/*
 * Implementação de locks recursivos.
 */

#include "lr.h"

int rec_mutex_init(rec_mutex_t* rec_m) {
  pthread_mutex_init(&rec_m->lock, NULL);
  pthread_cond_init(&rec_m->cond, NULL);
  return 0;
}

int rec_mutex_lock(rec_mutex_t* rec_m) {
  pthread_mutex_lock(&rec_m->lock);
  if (rec_m->c == 0) {  /* Lock livre */
    rec_m->c = 1;
    rec_m->thr = pthread_self();
  } else  /* Mesma thread */
    if (pthread_equal(rec_m->thr,
                       pthread_self()))
        rec_m->c++;
    else {
     /* Thread deve esperar */
      while (rec_m->c != 0) 
	pthread_cond_wait(&rec_m->cond,
                         &rec_m->lock);
      rec_m->thr = pthread_self();
      rec_m->c = 1;
    }
  pthread_mutex_unlock(&rec_m->lock);
  return 0;
}

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

int rec_mutex_destroy(rec_mutex_t* rec_m) {
  return 0;
}