tdb2: implement tdb_firstkey/tdb_nextkey.

ccan/tdb2/hash.c

@@ -131,14 +131,15 @@ bool is_subhash(tdb_off_t val)
 
 /* This is the core routine which searches the hashtable for an entry.
  * On error, no locks are held and TDB_OFF_ERR is returned.
- * Otherwise, hinfo is filled in.
+ * Otherwise, hinfo is filled in (and the optional tinfo).
  * If not found, the return value is 0.
  * If found, the return value is the offset, and *rec is the record. */
 tdb_off_t find_and_lock(struct tdb_context *tdb,
 			struct tdb_data key,
 			int ltype,
 			struct hash_info *h,
-			struct tdb_used_record *rec)
+			struct tdb_used_record *rec,
+			struct traverse_info *tinfo)
 {
 	uint32_t i, group;
 	tdb_off_t hashtable;
@@ -158,6 +159,14 @@ tdb_off_t find_and_lock(struct tdb_context *tdb,
 		return TDB_OFF_ERR;
 
 	hashtable = offsetof(struct tdb_header, hashtable);
+	if (tinfo) {
+		tinfo->toplevel_group = group;
+		tinfo->num_levels = 1;
+		tinfo->levels[0].entry = 0;
+		tinfo->levels[0].hashtable = hashtable 
+			+ (group << TDB_HASH_GROUP_BITS) * sizeof(tdb_off_t);
+		tinfo->levels[0].total_buckets = 1 << TDB_HASH_GROUP_BITS;
+	}
 
 	while (likely(h->hash_used < 64)) {
 		/* Read in the hash group. */
@@ -172,9 +181,23 @@ tdb_off_t find_and_lock(struct tdb_context *tdb,
 		if (is_subhash(h->group[h->home_bucket])) {
 			hashtable = (h->group[h->home_bucket] & TDB_OFF_MASK)
 				+ sizeof(struct tdb_used_record);
+			if (tinfo) {
+				/* When we come back, use *next* bucket */
+				tinfo->levels[tinfo->num_levels-1].entry
+					+= h->home_bucket + 1;
+			}
 			group = use_bits(h, TDB_SUBLEVEL_HASH_BITS
 					 - TDB_HASH_GROUP_BITS);
 			h->home_bucket = use_bits(h, TDB_HASH_GROUP_BITS);
+			if (tinfo) {
+				tinfo->levels[tinfo->num_levels].hashtable
+					= hashtable;
+				tinfo->levels[tinfo->num_levels].total_buckets
+					= 1 << TDB_SUBLEVEL_HASH_BITS;
+				tinfo->levels[tinfo->num_levels].entry
+					= group << TDB_HASH_GROUP_BITS;
+				tinfo->num_levels++;
+			}
 			continue;
 		}
 
@@ -189,8 +212,14 @@ tdb_off_t find_and_lock(struct tdb_context *tdb,
 			if (!h->group[h->found_bucket])
 				break;
 
-			if (match(tdb, h, &key, h->group[h->found_bucket], rec))
+			if (match(tdb, h, &key, h->group[h->found_bucket],
+				  rec)) {
+				if (tinfo) {
+					tinfo->levels[tinfo->num_levels-1].entry
+						+= h->found_bucket;
+				}
 				return h->group[h->found_bucket] & TDB_OFF_MASK;
+			}
 		}
 		/* Didn't find it: h indicates where it would go. */
 		return 0;
@@ -470,17 +499,18 @@ again:
 		if (unlikely(val == TDB_OFF_ERR))
 			return TDB_OFF_ERR;
 
+		off = val & TDB_OFF_MASK;
+
 		/* This makes the delete-all-in-traverse case work
 		 * (and simplifies our logic a little). */
-		if (val == tinfo->prev)
+		if (off == tinfo->prev)
 			continue;
 
 		tlevel->entry = i;
-		off = val & TDB_OFF_MASK;
 
 		if (!is_subhash(val)) {
 			/* Found one. */
-			tinfo->prev = val;
+			tinfo->prev = off;
 			return off;
 		}
 
