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+/*****************************************************************************
+
+Copyright (c) 2006, 2014, Oracle and/or its affiliates. All Rights Reserved.
+Copyright (c) 2017, 2021, 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/ut0wqueue.h
+A work queue
+
+Created 4/26/2006 Osku Salerma
+************************************************************************/
+
+/*******************************************************************//**
+A Work queue. Threads can add work items to the queue and other threads can
+wait for work items to be available and take them off the queue for
+processing.
+************************************************************************/
+
+#pragma once
+
+#include "ut0list.h"
+#include "mem0mem.h"
+
+// Forward declaration
+struct ib_list_t;
+
+/** Work queue */
+struct ib_wqueue_t
+{
+  /** Mutex protecting everything */
+  mysql_mutex_t mutex;
+  /** Work item list */
+  ib_list_t *items;
+  /** ib_list_len(*items) */
+  size_t length;
+};
+
+/****************************************************************//**
+Create a new work queue.
+@return work queue */
+ib_wqueue_t*
+ib_wqueue_create();
+/*===============*/
+
+/****************************************************************//**
+Free a work queue. */
+void
+ib_wqueue_free(
+/*===========*/
+	ib_wqueue_t*	wq);		/*!< in: work queue */
+
+/** Add a work item to the queue.
+@param[in,out]	wq		work queue
+@param[in]	item		work item
+@param[in,out]	heap		memory heap to use for allocating list node
+@param[in]	wq_locked	work queue mutex locked */
+void
+ib_wqueue_add(ib_wqueue_t* wq, void* item, mem_heap_t* heap,
+	      bool wq_locked = false);
+
+/** Check if queue is empty.
+@param wq wait queue
+@return whether the queue is empty */
+bool ib_wqueue_is_empty(ib_wqueue_t* wq);
+
+/********************************************************************
+Return first item on work queue or NULL if queue is empty
+@return work item or NULL */
+void*
+ib_wqueue_nowait(
+/*=============*/
+	ib_wqueue_t*	wq);		/*<! in: work queue */