/*
Trivial Database 2: traverse function.
Copyright (C) Rusty Russell 2010
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 3 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, see .
*/
#include "private.h"
#include
static int64_t traverse(struct tdb_context *tdb, int ltype,
tdb_traverse_func fn, void *p)
{
uint64_t i, num, count = 0;
tdb_off_t off, prev_bucket;
struct tdb_used_record rec;
struct tdb_data k, d;
bool finish = false;
/* FIXME: Do we need to start at 0? */
prev_bucket = tdb_lock_list(tdb, 0, ltype, TDB_LOCK_WAIT);
if (prev_bucket != 0)
return -1;
num = (1ULL << tdb->header.v.hash_bits);
for (i = tdb_find_nonzero_off(tdb, hash_off(tdb, 0), num);
i != num && !finish;
i += tdb_find_nonzero_off(tdb, hash_off(tdb, i), num - i)) {
if (tdb_lock_list(tdb, i, ltype, TDB_LOCK_WAIT) != i)
goto fail;
off = tdb_read_off(tdb, hash_off(tdb, i));
if (off == TDB_OFF_ERR) {
tdb_unlock_list(tdb, i, ltype);
goto fail;
}
/* This race can happen, but look again. */
if (off == 0) {
tdb_unlock_list(tdb, i, ltype);
continue;
}
/* Drop previous lock. */
tdb_unlock_list(tdb, prev_bucket, ltype);
prev_bucket = i;
if (tdb_read_convert(tdb, off, &rec, sizeof(rec)) != 0)
goto fail;
k.dsize = rec_key_length(&rec);
d.dsize = rec_data_length(&rec);
if (ltype == F_RDLCK) {
/* Read traverses can keep the lock. */
k.dptr = (void *)tdb_access_read(tdb,
off + sizeof(rec),
k.dsize + d.dsize,
false);
} else {
k.dptr = tdb_alloc_read(tdb, off + sizeof(rec),
k.dsize + d.dsize);
}
if (!k.dptr)
goto fail;
d.dptr = k.dptr + k.dsize;
count++;
if (ltype == F_WRLCK) {
/* Drop lock before calling out. */
tdb_unlock_list(tdb, i, ltype);
}
if (fn && fn(tdb, k, d, p))
finish = true;
if (ltype == F_WRLCK) {
free(k.dptr);
/* Regain lock. FIXME: Is this necessary? */
if (tdb_lock_list(tdb, i, ltype, TDB_LOCK_WAIT) != i)
return -1;
/* This makes deleting under ourselves a bit nicer. */
if (tdb_read_off(tdb, hash_off(tdb, i)) == off)
i++;
} else {
tdb_access_release(tdb, k.dptr);
i++;
}
}
/* Drop final lock. */
tdb_unlock_list(tdb, prev_bucket, ltype);
return count;
fail:
tdb_unlock_list(tdb, prev_bucket, ltype);
return -1;
}
int64_t tdb_traverse(struct tdb_context *tdb, tdb_traverse_func fn, void *p)
{
return traverse(tdb, F_WRLCK, fn, p);
}
int64_t tdb_traverse_read(struct tdb_context *tdb,
tdb_traverse_func fn, void *p)
{
int64_t ret;
bool was_ro = tdb->read_only;
tdb->read_only = true;
ret = traverse(tdb, F_RDLCK, fn, p);
tdb->read_only = was_ro;
return ret;
}