@@ -572,3 +602,41 @@ int first_in_hash(struct tdb_context *tdb, int ltype,
 
 	return next_in_hash(tdb, ltype, tinfo, kbuf, dlen);
 }
+
+TDB_DATA tdb_firstkey(struct tdb_context *tdb)
+{
+	struct traverse_info tinfo;
+	struct tdb_data k;
+	switch (first_in_hash(tdb, F_RDLCK, &tinfo, &k, NULL)) {
+	case 1:
+		return k;
+	case 0:
+		tdb->ecode = TDB_SUCCESS;
+		/* Fall thru... */
+	default:
+		return tdb_null;
+	}
+}		
+
+/* We lock twice, not very efficient.  We could keep last key & tinfo cached. */
+TDB_DATA tdb_nextkey(struct tdb_context *tdb, TDB_DATA key)
+{
+	struct traverse_info tinfo;
+	struct hash_info h;
+	struct tdb_used_record rec;
+
+	tinfo.prev = find_and_lock(tdb, key, F_RDLCK, &h, &rec, &tinfo);
+	if (unlikely(tinfo.prev == TDB_OFF_ERR))
+		return tdb_null;
+	tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_RDLCK);
+
+	switch (next_in_hash(tdb, F_RDLCK, &tinfo, &key, NULL)) {
+	case 1:
+		return key;
+	case 0:
+		tdb->ecode = TDB_SUCCESS;
+		/* Fall thru... */
+	default:
+		return tdb_null;
+	}
+}		

ccan/tdb2/private.h

@@ -349,7 +349,8 @@ tdb_off_t find_and_lock(struct tdb_context *tdb,
 			struct tdb_data key,
 			int ltype,
 			struct hash_info *h,
-			struct tdb_used_record *rec);
+			struct tdb_used_record *rec,
+			struct traverse_info *tinfo);
 
 int replace_in_hash(struct tdb_context *tdb,
 		    struct hash_info *h,

ccan/tdb2/tdb.c

@@ -432,7 +432,7 @@ int tdb_store(struct tdb_context *tdb,
 	struct tdb_used_record rec;
 	int ret;
 
-	off = find_and_lock(tdb, key, F_WRLCK, &h, &rec);
+	off = find_and_lock(tdb, key, F_WRLCK, &h, &rec, NULL);
 	if (unlikely(off == TDB_OFF_ERR))
 		return -1;
 
@@ -494,7 +494,7 @@ int tdb_append(struct tdb_context *tdb,
 	struct tdb_data new_dbuf;
 	int ret;
 
-	off = find_and_lock(tdb, key, F_WRLCK, &h, &rec);
+	off = find_and_lock(tdb, key, F_WRLCK, &h, &rec, NULL);
 	if (unlikely(off == TDB_OFF_ERR))
 		return -1;
 
@@ -562,7 +562,7 @@ struct tdb_data tdb_fetch(struct tdb_context *tdb, struct tdb_data key)
 	struct hash_info h;
 	struct tdb_data ret;
 
-	off = find_and_lock(tdb, key, F_RDLCK, &h, &rec);
+	off = find_and_lock(tdb, key, F_RDLCK, &h, &rec, NULL);
 	if (unlikely(off == TDB_OFF_ERR))
 		return tdb_null;
 
@@ -585,7 +585,7 @@ int tdb_delete(struct tdb_context *tdb, struct tdb_data key)
 	struct tdb_used_record rec;
 	struct hash_info h;
 
