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3 ** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
4 ** Contact: http://www.qt-project.org/legal
6 ** This file is part of the Qt Solutions component.
8 ** $QT_BEGIN_LICENSE:BSD$
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15 ** notice, this list of conditions and the following disclaimer.
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39 ****************************************************************************/
41 #include "qtlockedfile.h"
42 #include <qt_windows.h>
45 #define MUTEX_PREFIX "QtLockedFile mutex "
46 // Maximum number of concurrent read locks. Must not be greater than MAXIMUM_WAIT_OBJECTS
47 #define MAX_READERS MAXIMUM_WAIT_OBJECTS
49 #if QT_VERSION >= 0x050000
50 #define QT_WA(unicode, ansi) unicode
53 Qt::HANDLE QtLockedFile::getMutexHandle(int idx, bool doCreate)
55 if (mutexname.isEmpty()) {
57 mutexname = QString::fromLatin1(MUTEX_PREFIX)
58 + fi.absoluteFilePath().toLower();
60 QString mname(mutexname);
62 mname += QString::number(idx);
66 QT_WA( { mutex = CreateMutexW(NULL, FALSE, (LPCWSTR)mname.utf16()); },
67 { mutex = CreateMutexA(NULL, FALSE, mname.toLocal8Bit().constData()); } );
69 qErrnoWarning("QtLockedFile::lock(): CreateMutex failed");
74 QT_WA( { mutex = OpenMutexW(SYNCHRONIZE | MUTEX_MODIFY_STATE, FALSE, (LPCWSTR)mname.utf16()); },
75 { mutex = OpenMutexA(SYNCHRONIZE | MUTEX_MODIFY_STATE, FALSE, mname.toLocal8Bit().constData()); } );
77 if (GetLastError() != ERROR_FILE_NOT_FOUND)
78 qErrnoWarning("QtLockedFile::lock(): OpenMutex failed");
85 bool QtLockedFile::waitMutex(Qt::HANDLE mutex, bool doBlock)
88 DWORD res = WaitForSingleObject(mutex, doBlock ? INFINITE : 0);
97 qErrnoWarning("QtLockedFile::lock(): WaitForSingleObject failed");
104 bool QtLockedFile::lock(LockMode mode, bool block)
107 qWarning("QtLockedFile::lock(): file is not opened");
114 if (mode == m_lock_mode)
117 if (m_lock_mode != NoLock)
120 if (!wmutex && !(wmutex = getMutexHandle(-1, true)))
123 if (!waitMutex(wmutex, block))
126 if (mode == ReadLock) {
128 for (; idx < MAX_READERS; idx++) {
129 rmutex = getMutexHandle(idx, false);
130 if (!rmutex || waitMutex(rmutex, false))
135 if (idx >= MAX_READERS) {
136 qWarning("QtLockedFile::lock(): too many readers");
141 rmutex = getMutexHandle(idx, true);
142 if (!rmutex || !waitMutex(rmutex, false))
149 ReleaseMutex(wmutex);
154 Q_ASSERT(rmutexes.isEmpty());
155 for (int i = 0; i < MAX_READERS; i++) {
156 Qt::HANDLE mutex = getMutexHandle(i, false);
158 rmutexes.append(mutex);
160 if (rmutexes.size()) {
161 DWORD res = WaitForMultipleObjects(rmutexes.size(), rmutexes.constData(),
162 TRUE, block ? INFINITE : 0);
163 if (res != WAIT_OBJECT_0 && res != WAIT_ABANDONED) {
164 if (res != WAIT_TIMEOUT)
165 qErrnoWarning("QtLockedFile::lock(): WaitForMultipleObjects failed");
166 m_lock_mode = WriteLock; // trick unlock() to clean up - semiyucky
177 bool QtLockedFile::unlock()
180 qWarning("QtLockedFile::unlock(): file is not opened");
187 if (m_lock_mode == ReadLock) {
188 ReleaseMutex(rmutex);
193 foreach(Qt::HANDLE mutex, rmutexes) {
198 ReleaseMutex(wmutex);
201 m_lock_mode = QtLockedFile::NoLock;
205 QtLockedFile::~QtLockedFile()