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1// © 2016 and later: Unicode, Inc. and others.
2// License & terms of use: http://www.unicode.org/copyright.html
3/*
4******************************************************************************
5*
6* Copyright (C) 1997-2013, International Business Machines
7* Corporation and others. All Rights Reserved.
8*
9******************************************************************************
10*/
11//----------------------------------------------------------------------------
12// File: mutex.h
13//
14// Lightweight C++ wrapper for umtx_ C mutex functions
15//
16// Author: Alan Liu 1/31/97
17// History:
18// 06/04/97 helena Updated setImplementation as per feedback from 5/21 drop.
19// 04/07/1999 srl refocused as a thin wrapper
20//
21//----------------------------------------------------------------------------
22#ifndef MUTEX_H
23#define MUTEX_H
24
25#include "unicode/utypes.h"
26#include "unicode/uobject.h"
27#include "umutex.h"
28
29U_NAMESPACE_BEGIN
30
31/**
32 * Mutex is a helper class for convenient locking and unlocking of a UMutex.
33 *
34 * Creating a local scope Mutex will lock a UMutex, holding the lock until the Mutex
35 * goes out of scope.
36 *
37 * If no UMutex is specified, the ICU global mutex is implied.
38 *
39 * For example:
40 *
41 * static UMutex myMutex;
42 *
43 * void Function(int arg1, int arg2)
44 * {
45 * static Object* foo; // Shared read-write object
46 * Mutex mutex(&myMutex); // or no args for the global lock
47 * foo->Method();
48 * // When 'mutex' goes out of scope and gets destroyed here, the lock is released
49 * }
50 *
51 * Note: Do NOT use the form 'Mutex mutex();' as that merely forward-declares a function
52 * returning a Mutex. This is a common mistake which silently slips through the
53 * compiler!!
54 */
55
56class U_COMMON_API Mutex : public UMemory {
57public:
58 Mutex(UMutex *mutex = nullptr) : fMutex(mutex) {
59 umtx_lock(fMutex);
60 }
61 ~Mutex() {
62 umtx_unlock(fMutex);
63 }
64
65 Mutex(const Mutex &other) = delete; // forbid assigning of this class
66 Mutex &operator=(const Mutex &other) = delete; // forbid copying of this class
67 void *operator new(size_t s) = delete; // forbid heap allocation. Locals only.
68
69private:
70 UMutex *fMutex;
71};
72
73
74U_NAMESPACE_END
75
76#endif //_MUTEX_
77//eof