lib/ntdb/traverse.c

   1  /*
   2    Trivial Database 2: traverse function.
   3    Copyright (C) Rusty Russell 2010
   4
   5    This library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 3 of the License, or (at your option) any later version.
   9
  10    This library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with this library; if not, see <http://www.gnu.org/licenses/>.
  17 */
  18 #include "private.h"
  19 #include <ccan/likely/likely.h>
  20
  21 _PUBLIC_ int64_t ntdb_traverse_(struct ntdb_context *ntdb,
  22                       int (*fn)(struct ntdb_context *,
  23                                 NTDB_DATA, NTDB_DATA, void *),
  24                       void *p)
  25 {
  26         enum NTDB_ERROR ecode;
  27         struct traverse_info tinfo;
  28         NTDB_DATA k, d;
  29         int64_t count = 0;
  30
  31         k.dptr = NULL;
  32         for (ecode = first_in_hash(ntdb, &tinfo, &k, &d.dsize);
  33              ecode == NTDB_SUCCESS;
  34              ecode = next_in_hash(ntdb, &tinfo, &k, &d.dsize)) {
  35                 d.dptr = k.dptr + k.dsize;
  36
  37                 count++;
  38                 if (fn && fn(ntdb, k, d, p)) {
  39                         ntdb->free_fn(k.dptr, ntdb->alloc_data);
  40                         return count;
  41                 }
  42                 ntdb->free_fn(k.dptr, ntdb->alloc_data);
  43         }
  44
  45         if (ecode != NTDB_ERR_NOEXIST) {
  46                 return NTDB_ERR_TO_OFF(ecode);
  47         }
  48         return count;
  49 }
  50
  51 _PUBLIC_ enum NTDB_ERROR ntdb_firstkey(struct ntdb_context *ntdb, NTDB_DATA *key)
  52 {
  53         struct traverse_info tinfo;
  54
  55         return first_in_hash(ntdb, &tinfo, key, NULL);
  56 }
  57
  58 /* We lock twice, not very efficient.  We could keep last key & tinfo cached. */
  59 _PUBLIC_ enum NTDB_ERROR ntdb_nextkey(struct ntdb_context *ntdb, NTDB_DATA *key)
  60 {
  61         struct traverse_info tinfo;
  62         struct hash_info h;
  63         struct ntdb_used_record rec;
  64
  65         tinfo.prev = find_and_lock(ntdb, *key, F_RDLCK, &h, &rec, &tinfo);
  66         ntdb->free_fn(key->dptr, ntdb->alloc_data);
  67         if (NTDB_OFF_IS_ERR(tinfo.prev)) {
  68                 return NTDB_OFF_TO_ERR(tinfo.prev);
  69         }
  70         ntdb_unlock_hashes(ntdb, h.hlock_start, h.hlock_range, F_RDLCK);
  71
  72         return next_in_hash(ntdb, &tinfo, key, NULL);
  73 }
  74
  75 static int wipe_one(struct ntdb_context *ntdb,
  76                     NTDB_DATA key, NTDB_DATA data, enum NTDB_ERROR *ecode)
  77 {
  78         *ecode = ntdb_delete(ntdb, key);
  79         return (*ecode != NTDB_SUCCESS);
  80 }
  81
  82 _PUBLIC_ enum NTDB_ERROR ntdb_wipe_all(struct ntdb_context *ntdb)
  83 {
  84         enum NTDB_ERROR ecode;
  85         int64_t count;
  86
  87         ecode = ntdb_allrecord_lock(ntdb, F_WRLCK, NTDB_LOCK_WAIT, false);
  88         if (ecode != NTDB_SUCCESS)
  89                 return ecode;
  90
  91         /* FIXME: Be smarter. */
  92         count = ntdb_traverse(ntdb, wipe_one, &ecode);
  93         if (count < 0)
  94                 ecode = NTDB_OFF_TO_ERR(count);
  95         ntdb_allrecord_unlock(ntdb, F_WRLCK);
  96         return ecode;
  97 }