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

Copyright (c) 1996, 2009, Innobase Oy. 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 St, Fifth Floor, Boston, MA 02110-1301 USA

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

/**************************************************//**
@file include/lock0lock.ic
The transaction lock system

Created 5/7/1996 Heikki Tuuri
*******************************************************/

#include "sync0sync.h"
#include "srv0srv.h"
#include "dict0dict.h"
#include "row0row.h"
#include "trx0sys.h"
#include "trx0trx.h"
#include "buf0buf.h"
#include "page0page.h"
#include "page0cur.h"
#include "row0vers.h"
#include "que0que.h"
#include "btr0cur.h"
#include "read0read.h"
#include "log0recv.h"

/*********************************************************************//**
Calculates the fold value of a page file address: used in inserting or
searching for a lock in the hash table.
@return	folded value */
UNIV_INLINE
ulint
lock_rec_fold(
/*==========*/
	ulint	space,	/*!< in: space */
	ulint	page_no)/*!< in: page number */
{
	return(ut_fold_ulint_pair(space, page_no));
}

/*********************************************************************//**
Calculates the hash value of a page file address: used in inserting or
searching for a lock in the hash table.
@return	hashed value */
UNIV_INLINE
ulint
lock_rec_hash(
/*==========*/
	ulint	space,	/*!< in: space */
	ulint	page_no)/*!< in: page number */
{
	return(hash_calc_hash(lock_rec_fold(space, page_no),
			      lock_sys->rec_hash));
}

/*********************************************************************//**
Checks if some transaction has an implicit x-lock on a record in a clustered
index.
@return	transaction which has the x-lock, or NULL */
UNIV_INLINE
trx_t*
lock_clust_rec_some_has_impl(
/*=========================*/
	const rec_t*		rec,	/*!< in: user record */
	const dict_index_t*	index,	/*!< in: clustered index */
	const ulint*		offsets)/*!< in: rec_get_offsets(rec, index) */
{
	trx_id_t	trx_id;

	ut_ad(mutex_own(&kernel_mutex));
	ut_ad(dict_index_is_clust(index));
	ut_ad(page_rec_is_user_rec(rec));

	trx_id = row_get_rec_trx_id(rec, index, offsets);

	if (trx_is_active(trx_id)) {
		/* The modifying or inserting transaction is active */

		return(trx_get_on_id(trx_id));
	}

	return(NULL);
}

/*********************************************************************//**
Gets the heap_no of the smallest user record on a page.
@return	heap_no of smallest user record, or PAGE_HEAP_NO_SUPREMUM */
UNIV_INLINE
ulint
lock_get_min_heap_no(
/*=================*/
	const buf_block_t*	block)	/*!< in: buffer block */
{
	const page_t*	page	= block->frame;

	if (page_is_comp(page)) {
		return(rec_get_heap_no_new(
			       page
			       + rec_get_next_offs(page + PAGE_NEW_INFIMUM,
						   TRUE)));
	} else {
		return(rec_get_heap_no_old(
			       page
			       + rec_get_next_offs(page + PAGE_OLD_INFIMUM,
						   FALSE)));
	}
}

/*******************************************************************//**
Check if there are any locks (table or rec) against table.
@return	TRUE if table has either table or record locks. */
UNIV_INLINE
ibool
lock_table_has_locks(
/*=================*/
	const dict_table_t*	table)	/*!< in: check if there are any locks
					held on records in this table or on the
					table itself */
{
	return(UT_LIST_GET_LEN(table->locks) > 0);
}