1/****************************************************************************
2**
3** Copyright (C) 2016 The Qt Company Ltd.
4** Contact: https://www.qt.io/licensing/
5**
6** This file is part of the QtCore module of the Qt Toolkit.
7**
8** $QT_BEGIN_LICENSE:LGPL$
9** Commercial License Usage
10** Licensees holding valid commercial Qt licenses may use this file in
11** accordance with the commercial license agreement provided with the
12** Software or, alternatively, in accordance with the terms contained in
13** a written agreement between you and The Qt Company. For licensing terms
14** and conditions see https://www.qt.io/terms-conditions. For further
15** information use the contact form at https://www.qt.io/contact-us.
16**
17** GNU Lesser General Public License Usage
18** Alternatively, this file may be used under the terms of the GNU Lesser
19** General Public License version 3 as published by the Free Software
20** Foundation and appearing in the file LICENSE.LGPL3 included in the
21** packaging of this file. Please review the following information to
22** ensure the GNU Lesser General Public License version 3 requirements
23** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
24**
25** GNU General Public License Usage
26** Alternatively, this file may be used under the terms of the GNU
27** General Public License version 2.0 or (at your option) the GNU General
28** Public license version 3 or any later version approved by the KDE Free
29** Qt Foundation. The licenses are as published by the Free Software
30** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
31** included in the packaging of this file. Please review the following
32** information to ensure the GNU General Public License requirements will
33** be met: https://www.gnu.org/licenses/gpl-2.0.html and
34** https://www.gnu.org/licenses/gpl-3.0.html.
35**
36** $QT_END_LICENSE$
37**
38****************************************************************************/
39
40#ifndef QSHAREDMEMORY_P_H
41#define QSHAREDMEMORY_P_H
42
43//
44// W A R N I N G
45// -------------
46//
47// This file is not part of the Qt API. It exists purely as an
48// implementation detail. This header file may change from version to
49// version without notice, or even be removed.
50//
51// We mean it.
52//
53
54#include "qsharedmemory.h"
55
56#include <QtCore/qstring.h>
57
58#ifdef QT_NO_SHAREDMEMORY
59# ifndef QT_NO_SYSTEMSEMAPHORE
60namespace QSharedMemoryPrivate
61{
62 int createUnixKeyFile(const QString &fileName);
63 QString makePlatformSafeKey(const QString &key,
64 const QString &prefix = QLatin1String("qipc_sharedmemory_"));
65}
66#endif
67#else
68
69#include "qsystemsemaphore.h"
70
71#ifndef QT_NO_QOBJECT
72# include "private/qobject_p.h"
73#endif
74
75#if !defined(Q_OS_WIN) && !defined(Q_OS_ANDROID) && !defined(Q_OS_INTEGRITY) && !defined(Q_OS_RTEMS)
76# include <sys/sem.h>
77#endif
78
79QT_BEGIN_NAMESPACE
80
81#ifndef QT_NO_SYSTEMSEMAPHORE
82/*!
83 Helper class
84 */
85class QSharedMemoryLocker
86{
87
88public:
89 inline QSharedMemoryLocker(QSharedMemory *sharedMemory) : q_sm(sharedMemory)
90 {
91 Q_ASSERT(q_sm);
92 }
93
94 inline ~QSharedMemoryLocker()
95 {
96 if (q_sm)
97 q_sm->unlock();
98 }
99
100 inline bool lock()
101 {
102 if (q_sm && q_sm->lock())
103 return true;
104 q_sm = nullptr;
105 return false;
106 }
107
108private:
109 QSharedMemory *q_sm;
110};
111#endif // QT_NO_SYSTEMSEMAPHORE
112
113class Q_AUTOTEST_EXPORT QSharedMemoryPrivate
114#ifndef QT_NO_QOBJECT
115 : public QObjectPrivate
116#endif
117{
118#ifndef QT_NO_QOBJECT
119 Q_DECLARE_PUBLIC(QSharedMemory)
120#endif
121
122public:
123 QSharedMemoryPrivate();
124
125 void *memory;
126 int size;
127 QString key;
128 QString nativeKey;
129 QSharedMemory::SharedMemoryError error;
130 QString errorString;
131#ifndef QT_NO_SYSTEMSEMAPHORE
132 QSystemSemaphore systemSemaphore;
133 bool lockedByMe;
134#endif
135
136 static int createUnixKeyFile(const QString &fileName);
137 static QString makePlatformSafeKey(const QString &key,
138 const QString &prefix = QLatin1String("qipc_sharedmemory_"));
139#ifdef Q_OS_WIN
140 Qt::HANDLE handle();
141#elif defined(QT_POSIX_IPC)
142 int handle();
143#else
144 key_t handle();
145#endif
146 bool initKey();
147 bool cleanHandle();
148 bool create(int size);
149 bool attach(QSharedMemory::AccessMode mode);
150 bool detach();
151
152 void setErrorString(QLatin1String function);
153
154#ifndef QT_NO_SYSTEMSEMAPHORE
155 bool tryLocker(QSharedMemoryLocker *locker, const QString &function) {
156 if (!locker->lock()) {
157 errorString = QSharedMemory::tr(s: "%1: unable to lock").arg(a: function);
158 error = QSharedMemory::LockError;
159 return false;
160 }
161 return true;
162 }
163#endif // QT_NO_SYSTEMSEMAPHORE
164
165private:
166#ifdef Q_OS_WIN
167 Qt::HANDLE hand;
168#elif defined(QT_POSIX_IPC)
169 int hand;
170#else
171 key_t unix_key;
172#endif
173};
174
175QT_END_NAMESPACE
176
177#endif // QT_NO_SHAREDMEMORY
178
179#endif // QSHAREDMEMORY_P_H
180
181

source code of qtbase/src/corelib/kernel/qsharedmemory_p.h