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

Copyright (c) 1994, 2021, 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,
as published by the Free Software Foundation.

This program is also distributed with certain software (including
but not limited to OpenSSL) that is licensed under separate terms,
as designated in a particular file or component or in included license
documentation.  The authors of MySQL hereby grant you an additional
permission to link the program and your derivative works with the
separately licensed software that they have included with MySQL.

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, version 2.0, 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 Street, Suite 500, Boston, MA 02110-1335 USA

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

/**************************************************//**
@file include/btr0cur.ic
The index tree cursor

Created 10/16/1994 Heikki Tuuri
*******************************************************/

#ifndef UNIV_HOTBACKUP
#include "btr0btr.h"

#ifdef UNIV_DEBUG
# define LIMIT_OPTIMISTIC_INSERT_DEBUG(NREC, CODE)\
if (btr_cur_limit_optimistic_insert_debug > 1\
    && (NREC) >= (ulint)btr_cur_limit_optimistic_insert_debug) {\
        CODE;\
}
#else
# define LIMIT_OPTIMISTIC_INSERT_DEBUG(NREC, CODE)
#endif /* UNIV_DEBUG */

#ifdef UNIV_DEBUG
/*********************************************************//**
Returns the page cursor component of a tree cursor.
@return pointer to page cursor component */
UNIV_INLINE
page_cur_t*
btr_cur_get_page_cur(
/*=================*/
	const btr_cur_t*	cursor)	/*!< in: tree cursor */
{
	return(&((btr_cur_t*) cursor)->page_cur);
}

/*********************************************************//**
Returns the buffer block on which the tree cursor is positioned.
@return pointer to buffer block */
UNIV_INLINE
buf_block_t*
btr_cur_get_block(
/*==============*/
	const btr_cur_t*	cursor)	/*!< in: tree cursor */
{
	return(page_cur_get_block(btr_cur_get_page_cur(cursor)));
}

/*********************************************************//**
Returns the record pointer of a tree cursor.
@return pointer to record */
UNIV_INLINE
rec_t*
btr_cur_get_rec(
/*============*/
	const btr_cur_t*	cursor)	/*!< in: tree cursor */
{
	return(page_cur_get_rec(btr_cur_get_page_cur(cursor)));
}
#endif /* UNIV_DEBUG */

/*********************************************************//**
Returns the compressed page on which the tree cursor is positioned.
@return pointer to compressed page, or NULL if the page is not compressed */
UNIV_INLINE
page_zip_des_t*
btr_cur_get_page_zip(
/*=================*/
	btr_cur_t*	cursor)	/*!< in: tree cursor */
{
	return(buf_block_get_page_zip(btr_cur_get_block(cursor)));
}

/*********************************************************//**
Returns the page of a tree cursor.
@return pointer to page */
UNIV_INLINE
page_t*
btr_cur_get_page(
/*=============*/
	btr_cur_t*	cursor)	/*!< in: tree cursor */
{
	return(page_align(page_cur_get_rec(&(cursor->page_cur))));
}

/*********************************************************//**
Positions a tree cursor at a given record. */
UNIV_INLINE
void
btr_cur_position(
/*=============*/
	dict_index_t*	index,	/*!< in: index */
	rec_t*		rec,	/*!< in: record in tree */
	buf_block_t*	block,	/*!< in: buffer block of rec */
	btr_cur_t*	cursor)	/*!< out: cursor */
{
	ut_ad(page_align(rec) == block->frame);

	page_cur_position(rec, block, btr_cur_get_page_cur(cursor));

	cursor->index = index;
}

/*********************************************************************//**
Checks if compressing an index page where a btr cursor is placed makes
sense.
@return TRUE if compression is recommended */
UNIV_INLINE
ibool
btr_cur_compress_recommendation(
/*============================*/
	btr_cur_t*	cursor,	/*!< in: btr cursor */
	mtr_t*		mtr)	/*!< in: mtr */
{
	const page_t*	page;

	ut_ad(mtr_is_block_fix(
		mtr, btr_cur_get_block(cursor),
		MTR_MEMO_PAGE_X_FIX, cursor->index->table));

	page = btr_cur_get_page(cursor);

	LIMIT_OPTIMISTIC_INSERT_DEBUG(page_get_n_recs(page) * 2,
				      return(FALSE));

	if ((page_get_data_size(page)
	     < BTR_CUR_PAGE_COMPRESS_LIMIT(cursor->index))
	    || ((btr_page_get_next(page, mtr) == FIL_NULL)
		&& (btr_page_get_prev(page, mtr) == FIL_NULL))) {

		/* The page fillfactor has dropped below a predefined
		minimum value OR the level in the B-tree contains just
		one page: we recommend compression if this is not the
		root page. */

		return(dict_index_get_page(cursor->index)
		       != page_get_page_no(page));
	}

	return(FALSE);
}

/*********************************************************************//**
Checks if the record on which the cursor is placed can be deleted without
making tree compression necessary (or, recommended).
@return TRUE if can be deleted without recommended compression */
UNIV_INLINE
ibool
btr_cur_can_delete_without_compress(
/*================================*/
	btr_cur_t*	cursor,	/*!< in: btr cursor */
	ulint		rec_size,/*!< in: rec_get_size(btr_cur_get_rec(cursor))*/
	mtr_t*		mtr)	/*!< in: mtr */
{
	page_t*		page;

	ut_ad(mtr_memo_contains(mtr, btr_cur_get_block(cursor),
				MTR_MEMO_PAGE_X_FIX));

	page = btr_cur_get_page(cursor);

	if ((page_get_data_size(page) - rec_size
	     < BTR_CUR_PAGE_COMPRESS_LIMIT(cursor->index))
	    || ((btr_page_get_next(page, mtr) == FIL_NULL)
		&& (btr_page_get_prev(page, mtr) == FIL_NULL))
	    || (page_get_n_recs(page) < 2)) {

		/* The page fillfactor will drop below a predefined
		minimum value, OR the level in the B-tree contains just
		one page, OR the page will become empty: we recommend
		compression if this is not the root page. */

		return(dict_index_get_page(cursor->index)
		       == page_get_page_no(page));
	}

	return(TRUE);
}

/*******************************************************************//**
Determine if an operation on off-page columns is an update.
@return TRUE if op != BTR_STORE_INSERT */
UNIV_INLINE
ibool
btr_blob_op_is_update(
/*==================*/
	enum blob_op	op)	/*!< in: operation */
{
	switch (op) {
	case BTR_STORE_INSERT:
	case BTR_STORE_INSERT_BULK:
		return(FALSE);
	case BTR_STORE_INSERT_UPDATE:
	case BTR_STORE_UPDATE:
		return(TRUE);
	}

	ut_ad(0);
	return(FALSE);
}

/******************************************************//**
The following function is used to set the deleted bit of a record. */
UNIV_INLINE
void
btr_rec_set_deleted_flag(
/*=====================*/
	rec_t*		rec,	/*!< in/out: physical record */
	page_zip_des_t*	page_zip,/*!< in/out: compressed page (or NULL) */
	ulint		flag)	/*!< in: nonzero if delete marked */
{
	if (page_rec_is_comp(rec)) {
		rec_set_deleted_flag_new(rec, page_zip, flag);
	} else {
		ut_ad(!page_zip);
		rec_set_deleted_flag_old(rec, flag);
	}
}

#endif /* !UNIV_HOTBACKUP */