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/*
 *
 * Copyright (c) 2006 The Apache Software Foundation
 *
 * Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */
#ifndef _LFProcessor_
#define _LFProcessor_

#include "apr-1/apr_poll.h"
#include <iostream>
#include <vector>
#include <qpid/sys/Monitor.h>
#include "qpid/sys/Runnable.h"
#include "qpid/sys/Thread.h"

namespace qpid {
namespace sys {

    class LFSessionContext;

    /**
     * This class processes a poll set using the leaders-followers
     * pattern for thread synchronization: the leader will poll and on
     * the poll returning, it will remove a session, promote a
     * follower to leadership, then process the session.
     */
    class LFProcessor : private virtual qpid::sys::Runnable
    {
        typedef std::vector<LFSessionContext*>::iterator iterator;
        
        const int size;
        const apr_interval_time_t timeout;
        apr_pollset_t* pollset;
        int signalledCount;
        int current;
        const apr_pollfd_t* signalledFDs;
        int count;
        const int workerCount;
        bool hasLeader;
        qpid::sys::Thread* workers;
        qpid::sys::Monitor leadLock;
        qpid::sys::Mutex countLock;
        std::vector<LFSessionContext*> sessions;
        volatile bool stopped;

        const apr_pollfd_t* getNextEvent();
        void waitToLead();
        void relinquishLead();
        void poll();        
        virtual void run();        

    public:
        LFProcessor(apr_pool_t* pool, int workers, int size, int timeout);
        /**
         * Add the fd to the poll set. Relies on the client_data being
         * an instance of LFSessionContext.
         */
        void add(const apr_pollfd_t* const fd);
        /**
         * Remove the fd from the poll set.
         */
        void remove(const apr_pollfd_t* const fd);
        /**
         * Signal that the fd passed in, already part of the pollset,
         * has had its flags altered.
         */
        void update(const apr_pollfd_t* const fd);
        /**
         * Add an fd back to the poll set after deactivation.
         */
        void reactivate(const apr_pollfd_t* const fd);
        /**
         * Temporarily remove the fd from the poll set. Called when processing
         * is about to begin.
         */
        void deactivate(const apr_pollfd_t* const fd);
        /**
         * Indicates whether the capacity of this processor has been
         * reached (or whether it can still handle further fd's).
         */
        bool full();
        /**
         * Indicates whether there are any fd's registered.
         */
        bool empty();
        /**
         * Stop processing.
         */
        void stop();
        /**
         * Start processing.
         */
        void start();
        /**
         * Is processing stopped?
         */
        bool isStopped();
        
	~LFProcessor();
    };

}
}


#endif