/******************************************************
The transaction lock system

(c) 1996 Innobase Oy

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. */
UNIV_INLINE
ulint
lock_rec_fold(
/*==========*/
			/* out: folded value */
	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. */
UNIV_INLINE
ulint
lock_rec_hash(
/*==========*/
			/* out: hashed value */
	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. */
UNIV_INLINE
trx_t*
lock_clust_rec_some_has_impl(
/*=========================*/
				/* out: transaction which has the x-lock, or
				NULL */
	rec_t*		rec,	/* in: user record */
	dict_index_t*	index,	/* in: clustered index */
	const ulint*	offsets)/* in: rec_get_offsets(rec, index) */
{
	dulint	trx_id;

#ifdef UNIV_SYNC_DEBUG
	ut_ad(mutex_own(&kernel_mutex));
#endif /* UNIV_SYNC_DEBUG */
	ut_ad(index->type & DICT_CLUSTERED);
	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);
}