/*
 * %CopyrightBegin%
 *
 * Copyright Ericsson AB 2010. All Rights Reserved.
 *
 * The contents of this file are subject to the Erlang Public License,
 * Version 1.1, (the "License"); you may not use this file except in
 * compliance with the License. You should have received a copy of the
 * Erlang Public License along with this software. If not, it can be
 * retrieved online at http://www.erlang.org/.
 *
 * Software distributed under the License is distributed on an "AS IS"
 * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
 * the License for the specific language governing rights and limitations
 * under the License.
 *
 * %CopyrightEnd%
 */

/*
 * Description: Pthread implementation of the ethread library
 * Author: Rickard Green
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#define ETHR_CHILD_WAIT_SPIN_COUNT 4000

#include <stdio.h>
#ifdef ETHR_TIME_WITH_SYS_TIME
#  include <time.h>
#  include <sys/time.h>
#else
#  ifdef ETHR_HAVE_SYS_TIME_H
#    include <sys/time.h>
#  else
#    include <time.h>
#  endif
#endif
#include <sys/types.h>
#include <unistd.h>
#include <signal.h>

#include <limits.h>

#define ETHR_INLINE_FUNC_NAME_(X) X ## __
#define ETHREAD_IMPL__

#include "ethread.h"
#include "ethr_internal.h"

#ifndef ETHR_HAVE_ETHREAD_DEFINES
#error Missing configure defines
#endif

pthread_key_t ethr_ts_event_key__;
static int child_wait_spin_count;

/*
 * --------------------------------------------------------------------------
 * Static functions
 * --------------------------------------------------------------------------
 */

static void thr_exit_cleanup(void)
{
    ethr_run_exit_handlers__();
}


/* Argument passed to thr_wrapper() */
typedef struct {
    ethr_atomic_t result;
    ethr_ts_event *tse;
    void *(*thr_func)(void *);
    void *arg;
    void *prep_func_res;
} ethr_thr_wrap_data__;

static void *thr_wrapper(void *vtwd)
{
    long result;
    void *res;
    ethr_thr_wrap_data__ *twd = (ethr_thr_wrap_data__ *) vtwd;
    void *(*thr_func)(void *) = twd->thr_func;
    void *arg = twd->arg;
    ethr_ts_event *tsep = NULL;

    result = (long) ethr_make_ts_event__(&tsep);

    if (result == 0) {
	tsep->iflgs |= ETHR_TS_EV_ETHREAD;
	if (ethr_thr_child_func__)
	    ethr_thr_child_func__(twd->prep_func_res);
    }

    tsep = twd->tse; /* We aren't allowed to follow twd after
			result has been set! */

    ethr_atomic_set(&twd->result, result);

    ethr_event_set(&tsep->event);

    res = result == 0 ? (*thr_func)(arg) : NULL;

    thr_exit_cleanup();
    return res;
}

/* internal exports */

int ethr_set_tse__(ethr_ts_event *tsep)
{
    return pthread_setspecific(ethr_ts_event_key__, (void *) tsep);
}

ethr_ts_event *ethr_get_tse__(void)
{
    return pthread_getspecific(ethr_ts_event_key__);
}

/*
 * --------------------------------------------------------------------------
 * Exported functions
 * --------------------------------------------------------------------------
 */

int
ethr_init(ethr_init_data *id)
{
    int res;

    if (!ethr_not_inited__)
	return EINVAL;

    ethr_not_inited__ = 0;

    res = ethr_init_common__(id);
    if (res != 0)
	goto error;

    child_wait_spin_count = ETHR_CHILD_WAIT_SPIN_COUNT;
    if (erts_get_cpu_configured(ethr_cpu_info__) == 1)
	child_wait_spin_count = 0;

    res = pthread_key_create(&ethr_ts_event_key__, ethr_ts_event_destructor__);

    return 0;
 error:
    ethr_not_inited__ = 1;
    return res;

