+ /*
+ 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 <http://www.gnu.org/licenses/>.
+*/
+#include "private.h"
+#include <ccan/likely/likely.h>
+
+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;
+}