#include "pthread_impl.h"
#include <threads.h>

void __pthread_testcancel(void);

struct cm {
	cnd_t *c;
	mtx_t *m;
};

static void unwait(cnd_t *c, mtx_t *m)
{
	__THRD_ABI_MARK;
	/* Removing a waiter is non-trivial if we could be using requeue
	 * based broadcast signals, due to mutex access issues, etc. */

	while (a_swap(&c->_c_lock, 1))
		__wait(&c->_c_lock, &c->_c_lockwait, 1, 1);

	if (c->_c_waiters2) c->_c_waiters2--;
	else a_dec(&m->_m_waiters);

	a_store(&c->_c_lock, 0);
	if (c->_c_lockwait) __wake(&c->_c_lock, 1, 1);

	a_dec(&c->_c_waiters);
	if (c->_c_destroy) __wake(&c->_c_waiters, 1, 1);
}

static void cleanup(void *p)
{
	struct cm *cm = p;
	unwait(cm->c, cm->m);
	mtx_lock(cm->m);
}

int cnd_timedwait(cnd_t *restrict c, mtx_t *restrict m, const struct timespec *restrict ts)
{
	struct cm cm = { .c=c, .m=m };
	int r, e=0, seq;

	if (m->_m_type && (m->_m_lock&INT_MAX) != __pthread_self()->tid)
		return thrd_error;

	if (ts && ts->tv_nsec >= 1000000000UL)
		return thrd_error;

	__pthread_testcancel();

	a_inc(&c->_c_waiters);

	c->_c_mutex = m;
	while (a_swap(&c->_c_lock, 1))
		__wait(&c->_c_lock, &c->_c_lockwait, 1, 1);
	c->_c_waiters2++;
	a_store(&c->_c_lock, 0);
	if (c->_c_lockwait) __wake(&c->_c_lock, 1, 1);

	seq = c->_c_seq;

	mtx_unlock(m);

	do e = __timedwait(&c->_c_seq, seq, CLOCK_REALTIME, ts, cleanup, &cm, 0);
	while (c->_c_seq == seq && (!e || e==EINTR));
	if (e == EINTR) e = 0;

	unwait(c, m);

	if (mtx_lock(m) != thrd_success)
	 return thrd_error;

	switch (e) {
	case 0:
		if (thrd_success == 0) break;
		else return thrd_success;
	case ETIMEDOUT:
		if (thrd_timedout == ETIMEDOUT) break;
		else return thrd_timedout;
	}
        return e;
}