-	off = find_and_lock(tdb, key, F_WRLCK, &h, &rec);
+	off = find_and_lock(tdb, key, F_WRLCK, &h, &rec, NULL);
 	if (unlikely(off == TDB_OFF_ERR))
 		return -1;
 

ccan/tdb2/test/run-04-basichash.c

@@ -45,7 +45,7 @@ int main(int argc, char *argv[])
 
 		v = 0;
 		/* Should not find it. */
-		ok1(find_and_lock(tdb, key, F_WRLCK, &h, &rec) == 0);
+		ok1(find_and_lock(tdb, key, F_WRLCK, &h, &rec, NULL) == 0);
 		/* Should have created correct hash. */
 		ok1(h.h == tdb_hash(tdb, key.dptr, key.dsize));
 		/* Should have located space in group 0, bucket 0. */
@@ -84,7 +84,8 @@ int main(int argc, char *argv[])
 		ok1(tdb_check(tdb, NULL, NULL) == 0);
 
 		/* Now, this should give a successful lookup. */
-		ok1(find_and_lock(tdb, key, F_WRLCK, &h, &rec) == new_off);
+		ok1(find_and_lock(tdb, key, F_WRLCK, &h, &rec, NULL)
+		    == new_off);
 		/* Should have created correct hash. */
 		ok1(h.h == tdb_hash(tdb, key.dptr, key.dsize));
 		/* Should have located space in group 0, bucket 0. */
@@ -110,7 +111,7 @@ int main(int argc, char *argv[])
 
 		/* Test expansion. */
 		v = 1;
-		ok1(find_and_lock(tdb, key, F_WRLCK, &h, &rec) == 0);
+		ok1(find_and_lock(tdb, key, F_WRLCK, &h, &rec, NULL) == 0);
 		/* Should have created correct hash. */
 		ok1(h.h == tdb_hash(tdb, key.dptr, key.dsize));
 		/* Should have located space in group 0, bucket 1. */
@@ -146,7 +147,8 @@ int main(int argc, char *argv[])
 
 		/* Should be able to find it. */
 		v = 0;
-		ok1(find_and_lock(tdb, key, F_WRLCK, &h, &rec) == new_off);
+		ok1(find_and_lock(tdb, key, F_WRLCK, &h, &rec, NULL)
+		    == new_off);
 		/* Should have created correct hash. */
 		ok1(h.h == tdb_hash(tdb, key.dptr, key.dsize));
 		/* Should have located space in expanded group 0, bucket 0. */
@@ -178,7 +180,7 @@ int main(int argc, char *argv[])
 
 		/* Test second-level expansion: should expand 0th bucket. */
 		v = 0;
-		ok1(find_and_lock(tdb, key, F_WRLCK, &h, &rec) == 0);
+		ok1(find_and_lock(tdb, key, F_WRLCK, &h, &rec, NULL) == 0);
 		/* Should have created correct hash. */
 		ok1(h.h == tdb_hash(tdb, key.dptr, key.dsize));
 		/* Should have located space in group 0, bucket 0. */
@@ -210,7 +212,7 @@ int main(int argc, char *argv[])
 		/* Should be happy with expansion. */
 		ok1(tdb_check(tdb, NULL, NULL) == 0);
 
-		ok1(find_and_lock(tdb, key, F_WRLCK, &h, &rec) == 0);
+		ok1(find_and_lock(tdb, key, F_WRLCK, &h, &rec, NULL) == 0);
 		/* Should have created correct hash. */
 		ok1(h.h == tdb_hash(tdb, key.dptr, key.dsize));
 		/* Should have located space in group 0, bucket 0. */
@@ -241,7 +243,8 @@ int main(int argc, char *argv[])
 
 		/* Should be able to find it. */
 		v = 0;
-		ok1(find_and_lock(tdb, key, F_WRLCK, &h, &rec) == new_off);
+		ok1(find_and_lock(tdb, key, F_WRLCK, &h, &rec, NULL)
+		    == new_off);
 		/* Should have created correct hash. */
 		ok1(h.h == tdb_hash(tdb, key.dptr, key.dsize));
 		/* Should have located space in expanded group 0, bucket 0. */

ccan/tdb2/test/run-20-growhash.c

@@ -76,7 +76,7 @@ int main(int argc, char *argv[])
 
