/*****************************************************************************

 * error.c: Error handling for libvlc

 *****************************************************************************

 * Copyright (C) 2009 Rémi Denis-Courmont

 *

 * This program is free software; you can redistribute it and/or modify it

 * under the terms of the GNU Lesser General Public License as published by

 * the Free Software Foundation; either version 2.1 of the License, or

 * (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the

 * GNU Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public License

 * along with this program; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.

 *****************************************************************************/

#ifdef HAVE_CONFIG_H

# include "config.h"

#endif

#include "libvlc_internal.h"

#include <stdarg.h>

#include <stdio.h>

#include <assert.h>

#include <vlc/libvlc.h>

static const char oom[] = "Out of memory";

/* TODO: use only one thread-specific key for whole libvlc */

static vlc_threadvar_t context;

static char *get_error (void)

{

    return vlc_threadvar_get (context);

}

static void free_msg (void *msg)

{

    if (msg != oom)

        free (msg);

}

static void free_error (void)

{

    free_msg (get_error ());

}

static vlc_mutex_t lock = VLC_STATIC_MUTEX;

static uintptr_t refs = 0;

void libvlc_threads_init (void)

{

    vlc_mutex_lock (&lock);

    if (refs++ == 0)

        vlc_threadvar_create (&context, free_msg);

    vlc_mutex_unlock (&lock);

}

void libvlc_threads_deinit (void)

{

    vlc_mutex_lock (&lock);

    assert (refs > 0);

    if (--refs == 0)

    {

        free_error ();

        vlc_threadvar_delete (&context);

    }

    vlc_mutex_unlock (&lock);

}

/**

 * Gets a human-readable error message for the last LibVLC error in the calling

 * thread. The resulting string is valid until another error occurs (at least

 * until the next LibVLC call).

 *

 * @return NULL if there was no error, a nul-terminated string otherwise.

 */

const char *libvlc_errmsg (void)

{

    return get_error ();

}

/**

 * Clears the LibVLC error status for the current thread. This is optional.

 * By default, the error status is automatically overridden when a new error

 * occurs, and destroyed when the thread exits.

 */

void libvlc_clearerr (void)

{

    free_error ();

    int ret = vlc_threadvar_set (context, NULL);

    if(unlikely(ret != 0))

        abort();

}

/**

 * Sets the LibVLC error status and message for the current thread.

 * Any previous error is overridden.

 * \param fmt the format string

 * \param ap the arguments

 * \return a nul terminated string in any case

 */

static const char *libvlc_vprinterr (const char *fmt, va_list ap)

{

    char *msg;

    assert (fmt != NULL);

    if (vasprintf (&msg, fmt, ap) == -1)

        msg = (char *)oom;

    free_error ();

    int ret = vlc_threadvar_set (context, msg);

    if(unlikely(ret != 0))

        abort();

    return msg;

}

/**

 * Sets the LibVLC error status and message for the current thread.

 * Any previous error is overridden.

 * @return a nul terminated string (always)

 */

const char *libvlc_printerr (const char *fmt, ...)

{

    va_list ap;

    const char *msg;

    va_start (ap, fmt);

    msg = libvlc_vprinterr (fmt, ap);

    va_end (ap);

    return msg;

}