/*      $NetBSD: citrus_lookup.c,v 1.7 2012/05/04 16:45:05 joerg Exp $  */

/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c)2003 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.
 */

#include <sys/types.h>

#include <assert.h>
#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <paths.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "citrus_namespace.h"
#include "citrus_bcs.h"
#include "citrus_region.h"
#include "citrus_memstream.h"
#include "citrus_mmap.h"
#include "citrus_db.h"
#include "citrus_db_hash.h"
#include "citrus_lookup.h"
#include "citrus_lookup_file.h"

struct _citrus_lookup {
        union {
                struct {
                        struct _citrus_db *db;
                        struct _citrus_region file;
                        int num, idx;
                        struct _db_locator locator;
                } db;
                struct {
                        struct _region r;
                        struct _memstream ms;
                } plain;
        } u;
#define cl_db           u.db.db
#define cl_dbidx        u.db.idx
#define cl_dbfile       u.db.file
#define cl_dbnum        u.db.num
#define cl_dblocator    u.db.locator
#define cl_plainr       u.plain.r
#define cl_plainms      u.plain.ms
        int cl_ignore_case;
        int cl_rewind;
        char *cl_key;
        size_t cl_keylen;
        int (*cl_next)(struct _citrus_lookup *, struct _region *,
                       struct _region *);
        int (*cl_lookup)(struct _citrus_lookup *, const char *,
                         struct _region *);
        int (*cl_num_entries)(struct _citrus_lookup *);
        void (*cl_close)(struct _citrus_lookup *);
};

static int
seq_get_num_entries_db(struct _citrus_lookup *cl)
{

        return (cl->cl_dbnum);
}

static int
seq_next_db(struct _citrus_lookup *cl, struct _region *key,
    struct _region *data)
{

        if (cl->cl_key) {
                if (key)
                        _region_init(key, cl->cl_key, cl->cl_keylen);
                return (_db_lookup_by_s(cl->cl_db, cl->cl_key, data,
                    &cl->cl_dblocator));
        }

        if (cl->cl_rewind) {
                cl->cl_dbidx = 0;
        }
        cl->cl_rewind = 0;
        if (cl->cl_dbidx >= cl->cl_dbnum)
                return (ENOENT);

        return (_db_get_entry(cl->cl_db, cl->cl_dbidx++, key, data));
}

static int
seq_lookup_db(struct _citrus_lookup *cl, const char *key, struct _region *data)
{

        cl->cl_rewind = 0;
        free(cl->cl_key);
        cl->cl_key = strdup(key);
        if (cl->cl_ignore_case)
                _bcs_convert_to_lower(cl->cl_key);
        cl->cl_keylen = strlen(cl->cl_key);
        _db_locator_init(&cl->cl_dblocator);
        return (_db_lookup_by_s(cl->cl_db, cl->cl_key, data,
            &cl->cl_dblocator));
}

static void
seq_close_db(struct _citrus_lookup *cl)
{

        _db_close(cl->cl_db);
        _unmap_file(&cl->cl_dbfile);
}

static int
seq_open_db(struct _citrus_lookup *cl, const char *name)
{
        struct _region r;
        char path[PATH_MAX];
        int ret;

        snprintf(path, sizeof(path), "%s.db", name);
        ret = _map_file(&r, path);
        if (ret)
                return (ret);

        ret = _db_open(&cl->cl_db, &r, _CITRUS_LOOKUP_MAGIC,
            _db_hash_std, NULL);
        if (ret) {
                _unmap_file(&r);
                return (ret);
        }

        cl->cl_dbfile = r;
        cl->cl_dbnum = _db_get_num_entries(cl->cl_db);
        cl->cl_dbidx = 0;
        cl->cl_rewind = 1;
        cl->cl_lookup = &seq_lookup_db;
        cl->cl_next = &seq_next_db;
        cl->cl_num_entries = &seq_get_num_entries_db;
        cl->cl_close = &seq_close_db;

        return (0);
}

#define T_COMM '#'
static int
seq_next_plain(struct _citrus_lookup *cl, struct _region *key,
               struct _region *data)
{
        const char *p, *q;
        size_t len;

        if (cl->cl_rewind)
                _memstream_bind(&cl->cl_plainms, &cl->cl_plainr);
        cl->cl_rewind = 0;

retry:
        p = _memstream_getln(&cl->cl_plainms, &len);
        if (p == NULL)
                return (ENOENT);
        /* ignore comment */
        q = memchr(p, T_COMM, len);
        if (q) {
                len = q - p;
        }
        /* ignore trailing spaces */
        _bcs_trunc_rws_len(p, &len);
        p = _bcs_skip_ws_len(p, &len);
        q = _bcs_skip_nonws_len(p, &len);
        if (p == q)
                goto retry;
        if (cl->cl_key && ((size_t)(q - p) != cl->cl_keylen ||
            memcmp(p, cl->cl_key, (size_t)(q - p)) != 0))
                goto retry;

