2 Unix SMB/CIFS implementation.
3 Database interface wrapper around red-black trees
4 Copyright (C) Volker Lendecke 2007, 2008
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 3 of the License, or
9 (at your option) any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program. If not, see <http://www.gnu.org/licenses/>.
21 #include "dbwrap/dbwrap.h"
22 #include "../lib/util/rbtree.h"
24 #define DBWRAP_RBT_ALIGN(_size_) (((_size_)+15)&~15)
31 struct db_rbt_ctx *db_ctx;
32 struct db_rbt_node *node;
35 /* The structure that ends up in the tree */
38 struct rb_node rb_node;
39 size_t keysize, valuesize;
42 * key and value are appended implicitly, "data" is only here as a
43 * target for offsetof()
50 * Hide the ugly pointer calculations in a function
53 static struct db_rbt_node *db_rbt2node(struct rb_node *node)
55 return (struct db_rbt_node *)
56 ((char *)node - offsetof(struct db_rbt_node, rb_node));
63 static int db_rbt_compare(TDB_DATA a, TDB_DATA b)
67 res = memcmp(a.dptr, b.dptr, MIN(a.dsize, b.dsize));
69 if ((res < 0) || ((res == 0) && (a.dsize < b.dsize))) {
72 if ((res > 0) || ((res == 0) && (a.dsize > b.dsize))) {
79 * dissect a db_rbt_node into its implicit key and value parts
82 static void db_rbt_parse_node(struct db_rbt_node *node,
83 TDB_DATA *key, TDB_DATA *value)
85 key->dptr = ((uint8 *)node) + offsetof(struct db_rbt_node, data);
86 key->dsize = node->keysize;
87 value->dptr = key->dptr + node->keysize;
88 value->dsize = node->valuesize;
91 static NTSTATUS db_rbt_store(struct db_record *rec, TDB_DATA data, int flag)
93 struct db_rbt_rec *rec_priv = (struct db_rbt_rec *)rec->private_data;
94 struct db_rbt_node *node;
97 struct rb_node * parent;
99 TDB_DATA this_key, this_val;
101 if (rec_priv->node != NULL) {
104 * The record was around previously
107 db_rbt_parse_node(rec_priv->node, &this_key, &this_val);
109 SMB_ASSERT(this_key.dsize == rec->key.dsize);
110 SMB_ASSERT(memcmp(this_key.dptr, rec->key.dptr,
111 this_key.dsize) == 0);
113 if (this_val.dsize >= data.dsize) {
115 * The new value fits into the old space
117 memcpy(this_val.dptr, data.dptr, data.dsize);
118 rec_priv->node->valuesize = data.dsize;
123 * We need to delete the key from the tree and start fresh,
124 * there's not enough space in the existing record
127 rb_erase(&rec_priv->node->rb_node, &rec_priv->db_ctx->tree);
130 * Keep the existing node around for a while: If the record
131 * existed before, we reference the key data in there.
135 node = (struct db_rbt_node *)talloc_size(rec_priv->db_ctx,
136 offsetof(struct db_rbt_node, data) + rec->key.dsize
140 TALLOC_FREE(rec_priv->node);
141 return NT_STATUS_NO_MEMORY;
144 ZERO_STRUCT(node->rb_node);
146 node->keysize = rec->key.dsize;
147 node->valuesize = data.dsize;
149 db_rbt_parse_node(node, &this_key, &this_val);
151 memcpy(this_key.dptr, rec->key.dptr, node->keysize);
152 TALLOC_FREE(rec_priv->node);
154 memcpy(this_val.dptr, data.dptr, node->valuesize);
157 p = &rec_priv->db_ctx->tree.rb_node;
160 struct db_rbt_node *r;
161 TDB_DATA search_key, search_val;
168 db_rbt_parse_node(r, &search_key, &search_val);
170 res = db_rbt_compare(this_key, search_key);
179 smb_panic("someone messed with the tree");
183 rb_link_node(&node->rb_node, parent, p);
184 rb_insert_color(&node->rb_node, &rec_priv->db_ctx->tree);
189 static NTSTATUS db_rbt_delete(struct db_record *rec)
191 struct db_rbt_rec *rec_priv = (struct db_rbt_rec *)rec->private_data;
