object, transfer the call to New_Object.E,
- -- executing or queuing it as appropriate.
- --
- -- With_Abort---True if the call is to be queued abortably, false
- -- otherwise.
-
- procedure Requeue_Task_To_Protected_Entry
- (New_Object : Entries.Protection_Entries_Access;
- E : Protected_Entry_Index;
- With_Abort : Boolean);
- -- Transfer task entry call currently being serviced to entry E
- -- on New_Object.
- --
- -- With_Abort---True if the call is to be queued abortably, false
- -- otherwise.
-
- function Protected_Count
- (Object : Entries.Protection_Entries'Class;
- E : Protected_Entry_Index)
- return Natural;
- -- Return the number of entry calls to E on Object.
-
- function Protected_Entry_Caller
- (Object : Entries.Protection_Entries'Class) return Task_ID;
- -- Return value of E'Caller, where E is the protected entry currently
- -- being handled. This will only work if called from within an entry
- -- body, as required by the LRM (C.7.1(14)).
-
- -- For internal use only:
-
- procedure PO_Do_Or_Queue
- (Self_ID : Task_ID;
- Object : Entries.Protection_Entries_Access;
- Entry_Call : Entry_Call_Link;
- With_Abort : Boolean);
- -- This procedure either executes or queues an entry call, depending
- -- on the status of the corresponding barrier. It assumes that abortion
- -- is deferred and that the specified object is locked.
-
-private
- type Communication_Block is record
- Self : Task_ID;
- Enqueued : Boolean := True;
- Cancelled : Boolean := False;
- end record;
- pragma Volatile (Communication_Block);
-
- -- ?????
- -- The Communication_Block seems to be a relic.
- -- At the moment, the compiler seems to be generating
- -- unnecessary conditional code based on this block.
- -- See the code generated for async. select with task entry
- -- call for another way of solving this.
-
-end System.Tasking.Protected_Objects.Operations;
projects / msp430-gcc.git / blobdiff