/*	$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/cdefs.h>
#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);
}