/*
 *  Paglo Crawler
 *  Copyright (C) 2006-2008 Paglo Labs Inc. All rights reserved.
 *  www.paglo.com
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of version 2 of the GNU General Public License as
 *  published by the Free Software Foundation.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 */
//---------------------------------------------------------------------------
#ifndef EventQueueH
#define EventQueueH
//---------------------------------------------------------------------------

#include <vector>
#include <pthread.h>
#include "Condition.h"
#include "Event.h"

class TEventQueue {

  /*
   * Let StopScans() have direct access to the EventQueue vector, so that it can
   * remove scans that are not currently permitted according to the subnet schedules.
   */
  friend void StopScans(void *Arg);

public:
  TEventQueue(void);
  ~TEventQueue(void);

  /*
   *  Insert an event at the back of the queue.  The queue is not responsible for freeing
   *  the event and the caller should not access it anymore
   */
  void Put(TPEvent *Evt);

  /*
   * Insert an event at the front of the queue. The queue is not responsible for
   * freeing the event and the caller should not access it anymore.
   */
  void PutFront(TPEvent *Evt);
  

  /*
   *  Remove an event from queue and return a pointer to it to the caller.
   *  The caller is responsible for freeing the event object
   */
  TPEvent *Get(void);

  /*
   * Get the specified item from the queue. This must only be done while the
   * queue is locked and the event must not be freed.
   */ 
  TPEvent *Get(int Index) { return EventQueue[Index]; }
  
  /*
   * Remove the specified element.
   */
  void Remove(int Index) { EventQueue.erase(EventQueue.begin() + Index); }
  
  /*
   * Wrappers for std::queue methods
   */
  int Size(void) { return EventQueue.size(); };
  bool IsEmpty(void) { return EventQueue.empty(); };

  /*
   * Allows callers to get/set condition variable associated with queue inserts
   * so that they can wait on it
   */
  void SetCond(TCondition *);
  TCondition *GetCond(void){ return QueueCond; };

  /*
   * Lock the entire queue. Useful when iterative through all events in the
   * queue.
   */
  void Lock() { pthread_mutex_lock(&QueueMutex); }
  void Unlock() { pthread_mutex_unlock(&QueueMutex); }

private:
  std::vector<TPEvent *> EventQueue;
  pthread_mutex_t QueueMutex;
  TCondition *QueueCond;

  bool ExternalCond;  // was the QueueCond set by something else
};
//---------------------------------------------------------------------------

#endif