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/**
* @file tree_data_hash.c
* @author Radek Krejci <rkrejci@cesnet.cz>
* @brief Functions to manipulate with the data node's hashes.
*
* Copyright (c) 2019 CESNET, z.s.p.o.
*
* This source code is licensed under BSD 3-Clause License (the "License").
* You may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://opensource.org/licenses/BSD-3-Clause
*/
#include <assert.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include "common.h"
#include "compat.h"
#include "hash_table.h"
#include "log.h"
#include "plugins_types.h"
#include "tree.h"
#include "tree_data.h"
#include "tree_schema.h"
LY_ERR
lyd_hash(struct lyd_node *node)
{
struct lyd_node *iter;
const void *hash_key;
ly_bool dyn;
size_t key_len;
if (!node->schema) {
return LY_SUCCESS;
}
/* hash always starts with the module and schema name */
node->hash = dict_hash_multi(0, node->schema->module->name, strlen(node->schema->module->name));
node->hash = dict_hash_multi(node->hash, node->schema->name, strlen(node->schema->name));
if (node->schema->nodetype == LYS_LIST) {
if (node->schema->flags & LYS_KEYLESS) {
/* key-less list simply calls hash function again with empty key,
* just so that it differs from the first-instance hash
*/
node->hash = dict_hash_multi(node->hash, NULL, 0);
} else {
struct lyd_node_inner *list = (struct lyd_node_inner *)node;
/* list hash is made up from its keys */
for (iter = list->child; iter && iter->schema && (iter->schema->flags & LYS_KEY); iter = iter->next) {
struct lyd_node_term *key = (struct lyd_node_term *)iter;
hash_key = key->value.realtype->plugin->print(NULL, &key->value, LY_VALUE_LYB, NULL, &dyn, &key_len);
node->hash = dict_hash_multi(node->hash, hash_key, key_len);
if (dyn) {
free((void *)hash_key);
}
}
}
} else if (node->schema->nodetype == LYS_LEAFLIST) {
/* leaf-list adds its hash key */
struct lyd_node_term *llist = (struct lyd_node_term *)node;
hash_key = llist->value.realtype->plugin->print(NULL, &llist->value, LY_VALUE_LYB, NULL, &dyn, &key_len);
node->hash = dict_hash_multi(node->hash, hash_key, key_len);
if (dyn) {
free((void *)hash_key);
}
}
/* finish the hash */
node->hash = dict_hash_multi(node->hash, NULL, 0);
return LY_SUCCESS;
}
/**
* @brief Compare callback for values in hash table.
*
* Implementation of ::lyht_value_equal_cb.
*/
static ly_bool
lyd_hash_table_val_equal(void *val1_p, void *val2_p, ly_bool mod, void *UNUSED(cb_data))
{
struct lyd_node *val1, *val2;
val1 = *((struct lyd_node **)val1_p);
val2 = *((struct lyd_node **)val2_p);
if (mod) {
if (val1 == val2) {
return 1;
} else {
return 0;
}
}
if (val1->schema->nodetype & (LYS_LIST | LYS_LEAFLIST)) {
/* match on exact instance */
if (!lyd_compare_single(val1, val2, 0)) {
return 1;
}
} else if (val1->schema == val2->schema) {
/* just schema match */
return 1;
}
return 0;
}
/**
* @brief Add single node into children hash table.
*
* @param[in] ht Children hash table.
* @param[in] node Node to insert.
* @param[in] empty_ht Whether we started with an empty HT meaning no nodes were inserted yet.
* @return LY_ERR value.
*/
static LY_ERR
lyd_insert_hash_add(struct hash_table *ht, struct lyd_node *node, ly_bool empty_ht)
{
uint32_t hash;
assert(ht && node && node->schema);
/* add node itself */
if (lyht_insert(ht, &node, node->hash, NULL)) {
LOGINT_RET(LYD_CTX(node));
}
/* add first instance of a (leaf-)list */
if ((node->schema->nodetype & (LYS_LIST | LYS_LEAFLIST)) &&
(!node->prev->next || (node->prev->schema != node->schema))) {
/* get the simple hash */
hash = dict_hash_multi(0, node->schema->module->name, strlen(node->schema->module->name));
hash = dict_hash_multi(hash, node->schema->name, strlen(node->schema->name));
hash = dict_hash_multi(hash, NULL, 0);
/* remove any previous stored instance, only if we did not start with an empty HT */
if (!empty_ht && node->next && (node->next->schema == node->schema)) {
if (lyht_remove(ht, &node->next, hash)) {
LOGINT_RET(LYD_CTX(node));
}
}
/* in this case there would be the exact same value twice in the hash table, not supported (by the HT) */
assert(hash != node->hash);
/* insert this instance as the first (leaf-)list instance */
if (lyht_insert(ht, &node, hash, NULL)) {
LOGINT_RET(LYD_CTX(node));
}
}
return LY_SUCCESS;
}
LY_ERR
lyd_insert_hash(struct lyd_node *node)
{
struct lyd_node *iter;
uint32_t u;
if (!node->parent || !node->schema || !node->parent->schema) {
/* nothing to do */
return LY_SUCCESS;
}
/* create parent hash table if required, otherwise just add the new child */
if (!node->parent->children_ht) {
/* the hash table is created only when the number of children in a node exceeds the
* defined minimal limit LYD_HT_MIN_ITEMS
*/
u = 0;
LY_LIST_FOR(node->parent->child, iter) {
if (iter->schema) {
++u;
}
}
if (u >= LYD_HT_MIN_ITEMS) {
/* create hash table, insert all the children */
node->parent->children_ht = lyht_new(1, sizeof(struct lyd_node *), lyd_hash_table_val_equal, NULL, 1);
LY_LIST_FOR(node->parent->child, iter) {
if (iter->schema) {
LY_CHECK_RET(lyd_insert_hash_add(node->parent->children_ht, iter, 1));
}
}
}
} else {
LY_CHECK_RET(lyd_insert_hash_add(node->parent->children_ht, node, 0));
}
return LY_SUCCESS;
}
void
lyd_unlink_hash(struct lyd_node *node)
{
uint32_t hash;
if (!node->parent || !node->schema || !node->parent->schema || !node->parent->children_ht) {
/* not in any HT */
return;
}
/* remove from the parent HT */
if (lyht_remove(node->parent->children_ht, &node, node->hash)) {
LOGINT(LYD_CTX(node));
return;
}
/* first instance of the (leaf-)list, needs to be removed from HT */
if ((node->schema->nodetype & (LYS_LIST | LYS_LEAFLIST)) && (!node->prev->next || (node->prev->schema != node->schema))) {
/* get the simple hash */
hash = dict_hash_multi(0, node->schema->module->name, strlen(node->schema->module->name));
hash = dict_hash_multi(hash, node->schema->name, strlen(node->schema->name));
hash = dict_hash_multi(hash, NULL, 0);
/* remove the instance */
if (lyht_remove(node->parent->children_ht, &node, hash)) {
LOGINT(LYD_CTX(node));
return;
}
/* add the next instance */
if (node->next && (node->next->schema == node->schema)) {
if (lyht_insert(node->parent->children_ht, &node->next, hash, NULL)) {
LOGINT(LYD_CTX(node));
return;
}
}
}
}
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