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

Copyright (c) 1994, 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/btr0btr.ic
The B-tree

Created 6/2/1994 Heikki Tuuri
*******************************************************/

#include "mach0data.h"
#ifndef UNIV_HOTBACKUP
#include "mtr0mtr.h"
#include "mtr0log.h"
#include "page0zip.h"

#define BTR_MAX_NODE_LEVEL	50	/*!< Maximum B-tree page level
					(not really a hard limit).
					Used in debug assertions
					in btr_page_set_level and
					btr_page_get_level_low */

/**************************************************************//**
Gets a buffer page and declares its latching order level. */
UNIV_INLINE
buf_block_t*
btr_block_get(
/*==========*/
	ulint	space,		/*!< in: space id */
	ulint	zip_size,	/*!< in: compressed page size in bytes
				or 0 for uncompressed pages */
	ulint	page_no,	/*!< in: page number */
	ulint	mode,		/*!< in: latch mode */
	mtr_t*	mtr)		/*!< in: mtr */
{
	buf_block_t*	block;

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

	if (mode != RW_NO_LATCH) {

		buf_block_dbg_add_level(block, SYNC_TREE_NODE);
	}

	return(block);
}

/**************************************************************//**
Gets a buffer page and declares its latching order level. */
UNIV_INLINE
page_t*
btr_page_get(
/*=========*/
	ulint	space,		/*!< in: space id */
	ulint	zip_size,	/*!< in: compressed page size in bytes
				or 0 for uncompressed pages */
	ulint	page_no,	/*!< in: page number */
	ulint	mode,		/*!< in: latch mode */
	mtr_t*	mtr)		/*!< in: mtr */
{
	return(buf_block_get_frame(btr_block_get(space, zip_size, page_no,
						 mode, mtr)));
}

/**************************************************************//**
Sets the index id field of a page. */
UNIV_INLINE
void
btr_page_set_index_id(
/*==================*/
	page_t*		page,	/*!< in: page to be created */
	page_zip_des_t*	page_zip,/*!< in: compressed page whose uncompressed
				part will be updated, or NULL */
	dulint		id,	/*!< in: index id */
	mtr_t*		mtr)	/*!< in: mtr */
{
	if (UNIV_LIKELY_NULL(page_zip)) {
		mach_write_to_8(page + (PAGE_HEADER + PAGE_INDEX_ID), id);
		page_zip_write_header(page_zip,
				      page + (PAGE_HEADER + PAGE_INDEX_ID),
				      8, mtr);
	} else {
		mlog_write_dulint(page + (PAGE_HEADER + PAGE_INDEX_ID),
				  id, mtr);
	}
}
#endif /* !UNIV_HOTBACKUP */

/**************************************************************//**
Gets the index id field of a page.
@return	index id */
UNIV_INLINE
dulint
btr_page_get_index_id(
/*==================*/
	const page_t*	page)	/*!< in: index page */
{
	return(mach_read_from_8(page + PAGE_HEADER + PAGE_INDEX_ID));
}

#ifndef UNIV_HOTBACKUP
/********************************************************//**
Gets the node level field in an index page.
@return	level, leaf level == 0 */
UNIV_INLINE
ulint
btr_page_get_level_low(
/*===================*/
	const page_t*	page)	/*!< in: index page */
{
	ulint	level;

	ut_ad(page);

	level = mach_read_from_2(page + PAGE_HEADER + PAGE_LEVEL);

	ut_ad(level <= BTR_MAX_NODE_LEVEL);

	return(level);
}

/********************************************************//**
Gets the node level field in an index page.
@return	level, leaf level == 0 */
UNIV_INLINE
ulint
btr_page_get_level(
/*===============*/
	const page_t*	page,	/*!< in: index page */
	mtr_t*		mtr __attribute__((unused)))
				/*!< in: mini-transaction handle */
{
	ut_ad(page && mtr);

	return(btr_page_get_level_low(page));
}

/********************************************************//**
Sets the node level field in an index page. */
UNIV_INLINE
void
btr_page_set_level(
/*===============*/
	page_t*		page,	/*!< in: index page */
	page_zip_des_t*	page_zip,/*!< in: compressed page whose uncompressed
				part will be updated, or NULL */
	ulint		level,	/*!< in: level, leaf level == 0 */
	mtr_t*		mtr)	/*!< in: mini-transaction handle */
{
	ut_ad(page && mtr);
	ut_ad(level <= BTR_MAX_NODE_LEVEL);

	if (UNIV_LIKELY_NULL(page_zip)) {
		mach_write_to_2(page + (PAGE_HEADER + PAGE_LEVEL), level);
		page_zip_write_header(page_zip,
				      page + (PAGE_HEADER + PAGE_LEVEL),
				      2, mtr);
	} else {
		mlog_write_ulint(page + (PAGE_HEADER + PAGE_LEVEL), level,
				 MLOG_2BYTES, mtr);
	}
}