193 if (rec_priv->node == NULL) {
197 rb_erase(&rec_priv->node->rb_node, &rec_priv->db_ctx->tree);
198 TALLOC_FREE(rec_priv->node);
203 static struct db_record *db_rbt_fetch_locked(struct db_context *db_ctx,
207 struct db_rbt_ctx *ctx = talloc_get_type_abort(
208 db_ctx->private_data, struct db_rbt_ctx);
210 struct db_rbt_rec *rec_priv;
211 struct db_record *result;
215 struct db_rbt_node *r = NULL;
216 TDB_DATA search_key = tdb_null, search_val = tdb_null;
218 n = ctx->tree.rb_node;
225 db_rbt_parse_node(r, &search_key, &search_val);
227 res = db_rbt_compare(key, search_key);
242 * In this low-level routine, play tricks to reduce the number of
243 * tallocs to one. Not recommened for general use, but here it pays
247 size = DBWRAP_RBT_ALIGN(sizeof(struct db_record))
248 + sizeof(struct db_rbt_rec);
252 * We need to keep the key around for later store
257 result = (struct db_record *)talloc_size(mem_ctx, size);
258 if (result == NULL) {
262 rec_priv = (struct db_rbt_rec *)
263 ((char *)result + DBWRAP_RBT_ALIGN(sizeof(struct db_record)));
264 rec_priv->db_ctx = ctx;
266 result->store = db_rbt_store;
267 result->delete_rec = db_rbt_delete;
268 result->private_data = rec_priv;
272 result->key = search_key;
273 result->value = search_val;
276 rec_priv->node = NULL;
277 result->key.dptr = (uint8 *)
278 ((char *)rec_priv + sizeof(*rec_priv));
279 result->key.dsize = key.dsize;
280 memcpy(result->key.dptr, key.dptr, key.dsize);
282 result->value = tdb_null;
288 static int db_rbt_fetch(struct db_context *db, TALLOC_CTX *mem_ctx,
289 TDB_DATA key, TDB_DATA *data)
291 struct db_rbt_ctx *ctx = talloc_get_type_abort(
292 db->private_data, struct db_rbt_ctx);
296 struct db_rbt_node *r = NULL;
297 TDB_DATA search_key, search_val;
300 n = ctx->tree.rb_node;
307 db_rbt_parse_node(r, &search_key, &search_val);
309 res = db_rbt_compare(key, search_key);
328 result = (uint8 *)talloc_memdup(mem_ctx, search_val.dptr,
330 if (result == NULL) {
335 data->dsize = search_val.dsize;
339 static int db_rbt_traverse_internal(struct rb_node *n,
340 int (*f)(struct db_record *db,
344 struct db_rbt_node *r;
345 struct db_record rec;
352 ret = db_rbt_traverse_internal(n->rb_left, f, private_data);
359 db_rbt_parse_node(r, &rec.key, &rec.value);
361 ret = f(&rec, private_data);
366 return db_rbt_traverse_internal(n->rb_right, f, private_data);
369 static int db_rbt_traverse(struct db_context *db,
370 int (*f)(struct db_record *db,
374 struct db_rbt_ctx *ctx = talloc_get_type_abort(
375 db->private_data, struct db_rbt_ctx);
377 return db_rbt_traverse_internal(ctx->tree.rb_node, f, private_data);
380 static int db_rbt_get_seqnum(struct db_context *db)
385 static int db_rbt_trans_dummy(struct db_context *db)
388 * Transactions are pretty pointless in-memory, just return success.
393 struct db_context *db_open_rbt(TALLOC_CTX *mem_ctx)
395 struct db_context *result;
397 result = talloc(mem_ctx, struct db_context);
399 if (result == NULL) {
403 result->private_data = talloc_zero(result, struct db_rbt_ctx);
405 if (result->private_data == NULL) {
410 result->fetch_locked = db_rbt_fetch_locked;
411 result->fetch = db_rbt_fetch;
412 result->traverse = db_rbt_traverse;
413 result->traverse_read = db_rbt_traverse;
414 result->get_seqnum = db_rbt_get_seqnum;
415 result->transaction_start = db_rbt_trans_dummy;
416 result->transaction_commit = db_rbt_trans_dummy;
417 result->transaction_cancel = db_rbt_trans_dummy;