OpenShot Library | libopenshot-audio 0.2.0
juce_InterProcessLock.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
27namespace juce
28{
29
30//==============================================================================
31/**
32 Acts as a critical section which processes can use to block each other.
33
34 @see CriticalSection
35
36 @tags{Core}
37*/
39{
40public:
41 //==============================================================================
42 /** Creates a lock object.
43 @param name a name that processes will use to identify this lock object
44 */
45 explicit InterProcessLock (const String& name);
46
47 /** Destructor.
48 This will also release the lock if it's currently held by this process.
49 */
51
52 //==============================================================================
53 /** Attempts to lock the critical section.
54
55 @param timeOutMillisecs how many milliseconds to wait if the lock is already
56 held by another process - a value of 0 will return
57 immediately, negative values will wait forever
58 @returns true if the lock could be gained within the timeout period, or
59 false if the timeout expired.
60 */
61 bool enter (int timeOutMillisecs = -1);
62
63 /** Releases the lock if it's currently held by this process. */
64 void exit();
65
66 //==============================================================================
67 /**
68 Automatically locks and unlocks an InterProcessLock object.
69
70 This works like a ScopedLock, but using an InterprocessLock rather than
71 a CriticalSection.
72
73 @see ScopedLock
74 */
76 {
77 public:
78 //==============================================================================
79 /** Creates a scoped lock.
80
81 As soon as it is created, this will lock the InterProcessLock, and
82 when the ScopedLockType object is deleted, the InterProcessLock will
83 be unlocked.
84
85 Note that since an InterprocessLock can fail due to errors, you should check
86 isLocked() to make sure that the lock was successful before using it.
87
88 Make sure this object is created and deleted by the same thread,
89 otherwise there are no guarantees what will happen! Best just to use it
90 as a local stack object, rather than creating one with the new() operator.
91 */
92 explicit ScopedLockType (InterProcessLock& l) : ipLock (l) { lockWasSuccessful = l.enter(); }
93
94 /** Destructor.
95
96 The InterProcessLock will be unlocked when the destructor is called.
97
98 Make sure this object is created and deleted by the same thread,
99 otherwise there are no guarantees what will happen!
100 */
101 inline ~ScopedLockType() { ipLock.exit(); }
102
103 /** Returns true if the InterProcessLock was successfully locked. */
104 bool isLocked() const noexcept { return lockWasSuccessful; }
105
106 private:
107 //==============================================================================
108 InterProcessLock& ipLock;
109 bool lockWasSuccessful;
110
111 JUCE_DECLARE_NON_COPYABLE (ScopedLockType)
112 };
113
114private:
115 //==============================================================================
116 class Pimpl;
117 std::unique_ptr<Pimpl> pimpl;
118
119 CriticalSection lock;
120 String name;
121
122 JUCE_DECLARE_NON_COPYABLE (InterProcessLock)
123};
124
125} // namespace juce
126
127/** @}*/
Automatically locks and unlocks an InterProcessLock object.
bool isLocked() const noexcept
Returns true if the InterProcessLock was successfully locked.
ScopedLockType(InterProcessLock &l)
Creates a scoped lock.
Acts as a critical section which processes can use to block each other.
~InterProcessLock()
Destructor.
void exit()
Releases the lock if it's currently held by this process.
bool enter(int timeOutMillisecs=-1)
Attempts to lock the critical section.
InterProcessLock(const String &name)
Creates a lock object.
The JUCE String class!
Definition juce_String.h:43
#define JUCE_API
This macro is added to all JUCE public class declarations.