/*      $NetBSD: gettext_iconv.c,v 1.9 2019/10/24 18:18:00 kamil Exp $  */

/*-
* Copyright (c) 2004 Citrus Project,
* All rights reserved.
*
* 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.
*
* $Citrus$
*/


#include <sys/types.h>
#include <sys/param.h>

#include <errno.h>
#include <iconv.h>
#include <libintl.h>
#include <langinfo.h>
#include <search.h>
#include <stdlib.h>
#include <string.h>

#include "libintl_local.h"

struct cache {
       const char *c_origmsg;
       const char *c_resultmsg;
};

static const struct cache *cache_find(const char *, struct domainbinding *);
static int cache_enter(const char *, const char *);
static int cache_cmp(const void *, const void *);

static void *cacheroot;

/* ARGSUSED1 */
static const struct cache *
cache_find(const char *msg, struct domainbinding *db)
{
       struct cache key;
       struct cache **c;

       key.c_origmsg = msg;
       c = tfind(&key, &cacheroot, cache_cmp);

       return c ? *c : NULL;
}

static int
cache_enter(const char *origmsg, const char *resultmsg)
{
       struct cache *c;

       c = malloc(sizeof(*c));
       if (c == NULL)
               return -1;

       c->c_origmsg = origmsg;
       c->c_resultmsg = resultmsg;

       if (tsearch(c, &cacheroot, cache_cmp) == NULL) {
               free(c);
               return -1;
       }

       return 0;
}

static int
cache_cmp(const void *va, const void *vb)
{
       const struct cache *a = va;
       const struct cache *b = vb;
       int result;

       if (a->c_origmsg > b->c_origmsg) {
               result = 1;
       } else if (a->c_origmsg < b->c_origmsg) {
               result = -1;
       } else {
               result = 0;
       }

       return result;
}

#define GETTEXT_ICONV_MALLOC_CHUNK      (16 * 1024)

const char *
__gettext_iconv(const char *origmsg, struct domainbinding *db)
{
       const char *tocode;
       const char *fromcode = db->mohandle.mo.mo_charset;
       const struct cache *cache;
       const char *result;
       iconv_t cd;
       const char *src;
       char *dst;
       size_t origlen;
       size_t srclen;
       size_t dstlen;
       size_t nvalid;
       int savederrno = errno;

       /*
        * static buffer for converted texts.
        *
        * note:
        * we never free buffers once returned to callers.
        * because of interface design of gettext, we can't know
        * the lifetime of them.
        */
       static char *buffer;
       static size_t bufferlen;

       /*
        * don't convert message if *.mo doesn't specify codeset.
        */
       if (fromcode == NULL)
               return origmsg;

       tocode = db->codeset;
       if (tocode == NULL) {
               /*
                * codeset isn't specified explicitly by
                * bind_textdomain_codeset().
                * use current locale(LC_CTYPE)'s codeset.
                *
                * XXX maybe wrong; it can mismatch with
                * environment variable setting.
                */
               tocode = nl_langinfo(CODESET);
       }

       /*
        * shortcut if possible.
        * XXX should handle aliases
        */
       if (!strcasecmp(tocode, fromcode))
               return origmsg;

       /* XXX LOCK */

       /* XXX should detect change of tocode and purge caches? */

       /*
        * see if we have already converted this message.
        */
       cache = cache_find(origmsg, db);
       if (cache) {
               result = cache->c_resultmsg;
               goto out;
       }

       origlen = strlen(origmsg) + 1;
again:
       cd = iconv_open(tocode, fromcode);
       if (cd == (iconv_t)-1) {
               result = origmsg;
               goto out;
       }

       src = origmsg;
       srclen = origlen;
       dst = buffer;
       dstlen = bufferlen;
       nvalid = iconv(cd, __UNCONST(&src), &srclen, &dst, &dstlen);
       iconv_close(cd);

       if (nvalid == (size_t)-1) {
               /*
                * try to allocate a new buffer.
                *
                * just give up if GETTEXT_ICONV_MALLOC_CHUNK was not enough.
                */
               if (errno == E2BIG &&
                   bufferlen != GETTEXT_ICONV_MALLOC_CHUNK) {
                       buffer = malloc(GETTEXT_ICONV_MALLOC_CHUNK);
                       if (buffer) {
                               bufferlen = GETTEXT_ICONV_MALLOC_CHUNK;
                               goto again;
                       }
               }

               result = origmsg;
       } else if (cache_enter(origmsg, buffer)) {
               /*
                * failed to enter cache.  give up.
                */
               result = origmsg;
       } else {
               size_t resultlen = dst - buffer;

               result = buffer;
               bufferlen -= resultlen;
               buffer += resultlen;
       }

out:
       /* XXX UNLOCK */
       errno = savederrno;

       return result;
}