~drizzle-trunk/drizzle/development

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

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., 59 Temple

Place, Suite 330, Boston, MA 02111-1307 USA

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

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

@file include/trx0rseg.ic

Rollback segment

Created 3/26/1996 Heikki Tuuri

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

#include "srv0srv.h"

#include "mtr0log.h"

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

Gets a rollback segment header.

@return	rollback segment header, page x-latched */

UNIV_INLINE

trx_rsegf_t*

trx_rsegf_get(

/*==========*/

	ulint	space,		/*!< in: space where placed */

	ulint	zip_size,	/*!< in: compressed page size in bytes

				or 0 for uncompressed pages */

	ulint	page_no,	/*!< in: page number of the header */

	mtr_t*	mtr)		/*!< in: mtr */

{

	buf_block_t*	block;

	trx_rsegf_t*	header;

	block = buf_page_get(space, zip_size, page_no, RW_X_LATCH, mtr);

	buf_block_dbg_add_level(block, SYNC_RSEG_HEADER);

	header = TRX_RSEG + buf_block_get_frame(block);

	return(header);

}

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

Gets a newly created rollback segment header.

@return	rollback segment header, page x-latched */

UNIV_INLINE

trx_rsegf_t*

trx_rsegf_get_new(

/*==============*/

	ulint	space,		/*!< in: space where placed */

	ulint	zip_size,	/*!< in: compressed page size in bytes

				or 0 for uncompressed pages */

	ulint	page_no,	/*!< in: page number of the header */

	mtr_t*	mtr)		/*!< in: mtr */

{

	buf_block_t*	block;

	trx_rsegf_t*	header;

	block = buf_page_get(space, zip_size, page_no, RW_X_LATCH, mtr);

	buf_block_dbg_add_level(block, SYNC_RSEG_HEADER_NEW);

	header = TRX_RSEG + buf_block_get_frame(block);

	return(header);

}

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

Gets the file page number of the nth undo log slot.

@return	page number of the undo log segment */

UNIV_INLINE

ulint

trx_rsegf_get_nth_undo(

/*===================*/

	trx_rsegf_t*	rsegf,	/*!< in: rollback segment header */

	ulint		n,	/*!< in: index of slot */

	mtr_t*		mtr)	/*!< in: mtr */

{

	if (UNIV_UNLIKELY(n >= TRX_RSEG_N_SLOTS)) {

		fprintf(stderr,

			"InnoDB: Error: trying to get slot %lu of rseg\n",

			(ulong) n);

		ut_error;

	}

	return(mtr_read_ulint(rsegf + TRX_RSEG_UNDO_SLOTS

			      + n * TRX_RSEG_SLOT_SIZE, MLOG_4BYTES, mtr));

}

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

Sets the file page number of the nth undo log slot. */

UNIV_INLINE

void

trx_rsegf_set_nth_undo(

/*===================*/

	trx_rsegf_t*	rsegf,	/*!< in: rollback segment header */

	ulint		n,	/*!< in: index of slot */

	ulint		page_no,/*!< in: page number of the undo log segment */

	mtr_t*		mtr)	/*!< in: mtr */

{

	if (UNIV_UNLIKELY(n >= TRX_RSEG_N_SLOTS)) {

		fprintf(stderr,

			"InnoDB: Error: trying to set slot %lu of rseg\n",

			(ulong) n);

		ut_error;

	}

	mlog_write_ulint(rsegf + TRX_RSEG_UNDO_SLOTS + n * TRX_RSEG_SLOT_SIZE,

			 page_no, MLOG_4BYTES, mtr);

}

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

Looks for a free slot for an undo log segment.

@return	slot index or ULINT_UNDEFINED if not found */

UNIV_INLINE

ulint

trx_rsegf_undo_find_free(

/*=====================*/

	trx_rsegf_t*	rsegf,	/*!< in: rollback segment header */

	mtr_t*		mtr)	/*!< in: mtr */

{

	ulint		i;

	ulint		page_no;

	for (i = 0; i < TRX_RSEG_N_SLOTS; i++) {

		page_no = trx_rsegf_get_nth_undo(rsegf, i, mtr);

		if (page_no == FIL_NULL) {

			return(i);

		}

	}

	return(ULINT_UNDEFINED);

}