/*
 * Implementação de locks recursivos.
 */

#include "lr.h"

int rec_mutex_init(rec_mutex_t* rec_m) {
  pthread_mutex_init(&rec_m->lock_var,0);
  pthread_cond_init(&rec_m->cond,0);
  rec_m->c = 0;
  return 0;
}

int rec_mutex_lock(rec_mutex_t* rec_m) {
  pthread_mutex_lock(&rec_m->lock_var);
  if (rec_m->c == 0) {   
    rec_m->thr = pthread_self();
    rec_m->c = 1;
  } else 
    if (pthread_equal(rec_m->thr, pthread_self()))
      rec_m->c++;
  else {
    while (rec_m->c != 0)
      pthread_cond_wait(&rec_m->cond, &rec_m->lock_var);
    rec_m->thr = pthread_self();
    rec_m->c = 1;
  }
  pthread_mutex_unlock(&rec_m->lock_var);
  return 0;
}

int rec_mutex_unlock(rec_mutex_t* rec_m) {
  pthread_mutex_lock(&rec_m->lock_var);
  rec_m->c--;
  if (rec_m->c == 0) 
    pthread_cond_signal(&rec_m->cond);
  pthread_mutex_unlock(&rec_m->lock_var);
  return 0;
}

int rec_mutex_destroy(rec_mutex_t* rec_m) {
  if (rec_m->c > 0)
    return -1;
  pthread_mutex_destroy(&rec_m->lock_var);
  pthread_cond_destroy(&rec_m->cond);
  return 0;
}