summaryrefslogtreecommitdiff
path: root/storage/innobase/ut/ut0wqueue.cc
blob: 53bb0c8b1480a33d87484f7ea90e2a8050482b9a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
/*****************************************************************************

Copyright (c) 2006, 2015, Oracle and/or its affiliates. All Rights Reserved.
Copyright (c) 2019, 2020, 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

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

#include "ut0list.h"
#include "mem0mem.h"
#include "ut0wqueue.h"

/*******************************************************************//**
@file ut/ut0wqueue.cc
A work queue

Created 4/26/2006 Osku Salerma
************************************************************************/

/****************************************************************//**
Create a new work queue.
@return work queue */
ib_wqueue_t*
ib_wqueue_create(void)
/*===================*/
{
	ib_wqueue_t*	wq = static_cast<ib_wqueue_t*>(
		ut_malloc_nokey(sizeof(*wq)));

	/* Function ib_wqueue_create() has not been used anywhere,
	not necessary to instrument this mutex */

	mutex_create(LATCH_ID_WORK_QUEUE, &wq->mutex);

	wq->items = ib_list_create();

	return(wq);
}

/****************************************************************//**
Free a work queue. */
void
ib_wqueue_free(
/*===========*/
	ib_wqueue_t*	wq)	/*!< in: work queue */
{
	mutex_free(&wq->mutex);
	ib_list_free(wq->items);

	ut_free(wq);
}

/** 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)
{
	if (!wq_locked) {
		mutex_enter(&wq->mutex);
	}

	ib_list_add_last(wq->items, item, heap);

	if (!wq_locked) {
		mutex_exit(&wq->mutex);
	}
}

/********************************************************************
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 */
{
	ib_list_node_t*	node = NULL;

	mutex_enter(&wq->mutex);

	if(!ib_list_is_empty(wq->items)) {
		node = ib_list_get_first(wq->items);

		if (node) {
			ib_list_remove(wq->items, node);
		}
	}

	mutex_exit(&wq->mutex);

	return (node ? node->data : NULL);
}
/** Check if queue is empty.
@param wq wait queue
@return whether the queue is empty */
bool ib_wqueue_is_empty(ib_wqueue_t* wq)
{
	mutex_enter(&wq->mutex);
	bool is_empty = ib_list_is_empty(wq->items);
	mutex_exit(&wq->mutex);
	return is_empty;
}

/********************************************************************
Get number of items on queue.
@return number of items on queue */
ulint
ib_wqueue_len(
/*==========*/
	ib_wqueue_t*	wq)		/*<! in: work queue */
{
	ulint len = 0;

	mutex_enter(&wq->mutex);
	len = ib_list_len(wq->items);
	mutex_exit(&wq->mutex);

        return(len);
}