lib/tdb2/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 int64_t tdb_traverse_(struct tdb_context *tdb,
  22                       int (*fn)(struct tdb_context *,
  23                                 TDB_DATA, TDB_DATA, void *),
  24                       void *p)
  25 {
  26         enum TDB_ERROR ecode;
  27         struct traverse_info tinfo;
  28         struct tdb_data k, d;
  29         int64_t count = 0;
  30
  31         k.dptr = NULL;
  32         for (ecode = first_in_hash(tdb, &tinfo, &k, &d.dsize);
  33              ecode == TDB_SUCCESS;
  34              ecode = next_in_hash(tdb, &tinfo, &k, &d.dsize)) {
  35                 d.dptr = k.dptr + k.dsize;
  36
  37                 count++;
  38                 if (fn && fn(tdb, k, d, p)) {
  39                         free(k.dptr);
  40                         tdb->last_error = TDB_SUCCESS;
  41                         return count;
  42                 }
  43                 free(k.dptr);
  44         }
  45
  46         if (ecode != TDB_ERR_NOEXIST) {
  47                 return tdb->last_error = ecode;
  48         }
  49         tdb->last_error = TDB_SUCCESS;
  50         return count;
  51 }
  52
  53 enum TDB_ERROR tdb_firstkey(struct tdb_context *tdb, struct tdb_data *key)
  54 {
  55         struct traverse_info tinfo;
  56
  57         return tdb->last_error = first_in_hash(tdb, &tinfo, key, NULL);
  58 }
  59
  60 /* We lock twice, not very efficient.  We could keep last key & tinfo cached. */
  61 enum TDB_ERROR tdb_nextkey(struct tdb_context *tdb, struct tdb_data *key)
  62 {
  63         struct traverse_info tinfo;
  64         struct hash_info h;
  65         struct tdb_used_record rec;
  66
  67         tinfo.prev = find_and_lock(tdb, *key, F_RDLCK, &h, &rec, &tinfo);
  68         free(key->dptr);
  69         if (TDB_OFF_IS_ERR(tinfo.prev)) {
  70                 return tdb->last_error = tinfo.prev;
  71         }
  72         tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_RDLCK);
  73
  74         return tdb->last_error = next_in_hash(tdb, &tinfo, key, NULL);
  75 }
  76
  77 static int wipe_one(struct tdb_context *tdb,
  78                     TDB_DATA key, TDB_DATA data, enum TDB_ERROR *ecode)
  79 {
  80         *ecode = tdb_delete(tdb, key);
  81         return (*ecode != TDB_SUCCESS);
  82 }
  83
  84 enum TDB_ERROR tdb_wipe_all(struct tdb_context *tdb)
  85 {
  86         enum TDB_ERROR ecode;
  87         int64_t count;
  88
  89         ecode = tdb_allrecord_lock(tdb, F_WRLCK, TDB_LOCK_WAIT, false);
  90         if (ecode != TDB_SUCCESS)
  91                 return tdb->last_error = ecode;
  92
  93         /* FIXME: Be smarter. */
  94         count = tdb_traverse(tdb, wipe_one, &ecode);
  95         if (count < 0)
  96                 ecode = count;
  97         tdb_allrecord_unlock(tdb, F_WRLCK);
  98         return tdb->last_error = ecode;
  99 }