source: branches/samba-3.5.x/source3/lib/talloc_dict.c

/*
   Unix SMB/CIFS implementation.
   Little dictionary style data structure based on dbwrap_rbt
   Copyright (C) Volker Lendecke 2009

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program 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 General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#include "includes.h"

struct talloc_dict {
        struct db_context *db;
};

struct talloc_dict *talloc_dict_init(TALLOC_CTX *mem_ctx)
{
        struct talloc_dict *result;

        result = talloc(mem_ctx, struct talloc_dict);
        if (result == NULL) {
                return NULL;
        }
        result->db = db_open_rbt(result);
        if (result->db == NULL) {
                TALLOC_FREE(result);
                return NULL;
        }
        return result;
}

/*
 * Add a talloced object to the dict. Nulls out the pointer to indicate that
 * the talloc ownership has been taken. If an object for "key" already exists,
 * the existing object is talloc_free()ed and overwritten by the new
 * object. If "data" is NULL, object for key "key" is deleted. Return false
 * for "no memory".
 */

bool talloc_dict_set(struct talloc_dict *dict, DATA_BLOB key, void *pdata)
{
        struct db_record *rec;
        NTSTATUS status = NT_STATUS_OK;
        void *data = *(void **)pdata;

        rec = dict->db->fetch_locked(dict->db, talloc_tos(),
                                     make_tdb_data(key.data, key.length));
        if (rec == NULL) {
                return false;
        }
        if (rec->value.dsize != 0) {
                void *old_data;
                if (rec->value.dsize != sizeof(void *)) {
                        TALLOC_FREE(rec);
                        return false;
                }
                old_data = *(void **)(rec->value.dptr);
                TALLOC_FREE(old_data);
                if (data == NULL) {
                        status = rec->delete_rec(rec);
                }
        }
        if (data != NULL) {
                void *mydata = talloc_move(dict->db, &data);
                *(void **)pdata = NULL;
                status = rec->store(rec, make_tdb_data((uint8_t *)&mydata,
                                                       sizeof(mydata)), 0);
        }
        TALLOC_FREE(rec);
        return NT_STATUS_IS_OK(status);
}

/*
 * Fetch a talloced object. If "mem_ctx!=NULL", talloc_move the object there
 * and delete it from the dict.
 */

void *talloc_dict_fetch(struct talloc_dict *dict, DATA_BLOB key,
                        TALLOC_CTX *mem_ctx)
{
        struct db_record *rec;
        void *result;

        rec = dict->db->fetch_locked(dict->db, talloc_tos(),
                                     make_tdb_data(key.data, key.length));
        if (rec == NULL) {
                return NULL;
        }
        if (rec->value.dsize != sizeof(void *)) {
                TALLOC_FREE(rec);
                return NULL;
        }
        result = *(void **)rec->value.dptr;

        if (mem_ctx != NULL) {
                NTSTATUS status;
                status = rec->delete_rec(rec);
                if (!NT_STATUS_IS_OK(status)) {
                        TALLOC_FREE(rec);
                        return NULL;
                }
                result = talloc_move(mem_ctx, &result);
        }

        return result;
}

struct talloc_dict_traverse_state {
        int (*fn)(DATA_BLOB key, void *data, void *private_data);
        void *private_data;
};

static int talloc_dict_traverse_fn(struct db_record *rec, void *private_data)
{
        struct talloc_dict_traverse_state *state =
                (struct talloc_dict_traverse_state *)private_data;

        if (rec->value.dsize != sizeof(void *)) {
                return -1;
        }
        return state->fn(data_blob_const(rec->key.dptr, rec->key.dsize),
                         *(void **)rec->value.dptr, state->private_data);
}

/*
 * Traverse a talloc_dict. If "fn" returns non-null, quit the traverse
 */

int talloc_dict_traverse(struct talloc_dict *dict,
                         int (*fn)(DATA_BLOB key, void *data,
                                   void *private_data),
                         void *private_data)
{
        struct talloc_dict_traverse_state state;
        state.fn = fn;
        state.private_data = private_data;
        return dict->db->traverse(dict->db, talloc_dict_traverse_fn, &state);
}