lock_server.cc

// the lock server implementation

#include "lock_server.h"
#include <sstream>
#include <stdio.h>
#include <unistd.h>
#include <arpa/inet.h>
lock_server::lock_server():
nacquire (0)
{
    pthread_mutex_init(&mutex,NULL);
    pthread_cond_init(&cond,NULL);
}

lock_protocol::status
lock_server::stat(int clt, lock_protocol::lockid_t lid, int &r)
{
lock_protocol::status ret = lock_protocol::OK;
printf("stat request from clt %d\n", clt);
r = nacquire;
return ret;
}

lock_protocol::status lock_server::acquire(int clt, lock_protocol::lockid_t lid, int &r)
{
    lock_protocol::status ret = lock_protocol::OK;
    // Your lab4 code goes here
    pthread_mutex_lock(&mutex);
    if (locktable.find(lid) != locktable.end()) {
        
        while(locktable[lid] == true){
            pthread_cond_wait(&cond, &mutex);
        }
        locktable[lid] = true;
    }
    else {
        locktable.insert(std::pair<lock_protocol::lockid_t, bool>(lid, true));
        
    }
    pthread_mutex_unlock(&mutex);
    return ret;
}

lock_protocol::status lock_server::release(int clt, lock_protocol::lockid_t lid, int &r)
{
    lock_protocol::status ret = lock_protocol::OK;
    pthread_mutex_lock(&mutex);
    // Your lab4 code goes here
    if (locktable.find(lid) != locktable.end()) {
        locktable[lid] = false;
        pthread_cond_signal(&cond);
    }
    else {
        pthread_mutex_unlock(&mutex);
        return lock_protocol::NOENT;
    }
    pthread_mutex_unlock(&mutex);
    return ret;
}