        /* found a entry */
        if (key)
                _region_init(key, __DECONST(void *, p), (size_t)(q - p));
        p = _bcs_skip_ws_len(q, &len);
        if (data)
                _region_init(data, len ? __DECONST(void *, p) : NULL, len);

        return (0);
}

static int
seq_get_num_entries_plain(struct _citrus_lookup *cl)
{
        int num;

        num = 0;
        while (seq_next_plain(cl, NULL, NULL) == 0)
                num++;

        return (num);
}

static int
seq_lookup_plain(struct _citrus_lookup *cl, const char *key,
    struct _region *data)
{
        size_t len;
        const char *p;

        cl->cl_rewind = 0;
        free(cl->cl_key);
        cl->cl_key = strdup(key);
        if (cl->cl_ignore_case)
                _bcs_convert_to_lower(cl->cl_key);
        cl->cl_keylen = strlen(cl->cl_key);
        _memstream_bind(&cl->cl_plainms, &cl->cl_plainr);
        p = _memstream_matchline(&cl->cl_plainms, cl->cl_key, &len, 0);
        if (p == NULL)
                return (ENOENT);
        if (data)
                _region_init(data, __DECONST(void *, p), len);

        return (0);
}

static void
seq_close_plain(struct _citrus_lookup *cl)
{

        _unmap_file(&cl->cl_plainr);
}

static int
seq_open_plain(struct _citrus_lookup *cl, const char *name)
{
        int ret;

        /* open read stream */
        ret = _map_file(&cl->cl_plainr, name);
        if (ret)
                return (ret);

        cl->cl_rewind = 1;
        cl->cl_next = &seq_next_plain;
        cl->cl_lookup = &seq_lookup_plain;
        cl->cl_num_entries = &seq_get_num_entries_plain;
        cl->cl_close = &seq_close_plain;

        return (0);
}

int
_citrus_lookup_seq_open(struct _citrus_lookup **rcl, const char *name,
    int ignore_case)
{
        int ret;
        struct _citrus_lookup *cl;

        cl = malloc(sizeof(*cl));
        if (cl == NULL)
                return (errno);

        cl->cl_key = NULL;
        cl->cl_keylen = 0;
        cl->cl_ignore_case = ignore_case;
        ret = seq_open_db(cl, name);
        if (ret == ENOENT)
                ret = seq_open_plain(cl, name);
        if (!ret)
                *rcl = cl;
        else
                free(cl);

        return (ret);
}

void
_citrus_lookup_seq_rewind(struct _citrus_lookup *cl)
{

        cl->cl_rewind = 1;
        free(cl->cl_key);
        cl->cl_key = NULL;
        cl->cl_keylen = 0;
}

int
_citrus_lookup_seq_next(struct _citrus_lookup *cl,
    struct _region *key, struct _region *data)
{

        return ((*cl->cl_next)(cl, key, data));
}

int
_citrus_lookup_seq_lookup(struct _citrus_lookup *cl, const char *key,
    struct _region *data)
{

        return ((*cl->cl_lookup)(cl, key, data));
}

int
_citrus_lookup_get_number_of_entries(struct _citrus_lookup *cl)
{

        return ((*cl->cl_num_entries)(cl));
}

void
_citrus_lookup_seq_close(struct _citrus_lookup *cl)
{

        free(cl->cl_key);
        (*cl->cl_close)(cl);
        free(cl);
}

char *
_citrus_lookup_simple(const char *name, const char *key,
    char *linebuf, size_t linebufsize, int ignore_case)
{
        struct _citrus_lookup *cl;
        struct _region data;
        int ret;

        ret = _citrus_lookup_seq_open(&cl, name, ignore_case);
        if (ret)
                return (NULL);

        ret = _citrus_lookup_seq_lookup(cl, key, &data);
        if (ret) {
                _citrus_lookup_seq_close(cl);
                return (NULL);
        }

        snprintf(linebuf, linebufsize, "%.*s", (int)_region_size(&data),
            (const char *)_region_head(&data));

        _citrus_lookup_seq_close(cl);

        return (linebuf);
}