/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2011 The FreeBSD Foundation
 *
 * This software was developed by David Chisnall under sponsorship from
 * the FreeBSD Foundation.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <pthread.h>
#include <stdio.h>
#include <string.h>
#include <runetype.h>
#include "libc_private.h"
#include "xlocale_private.h"

/**
 * Each locale loader declares a global component.  This is used by setlocale()
 * and also by xlocale with LC_GLOBAL_LOCALE..
 */
extern struct xlocale_component __xlocale_global_collate;
extern struct xlocale_component __xlocale_global_ctype;
extern struct xlocale_component __xlocale_global_monetary;
extern struct xlocale_component __xlocale_global_numeric;
extern struct xlocale_component __xlocale_global_time;
extern struct xlocale_component __xlocale_global_messages;
/*
 * And another version for the statically-allocated C locale.  We only have
 * components for the parts that are expected to be sensible.
 */
extern struct xlocale_component __xlocale_C_collate;
extern struct xlocale_component __xlocale_C_ctype;

/*
 * The locale for this thread.
 */
_Thread_local locale_t __thread_locale;

/*
 * Flag indicating that one or more per-thread locales exist.
 */
int __has_thread_locale;

/*
 * Private functions in setlocale.c.
 */
const char *__get_locale_env(int category);
int __detect_path_locale(void);

struct _xlocale __xlocale_global_locale = {
        {0},
        {
                &__xlocale_global_collate,
                &__xlocale_global_ctype,
                &__xlocale_global_monetary,
                &__xlocale_global_numeric,
                &__xlocale_global_time,
                &__xlocale_global_messages
        },
        1,
        0,
        1,
        0
};

struct _xlocale __xlocale_C_locale = {
        {0},
        {
                &__xlocale_C_collate,
                &__xlocale_C_ctype,
                0, 0, 0, 0
        },
        1,
        0,
        1,
        0
};

static void *(*constructors[])(const char *, locale_t) =
{
        __collate_load,
        __ctype_load,
        __monetary_load,
        __numeric_load,
        __time_load,
        __messages_load
};

static pthread_key_t locale_info_key;
static int fake_tls;
static locale_t thread_local_locale;

static void
init_key(void)
{
        int error;

        error = pthread_key_create(&locale_info_key, xlocale_release);
        if (error == 0) {
                pthread_setspecific(locale_info_key, (void*)42);
                if (pthread_getspecific(locale_info_key) == (void*)42) {
                        pthread_setspecific(locale_info_key, 0);
                } else {
                        fake_tls = 1;
                }
        } else {
                fake_tls = 1;
        }
        /* At least one per-thread locale has now been set. */
        __has_thread_locale = 1;
        __detect_path_locale();
}

static pthread_once_t once_control = PTHREAD_ONCE_INIT;

static locale_t
get_thread_locale(void)
{

        _once(&once_control, init_key);
        
        return (fake_tls ? thread_local_locale :
            pthread_getspecific(locale_info_key));
}

static void
set_thread_locale(locale_t loc)
{
        locale_t l = (loc == LC_GLOBAL_LOCALE) ? 0 : loc;

        _once(&once_control, init_key);
        
        if (NULL != l) {
                xlocale_retain((struct xlocale_refcounted*)l);
        }
        locale_t old = get_thread_locale();
        if ((NULL != old) && (l != old)) {
                xlocale_release((struct xlocale_refcounted*)old);
        }
        if (fake_tls) {
                thread_local_locale = l;
        } else {
                pthread_setspecific(locale_info_key, l);
        }
        __thread_locale = l;
        __set_thread_rune_locale(loc);
}

/**
 * Clean up a locale, once its reference count reaches zero.  This function is
 * called by xlocale_release(), it should not be called directly.
 */
static void
destruct_locale(void *l)
{
        locale_t loc = l;

        for (int type=0 ; type<XLC_LAST ; type++) {
                if (loc->components[type]) {
                        xlocale_release(loc->components[type]);
                }
        }
        if (loc->csym) {
                free(loc->csym);
        }
        free(l);
}