 		/* Check first still exists. */
 		kdata = make_key(0, 0, 0, 0, 0, 0);
-		ok1(find_and_lock(tdb, key, F_RDLCK, &h, &rec) != 0);
+		ok1(find_and_lock(tdb, key, F_RDLCK, &h, &rec, NULL) != 0);
 		/* Should have created correct hash. */
 		ok1(h.h == tdb_hash(tdb, key.dptr, key.dsize));
 		/* Should have located space in group 0, bucket 0. */
@@ -98,7 +98,7 @@ int main(int argc, char *argv[])
 			ok1(tdb_store(tdb, key, dbuf, TDB_INSERT) == 0);
 			ok1(tdb_check(tdb, NULL, NULL) == 0);
 
-			ok1(find_and_lock(tdb, key, F_RDLCK, &h, &rec) != 0);
+			ok1(find_and_lock(tdb, key, F_RDLCK, &h, &rec, NULL));
 			/* Should have created correct hash. */
 			ok1(h.h == tdb_hash(tdb, key.dptr, key.dsize));
 			/* Should have moved to subhash */
@@ -122,7 +122,7 @@ int main(int argc, char *argv[])
 			ok1(tdb_store(tdb, key, dbuf, TDB_INSERT) == 0);
 			ok1(tdb_check(tdb, NULL, NULL) == 0);
 
-			ok1(find_and_lock(tdb, key, F_RDLCK, &h, &rec) != 0);
+			ok1(find_and_lock(tdb, key, F_RDLCK, &h, &rec, NULL));
 			/* Should have created correct hash. */
 			ok1(h.h == tdb_hash(tdb, key.dptr, key.dsize));
 			/* Should have moved to subhash */

