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

Copyright (c) 1994, 2023, Oracle and/or its affiliates.

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License, version 2.0,
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as designated in a particular file or component or in included license
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*****************************************************************************/

/**************************************************//**
@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.
@param[in]	page_id	page id
@param[in]	mode	latch mode
@param[in]	file	file name
@param[in]	line	line where called
@param[in]	index	index tree, may be NULL if it is not an insert buffer
tree
@param[in,out]	mtr	mini-transaction
@return block */
UNIV_INLINE
buf_block_t*
btr_block_get_func(
	const page_id_t&	page_id,
	const page_size_t&	page_size,
	ulint			mode,
	const char*		file,
	ulint			line,
# ifdef UNIV_DEBUG
	const dict_index_t*	index,
# endif /* UNIV_DEBUG */
	mtr_t*		mtr)
{
	buf_block_t*	block;

	block = buf_page_get_gen(
		page_id, page_size, mode, NULL, BUF_GET, file, line, mtr);

	if (mode != RW_NO_LATCH) {

		buf_block_dbg_add_level(
			block, index != NULL && dict_index_is_ibuf(index)
			? SYNC_IBUF_TREE_NODE : SYNC_TREE_NODE);
	}

	return(block);
}

/**************************************************************//**
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 */
	index_id_t	id,	/*!< in: index id */
	mtr_t*		mtr)	/*!< in: mtr */
{
	if (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_ull(page + (PAGE_HEADER + PAGE_INDEX_ID), id, mtr);
	}
}
#endif /* !UNIV_HOTBACKUP */

/**************************************************************//**
Gets the index id field of a page.
@return index id */
UNIV_INLINE
index_id_t
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);
}

/********************************************************//**
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 != NULL);
	ut_ad(mtr != NULL);
	ut_ad(level <= BTR_MAX_NODE_LEVEL);

	if (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 MY_ATTRIBUTE((unused)))
				/*!< in: mini-transaction handle */
{
	ut_ad(page != NULL);
	ut_ad(mtr != NULL);

	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 != NULL);
	ut_ad(mtr != NULL);

	if (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 MY_ATTRIBUTE((unused))) /*!< in: mini-transaction handle */
{
	ut_ad(page != NULL);
	ut_ad(mtr != NULL);

	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 != NULL);
	ut_ad(mtr != NULL);

	if (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.
NOTE: the offsets array must contain all offsets for the record since
we read the last field according to offsets and assume that it contains
the child page number. In other words offsets must have been retrieved
with rec_get_offsets(n_fields=ULINT_UNDEFINED).
@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);
	ut_ad(page_no > 1);

	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
	      || latch_mode == BTR_NO_LATCHES);

	ut_ad(!mtr_memo_contains(mtr, block, MTR_MEMO_MODIFY));

	ulint mode;
	switch (latch_mode) {
		case BTR_SEARCH_LEAF:
			mode = MTR_MEMO_PAGE_S_FIX;
			break;
		case BTR_MODIFY_LEAF:
			mode = MTR_MEMO_PAGE_X_FIX;
			break;
		case BTR_NO_LATCHES:
			mode = MTR_MEMO_BUF_FIX;
			break;
		default:
			ut_a(0);
	}

	mtr->memo_release(block, mode);
}
#endif /* !UNIV_HOTBACKUP */