/********************************************************//**
Gets the next index page number.
@return	next page number */
UNIV_INLINE
ulint
btr_page_get_next(
/*==============*/
	const page_t*	page,	/*!< in: index page */
	mtr_t*		mtr __attribute__((unused)))
				/*!< in: mini-transaction handle */
{
	ut_ad(page && mtr);
	ut_ad(mtr_memo_contains_page(mtr, page, MTR_MEMO_PAGE_X_FIX)
	      || mtr_memo_contains_page(mtr, page, MTR_MEMO_PAGE_S_FIX));

	return(mach_read_from_4(page + FIL_PAGE_NEXT));
}

/********************************************************//**
Sets the next index page field. */
UNIV_INLINE
void
btr_page_set_next(
/*==============*/
	page_t*		page,	/*!< in: index page */
	page_zip_des_t*	page_zip,/*!< in: compressed page whose uncompressed
				part will be updated, or NULL */
	ulint		next,	/*!< in: next page number */
	mtr_t*		mtr)	/*!< in: mini-transaction handle */
{
	ut_ad(page && mtr);

	if (UNIV_LIKELY_NULL(page_zip)) {
		mach_write_to_4(page + FIL_PAGE_NEXT, next);
		page_zip_write_header(page_zip, page + FIL_PAGE_NEXT, 4, mtr);
	} else {
		mlog_write_ulint(page + FIL_PAGE_NEXT, next, MLOG_4BYTES, mtr);
	}
}

/********************************************************//**
Gets the previous index page number.
@return	prev page number */
UNIV_INLINE
ulint
btr_page_get_prev(
/*==============*/
	const page_t*	page,	/*!< in: index page */
	mtr_t*	mtr __attribute__((unused))) /*!< in: mini-transaction handle */
{
	ut_ad(page && mtr);

	return(mach_read_from_4(page + FIL_PAGE_PREV));
}

/********************************************************//**
Sets the previous index page field. */
UNIV_INLINE
void
btr_page_set_prev(
/*==============*/
	page_t*		page,	/*!< in: index page */
	page_zip_des_t*	page_zip,/*!< in: compressed page whose uncompressed
				part will be updated, or NULL */
	ulint		prev,	/*!< in: previous page number */
	mtr_t*		mtr)	/*!< in: mini-transaction handle */
{
	ut_ad(page && mtr);

	if (UNIV_LIKELY_NULL(page_zip)) {
		mach_write_to_4(page + FIL_PAGE_PREV, prev);
		page_zip_write_header(page_zip, page + FIL_PAGE_PREV, 4, mtr);
	} else {
		mlog_write_ulint(page + FIL_PAGE_PREV, prev, MLOG_4BYTES, mtr);
	}
}

/**************************************************************//**
Gets the child node file address in a node pointer.
@return	child node address */
UNIV_INLINE
ulint
btr_node_ptr_get_child_page_no(
/*===========================*/
	const rec_t*	rec,	/*!< in: node pointer record */
	const ulint*	offsets)/*!< in: array returned by rec_get_offsets() */
{
	const byte*	field;
	ulint		len;
	ulint		page_no;

	ut_ad(!rec_offs_comp(offsets) || rec_get_node_ptr_flag(rec));

	/* The child address is in the last field */
	field = rec_get_nth_field(rec, offsets,
				  rec_offs_n_fields(offsets) - 1, &len);

	ut_ad(len == 4);

	page_no = mach_read_from_4(field);

	if (UNIV_UNLIKELY(page_no == 0)) {
		fprintf(stderr,
			"InnoDB: a nonsensical page number 0"
			" in a node ptr record at offset %lu\n",
			(ulong) page_offset(rec));
		buf_page_print(page_align(rec), 0);
	}

	return(page_no);
}

/**************************************************************//**
Releases the latches on a leaf page and bufferunfixes it. */
UNIV_INLINE
void
btr_leaf_page_release(
/*==================*/
	buf_block_t*	block,		/*!< in: buffer block */
	ulint		latch_mode,	/*!< in: BTR_SEARCH_LEAF or
					BTR_MODIFY_LEAF */
	mtr_t*		mtr)		/*!< in: mtr */
{
	ut_ad(latch_mode == BTR_SEARCH_LEAF || latch_mode == BTR_MODIFY_LEAF);
	ut_ad(!mtr_memo_contains(mtr, block, MTR_MEMO_MODIFY));

	mtr_memo_release(mtr, block,
			 latch_mode == BTR_SEARCH_LEAF
			 ? MTR_MEMO_PAGE_S_FIX
			 : MTR_MEMO_PAGE_X_FIX);
}
#endif /* !UNIV_HOTBACKUP */