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+/*****************************************************************************
+
+Copyright (c) 1997, 2016, Oracle and/or its affiliates. All Rights Reserved.
+Copyright (c) 2017, MariaDB Corporation.
+
+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.,
+51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 USA
+
+*****************************************************************************/
+
+/**************************************************//**
+@file include/row0undo.h
+Row undo
+
+Created 1/8/1997 Heikki Tuuri
+*******************************************************/
+
+#ifndef row0undo_h
+#define row0undo_h
+
+#include "trx0sys.h"
+#include "btr0types.h"
+#include "btr0pcur.h"
+#include "que0types.h"
+#include "row0types.h"
+
+/********************************************************************//**
+Creates a row undo node to a query graph.
+@return own: undo node */
+undo_node_t*
+row_undo_node_create(
+/*=================*/
+	trx_t*		trx,	/*!< in: transaction */
+	que_thr_t*	parent,	/*!< in: parent node, i.e., a thr node */
+	mem_heap_t*	heap);	/*!< in: memory heap where created */
+/***********************************************************//**
+Looks for the clustered index record when node has the row reference.
+The pcur in node is used in the search. If found, stores the row to node,
+and stores the position of pcur, and detaches it. The pcur must be closed
+by the caller in any case.
+@return true if found; NOTE the node->pcur must be closed by the
+caller, regardless of the return value */
+bool
+row_undo_search_clust_to_pcur(
+/*==========================*/
+	undo_node_t*	node)	/*!< in/out: row undo node */
+	MY_ATTRIBUTE((warn_unused_result));
+/***********************************************************//**
+Undoes a row operation in a table. This is a high-level function used
+in SQL execution graphs.
+@return query thread to run next or NULL */
+que_thr_t*
+row_undo_step(
+/*==========*/
+	que_thr_t*	thr);	/*!< in: query thread */
+
+/* A single query thread will try to perform the undo for all successive
+versions of a clustered index record, if the transaction has modified it
+several times during the execution which is rolled back. It may happen
+that the task is transferred to another query thread, if the other thread
+is assigned to handle an undo log record in the chain of different versions
+of the record, and the other thread happens to get the x-latch to the
+clustered index record at the right time.
+	If a query thread notices that the clustered index record it is looking
+for is missing, or the roll ptr field in the record doed not point to the
+undo log record the thread was assigned to handle, then it gives up the undo
+task for that undo log record, and fetches the next. This situation can occur
+just in the case where the transaction modified the same record several times
+and another thread is currently doing the undo for successive versions of
+that index record. */
+
+/** Execution state of an undo node */
+enum undo_exec {
+	UNDO_NODE_FETCH_NEXT = 1,	/*!< we should fetch the next
+					undo log record */
+	/** rollback an insert into persistent table */
+	UNDO_INSERT_PERSISTENT,
+	/** rollback an update (or delete) in a persistent table */
+	UNDO_UPDATE_PERSISTENT,
+	/** rollback an insert into temporary table */
+	UNDO_INSERT_TEMPORARY,
+	/** rollback an update (or delete) in a temporary table */
+	UNDO_UPDATE_TEMPORARY,
+};
+
+/** Undo node structure */
+struct undo_node_t{
+	que_common_t	common;	/*!< node type: QUE_NODE_UNDO */
+	undo_exec	state;	/*!< rollback execution state */
+	trx_t*		trx;	/*!< trx for which undo is done */
+	roll_ptr_t	roll_ptr;/*!< roll pointer to undo log record */
+	trx_undo_rec_t*	undo_rec;/*!< undo log record */
+	undo_no_t	undo_no;/*!< undo number of the record */
+	ulint		rec_type;/*!< undo log record type: TRX_UNDO_INSERT_REC,
+				... */
+	trx_id_t	new_trx_id; /*!< trx id to restore to clustered index
+				record */
+	btr_pcur_t	pcur;	/*!< persistent cursor used in searching the
+				clustered index record */
+	dict_table_t*	table;	/*!< table where undo is done */
+	ulint		cmpl_info;/*!< compiler analysis of an update */
+	upd_t*		update;	/*!< update vector for a clustered index
+				record */
+	const dtuple_t*	ref;	/*!< row reference to the next row to handle */
+	dtuple_t*	row;	/*!< a copy (also fields copied to heap) of the
+				row to handle */
+	row_ext_t*	ext;	/*!< NULL, or prefixes of the externally
+				stored columns of the row */
+	dtuple_t*	undo_row;/*!< NULL, or the row after undo */
+	row_ext_t*	undo_ext;/*!< NULL, or prefixes of the externally
+				stored columns of undo_row */
+	dict_index_t*	index;	/*!< the next index whose record should be
+				handled */
+	mem_heap_t*	heap;	/*!< memory heap used as auxiliary storage for
+				row; this must be emptied after undo is tried
+				on a row */
+};
+
+#endif