/**
 * Allocates a new, uninitialised, locale.
 */
static locale_t
alloc_locale(void)
{
        locale_t new = calloc(sizeof(struct _xlocale), 1);

        if (new == NULL)
                return (NULL);

        new->header.destructor = destruct_locale;
        new->monetary_locale_changed = 1;
        new->numeric_locale_changed = 1;
        return (new);
}

static void
copyflags(locale_t new, locale_t old)
{
        new->using_monetary_locale = old->using_monetary_locale;
        new->using_numeric_locale = old->using_numeric_locale;
        new->using_time_locale = old->using_time_locale;
        new->using_messages_locale = old->using_messages_locale;
}

static int
dupcomponent(int type, locale_t base, locale_t new)
{
        /* Always copy from the global locale, since it has mutable components.
         */
        struct xlocale_component *src = base->components[type];

        if (&__xlocale_global_locale == base) {
                new->components[type] = constructors[type](src->locale, new);
                if (new->components[type]) {
                        strncpy(new->components[type]->locale, src->locale,
                            ENCODING_LEN);
                        strncpy(new->components[type]->version, src->version,
                            XLOCALE_DEF_VERSION_LEN);
                }
        } else if (base->components[type]) {
                new->components[type] = xlocale_retain(base->components[type]);
        } else {
                /* If the component was NULL, return success - if base is a
                 * valid locale then the flag indicating that this isn't
                 * present should be set.  If it isn't a valid locale, then
                 * we're stuck anyway. */
                return 1;
        }
        return (0 != new->components[type]);
}

/*
 * Public interfaces.  These are the five public functions described by the
 * xlocale interface.  
 */

locale_t
newlocale(int mask, const char *locale, locale_t base)
{
        locale_t orig_base;
        int type;
        const char *realLocale = locale;
        int useenv = 0;
        int success = 1;

        locale_t new = alloc_locale();
        if (NULL == new) {
                return (NULL);
        }

        _once(&once_control, init_key);

        orig_base = base;
        FIX_LOCALE(base);
        copyflags(new, base);

        if (NULL == locale) {
                realLocale = "C";
        } else if ('\0' == locale[0]) {
                useenv = 1;
        }

        for (type=0 ; type<XLC_LAST ; type++) {
                if (mask & 1) {
                        if (useenv) {
                                realLocale = __get_locale_env(type + 1);
                        }
                        new->components[type] =
                             constructors[type](realLocale, new);
                        if (new->components[type]) {
                                strncpy(new->components[type]->locale,
                                     realLocale, ENCODING_LEN);
                        } else {
                                success = 0;
                                break;
                        }
                } else {
                        if (!dupcomponent(type, base, new)) {
                                success = 0;
                                break;
                        }
                }
                mask >>= 1;
        }
        if (0 == success) {
                xlocale_release(new);
                new = NULL;
        } else if (base == orig_base) {
                xlocale_release(base);
        }

        return (new);
}

locale_t
duplocale(locale_t base)
{
        locale_t new = alloc_locale();
        int type;

        if (NULL == new) {
                return (NULL);
        }
        
        _once(&once_control, init_key);

        FIX_LOCALE(base);
        copyflags(new, base);

        for (type=0 ; type<XLC_LAST ; type++) {
                dupcomponent(type, base, new);
        }

        return (new);
}

/*
 * Free a locale_t.  This is quite a poorly named function.  It actually
 * disclaims a reference to a locale_t, rather than freeing it.  
 */
void
freelocale(locale_t loc)
{

        /*
         * Fail if we're passed something that isn't a locale. If we're
         * passed the global locale, pretend that we freed it but don't
         * actually do anything.
         */
        if (loc != NULL && loc != LC_GLOBAL_LOCALE &&
            loc != &__xlocale_global_locale)
                xlocale_release(loc);
}

/*
 * Returns the name or version of the locale for a particular component of a
 * locale_t.
 */
const char *
querylocale(int mask, locale_t loc)
{
        int type = ffs(mask & ~LC_VERSION_MASK) - 1;
        FIX_LOCALE(loc);
        if (type >= XLC_LAST)
                return (NULL);
        if (mask & LC_VERSION_MASK) {
                if (loc->components[type])
                        return (loc->components[type]->version);
                return ("");
        } else {
                if (loc->components[type])
                        return (loc->components[type]->locale);
                return ("C");
        }
}

/*
 * Installs the specified locale_t as this thread's locale.
 */
locale_t
uselocale(locale_t loc)
{
        locale_t old = get_thread_locale();
        if (NULL != loc) {
                set_thread_locale(loc);
        }
        return (old ? old : LC_GLOBAL_LOCALE);
}