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

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

/**************************************************//**
@file include/row0sel.ic
Select

Created 12/19/1997 Heikki Tuuri
*******************************************************/

#include "que0que.h"

/*********************************************************************//**
Gets the plan node for the nth table in a join.
@return plan node */
UNIV_INLINE
plan_t*
sel_node_get_nth_plan(
/*==================*/
	sel_node_t*	node,	/*!< in: select node */
	ulint		i)	/*!< in: get ith plan node */
{
	ut_ad(i < node->n_tables);

	return(node->plans + i);
}

/*********************************************************************//**
Resets the cursor defined by sel_node to the SEL_NODE_OPEN state, which means
that it will start fetching from the start of the result set again, regardless
of where it was before, and it will set intention locks on the tables. */
UNIV_INLINE
void
sel_node_reset_cursor(
/*==================*/
	sel_node_t*	node)	/*!< in: select node */
{
	node->state = SEL_NODE_OPEN;
}

/**********************************************************************//**
Performs an execution step of an open or close cursor statement node.
@return query thread to run next or NULL */
UNIV_INLINE
que_thr_t*
open_step(
/*======*/
	que_thr_t*	thr)	/*!< in: query thread */
{
	sel_node_t*	sel_node;
	open_node_t*	node;
	ulint		err;

	ut_ad(thr);

	node = (open_node_t*) thr->run_node;
	ut_ad(que_node_get_type(node) == QUE_NODE_OPEN);

	sel_node = node->cursor_def;

	err = DB_SUCCESS;

	if (node->op_type == ROW_SEL_OPEN_CURSOR) {

		/*		if (sel_node->state == SEL_NODE_CLOSED) { */

		sel_node_reset_cursor(sel_node);
		/*		} else {
		err = DB_ERROR;
		} */
	} else {
		if (sel_node->state != SEL_NODE_CLOSED) {

			sel_node->state = SEL_NODE_CLOSED;
		} else {
			err = DB_ERROR;
		}
	}

	if (err != DB_SUCCESS) {
		/* SQL error detected */
		fprintf(stderr, "SQL error %lu\n", (ulong) err);

		ut_error;
	}

	thr->run_node = que_node_get_parent(node);

	return(thr);
}


/** Searches for rows in the database. This is used in the interface to
MySQL. This function opens a cursor, and also implements fetch next
and fetch prev. NOTE that if we do a search with a full key value
from a unique index (ROW_SEL_EXACT), then we will not store the cursor
position and fetch next or fetch prev must not be tried to the cursor!

@param[out]	buf		buffer for the fetched row in MySQL format
@param[in]	mode		search mode PAGE_CUR_L
@param[in,out]	prebuilt	prebuilt struct for the table handler;
				this contains the info to search_tuple,
				index; if search tuple contains 0 field then
				we position the cursor at start or the end of
				index, depending on 'mode'
@param[in]	match_mode	0 or ROW_SEL_EXACT or ROW_SEL_EXACT_PREFIX
@param[in]	direction	0 or ROW_SEL_NEXT or ROW_SEL_PREV;
				Note: if this is != 0, then prebuilt must has a
				pcur with stored position! In opening of a
				cursor 'direction' should be 0.
@return DB_SUCCESS, DB_RECORD_NOT_FOUND, DB_END_OF_INDEX, DB_DEADLOCK,
DB_LOCK_TABLE_FULL, DB_CORRUPTION, or DB_TOO_BIG_RECORD */
UNIV_INLINE
dberr_t
row_search_for_mysql(
	byte*			buf,
	page_cur_mode_t		mode,
	row_prebuilt_t*		prebuilt,
	ulint			match_mode,
	ulint			direction)
{
	if (!dict_table_is_intrinsic(prebuilt->table)) {
		return(row_search_mvcc(
			buf, mode, prebuilt, match_mode, direction));
	} else {
		return(row_search_no_mvcc(
			buf, mode, prebuilt, match_mode, direction));
	}
}