OpenShot Library | libopenshot-audio
0.2.0
juce_SpinLock.h
1
2
/** @weakgroup juce_core-threads
3
* @{
4
*/
5
/*
6
==============================================================================
7
8
This file is part of the JUCE library.
9
Copyright (c) 2017 - ROLI Ltd.
10
11
JUCE is an open source library subject to commercial or open-source
12
licensing.
13
14
The code included in this file is provided under the terms of the ISC license
15
http://www.isc.org/downloads/software-support-policy/isc-license. Permission
16
To use, copy, modify, and/or distribute this software for any purpose with or
17
without fee is hereby granted provided that the above copyright notice and
18
this permission notice appear in all copies.
19
20
JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
21
EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
22
DISCLAIMED.
23
24
==============================================================================
25
*/
26
27
namespace
juce
28
{
29
30
//==============================================================================
31
/**
32
A simple spin-lock class that can be used as a simple, low-overhead mutex for
33
uncontended situations.
34
35
Note that unlike a CriticalSection, this type of lock is not re-entrant, and may
36
be less efficient when used in a highly contended situation, but it's very small and
37
requires almost no initialisation.
38
It's most appropriate for simple situations where you're only going to hold the
39
lock for a very brief time.
40
41
@see CriticalSection
42
43
@tags{Core}
44
*/
45
class
JUCE_API
SpinLock
46
{
47
public
:
48
inline
SpinLock
() =
default
;
49
inline
~
SpinLock
() =
default
;
50
51
/** Acquires the lock.
52
This will block until the lock has been successfully acquired by this thread.
53
Note that a SpinLock is NOT re-entrant, and is not smart enough to know whether the
54
caller thread already has the lock - so if a thread tries to acquire a lock that it
55
already holds, this method will never return!
56
57
It's strongly recommended that you never call this method directly - instead use the
58
ScopedLockType class to manage the locking using an RAII pattern instead.
59
*/
60
void
enter()
const
noexcept;
61
62
/** Attempts to acquire the lock, returning true if this was successful. */
63
inline
bool
tryEnter
() const noexcept
64
{
65
return
lock.compareAndSetBool (1, 0);
66
}
67
68
/** Releases the lock. */
69
inline
void
exit
() const noexcept
70
{
71
jassert (lock.get() == 1);
// Agh! Releasing a lock that isn't currently held!
72
lock = 0;
73
}
74
75
//==============================================================================
76
/** Provides the type of scoped lock to use for locking a SpinLock. */
77
using
ScopedLockType
=
GenericScopedLock<SpinLock>
;
78
79
/** Provides the type of scoped unlocker to use with a SpinLock. */
80
using
ScopedUnlockType
=
GenericScopedUnlock<SpinLock>
;
81
82
private
:
83
//==============================================================================
84
mutable
Atomic<int>
lock;
85
86
JUCE_DECLARE_NON_COPYABLE (
SpinLock
)
87
};
88
89
}
// namespace juce
90
91
/** @}*/
juce::Atomic< int >
JUCE_API
#define JUCE_API
This macro is added to all JUCE public class declarations.
Definition:
juce_StandardHeader.h:143
juce::SpinLock::exit
void exit() const noexcept
Releases the lock.
Definition:
juce_SpinLock.h:69
juce::GenericScopedLock
Automatically locks and unlocks a mutex object.
Definition:
juce_ScopedLock.h:58
juce::SpinLock
A simple spin-lock class that can be used as a simple, low-overhead mutex for uncontended situations.
Definition:
juce_SpinLock.h:45
juce::SpinLock::tryEnter
bool tryEnter() const noexcept
Attempts to acquire the lock, returning true if this was successful.
Definition:
juce_SpinLock.h:63
juce::GenericScopedUnlock
Automatically unlocks and re-locks a mutex object.
Definition:
juce_ScopedLock.h:129
juce_core
threads
juce_SpinLock.h
Generated on Wed Jun 24 2020 20:19:20 for OpenShot Library | libopenshot-audio by
1.8.17