#ifndef THREADIF_HXX
#define THREADIF_HXX

/* ====================================================================
 * The Vovida Software License, Version 1.0 
 * 
 * Copyright (c) 2000 Vovida Networks, Inc.  All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 
 * 3. The names "VOCAL", "Vovida Open Communication Application Library",
 *    and "Vovida Open Communication Application Library (VOCAL)" must
 *    not be used to endorse or promote products derived from this
 *    software without prior written permission. For written
 *    permission, please contact vocal@vovida.org.
 *
 * 4. Products derived from this software may not be called "VOCAL", nor
 *    may "VOCAL" appear in their name, without prior written
 *    permission of Vovida Networks, Inc.
 * 
 * THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, TITLE AND
 * NON-INFRINGEMENT ARE DISCLAIMED.  IN NO EVENT SHALL VOVIDA
 * NETWORKS, INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT DAMAGES
 * IN EXCESS OF $1,000, NOR FOR ANY INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
 * USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
 * DAMAGE.
 * 
 * ====================================================================
 * 
 * This software consists of voluntary contributions made by Vovida
 * Networks, Inc. and many individuals on behalf of Vovida Networks,
 * Inc.  For more information on Vovida Networks, Inc., please see
 * <http://www.vovida.org/>.
 *
 */

#include <cassert>
#include "VThread.hxx"
#include "VMutex.h"

static const char* const ThreadIf_hxx_version = 
"$Id: ThreadIf.hxx,v 1.2 2001/06/29 03:41:33 bko Exp $";

/*

TODO:

move constructor and operator= to private.  This cannot be done
immediately since SipThread inherits from this and it has both a copy
constructor and an operator=.

*/

/** A wrapper class to create and spawn a thread.  It is a base class.
 * ThreadIf::thread() is a pure virtual method .
 *
 * <P>Usage:
 * To use this class, derive from it and override the thread() method.
 * To start the thread, call the run() method.  The code in thread() will
 * run in a separate thread.
 *
 * <P>Call shutdown() from the constructing thread to shut down the
 * code.  This will set the bool shutdown_ to true.  The code in
 * thread() should react properly to shutdown_ being set, by
 * returning.  Call join() to join the code.
 * <P>Sample:
 * <PRE>
 * ...
 *     DerivedThreadIf thread;
 *     thread.run();
 * ... do stuff ...
 *     thread.shutdown();
 *     thread.join();
 * </PRE>
 */
class ThreadIf
{
    public:
        /// default constructor
        ThreadIf();
        /// destructor
        virtual ~ThreadIf();
        /// runs the code in thread() .  Returns immediately
        virtual void run();
        /// joins to the thread running thread()
        virtual void join()
        {
            itsThread.join();
        }

        /// forces the thread running to exit()
        virtual void exit()
        {
            itsThread.exit();
        }

	/** request the thread running thread() to return, by setting
	 * the bool shutdown_ 
	 */
        void shutdown();

	/** returns true if the thread has been asked to shutdown_ or
	 * if the thread is not running
	 */
        bool isShutdown() const;

        /** thread is a virtual method.  Users should derive and define
	 * thread() such that it returns when isShutdown() is true.
	 */
        virtual void thread() = 0;

    protected:
	/// itsThread is protected so that thread() can retrieve its threadId 
        VThread itsThread;

    private:

        bool shutdown_;
        mutable VMutex shutdownMutex_;

        /** Suppress copying
         */
        ThreadIf(const ThreadIf &);

        /** Suppress copying
         */
        const ThreadIf & operator=(const ThreadIf &);

};


// THREADIF_HXX

#endif