blob: 739f56658c7052fbec491d8033483981bb72be3b (
plain) (
blame)
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
|
/*
* Copyright (C) 2003-2013 The Music Player Daemon Project
* http://www.musicpd.org
*
* 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; either version 2 of the License, or
* (at your option) any later version.
*
* 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 02110-1301 USA.
*/
/** \file
*
* Support for locking data structures from the database, for safe
* multi-threading.
*/
#ifndef MPD_DB_LOCK_HXX
#define MPD_DB_LOCK_HXX
#include "check.h"
#include "thread/Mutex.hxx"
#include "gcc.h"
#include <glib.h>
#include <assert.h>
extern Mutex db_mutex;
#ifndef NDEBUG
extern GThread *db_mutex_holder;
/**
* Does the current thread hold the database lock?
*/
gcc_pure
static inline bool
holding_db_lock(void)
{
return db_mutex_holder == g_thread_self();
}
#endif
/**
* Obtain the global database lock. This is needed before
* dereferencing a #song or #directory. It is not recursive.
*/
static inline void
db_lock(void)
{
assert(!holding_db_lock());
db_mutex.lock();
assert(db_mutex_holder == NULL);
#ifndef NDEBUG
db_mutex_holder = g_thread_self();
#endif
}
/**
* Release the global database lock.
*/
static inline void
db_unlock(void)
{
assert(holding_db_lock());
#ifndef NDEBUG
db_mutex_holder = NULL;
#endif
db_mutex.unlock();
}
#ifdef __cplusplus
class ScopeDatabaseLock {
public:
ScopeDatabaseLock() {
db_lock();
}
~ScopeDatabaseLock() {
db_unlock();
}
};
#endif
#endif
|
