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

/*-
 * 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>
#if defined(LIBC_SCCS) && !defined(lint)
__RCSID("$NetBSD: citrus_lookup.c,v 1.7 2012/05/04 16:45:05 joerg Exp $");
#endif /* LIBC_SCCS and not lint */

#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <limits.h>
#include <unistd.h>
#include <fcntl.h>
#include <paths.h>
#include <dirent.h>
#include <sys/types.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) {
  int ret;
  struct _region r;
  char path[PATH_MAX];

  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, __UNCONST(p), (size_t)(q - p));
  p = _bcs_skip_ws_len(q, &len);
  if (data)
    _region_init(data, len ? __UNCONST(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, __UNCONST(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 ENOMEM;

  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) {
  int ret;
  struct _citrus_lookup *cl;
  struct _region data;

  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;
}
