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/** @file include/ha0ha.ic
 The hash table with external chains

 Created 8/18/1994 Heikki Tuuri
 *************************************************************************/

#include "btr0types.h"
#include "mem0mem.h"
#include "ut0rnd.h"

/** Deletes a hash node. */
void ha_delete_hash_node(hash_table_t *table,  /*!< in: hash table */
                         ha_node_t *del_node); /*!< in: node to be deleted */

/** Gets a hash node data.
 @return pointer to the data */
UNIV_INLINE
const rec_t *ha_node_get_data(const ha_node_t *node) /*!< in: hash chain node */
{
  return (node->data);
}

/** Sets hash node data. */
UNIV_INLINE
void ha_node_set_data_func(
    ha_node_t *node, /*!< in: hash chain node */
#if defined UNIV_AHI_DEBUG || defined UNIV_DEBUG
    buf_block_t *block, /*!< in: buffer block containing the data */
#endif                  /* UNIV_AHI_DEBUG || UNIV_DEBUG */
    const rec_t *data)  /*!< in: pointer to the data */
{
#if defined UNIV_AHI_DEBUG || defined UNIV_DEBUG
  node->block = block;
#endif /* UNIV_AHI_DEBUG || UNIV_DEBUG */
  node->data = data;
}

#if defined UNIV_AHI_DEBUG || defined UNIV_DEBUG
/** Sets hash node data.
@param n in: hash chain node
@param b in: buffer block containing the data
@param d in: pointer to the data */
#define ha_node_set_data(n, b, d) ha_node_set_data_func(n, b, d)
#else /* UNIV_AHI_DEBUG || UNIV_DEBUG */
/** Sets hash node data.
@param n in: hash chain node
@param b in: buffer block containing the data
@param d in: pointer to the data */
#define ha_node_set_data(n, b, d) ha_node_set_data_func(n, d)
#endif /* UNIV_AHI_DEBUG || UNIV_DEBUG */

/** Gets the next node in a hash chain.
 @return next node, NULL if none */
UNIV_INLINE
ha_node_t *ha_chain_get_next(const ha_node_t *node) /*!< in: hash chain node */
{
  return (node->next);
}

/** Gets the first node in a hash chain.
 @return first node, NULL if none */
UNIV_INLINE
ha_node_t *ha_chain_get_first(
    hash_table_t *table, /*!< in: hash table */
    ulint fold)          /*!< in: fold value determining the chain */
{
  return (
      (ha_node_t *)hash_get_nth_cell(table, hash_calc_hash(fold, table))->node);
}

#ifdef UNIV_DEBUG
/** Assert that the synchronization object in a hash operation involving
 possible change in the hash table is held.
 Note that in case of mutexes we assert that mutex is owned while in case
 of rw-locks we assert that it is held in exclusive mode. */
UNIV_INLINE
void hash_assert_can_modify(hash_table_t *table, /*!< in: hash table */
                            ulint fold)          /*!< in: fold value */
{
  if (table->type == HASH_TABLE_SYNC_MUTEX) {
    ut_ad(mutex_own(hash_get_mutex(table, fold)));
  } else if (table->type == HASH_TABLE_SYNC_RW_LOCK) {
#if defined(UNIV_DEBUG) && !defined(UNIV_HOTBACKUP)
    rw_lock_t *lock = hash_get_lock(table, fold);
    ut_ad(rw_lock_own(lock, RW_LOCK_X));
#endif
  } else {
    ut_ad(table->type == HASH_TABLE_SYNC_NONE);
  }
}

/** Assert that the synchronization object in a hash search operation is held.
 Note that in case of mutexes we assert that mutex is owned while in case
 of rw-locks we assert that it is held either in x-mode or s-mode. */
UNIV_INLINE
void hash_assert_can_search(hash_table_t *table, /*!< in: hash table */
                            ulint fold)          /*!< in: fold value */
{
  if (table->type == HASH_TABLE_SYNC_MUTEX) {
    ut_ad(mutex_own(hash_get_mutex(table, fold)));
  } else if (table->type == HASH_TABLE_SYNC_RW_LOCK) {
#if defined(UNIV_DEBUG) && !defined(UNIV_HOTBACKUP)
    rw_lock_t *lock = hash_get_lock(table, fold);
    ut_ad(rw_lock_own(lock, RW_LOCK_X) || rw_lock_own(lock, RW_LOCK_S));
#endif
  } else {
    ut_ad(table->type == HASH_TABLE_SYNC_NONE);
  }
}
#endif /* UNIV_DEBUG */

/** Looks for an element in a hash table.
 @return pointer to the data of the first hash table node in chain
 having the fold number, NULL if not found */
UNIV_INLINE
const rec_t *ha_search_and_get_data(
    hash_table_t *table, /*!< in: hash table */
    ulint fold)          /*!< in: folded value of the searched data */
{
  hash_assert_can_search(table, fold);
  ut_ad(btr_search_enabled);

  for (const ha_node_t *node = ha_chain_get_first(table, fold); node != NULL;
       node = ha_chain_get_next(node)) {
    if (node->fold == fold) {
      return (node->data);
    }
  }

  return (NULL);
}

/** Looks for an element when we know the pointer to the data.
 @return pointer to the hash table node, NULL if not found in the table */
UNIV_INLINE
ha_node_t *ha_search_with_data(
    hash_table_t *table, /*!< in: hash table */
    ulint fold,          /*!< in: folded value of the searched data */
    const rec_t *data)   /*!< in: pointer to the data */
{
  ha_node_t *node;

  hash_assert_can_search(table, fold);

  ut_ad(btr_search_enabled);

  node = ha_chain_get_first(table, fold);

  while (node) {
    if (node->data == data) {
      return (node);
    }

    node = ha_chain_get_next(node);
  }

  return (NULL);
}

/** Looks for an element when we know the pointer to the data, and deletes
 it from the hash table, if found.
 @return true if found */
UNIV_INLINE
ibool ha_search_and_delete_if_found(
    hash_table_t *table, /*!< in: hash table */
    ulint fold,          /*!< in: folded value of the searched data */
    const rec_t *data)   /*!< in: pointer to the data */
{
  ha_node_t *node;

  hash_assert_can_modify(table, fold);
  ut_ad(btr_search_enabled);

  node = ha_search_with_data(table, fold, data);

  if (node) {
    ha_delete_hash_node(table, node);

    return (TRUE);
  }

  return (FALSE);
}