}

int
ethr_late_init(ethr_late_init_data *id)
{
    int res = ethr_late_init_common__(id);
    if (res != 0)
	return res;
    ethr_not_completely_inited__ = 0;
    return res;
}

int
ethr_thr_create(ethr_tid *tid, void * (*func)(void *), void *arg,
		ethr_thr_opts *opts)
{
    ethr_thr_wrap_data__ twd;
    pthread_attr_t attr;
    int res, dres;
    int use_stack_size = (opts && opts->suggested_stack_size >= 0
			  ? opts->suggested_stack_size
			  : -1 /* Use system default */);

#ifdef ETHR_MODIFIED_DEFAULT_STACK_SIZE
    if (use_stack_size < 0)
	use_stack_size = ETHR_MODIFIED_DEFAULT_STACK_SIZE;
#endif

#if ETHR_XCHK
    if (ethr_not_completely_inited__) {
	ETHR_ASSERT(0);
	return EACCES;
    }
    if (!tid || !func) {
	ETHR_ASSERT(0);
	return EINVAL;
    }
#endif

    ethr_atomic_init(&twd.result, -1);
    twd.tse = ethr_get_ts_event();
    twd.thr_func = func;
    twd.arg = arg;

    res = pthread_attr_init(&attr);
    if (res != 0)
	return res;

    /* Error cleanup needed after this point */

    /* Schedule child thread in system scope (if possible) ... */
    res = pthread_attr_setscope(&attr, PTHREAD_SCOPE_SYSTEM);
    if (res != 0 && res != ENOTSUP)
	goto error;

    if (use_stack_size >= 0) {
	size_t suggested_stack_size = (size_t) use_stack_size;
	size_t stack_size;
#ifdef ETHR_DEBUG
	suggested_stack_size /= 2; /* Make sure we got margin */
#endif
#ifdef ETHR_STACK_GUARD_SIZE
	/* The guard is at least on some platforms included in the stack size
	   passed when creating threads */
	suggested_stack_size += ETHR_B2KW(ETHR_STACK_GUARD_SIZE);
#endif
	if (suggested_stack_size < ethr_min_stack_size__)
	    stack_size = ETHR_KW2B(ethr_min_stack_size__);
	else if (suggested_stack_size > ethr_max_stack_size__)
	    stack_size = ETHR_KW2B(ethr_max_stack_size__);
	else
	    stack_size = ETHR_PAGE_ALIGN(ETHR_KW2B(suggested_stack_size));
	(void) pthread_attr_setstacksize(&attr, stack_size);
    }

#ifdef ETHR_STACK_GUARD_SIZE
    (void) pthread_attr_setguardsize(&attr, ETHR_STACK_GUARD_SIZE);
#endif

    /* Detached or joinable... */
    res = pthread_attr_setdetachstate(&attr,
				      (opts && opts->detached
				       ? PTHREAD_CREATE_DETACHED
				       : PTHREAD_CREATE_JOINABLE));
    if (res != 0)
	goto error;

    /* Call prepare func if it exist */
    if (ethr_thr_prepare_func__)
	twd.prep_func_res = ethr_thr_prepare_func__();
    else
	twd.prep_func_res = NULL;

    res = pthread_create((pthread_t *) tid, &attr, thr_wrapper, (void*) &twd);

    if (res == 0) {
	int spin_count = child_wait_spin_count;

	/* Wait for child to initialize... */
	while (1) {
	    long result;
	    ethr_event_reset(&twd.tse->event);

	    result = ethr_atomic_read(&twd.result);
	    if (result == 0)
		break;

	    if (result > 0) {
		res = (int) result;
		goto error;
	    }

	    res = ethr_event_swait(&twd.tse->event, spin_count);
	    if (res != 0 && res != EINTR)
		goto error;
	    spin_count = 0;
	}
    }

