#if !defined(VOCAL_CONDITION_HXX)
#define VOCAL_CONDITION_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/>.
 *
 */

static const char* const Condition_hxx_version =
    "$Id: Condition.hxx,v 1.1 2001/03/23 13:43:10 icahoon Exp $";


#include "NonCopyable.hxx"
#include "Mutex.hxx"


/** Infrastructure common to VOCAL.
 */
namespace Vocal 
{


/** Infrastructure common to VOCAL to create and manage threads.
 */
namespace Threads
{


/** Defines a simple conditional variable class which
 *  allows threads to block until shared data changes state.
 *  A VCondition must always be associated with a
 *  VMutex to avoid the race condition where a thread prepares to
 *  wait on a condition variable and another thread signals the
 *  condition just before the first thread actually waits on it.
 */
class Condition : public NonCopyable
{
    public:


        /** Create an Condition object initialized with operating system
         *  dependant defaults (if any). 
         */
        Condition();


        /** Delete a Condition object
         */
        virtual ~Condition();


        /** Block on the condition. Will return after the relativeTime, 
         *  specified in millseconds, has passed. If set to -1, the default,
         *  it will wait indefinately. Uses the specified mutex to synchronize 
         *  access to the condition. Returns 0, if successful, or an errorcode.
         */
        int wait (Mutex* mutex, int relativeTimeInMillis = -1);


        /** Block on the condition. Will return after the relativeTime, 
         *  specified in microseconds, has passed. If set to -1, the default,
         *  it will wait indefinately. Uses the specified mutex to synchronize 
         *  access to the condition. Returns 0, if successful, or an errorcode.
         */
        int uwait(Mutex* mutex, int relativeTimeInMicros = -1);


        /** Signal one waiting thread.
         *  Returns 0, if successful, or an errorcode.
         */
        int signal();


        /** Signal all waiting threads.
         *  Returns 0, if successful, or an errorcode.
         */
        int broadcast();
         

        /** Returns the operating system dependent unique id of the condition.
         */
        const vcondition_t*
        getId() const;

    private:

        mutable vcondition_t myId;
};


} // namespace Threads
} // namespace Vocal


/** usleep() replacement.<br><br> 
 *
 *  This will not throw a SIGALRM.
 */
void vusleep(unsigned long usec);


#endif // !defined(VOCAL_CONDITION_HXX)