lock.h

Go to the documentation of this file.

/*  Copyright (C) 2013  Eric Larson and Rochelle Palting
    elarson@seattleu.edu

    This file is part of the MDAT infrastructure.

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    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, see <http://www.gnu.org/licenses/>.
*/

#ifndef LOCK_H
#define LOCK_H

#include <string>
#include <vector>
#include <deque>
#include <pthread.h>
using namespace std;

class LockManager
{
  public:

    void addLock(const char *name, pthread_mutex_t *lock);

    void acquireLock(int id, pthread_mutex_t *lock);

    void releaseLock(int id, pthread_mutex_t *lock);

    string getLockTable() const;

  private:

    /* Lock data type */
    struct Lock {
      pthread_mutex_t *lock;    // corresponding lock variable
      string name;              // name of the lock
      bool isLocked;            // state of the lock
      int threadHolding;        // id of thread holding the lock (if held)
      deque<int> waiting;       // queue of threads waiting on lock
    };

    vector<Lock> lockArray;             // array of locks

    /* Finds and returns the desired lock record. */
    Lock* findLock(pthread_mutex_t *lp) {
      for (unsigned int i = 0; i < lockArray.size(); i++) {
        if (lockArray[i].lock == lp) return &lockArray[i];
      }
      return NULL;
    }
    Lock* findLock(string name) {
      for (unsigned int i = 0; i < lockArray.size(); i++) {
        if (lockArray[i].name == name) return &lockArray[i];
      }
      return NULL;
    }

};

extern LockManager locks;

#endif