ccan/tdb2/test/run-firstkey-nextkey.c

@@ -0,0 +1,149 @@
+#include <ccan/tdb2/tdb.c>
+#include <ccan/tdb2/free.c>
+#include <ccan/tdb2/lock.c>
+#include <ccan/tdb2/io.c>
+#include <ccan/tdb2/hash.c>
+#include <ccan/tdb2/check.c>
+#include <ccan/tdb2/traverse.c>
+#include <ccan/tap/tap.h>
+#include "logging.h"
+
+#define NUM_RECORDS 1000
+
+static bool store_records(struct tdb_context *tdb)
+{
+	int i;
+	struct tdb_data key = { (unsigned char *)&i, sizeof(i) };
+	struct tdb_data data = { (unsigned char *)&i, sizeof(i) };
+
+	for (i = 0; i < NUM_RECORDS; i++)
+		if (tdb_store(tdb, key, data, TDB_REPLACE) != 0)
+			return false;
+	return true;
+}
+
+struct trav_data {
+	unsigned int records[NUM_RECORDS];
+	unsigned int calls;
+};
+
+static int trav(struct tdb_context *tdb, TDB_DATA key, TDB_DATA dbuf, void *p)
+{
+	struct trav_data *td = p;
+	int val;
+
+	memcpy(&val, dbuf.dptr, dbuf.dsize);
+	td->records[td->calls++] = val;
+	return 0;
+}
+
+int main(int argc, char *argv[])
+{
+	unsigned int i, j;
+	int num;
+	struct trav_data td;
+	TDB_DATA k, k2;
+	struct tdb_context *tdb;
+	int flags[] = { TDB_INTERNAL, TDB_DEFAULT, TDB_NOMMAP,
+			TDB_INTERNAL|TDB_CONVERT, TDB_CONVERT, 
+			TDB_NOMMAP|TDB_CONVERT };
+
+	plan_tests(sizeof(flags) / sizeof(flags[0])
+		   * (NUM_RECORDS*4 + (NUM_RECORDS-1)*2 + 20) + 1);
+	for (i = 0; i < sizeof(flags) / sizeof(flags[0]); i++) {
+		tdb = tdb_open("run-traverse.tdb", flags[i],
+			       O_RDWR|O_CREAT|O_TRUNC, 0600, &tap_log_attr);
+		ok1(tdb);
+		if (!tdb)
+			continue;
+
+		ok1(tdb_firstkey(tdb).dptr == NULL);
+		ok1(tdb_error(tdb) == TDB_SUCCESS);
+
+		/* One entry... */
+		k.dptr = (unsigned char *)&num;
+		k.dsize = sizeof(num);
+		num = 0;
+		ok1(tdb_store(tdb, k, k, TDB_INSERT) == 0);
+		k = tdb_firstkey(tdb);
+		ok1(k.dsize == sizeof(num));
+		ok1(memcmp(k.dptr, &num, sizeof(num)) == 0);
+		k2 = tdb_nextkey(tdb, k);
+		ok1(k2.dsize == 0 && k2.dptr == NULL);
+		free(k.dptr);
+
+		/* Two entries. */
+		k.dptr = (unsigned char *)&num;
+		k.dsize = sizeof(num);
+		num = 1;
+		ok1(tdb_store(tdb, k, k, TDB_INSERT) == 0);
+		k = tdb_firstkey(tdb);
+		ok1(k.dsize == sizeof(num));
+		memcpy(&num, k.dptr, sizeof(num));
+		ok1(num == 0 || num == 1);
+		k2 = tdb_nextkey(tdb, k);
+		ok1(k2.dsize == sizeof(j));
+		free(k.dptr);
+		memcpy(&j, k2.dptr, sizeof(j));
+		ok1(j == 0 || j == 1);
+		ok1(j != num);
+		k = tdb_nextkey(tdb, k2);
+		ok1(k.dsize == 0 && k.dptr == NULL);
+		free(k2.dptr);
+
+		/* Clean up. */
+		k.dptr = (unsigned char *)&num;
+		k.dsize = sizeof(num);
+		num = 0;
+		ok1(tdb_delete(tdb, k) == 0);
+		num = 1;
+		ok1(tdb_delete(tdb, k) == 0);
+
+		/* Now lots of records. */
+		ok1(store_records(tdb));
+		td.calls = 0;
+
+		num = tdb_traverse_read(tdb, trav, &td);
+		ok1(num == NUM_RECORDS);
+		ok1(td.calls == NUM_RECORDS);
+
+		/* Simple loop should match tdb_traverse_read */
+		for (j = 0, k = tdb_firstkey(tdb); j < td.calls; j++) {
+			int val;
+
+			ok1(k.dsize == sizeof(val));
+			memcpy(&val, k.dptr, k.dsize);
+			ok1(td.records[j] == val);
+			k2 = tdb_nextkey(tdb, k);
+			free(k.dptr);
+			k = k2;
+		}
+
+		/* But arbitary orderings should work too. */
+		for (j = td.calls-1; j > 0; j--) {
+			k.dptr = (unsigned char *)&td.records[j-1];
+			k.dsize = sizeof(td.records[j-1]);
+			k = tdb_nextkey(tdb, k);
+			ok1(k.dsize == sizeof(td.records[j]));
+			ok1(memcmp(k.dptr, &td.records[j], k.dsize) == 0);
+			free(k.dptr);
+		}
+
+		/* Even delete should work. */
+		for (j = 0, k = tdb_firstkey(tdb); k.dptr; j++) {
+			ok1(k.dsize == 4);
+			ok1(tdb_delete(tdb, k) == 0);
+			k2 = tdb_nextkey(tdb, k);
+			free(k.dptr);
+			k = k2;
+		}
+
+		diag("delete using first/nextkey gave %u of %u records",
+		     j, NUM_RECORDS);
+		ok1(j == NUM_RECORDS);
+		tdb_close(tdb);
+	}
+
+	ok1(tap_log_messages == 0);
+	return exit_status();
+}