taskmanager.sm

SMC takes a state machine stored in a .sm file and generates a State pattern in twelve programming l

// -*- tab-width: 4; -*-
//
// The contents of this file are subject to the Mozilla Public
// License Version 1.1 (the "License"); you may not use this file
// except in compliance with the License. You may obtain a copy of
// the License at http://www.mozilla.org/MPL/
// 
// Software distributed under the License is distributed on an "AS
// IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
// implied. See the License for the specific language governing
// rights and limitations under the License.
// 
// The Original Code is State Machine Compiler (SMC).
// 
// The Initial Developer of the Original Code is Charles W. Rapp.
// Portions created by Charles W. Rapp are
// Copyright (C) 2000 - 2003 Charles W. Rapp.
// All Rights Reserved.
// 
// Contributor(s): 
//
// TaskManager --
//
//  The task manager is responsible for executing tasks. This
//  state machine tracks whether the manager has any tasks to run
//  and how long a task is executed.
//
// RCS ID
// $Id: taskManager.sm,v 1.5 2005/05/28 18:02:56 cwrapp Exp $
//
// CHANGE LOG
// $Log: taskManager.sm,v $
// Revision 1.5  2005/05/28 18:02:56  cwrapp
// Updated Tcl examples, removed EX6.
//
// Revision 1.0  2003/12/14 20:35:26  charlesr
// Initial revision
//

// Since this task manager does not have any tasks to
// run, it is in the idle state.
%start MainMap::Idle
%class TaskManager

%map MainMap
%%

// Wait here for some work to do.
Idle
Entry
{
    sendMessage(4 "Idle. Looking for a task to run.");
    checkTaskQueue();
}
{
    // Start the highest priority task running and start the slice
    // timer.
    RunTask
        RunningTask
        {
            startTask();
        }

    // There is now a task a run.
    TaskCreated
        RunningTask
        {
            startTask();
        }

    TaskUnblocked
        RunningTask
        {
            startTask();
        }

    Shutdown
        IdleShutdown
        {
            sendMessage(0 "Shutdown started.");
            setTimer("ShutdownTimeout" 2000);
        }

    // It is possible for the task to complete before it
    // receives the suspend request. When this happens, handle
    // this in the same manner as above.
    TaskDone
      [[$ctxt getRunnableTaskCount] > 0]
        RunningTask
        {
            startTask();
        }

    TaskDone
        Idle
        {
            stopTimer("ReplyTimeout");
        }
}

// A task has been started and is running.
RunningTask
Entry
{
    setTimer("SliceTimeout" 3000);
}
Exit
{
    stopTimer("SliceTimeout");
}
{
    // The time slice is up. Suspend the task.
    SliceTimeout
        SuspendingTask
        {
            suspendTask();
        }

    // The task has been blocked. Find another task to run.
    TaskBlocked
        Idle
        {}

    // The task has been deleted. Find another task to run.
    TaskDeleted
        Idle
        {}

    // The task has completed its work. Find another task to run.
    TaskDone
        Idle
        {}
}

// Wait here for the task to suspend.
SuspendingTask
Entry
{
    setTimer("ReplyTimeout" 500);
}
Exit
{
    stopTimer("ReplyTimeout");
}
{
    TaskSuspended
        Idle
        {}

    // Wait only so long for the task to reply.
    ReplyTimeout
        Idle
        {}

    // Just in case a task completes exactly at the same time
    // as the run slice ends.
    TaskDone
        Idle
        {}
}

// Wait here while the tasks report in.
ShuttingDown
{
    // A task is reporting it has stopped. When all tasks are
    // stopped, exit this application.
    TaskStopped
      [[$ctxt getRunningTask] == "" &&
       [$ctxt getRunnableTaskCount] == 0 &&
       [$ctxt getBlockedTaskCount] == 0]
        ShutdownComplete
        {
            stopTimer("ShutdownTimeout");
            sendMessage(0 "Shutdown completed.");
            exitApplication(0);
        }

    // Another task has stopped but there are more.
    TaskStopped
        nil
        {}

    // Timed out waiting for the tasks to die. Clean up and
    // exit anyway.
    ShutdownTimeout
        ShutdownComplete
        {
            sendMessage(0 "Timed out waiting for tasks to stop. Forcibly deleting tasks and exiting.");
            deleteAllTasks();
            exitApplication(1);
        }

    // Since we are shutting down, ignore task suspended
    // messages.
    TaskSuspended
        nil
        {}

    // If another shutdown is seen, ignore it.
    Shutdown
        nil
        {}
}

// The system was idle when the shutdown request occurred.
// Wait for the shutdown timeout, then exit.
IdleShutdown
{
    ShutdownTimeout
        ShutdownComplete
        {
            sendMessage(0 "Shutdown completed.");
            exitApplication(0);
        }
}

ShutdownComplete
{
    // Once this state is reached, don't do anything.
    Shutdown
        nil
        {}

    Default
        nil
        {}
}

Default
{
    // Tell all tasks to stop. Wait for them to reply but only
    // so long. If they fail to reply, kill 'em anyway.
    Shutdown
        ShuttingDown
        {
            sendMessage(0 "Shutdown started. Stopping all tasks.");
            stopAllTimers();
            stopAllTasks();
            setTimer("ShutdownTimeout" 5000);
        }

    // Ignore these events if already running a task.
    TaskCreated
        nil
        {}

    TaskUnblocked
        nil
        {}

    // Ignore timeouts when unexpected.
    SliceTimeout
        nil
        {}

    ReplyTimeout
        nil
        {}
}

%%