    /* Cleanup... */

 error:
    dres = pthread_attr_destroy(&attr);
    if (res == 0)
	res = dres;
    if (ethr_thr_parent_func__)
	ethr_thr_parent_func__(twd.prep_func_res);
    return res;
}

int
ethr_thr_join(ethr_tid tid, void **res)
{
#if ETHR_XCHK
    if (ethr_not_inited__) {
	ETHR_ASSERT(0);
	return EACCES;
    }
#endif
    return pthread_join((pthread_t) tid, res);
}

int
ethr_thr_detach(ethr_tid tid)
{
#if ETHR_XCHK
    if (ethr_not_inited__) {
	ETHR_ASSERT(0);
	return EACCES;
    }
#endif
    return pthread_detach((pthread_t) tid);
}

void
ethr_thr_exit(void *res)
{
#if ETHR_XCHK
    if (ethr_not_inited__) {
	ETHR_ASSERT(0);
	return;
    }
#endif
    thr_exit_cleanup();
    pthread_exit(res);
}

ethr_tid
ethr_self(void)
{
    return (ethr_tid) pthread_self();
}

int
ethr_equal_tids(ethr_tid tid1, ethr_tid tid2)
{
    return pthread_equal((pthread_t) tid1, (pthread_t) tid2);
}


/*
 * Thread specific events
 */

ethr_ts_event *
ethr_get_ts_event(void)
{
    return ethr_get_ts_event__();
}

void
ethr_leave_ts_event(ethr_ts_event *tsep)
{
    ethr_leave_ts_event__(tsep);
}

/*
 * Current time
 */

int
ethr_time_now(ethr_timeval *time)
{
    int res;
    struct timeval tv;
#if ETHR_XCHK
    if (ethr_not_inited__) {
	ETHR_ASSERT(0);
	return EACCES;
    }
    if (!time) {
	ETHR_ASSERT(0);
	return EINVAL;
    }
#endif

    res = gettimeofday(&tv, NULL);
    time->tv_sec = (long) tv.tv_sec;
    time->tv_nsec = ((long) tv.tv_usec)*1000;
    return res;
}

/*
 * Thread specific data
 */

int
ethr_tsd_key_create(ethr_tsd_key *keyp)
{
#if ETHR_XCHK
    if (ethr_not_inited__) {
	ETHR_ASSERT(0);
	return EACCES;
    }
    if (!keyp) {
	ETHR_ASSERT(0);
	return EINVAL;
    }
#endif
    return pthread_key_create((pthread_key_t *) keyp, NULL);
}

int
ethr_tsd_key_delete(ethr_tsd_key key)
{
#if ETHR_XCHK
    if (ethr_not_inited__) {
	ETHR_ASSERT(0);
	return EACCES;
    }
#endif
    return pthread_key_delete((pthread_key_t) key);
}

int
ethr_tsd_set(ethr_tsd_key key, void *value)
{
#if ETHR_XCHK
    if (ethr_not_inited__) {
	ETHR_ASSERT(0);
	return EACCES;
    }
#endif
    return pthread_setspecific((pthread_key_t) key, value);
}

void *
ethr_tsd_get(ethr_tsd_key key)
{
#if ETHR_XCHK
    if (ethr_not_inited__) {
	ETHR_ASSERT(0);
	return NULL;
    }
#endif
    return pthread_getspecific((pthread_key_t) key);
}

/*
 * Signal functions
 */

#if ETHR_HAVE_ETHR_SIG_FUNCS

int ethr_sigmask(int how, const sigset_t *set, sigset_t *oset)
{
#if ETHR_XCHK
    if (ethr_not_inited__) {
	ETHR_ASSERT(0);
	return EACCES;
    }
    if (!set && !oset) {
	ETHR_ASSERT(0);
	return EINVAL;
    }
#endif
  return pthread_sigmask(how, set, oset);
}

int ethr_sigwait(const sigset_t *set, int *sig)
{
#if ETHR_XCHK
    if (ethr_not_inited__) {
	ETHR_ASSERT(0);
	return EACCES;
    }
    if (!set || !sig) {
	ETHR_ASSERT(0);
	return EINVAL;
    }
#endif
    if (sigwait(set, sig) < 0)
	return errno;
    return 0;
}

#endif /* #if ETHR_HAVE_ETHR_SIG_FUNCS */

ETHR_IMPL_NORETURN__
ethr_abort__(void)
{
    abort();
}
