/*****************************************************************************

Copyright (c) 1996, 2011, Oracle and/or its affiliates. All Rights Reserved.

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; version 2 of the License.

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, write to the Free Software Foundation, Inc.,
51 Franklin Street, Suite 500, Boston, MA 02110-1335 USA

*****************************************************************************/

/********************************************************************//**
@file include/btr0sea.ic
The index tree adaptive search

Created 2/17/1996 Heikki Tuuri
*************************************************************************/

#include "dict0mem.h"
#include "btr0cur.h"
#include "buf0buf.h"

/*********************************************************************//**
Updates the search info. */
UNIV_INTERN
void
btr_search_info_update_slow(
/*========================*/
	btr_search_t*	info,	/*!< in/out: search info */
	btr_cur_t*	cursor);/*!< in: cursor which was just positioned */

/********************************************************************//**
Returns search info for an index.
@return	search info; search mutex reserved */
UNIV_INLINE
btr_search_t*
btr_search_get_info(
/*================*/
	dict_index_t*	index)	/*!< in: index */
{
	return(index->search_info);
}

/*********************************************************************//**
Updates the search info. */
UNIV_INLINE
void
btr_search_info_update(
/*===================*/
	dict_index_t*	index,	/*!< in: index of the cursor */
	btr_cur_t*	cursor)	/*!< in: cursor which was just positioned */
{
	btr_search_t*	info;

#ifdef UNIV_SYNC_DEBUG
	ut_ad(!rw_lock_own(btr_search_get_latch(index), RW_LOCK_SHARED));
	ut_ad(!rw_lock_own(btr_search_get_latch(index), RW_LOCK_EX));
#endif /* UNIV_SYNC_DEBUG */

	info = btr_search_get_info(index);

	info->hash_analysis++;

	if (info->hash_analysis < BTR_SEARCH_HASH_ANALYSIS) {

		/* Do nothing */

		return;

	}

	ut_ad(cursor->flag != BTR_CUR_HASH);

	btr_search_info_update_slow(info, cursor);
}

/********************************************************************//**
Returns the adaptive hash index table for a given index key.
@return the adaptive hash index table for a given index key */
UNIV_INLINE
hash_table_t*
btr_search_get_hash_table(
/*======================*/
	const dict_index_t*	index)	/*!< in: index */
{
	ut_ad(index);
	ut_ad(index->search_table);

	return(index->search_table);
}

/********************************************************************//**
Returns the adaptive hash index latch for a given index key.
@return the adaptive hash index latch for a given index key */
UNIV_INLINE
prio_rw_lock_t*
btr_search_get_latch(
/*=================*/
	const dict_index_t*	index)	/*!< in: index */
{
	ut_ad(index);
	ut_ad(index->search_latch >= btr_search_latch_arr &&
	      index->search_latch < btr_search_latch_arr +
	      btr_search_index_num);

	return(index->search_latch);
}

/*********************************************************************//**
Returns the AHI partition number corresponding to a given index ID. */
UNIV_INLINE
ulint
btr_search_get_key(
/*===============*/
	index_id_t	index_id)	/*!< in: index ID */
{
	return(index_id % btr_search_index_num);
}

/*********************************************************************//**
Initializes AHI-related fields in a newly created index. */
UNIV_INLINE
void
btr_search_index_init(
/*===============*/
	dict_index_t*	index)	/*!< in: index */
{
	ut_ad(index);

	index->search_latch =
		&btr_search_latch_arr[btr_search_get_key(index->id)];
	index->search_table =
		btr_search_sys->hash_tables[btr_search_get_key(index->id)];
}

/********************************************************************//**
Latches all adaptive hash index latches in exclusive mode.  */
UNIV_INLINE
void
btr_search_x_lock_all(void)
/*=======================*/
{
	ulint	i;

	for (i = 0; i < btr_search_index_num; i++) {
		rw_lock_x_lock(&btr_search_latch_arr[i]);
	}
}

/********************************************************************//**
Unlatches all adaptive hash index latches in exclusive mode.  */
UNIV_INLINE
void
btr_search_x_unlock_all(void)
/*==========================*/
{
	ulint	i;

	for (i = 0; i < btr_search_index_num; i++) {
		rw_lock_x_unlock(&btr_search_latch_arr[i]);
	}
}

#ifdef UNIV_SYNC_DEBUG
/******************************************************************//**
Checks if the thread has locked all the adaptive hash index latches in the
specified mode.

@return true if all latches are locked by the current thread, false
otherwise.  */
UNIV_INLINE
bool
btr_search_own_all(
/*===============*/
	ulint lock_type)
{
	ulint	i;

	for (i = 0; i < btr_search_index_num; i++) {
		if (!rw_lock_own(&btr_search_latch_arr[i], lock_type)) {
			return(false);
		}
	}

	return(true);
}

/********************************************************************//**
Checks if the thread owns any adaptive hash latches in either S or X mode.
@return	true if the thread owns at least one latch in any mode. */
UNIV_INLINE
bool
btr_search_own_any(void)
/*====================*/
{
	ulint	i;

	for (i = 0; i < btr_search_index_num; i++) {
		if (rw_lock_own(&btr_search_latch_arr[i], RW_LOCK_SHARED) ||
		    rw_lock_own(&btr_search_latch_arr[i], RW_LOCK_EX)) {
			return(true);
		}
	}

	return(false);
}
#endif /* UNIV_SYNC_DEBUG */