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BUG#: 5314
TITLE: IPC Refactoring

DESCRIPTION: IPC Refactoring Branch Work

//%2006////////////////////////////////////////////////////////////////////////
//
// Copyright (c) 2000, 2001, 2002 BMC Software; Hewlett-Packard Development
// Company, L.P.; IBM Corp.; The Open Group; Tivoli Systems.
// Copyright (c) 2003 BMC Software; Hewlett-Packard Development Company, L.P.;
// IBM Corp.; EMC Corporation, The Open Group.
// Copyright (c) 2004 BMC Software; Hewlett-Packard Development Company, L.P.;
// IBM Corp.; EMC Corporation; VERITAS Software Corporation; The Open Group.
// Copyright (c) 2005 Hewlett-Packard Development Company, L.P.; IBM Corp.;
// EMC Corporation; VERITAS Software Corporation; The Open Group.
// Copyright (c) 2006 Hewlett-Packard Development Company, L.P.; IBM Corp.;
// EMC Corporation; Symantec Corporation; The Open Group.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to
// deal in the Software without restriction, including without limitation the
// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
// sell copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
// 
// THE ABOVE COPYRIGHT NOTICE AND THIS PERMISSION NOTICE SHALL BE INCLUDED IN
// ALL COPIES OR SUBSTANTIAL PORTIONS OF THE SOFTWARE. THE SOFTWARE IS PROVIDED
// "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT
// LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
// HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
// ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//
//==============================================================================
//
// Author: Mike Day (mdday@us.ibm.com)
//
// Modified By: Markus Mueller
//              Roger Kumpf, Hewlett-Packard Company (roger_kumpf@hp.com)
//              Amit K Arora, IBM (amita@in.ibm.com) for PEP#101
//              David Dillard, VERITAS Software Corp.
//                  (david.dillard@veritas.com)
//              Sean Keenan, Hewlett-Packard Company (sean.keenan@hp.com)
//              Josephine Eskaline Joyce, IBM (jojustin@in.ibm.com) for Bug#2393
//
//%/////////////////////////////////////////////////////////////////////////////

#ifndef Pegasus_ThreadPool_h
#define Pegasus_ThreadPool_h

#include <Pegasus/Common/Config.h>
#include <Pegasus/Common/Linkage.h>
#include <Pegasus/Common/Thread.h>

PEGASUS_NAMESPACE_BEGIN 

class PEGASUS_COMMON_LINKAGE ThreadPool
{
public:

    /**
        Constructs a new ThreadPool object.
        @param initialSize The number of threads that are initially added to
            the thread pool.
        @param key A name for this thread pool that can be used to determine
            equality of two thread pool objects.  Only the first 16 characters
            of this value are used.
        @param minThreads The minimum number of threads that should be
            contained in this thread pool at any given time.
        @param maxThreads The maximum number of threads that should be
            contained in this thread pool at any given time.
        @param deallocateWait The minimum time that a thread should be idle
            before it is removed from the pool and cleaned up.
     */
    ThreadPool(Sint16 initialSize,
               const char *key,
               Sint16 minThreads,
               Sint16 maxThreads, struct timeval &deallocateWait);

    /**
        Destructs the ThreadPool object.
     */
     ~ThreadPool();

    /**
        Allocate and start a thread to do a unit of work.
        @param parm A generic parameter to pass to the thread
        @param work A pointer to the function that is to be executed by
                    the thread
        @param blocking A pointer to an optional semaphore which, if
                        specified, is signaled after the thread finishes
                        executing the work function
        @return PEGASUS_THREAD_OK if the thread is started successfully, 
		PEGASUS_THREAD_INSUFFICIENT_RESOURCES  if the
                resources necessary to start the thread are not currently
                available.  PEGASUS_THREAD_SETUP_FAILURE if the thread
                could not be setup properly. PEGASUS_THREAD_UNAVAILABLE
                if this service is shutting down and no more threads can
                be allocated.
        @exception IPCException
     */
    ThreadStatus allocate_and_awaken(void *parm,
                                     ThreadReturnType(PEGASUS_THREAD_CDECL *
                                                      work) (void *),
                                     Semaphore * blocking = 0);

    /**
        Cleans up idle threads if they have been running longer than the
        deallocate_wait configuration and more than the configured
        minimum number of threads is running.
        @return The number of threads that were cleaned up.
        @exception IPCException
     */
    Uint32 cleanupIdleThreads();

    void get_key(Sint8 * buf, int bufsize);

    inline void setMinThreads(Sint16 min)
    {
        _minThreads = min;
    }

    inline Sint16 getMinThreads() const
    {
        return _minThreads;
    }

    inline void setMaxThreads(Sint16 max)
    {
        _maxThreads = max;
    }

    inline Sint16 getMaxThreads() const
    {
        return _maxThreads;
    }

    inline Uint32 runningCount()
    {
        return _runningThreads.size();
    }

    inline Uint32 idleCount()
    {
        return _idleThreads.size();
    }

private:

    ThreadPool();               // Unimplemented
    ThreadPool(const ThreadPool &);     // Unimplemented
    ThreadPool & operator=(const ThreadPool &); // Unimplemented

    static ThreadReturnType PEGASUS_THREAD_CDECL _loop(void *);

    static Boolean _timeIntervalExpired(struct timeval *start,
                                        struct timeval *interval);

    static void _deleteSemaphore(void *p);

    void _cleanupThread(Thread * thread);
    Thread *_initializeThread();
    void _addToIdleThreadsQueue(Thread * th);

    Sint16 _maxThreads;
    Sint16 _minThreads;
    AtomicInt _currentThreads;
    struct timeval _deallocateWait;
    char _key[17];
    List < Thread, Mutex > _idleThreads;
    List < Thread, Mutex > _runningThreads;
    AtomicInt _dying;
};

PEGASUS_NAMESPACE_END

#endif // Pegasus_ThreadPool_h